The pharmacology of amphetamine and methylphenidate: Relevance to the neurobiology of attention-deficit/hyperactivity disorder and other psychiatric comorbidities

Accelerated aging mediates the association between rheumatoid arthritis and depression severity

BACKGROUND

This study aimed to investigate the associations among phenotypic age acceleration (PAA), the prevalence of rheumatoid arthritis (RA), and depression severity and to examine the potential mediating role of PAA in the RA-depression relationship.

METHODS

A retrospective cohort analysis was conducted using data from adult participants in the National Health and Nutrition Examination Survey (2005-2010). Participants with RA were identified on the basis of self-report of RA in personal interviews. Depression was assessed via the Patient Health Questionnaire-9 (PHQ-9). PAA was calculated with 9 clinical biomarkers and chronological age, with a relatively high RAA value indicating the acceleration of aging. Survey-weighted logistic regression models were used to explore the relationship between the prevalence of RA and PAA and the correlation between PAA and depression. Mediation analysis was employed to quantify the indirect effect of RA on depression through PAA.

RESULTS

A total of 9834 adults aged over 20 years were included. RA prevalence was positively associated with greater PAA (β = 1.60, 95 % confidence interval (CI): 0.86-2.35, P = 0.0002) and depression severity (β = 1.57, 95 % CI: 1.09-2.05, P < 0.0001). Additionally, PAA was correlated with depression severity (β = 0.04, 95 % CI: 0.02-0.06; P = 0.0001). Mediation analysis revealed that PAA significantly mediated the association between RA and depressive severity, explaining 2.26-5.57 % (all p < 0.001) of the total effect.

CONCLUSIONS

Individuals with RA exhibited accelerated biological aging, as represented by increased PAA, which partially mediated the relationship between RA and depression severity in this population.

The psychostimulant drug, fenethylline (captagon): Health risks, addiction and the global impact of illicit trade

Fenethylline (street name, captagon) is a synthetic amphetamine-type stimulant that is emerging as a significant public health and security concern, particularly in the Middle East. This systematic review synthesizes original research articles, epidemiological studies, systematic reviews, policy analyses, and case reports to provide a comprehensive analysis of fenethylline's health impacts, addiction potential, and dynamics of illicit trade. Initially developed for therapeutic use, fenethylline illicit production and use have escalated, raising concern about its physiological, psychological, and socio-economic impacts. This stimulant profoundly affects the central nervous system, enhancing wakefulness, concentration, and physical stamina while inducing euphoria. These effects come at the cost of serious adverse health outcomes, particularly with prolonged or heavy use, including cardiovascular complications, neurological damage, and addiction. The dependence-forming nature of captagon contributes to escalating substance use disorders, impacting healthcare systems. Beyond its biomedical implications, fenethylline trafficking has become a global issue, with supply chains deeply intertwined with politically unstable regions where illicit economies thrive. The geopolitical dimensions of captagon's trade amplify its global security threat, influencing international relations and regional stability. This paper underscores the urgent need for systematic data collection and coordinated efforts to regulate illicit fenethylline production and distribution. Strategies such as improved surveillance, public health interventions, and international cooperation are essential to mitigate its escalating risks. Addressing this issue requires a multidisciplinary approach, integrating public health, law enforcement, and policy development to curb its impact on global health and security.

The impact of methylphenidate on choice impulsivity is inversely associated with corpus callosum fiber integrity across sexes

BACKGROUND

Choice impulsivity represents preference towards smaller immediate rewards over larger delayed rewards. Extensive literature demonstrates that choice impulsivity can be manipulated using dopaminergic agonists such as methylphenidate (MPH), and that females exhibit elevated choice impulsivity compared to males. Sex differences are also frequently reported with respect to brain white matter (WM) fiber integrity. It has yet to be determined whether sex differences also exist in the impact of MPH on choice impulsivity, and whether these putative differences are accounted for by the integrity of differential WM fibers.

METHODS

Forty-eight healthy young adults completed the delay discounting (DD) task twice during MRI-DTI scans after receiving either MPH or placebo in a double-blind, placebo-controlled, within-subject design. WM fiber integrity was assessed using automated fiber quantification (AFQ) and tract-based spatial statistics (TBSS).

RESULTS

Compared to placebo, MPH yielded significantly reduced choice impulsivity in males but not in females. DTI data revealed reduced integrity in multiple WM fibers in females compared to males. Interestingly, the impact of MPH on choice impulsivity was negatively associated with fiber integrity in the forceps major of the corpus callosum for males only and positively associated with fiber integrity in the forceps minor of the corpus callosum for females only.

CONCLUSIONS

Taken together, results uncover sex-specific effects of MPH on choice impulsivity, accounted for by inverse associations between choice impulsivity under MPH and the structural integrity of distinct segments of the corpus callosum. These findings highlight the need to consider sex differences in the neurobiological mechanisms of impulsivity.

The Role of Methylphenidate and Aripiprazole in the Treatment of Emotion Dysregulation in Children With ADHD

PURPOSE

In this study, we examined the effectiveness of methylphenidate on emotion dysregulation among children with attention-deficit/hyperactivity disorder (ADHD), and the strategy of switching to or adding aripiprazole for nonresponders.

METHODS

We conducted a 3-step, 10-week, open-label trial including children (6-18 years old) with ADHD and emotion dysregulation, defined according to the Child Behavior Checklist-Dysregulation Profile. In step 1, patients received methylphenidate treatment for 4 weeks. In step 2, nonresponders were started on aripiprazole treatment for 4 weeks. Nonresponders in step 2 entered step 3, receiving a combination of methylphenidate and aripiprazole for 2 weeks. The primary outcome was the change from baseline in emotion dysregulation, assessed using the irritability subscale of the Aberrant Behavior Checklist. Secondary outcomes included the change from baseline in ADHD symptoms, cross-domain-associated symptoms, adaptive functioning, and neurocognitive profiles.

RESULTS

Among the 30 enrolled patients, 22 (73.3%) responded to methylphenidate (group MR), while 8 entered step 2 (aripiprazole treatment for methylphenidate nonresponders; group MN). In step 2, 5 patients responded to aripiprazole, while 2 patients entered step 3 and received methylphenidate plus aripiprazole. Patients who responded to methylphenidate or aripiprazole exhibited significant improvements in emotion dysregulation (Hedges' g: 2.62 and 1.30, respectively) and school adaptation. Emotion dysregulation severity was correlated with oppositional defiant disorder symptoms, but not with core symptoms of ADHD.

CONCLUSIONS

The nature of emotion dysregulation in ADHD is heterogeneous regarding the response to methylphenidate. For most patients, methylphenidate significantly improved emotion dysregulation. Aripiprazole could be effective and safe for methylphenidate nonresponders.

Dopaminergic medications as a preventive for myopia: insights derived from pediatric patients diagnosed with attention deficit hyperactivity disorder

BACKGROUND/OBJECTIVES

This study investigated the impact of dopaminergic medications on myopia progression by comparing myopia susceptibility in ADHD patients treated with dopaminergic agents to those untreated. A non-ADHD cohort was also established to assess myopia risk compared to individuals with ADHD.

SUBJECTS/METHODS

This population-based cohort study used Taiwan National Health Insurance data (2009-2020), stratifying participants by ADHD status. Myopia was identified using ICD-10 diagnostic codes, while ADHD-related drug usage (methylphenidate, atomoxetine, clonidine) was analyzed. Cox regression models compared hazard ratios (HRs) for myopia, with cumulative incidence curves generated via the Kaplan-Meier method.

RESULTS

Adjusting for sex, age, comorbidities, and follow-up time, the untreated ADHD cohort had a 1.22-fold higher myopia risk (95% CI: 1.21-1.24) compared to the non-ADHD cohort. In contrast, ADHD patients receiving treatment showed a 39% reduced myopia risk (adjusted HR (aHR): 0.61; 95% CI: 0.59-0.62). An increased number of ADHD-related medications correlated with a notable myopia risk reduction: one drug (aHR: 0.50; 95% CI: 0.49-0.51) and two drugs (aHR: 0.28; 95% CI: 0.26-0.31).

CONCLUSIONS

Untreated ADHD in children is linked to a higher myopia risk than both non-ADHD individuals and treated ADHD patients. Dopaminergic treatments may provide a therapeutic avenue for mitigating myopia progression by enhancing dopamine signaling pathways. Key messages What is already known on this topic  Dopamine release in the retina inhibits myopia progression, and ADHD is linked to dopaminergic dysfunction. ADHD treatments like methylphenidate enhance dopamine signaling, but their effect on myopia risk has not been thoroughly studied. What this study adds  This study shows that untreated ADHD children have a higher risk of myopia, while dopaminergic treatments significantly reduce this risk. The use of multiple ADHD medications further strengthens the protective effect. How this study might affect research, practice or policy  These findings suggest that ADHD treatments may serve as a new approach for myopia prevention, encouraging cross-field research and consideration of systemic therapies for managing comorbid conditions.

Transcranial direct current stimulation and methylphenidate interact to increase cognitive persistence as a core component of metacontrol: Evidence from aperiodic activity analyses

BACKGROUND

Metacontrol is the ability to optimize the balance between cognitive persistence and flexibility. Recent research points to aperiodic EEG activity as a neurophysiological marker for metacontrol and its modulations. However, the causal link between metacontrol and aperiodic activity is still unclear.

OBJECTIVE

We provide mechanistic insights into the neurobiological foundations of metacontrol and the means to enhance it. We evaluated the interplay of anodal transcranial direct current stimulation (atDCS) and Methylphenidate (MPH), both of which are known to alter cortical noise, a factor that can be measured by aperiodic exponents derived from EEG data.

METHODS

We examined the impact of right inferior frontal (midpoint between electrodes FC4 and F8) 20 min offline atDCS at 2-mA and MPH administration, both separately and combined, on aperiodic EEG activity while healthy adult participants (N = 98) performed a Go/NoGo task. We used the FOOOF (fitting oscillations & one over f) algorithm to examine aperiodic activity.

RESULTS

We obtained an interaction between atDCS stimulation and MPH administration, indicating that atDCS is effective in reducing aperiodic neural activity (i.e., increased aperiodic exponents) when being combined with MPH administration.

CONCLUSION

Aperiodic neural activity can be modulated through pharmacology-tuned atDCS. atDCS and MPH rely on overlapping neurobiological mechanisms. Metacontrol depending on aperiodic neural activity can be modulated through combined atDCS-MPH stimulation. Hence, atDCS and MPH are suitable tools to achieve an exogenous modulation of metacontrol bias and aperiodic exponents are indices to demonstrate the effectiveness of such tools.

The Sustained Attention Paradox: A Critical Commentary on the Theoretical Impossibility of Perfect Vigilance

The human capacity for sustained attention represents a critical cognitive paradox: while essential for numerous high-stakes tasks, perfect vigilance is fundamentally impossible. This commentary explores the theoretical impossibility of maintaining uninterrupted attention, drawing from extensive interdisciplinary research in cognitive science, neuroscience, and psychology. Multiple converging lines of evidence demonstrate that sustained attention is constrained by neural, biological, and cognitive limitations. Neural mechanisms reveal that attention operates through rhythmic oscillations, with inherent fluctuations in frontoparietal networks and default mode network interactions. Neurochemical systems and cellular adaptation effects further underscore the impossibility of continuous, perfect vigilance. Empirical research across domains-including aviation, healthcare, industrial safety, and security-consistently demonstrates rapid declines in attention performance over time, regardless of individual expertise or motivation. Even elite performers like military personnel and experienced meditators exhibit inevitable attention lapses. This paper presents an argument against traditional approaches that seek to overcome these limitations through training or willpower. Instead, it advocates for designing human-technology systems that work harmoniously with cognitive constraints. This requires developing adaptive automation, understanding individual and cultural attention variations, and creating frameworks that strategically balance human capabilities with technological support.

Standardization of decision-making skills but persistent impulsivity after chronic stimulant exposure in ADHD patients

Attention deficit hyperactivity disorder (ADHD) is commonly associated with deficits in executive function. Even though attention, hyperactivity, and impulsivity are the more distinctive symptoms, impairment in other cognitive processes, for instance memory, could be due to the interferences from these symptoms. However, it remains unclear whether information processing errors made by individuals with ADHD arise primarily from impulsive responding or reflect a more fundamental difference in how they process information, potentially due to compensatory mechanisms developed throughout childhood. This study analyzes pattern separation (distinguishing similar stimuli), recognition memory, decision-making, and impulsivity in both ADHD-diagnosed and non-diagnosed youth population. We further examined possible treatment effects by dividing the ADHD group into three cohorts based on stimulant medication duration. We evaluate their response latency and responses utilizing the signal detection theory method. While ADHD participants exhibited poorer recognition memory compared to controls, this pattern did not show a statistically significant difference in pattern separation. Additionally, both processes improved with longer treatment duration within the ADHD group, leading to decreased error commission. Decision-making analyses revealed sex-specific response strategies within the ADHD group, but both groups showed similar adjustment to task difficulty. However, the ADHD group responses were notably faster, associated with a higher error rate. Additionally, response times varied depending on the stimulus type, suggesting potential differences in how the ADHD group processed information compared to the control group. These findings collectively point towards a possible difference in information management in ADHD, that is also characterized by faster, but less accurate, processing.

Neural basis for individual differences in the attention-enhancing effects of methylphenidate

Stimulant drugs that boost dopamine, like methylphenidate (MP), enhance attention and are effective treatments for attention-deficit hyperactivity disorder (ADHD). Yet there is large individual variation in attentional capacity and response to MP. It is unclear whether this variation is driven by individual differences in relative density of dopamine receptor subtypes, magnitude of dopamine increases induced by MP, or both. Here, we extensively characterized the brain dopamine system with positron emission tomography (PET) imaging (including striatal dopamine D1 and D2/3 receptor availability and MP-induced dopamine increases) and measured attention task-evoked fMRI brain activity in two separate sessions (placebo and 60 mg oral MP; single-blind, counterbalanced) in 37 healthy adults. A network of lateral frontoparietal and visual cortices was sensitive to increasing attentional (and working memory) load, whose activity positively correlated with performance across individuals (partial r = 0.474, P = 0.008; controlling for age). MP-induced change in activity within this network correlated with MP-induced change in performance (partial r = 0.686, P < 0.001). The ratio of D1-to-D2/3 receptors in dorsomedial caudate positively correlated with baseline attentional network activity and negatively correlated with MP-induced changes in activity (all pFWE < 0.02). MP-induced changes in attentional load network activity mediated the association between D1-to-D2/3 ratio and MP-induced improvements in performance (mediation estimate = 23.20 [95%CI: -153.67 -81.79], P = 0.004). MP attention-boosting effects were not linked to the magnitude of striatal dopamine increases, but rather showed dependence on an individual's baseline receptor density. Individuals with lower D1-to-D2/3 ratios tended to have lower frontoparietal activity during sustained attention and experienced greater improvement in brain function and task performance with MP.

Puberty and ADHD: A scoping review and framework for future research

Individuals with ADHD may experience puberty differently from their peers, which has implications for their health and wellbeing. This scoping review characterised and summarised literature reporting quantitative analyses of puberty and ADHD. To identify studies, nine databases (MEDLINE Complete, Web of Science, Embase, PsycInfo, ERIC, CENTRAL, PsycExtra, WHO ICTRP, and ProQuest Dissertations & Theses) were searched using key terms related to puberty/pubertal hormones and ADHD/ADHD traits. From 2795 initial records, 89 studies were eligible. Relevant analyses in included studies were categorised under five topics: 1) pubertal group comparisons between participants with ADHD and control participants; 2) associations between puberty and ADHD; 3) prevalence of ADHD in atypical puberty conditions; 4) ADHD medication effects on puberty; and 5) puberty and co-occurring psychological conditions. With some exceptions, summarised findings for each topic were generally inconsistent, indicating further well-planned primary studies are needed. A framework for future research is provided, recommending methodological improvements, including use of approaches that capture the complexities of puberty and ADHD, more inclusive sampling, and employing theories/models that recognise dynamics between puberty, psychological, social, and other biological factors. Additionally, it is recommended that research priorities in this area are identified in collaboration with key stakeholders, especially the ADHD community.

Mapping ADHD Heterogeneity and Biotypes through Topological Deviations in Morphometric Similarity Networks

Attention-deficit/hyperactivity disorder (ADHD) is characterized by considerable clinical heterogeneity. This study investigates whether normative modelling of topological properties derived from brain morphometry similarity networks can provide robust stratification markers for ADHD children. Leveraging multisite neurodevelopmental datasets (discovery: 446 ADHD, 708 controls; validation: 554 ADHD, 123 controls), we constructed morphometric similarity networks and developed normative models for three topological metrics: degree centrality, nodal efficiency, and participation coefficient. Through semi-supervised clustering, we delineated putative biotypes and examined their clinical profiles. We further contextualized brain profiles of these biotypes in terms of their neurochemical and functional correlates using large-scale databases, and assessed model generalizability in an independent cohort. ADHD exhibited atypical hub organization across all three topological metrics, with significant case-control differences primarily localized to a covarying multi-metric component in the orbitofrontal cortex. Three biotypes emerged: one characterized by severe overall symptoms and longitudinally persistent emotional dysregulation, accompanied by pronounced topological alterations in the medial prefrontal cortex and pallidum; a second by predominant hyperactivity/impulsivity accompanied by changes in the anterior cingulate cortex and pallidum; and a third by marked inattention with alterations in the superior frontal gyrus. These neural profiles of each biotype showed distinct neurochemical and functional correlates. Critically, the core findings were replicated in an independent validation cohort. Our comprehensive approach reveals three distinct ADHD biotypes with unique clinical-neural patterns, advancing our understanding of ADHD's neurobiological heterogeneity and laying the groundwork for personalized treatment.

Exploring the bidirectional associations of ADHD symptomatology, nutritional status, and body composition in childhood: evidence from a Brazilian Birth Cohort Study

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) has been linked to excessive weight; however, the underlying mechanisms of this association are not well understood. To date, the bidirectional associations between ADHD and nutritional status in childhood have been explored in a limited number of studies, with particularly few of those incorporating body composition data. This study aims to evaluate the associations of ADHD symptoms, nutritional status, and body composition in childhood.

METHODS

We analyzed data from 3940 children from the 2015 Pelotas (Brazil) Birth Cohort at 4 and 6-7 years of age. Linear regression was performed to evaluate the association between ADHD symptoms and nutritional status (weight, height, and body mass index [BMI]) at ages 4 and 6-7, as well as body composition, specifically fat mass (FF) and fat-free mass (FFM) at ages 6-7. Moreover, a cross-lagged panel model (CLPM) analysis between ADHD symptoms and BMI was performed to explore the bidirectional associations.

RESULTS

ADHD symptoms were associated with increased height (β 0.01, 95%CI 0.001, 0.026) and FFM (β 0.02, 95%CI 0.008-0.035) at age 4, and increased BMI (β0.02, 95%IC 0.002, 0.038), weight (β 0. 02, 95%CI 0.005, 0.039), height (β 0.01, 95%CI 0.000, 0.024), and FFM (β 0.02, 95%CI 0.012, 0.040) at ages 6-7. Although the CLPM indicated a small effect suggesting a bidirectional relationship between ADHD symptoms and BMI, the observed associations were not statistically significant: ADHD scores at age 4 predicting BMI z-scores at ages 6-7 (β 0.003; 95% CI: -0.026, 0.020), and BMI z-scores at age 4 predicting ADHD scores at ages 6-7 (β 0.013; 95% CI: -0.018, 0.044).

CONCLUSION

Children with higher ADHD symptoms showed increased growth in weight, height, and BMI. The observed increase in weight and BMI was attributed to greater FFM in these children.

Methylphenidate promotes a frontoparietal-dominant brain state improving cognitive performance: a randomized trial

Methylphenidate (MP) is a widely used stimulant medication for the treatment of attention deficit hyperactivity disorder that enhances brain dopamine signaling and improves attention. However, how dopamine stimulation alters brain state dynamics to support improved attention during task performance is still unclear. To address this, we employed a multimodal neuroimaging approach combining positron emission tomography, functional magnetic resonance imaging, and behavioral tasks, to discover associations between dopamine signaling, brain dynamics, and cognition. Multimodal images were collected from 37 healthy adults under a single-blind, counterbalanced, placebo-controlled crossover study. Dynamic functional analysis was used to compare the alterations in dynamic features of brain states before and after MP. Subsequently, we analyzed the correlation between these brain state changes and baseline striatal D1 and D2 dopamine receptor (D1R, D2R) availability. We also examined alterations in dynamic brain states and their effects on visuospatial tasks. The results showed that MP primarily affected frontoparietal-dominant activated (FPN+), somatomotor-dominant activated (SOM+), and visual-dominant suppressed (VIS-) brain states. Specifically, the dwell time and fractional occupancy exhibited significant increases within the FPN+ and VIS- and an opposite trend within the SOM+. Furthermore, the increase of dwell time in FPN+, which was positively correlated with baseline striatal D1R availability, was also associated with quicker response in the 2-ball-track task, but not significantly for the 3-ball-track task. The findings suggest that MP's enhancement of brain states with FPN+ and VIS- while decreasing SOM+, in part through D1R signaling might underlie MP's improvement of attention for low demanding tasks in healthy populations.Significance statement Methylphenidate (MP) is primarily prescribed for Attention-Deficit/Hyperactivity Disorder (ADHD), but it is also misused as a cognitive enhancer by individuals seeking to improve cognitive performance. Using advanced brain imaging and behavioral tasks, this study investigates how MP affects dopamine signaling, brain activity and cognitive performance. Our results demonstrate that MP promoted a frontoparietal-dominant brain state which linked to improved task performance and D1 receptor availability. This research also introduces a multi-level neuroimaging approach to studying drug effects, offering a foundation for tailoring interventions by predicting individual variations in responses to medicine.

Vitamin D's Capacity to Increase Amphetamine-Induced Dopamine Release in Healthy Humans: A Clinical Translational [11C]-PHNO Positron Emission Tomography Study

BACKGROUND

Dopaminergic tone and phasic release have transdiagnostic relevance. Preclinical research suggests that the active form of vitamin D, calcitriol, increases subcortical tyrosine hydroxylase, D2/D3 receptors, and amphetamine-stimulated dopamine release in rodents. Comparable studies have not been conducted in humans.

METHODS

Healthy, vitamin D-sufficient adults (N = 18, 32.8 ± 6.6 years; 33% female) participated in a randomized, double-blind, placebo-controlled within-subjects study involving 4 total scans over 2 visits consisting of same-day preamphetamine and postamphetamine (0.3 mg/kg) [11C]-PHNO positron emission tomography scanning to examine D2/D3 receptor availability (nondisplaceable binding potential [BPND]) following active calcitriol (1.5 μg night before experimental day and 1.5 μg morning of experimental day) or placebo at least 6 days apart. Parametric images of [11C]-PHNO positron emission tomography BPND were computed using a simplified reference tissue model with the cerebellum as reference. Blood samples were acquired to measure serum calcitriol, amphetamine, and calcium levels. Regions of interest examined were the dorsal caudate, dorsal putamen, ventral striatum, globus pallidus, and substantia nigra.

RESULTS

For preamphetamine scans, there was a medication × region of interest interaction (F4,153 = 2.59, p = .039) and a main effect of medication (F1,153 = 4.88, p = .029) on BPND, with higher BPND values on calcitriol in the ventral striatum (t153 = 2.89, p = .004) and dorsal putamen (t153 = 2.15, p = .033). There was a main effect of medication on postamphetamine change in BPND (F4,153 = 5.93, p = .016), with greater decreases in calcitriol in the ventral striatum (t153 = 3.00, p = .003), substantia nigra (t153 = 2.49, p = .014), and dorsal caudate (t153 = 2.29, p = .023).

CONCLUSIONS

Results provide translational support for vitamin D to target dopaminergic tone, with implications for clinical disorders that involve dysregulated dopamine function.

Neurophysiological insights into catecholamine-dependent tDCS modulation of cognitive control

Goal-directed behavior requires resolving both consciously and subconsciously induced response conflicts. Neuronal gain control, which enhances processing efficacy, is crucial for conflict resolution and can be increased through pharmacological or brain stimulation interventions, though it faces inherent physical limits. This study examined the effects of anodal transcranial direct current stimulation (atDCS) and methylphenidate (MPH) on conflict processing. Healthy adults (n = 105) performed a flanker task, with electroencephalography (EEG) used to assess alpha and theta band activity (ABA, TBA). Results showed that combining atDCS with MPH enhanced cognitive control and reduced response conflicts more effectively than atDCS alone, particularly when both conflict types co-occurred. Both atDCS and atDCS + MPH exhibited similar task-induced ABA and TBA modulations in the (pre)supplementary motor area, indicating heightened gain control. Overlapping neuroanatomical effects in mid-superior frontal areas suggest that atDCS and MPH share a common neuronal mechanism of gain control, especially in high-conflict/-demand situations.

Methylphenidate for the cognitive and neurobehavioural sequelae of traumatic brain injury in adults: a systematic review and meta-analysis

Introduction

Traumatic brain injury (TBI) is a leading cause of death and disability globally and is associated with long-term cognitive and neurobehavioural deficits. Methylphenidate has been proposed to address these lasting symptoms, however comprehensive evidence is lacking.

Methods

This systematic review aimed to assess the effects of methylphenidate on multiple cognitive and neurobehavioural domains in adults with TBI. The search conducted across five databases yielded 1,019 results, of which 25 were relevant to this review. Meta-analyses were conducted where homogenous data was available.

Results

Significant results favouring methylphenidate were recorded by meta-analyses for one of five cognition outcome measures (Trail Making Test A) (p = 0.005, CI [-5.19, -0.91]), as well as the depression domain (p < 0.00001, CI [-0.78, -0.39]) and the fatigue domain (p < 0.00001, CI [-0.98, -0.67]). Insufficient data was available in the aggression, apathy, agitation, memory, motor function, post-concussion syndrome and sleep domains for inclusion in meta-analysis. Qualitative review of evidence in these domains found limited and mixed evidence on the efficacy of methylphenidate, though significant benefits have been demonstrated in these various domains in small, randomised studies. Eleven of the 25 studies were judged as containing some to high risk of bias. However, this review identified supportive evidence for the beneficial effects of methylphenidate to improve depression and fatigue in adults with TBI, with some possible benefits for cognition and other symptoms. Heterogeneity was high and risk of bias was variable across studies, somewhat limiting credibility of results.

Discussion

Methylphenidate may enhance the ongoing care of TBI patients, by addressing neurobehavioural and cognitive symptoms simultaneously. Further large-scale and high-quality clinical trials evaluating a comprehensive range of possible benefits to symptoms should be conducted to more conclusively elucidate the potential of methylphenidate for clinical efficacy in TBI.

Genetic and Regulatory Mechanisms of Comorbidity of Anxiety, Depression and ADHD: A GWAS Meta-Meta-Analysis Through the Lens of a System Biological and Pharmacogenomic Perspective in 18.5 M Subjects

Background: In the United States, approximately 1 in 5 children experience comorbidities with mental illness, including depression and anxiety, which lead to poor general health outcomes. Adolescents with substance use disorders exhibit high rates of co-occurring mental illness, with over 60% meeting diagnostic criteria for another psychiatric condition in community-based treatment programs. Comorbidities are influenced by both genetic (DNA antecedents) and environmental (epigenetic) factors. Given the significant impact of psychiatric comorbidities on individuals' lives, this study aims to uncover common mechanisms through a Genome-Wide Association Study (GWAS) meta-meta-analysis. Methods: GWAS datasets were obtained for each comorbid phenotype, followed by a GWAS meta-meta-analysis using a significance threshold of p < 5E-8 to validate the rationale behind combining all GWAS phenotypes. The combined and refined dataset was subjected to bioinformatic analyses, including Protein-Protein Interactions and Systems Biology. Pharmacogenomics (PGx) annotations for all potential genes with at least one PGx were tested, and the genes identified were combined with the Genetic Addiction Risk Severity (GARS) test, which included 10 genes and eleven Single Nucleotide Polymorphisms (SNPs). The STRING-MODEL was employed to discover novel networks and Protein-Drug interactions. Results: Autism Spectrum Disorder (ASD) was identified as the top manifestation derived from the known comorbid interaction of anxiety, depression, and attention deficit hyperactivity disorder (ADHD). The STRING-MODEL and Protein-Drug interaction analysis revealed a novel network associated with these psychiatric comorbidities. The findings suggest that these interactions are linked to the need to induce "dopamine homeostasis" as a therapeutic outcome. Conclusions: This study provides a reliable genetic and epigenetic map that could assist healthcare professionals in the therapeutic care of patients presenting with multiple psychiatric manifestations, including anxiety, depression, and ADHD. The results highlight the importance of targeting dopamine homeostasis in managing ASD linked to these comorbidities. These insights may guide future pharmacogenomic interventions to improve clinical outcomes in affected individuals.

Stimuli-responsive nanoscale drug delivery system for epilepsy theranostics

Epilepsy is a common neurological disease characterized by distinct pathological changes in the epileptogenic zone. Antiseizure drugs (ASDs) are widely used as the primary treatment for epilepsy. To improve the efficiency of ASDs medication, stimuli-responsive nanoscale drug delivery systems (nanoDDSs), triggered by either endogenous or exogenous factors, have been developed and been considered as a noninvasive and spatial-temporal approach to epilepsy theranostics. In this review, we introduce the pathological variations observed in epileptic lesions such as dysregulated neurotransmitter systems, disrupted ion homeostasis, and dynamic inflammatory cytokine networks. Furthermore, we summarize the recent advances in functional nano-assemblies that could be activated by endogenous stimuli of pathological alterations or exogenous stimuli such as electricity, light, and other interventions. Finally, we discuss the remaining challenges and prospect the insight into perspective of future development in this field. In summary, this review aims to highlight the potential of stimuli-responsive nanoDDSs as precise, controllable and efficient strategies for addressing unresolved issues in epilepsy theranostics. STATEMENT OF SIGNIFICANCE: This review summarizes recent progress in pathological changes such as dysregulated neurotransmitter system, disrupted ion homeostasis and dynamic inflammatory cytokine network, and emphasizes endogenous/exogenous stimuli-responsive nanoscale platforms including neurotransmitter-, ion-, and other stimuli-responsive nanoDDSs, providing the prospects of smart nanoDDSs applications and discussing the challenges to offer generalized guideline for further development of epilepsy theranostics.

Correlation between changes in apathy and cognition in Alzheimer's disease associated apathy: Analysis of the Apathy in Dementia Methylphenidate Trial 2 (ADMET 2)

BACKGROUND

Previous trials have shown improvements in both apathy and cognition with methylphenidate (MPH).

OBJECTIVES

To assess whether changes in apathy correlated with changes in cognition in the Apathy in Dementia Methylphenidate Trial 2 (ADMET 2).

PARTICIPANTS

Mild to moderate AD patients with clinically significant apathy randomized to MPH (20 mg/day) or placebo for 6 months.

MEASUREMENTS

Apathy was measured with the Neuropsychiatric Inventory-apathy (NPI-A) domain. Cognition was measured using the Mini-Mental State Exam (MMSE), Hopkins Verbal Learning (immediate [HVLT-I], delayed [HVLT-D] recall), Digit Span (Forward [DF], Backward [DB]), Trail Making (TMT-A, TMT-B), Action Verbal Fluency (AV), Category Fluency (CF), and the Short Boston Naming Test (BNT).

DESIGN

Linear mixed models included cognitive change scores as dependent variables and time, treatment, change in NPI-A and the interaction between treatment and change in NPI-A as independent variables, which were additionally adjusted for baseline NPI-A and cognitive scores, age, sex, level of education and presence of diabetes.

RESULTS

199 participants (66 % male) were included (98-MPH, 101-placebo). Among all participants, worsening CF was associated with worsening apathy (-0.15 (0.05), p = .003). In addition, change in HVLT-I was associated with the interaction between changes in apathy and treatment (-0.31 (0.07), p = 0.0000158).

CONCLUSION

Changes in apathy are mostly independent of cognitive changes and apathy response to MPH may be independent from cognition. These results are consistent with the view that apathy as a syndrome is related to but distinct from cognition.

Cognitive effects of early life exposure to PCBs in rats: Sex-specific behavioral, hormonal and neuromolecular mechanisms involving the brain dopamine system

Endocrine-disrupting chemicals (EDCs) are environmental toxicants that disrupt hormonal and neurodevelopmental processes. Among these chemicals, polychlorinated biphenyls (PCBs) are particularly concerning due to their resistance to biodegradation and tendency to bioaccumulate. PCBs affect neurodevelopmental function and disrupt the brain's dopamine (DA) system, which is crucial for attentional, affective, and reward processing. These disruptions may contribute to the rising prevalence of DA-mediated neuropsychiatric disorders such as ADHD, depression, and substance use disorders. Notably, these behaviors are sexually dimorphic in part due to differences in sex hormones and their receptors, which are targets of estrogenic PCBs. Therefore, this study determined effects of early life PCB exposure on behaviors and neurochemistry related to potential disruption of dopaminergic signaling. Male and female Sprague Dawley rats were exposed to the PCB mixture Aroclor 1221 (A1221) or vehicle perinatally and then underwent a series of behavioral tests in adulthood, including the sucrose preference test to measure anhedonia, conditioned orienting to assess incentive-motivational phenotype, and attentional set-shifting to evaluate cognitive flexibility and response latency. Following these tests, rats were euthanized, and serum estradiol (E2), DA cells in the midbrain ventral tegmental area (VTA) and substantia nigra (SN), and gene expression from those combined midbrain nuclei were measured. Female rats exposed perinatally to A1221 exhibited decreased sucrose preference, and both male and female A1221 rats had reduced response latency in the attentional set-shifting task compared to vehicle counterparts. Conditioned orienting and serum estradiol (E2)were not affected in either sex; however, A1221-exposed rats of both sexes displayed higher TH+ cell numbers in the VTA and increased expression of dopamine receptor 1 (Drd1) in the combined midbrain nuclei. Additionally, E2 uniquely predicted behavioral outcomes and VTA DAergic cell numbers in A1221-exposed female rats, whereas DA signaling genes were predictive of behavioral outcomes in males. These data highlight sex-specific effects of A1221 on neuromolecular and behavioral phenotypes.

Methylphenidate in Borderline Personality Disorder: Assessing Its Therapeutic Potential and Limitations

Impulsivity is increasingly recognized as a transdiagnostic feature that spans multiple psychiatric disorders, including borderline personality disorder (BPD), bipolar disorder, and substance use disorders. In BPD, impulsive behaviors manifest as substance misuse, risky sexual activity, self-injury, and other maladaptive patterns. This review article updates the clinical and preclinical literature to explore the biological and psychological bases of impulsivity in BPD and considers whether methylphenidate (MPH) can be used as a treatment in this context. Although no medication is specifically approved for BPD, limited evidence from patients with comorbid BPD and attention-deficit/hyperactivity disorder (ADHD) indicates that MPH may reduce impulsivity and improve key symptoms. In addition, real-world data indicate that MPH may be associated with better outcomes and a lower risk of suicidal behaviors in patients with BPD. Nevertheless, such evidence remains scant, particularly among those with a primary diagnosis of BPD without a diagnosis of ADHD. Larger, methodologically rigorous studies are needed to clarify the efficacy and safety of MPH in targeting impulsivity within this population. An improved understanding of dopaminergic mechanisms may eventually shed light on MPH's therapeutic role in BPD, although current data remain preliminary. Overall, recognizing impulsivity as a core symptom rather than focusing exclusively on diagnostic boundaries may facilitate more tailored and effective interventions for BPD.

Single-dose methylphenidate induces shift in functional connectivity associated with positive longer term clinical response in adult attention-deficit/hyperactivity disorder

Stimulants, such as methylphenidate (MPH), are beneficial for attention-deficit/hyperactivity disorder (ADHD), but individual response varies. A deeper understanding of the mechanisms underpinning response is needed. Previous studies suggest that a single MPH dose modulates resting-state functional connectivity (rs-fc). We investigated whether single-dose induced rs-fc changes were associated with post-dose optimization clinical response. Fifty-six adults with ADHD underwent rs-functional magnetic resonance imaging (rs-fMRI) under placebo and a single MPH dose, before starting MPH treatment. Clinical response was measured at two months. We tested if a single MPH dose (vs. placebo) shifted rs-fc; how these shifts were associated with treatment response (categorical approach); and whether these associations were driven by improvement on either ADHD symptom domain. A single MPH dose (vs. placebo) increased rs-fc in three subcortical-cortical and cerebellar-cortical clusters. Enhanced rs-fc between the cerebellar vermis (lobule 6) and the left precentral gyrus was associated with a greater probability of responding to treatment (χ2(7) = 22.740, p = .002) and with an improvement on both inattentive and hyperactive/impulsive symptoms (both p ≤ .001). We provide proof-of-concept that the brain functional response to a single MPH dose, administered before starting routine treatment, is indicative of two-month clinical response in adult ADHD. This may encourage future replication using clinically applicable measures.

Neurobiological influences on event perception: the role of catecholamines

BACKGROUND

Event segmentation, the cognitive process of parsing continuous experiences into discrete events, plays a fundamental role in how humans perceive and interact with their environment. Guided by Event Segmentation Theory, this study investigates the modulation of event segmentation by the catecholaminergic system by methylphenidate (MPH).

METHODS

Healthy adult participants (N = 52) engaged in a double-blind, counter-balanced, placebo-controlled experiment in which they watched a movie and identified event boundaries under placebo and MPH conditions.

RESULTS

With the same information given, MPH increased the likelihood that the information was considered meaningful. Crucially, the number of situational changes and participant's prior experience had an interactive effect on the probability of event segmentation. There was a stronger relationship between environmental information and segmentation probability when catecholaminergic levels were elevated by MPH in addition to previous experience.

CONCLUSIONS

The catecholaminergic system modulates how incoming information is segmented to build meaningful episodes. Prior experience supports the effects of MPH to unfold. These findings underscore the complex interplay between neurochemical modulation and cognitive processes involved in event perception.

Coupling Bio-Resonance Neurotechnology (BRNT) and Dual Hemispheric Repetitive Transcranial Magnetic Stimulation (rTMS) Reduces Comorbid Major Depressive Disorder (MDD) and Generalized Anxiety Disorder (GAD) as Demonstrated by PHQ-9 and GAD-7: Pilot Case Series

Major Depressive Disorder (MDD) and Generalized Anxiety Disorder (GAD) are prevalent comorbidities related to a greater likelihood of poor treatment outcomes and prolonged treatment for Reward Deficiency Syndrome (RDS) behaviors. The current exploratory case study of a small cohort (n=3; f=2 m=1) used novel neurotechnology to treat co-occurring MDD and GAD with a multifaceted intervention that combines the novel bio-resonance neurotechnology (BRNT) referred to as NuCalm®, to restore autonomic nervous system balance and dual hemispheric repetitive transcranial magnetic stimulation (rTMS) of the ipsilateral Dorsal Lateral Prefrontal Cortex (DLPFC) to treat the disrupted structural components of the brain. Neuroacoustic brainwave entrainment, electromagnetic frequency bio-resonance, and light-blocking combine to place patients into a parasympathetic dominant state. The paired t-tests indicated a significant decrease in comparing before and after the intervention. The Patient Health Questionnaire PHQ-9 scores from the first to the last time-point (mean difference = 20, t(2) = 6.55, p = 0.0226), with a 95% confidence interval of mean difference ranging from 6.86 to 33.14. Similarly, there was a significant decrease in General Anxiety Disorder GAD-7 questionnaire scores from the first to the last time point (mean difference = 18.67, t(2) = 12.85, p = 0.0060), with a 95% confidence interval of the mean difference ranging from 12.42 to 24.92. After applying the Bonferroni correction, the corrected p-values for PHQ-9 and GAD-7 are 0.0452 and 0.0120, respectively. Cohen's d standardized effect size indicated that the main effect size was 5.47 and 13.8 times the noise (variability), respectively, for the initial versus final PHQ-9 and GAD-7. Further, more extensive, much larger sham-controlled and blinded studies are required to confirm these encouraging results and explore this multifaceted intervention.

Do specific myelin autoantibodies and increased cerebral dopamine neurotrophic factor in the context of inflammation predict the diagnosis of attention deficit hyperactivity disorder in medication-free children?

BACKGROUND

The aim of this study was to investigate the serum levels of anti-myelin basic protein (anti-MBP), anti-myelin oligodentrocyte glycoprotein (anti-MOG), myelin-associated glycoprotein (MAG), high-sensitivity C-reactive protein (hs-CRP), cerebral dopamine neurotrophic factor (CDNF), cerebellin-1, and reelin and their relationships with clinical severity and irritability behaviours in children with attention deficit (AD) hyperactivity disorder (ADHD) and typically developing (TD) healthy controls.

METHODS

In this study, 141 children with ADHD between the ages of 8 and 14 years who were medication-free and 135 TD healthy controls were included. The serum levels of anti-MBP, anti-MOG, MAG, CDNF, hs-CRP, cerebellin, and reelin were measured using enzyme-linked immunosorbent assay kits. The Turgay Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV)-based Screening and Evaluation Scale for Attention Deficit and Disruptive Behavior Disorders-Parent Form (TDSM-IV-O) and the affective reactivity index (ARI) scale were used to assess clinical severity and irritability behaviours in the children.

RESULTS

The MAG, CDNF, hs-CRP, reelin, and cerebellin levels were significantly higher in the ADHD group than in the control group, but no significant differences in anti-MBP and anti-MOG levels were found between the groups. Compared with the controls, the patients with ADHD showed significantly higher scores on the ARI self- and parent-report scales. The reelin, hs-CRP, and MAG levels were significantly associated with the TDSM-IV-O AD scores, AD and oppositional defiant (OD) disorder scores and hyperactivity, and OD and conduct disorder scores, respectively. Hs-CRP was significantly associated with anti-MBP and cerebellin levels. In an analysis of covariance, the results were unchanged even after controlling for potential confounders such as age, body mass index, and sex.

CONCLUSION

This study demonstrates that MAG, CDNF, hs-CRP, reelin, and cerebellin levels may play a potential role in the pathogenesis of ADHD.

A Review of Sex and Gender Factors in Stimulant Treatment for ADHD: Knowledge Gaps and Future Directions

OBJECTIVE

Stimulant medications are the primary pharmacological intervention for ADHD, yet our understanding of how sex and gender impact stimulant treatment outcomes remains limited. Clinical guidelines do not differ for female and male individuals despite possible sex and gender-related differences in effectiveness, adverse events, and pharmacokinetics. This theoretical framework identifies five key knowledge gaps relating to sex and gender effects in stimulant treatment.

METHOD

We investigate the stimulant treatment trajectories of girls and women with ADHD from diagnosis and prescription to daily use and outcomes. We examine the impact of reproductive life transitions and hormonal fluctuations and their interactions with gender socialization and gendered expectations on treatment effectiveness, stigma, and adherence.

RESULTS

By synthesizing existing literature, proposing testable predictions, and suggesting future research directions, we highlight the urgent need for studies that systematically investigate these factors.

CONCLUSION

Addressing these gaps could significantly improve treatment outcomes for girls and women with ADHD, particularly during biological and gender role transitions.

Methylphenidate stabilizes dynamic brain network organization during tasks probing attention and reward processing in stimulant-naïve children with ADHD

Children with ADHD often exhibit fluctuations in attention and heightened reward sensitivity. Psychostimulants, such as methylphenidate (MPH), improve these behaviors in many, but not all, children with ADHD. Given the extent to which psychostimulants are prescribed for children, coupled with variable efficacy on an individual level, a better understanding of the mechanisms through which MPH changes brain function and behavior is necessary. MPH's primary action is on catecholamines, including dopamine and norepinephrine. Catecholaminergic signaling can influence the tradeoff between flexibility and stability of brain function, which is one candidate mechanism through which MPH may alter brain function and behavior. Time-varying functional connectivity, which models how functional brain networks reconfigure on short timescales, can be used to examine brain flexibility versus stability, and is thus well-suited to test how MPH impacts brain function. Here, we scanned stimulant-naïve children with ADHD (8-12 years) on and off a single dose of MPH. In the MRI machine, participants completed two attention-demanding tasks: 1) a standard go/no-go task and 2) a rewarded go/no-go task. For both tasks, using a within-subjects design, we compared the degree to which brain organization changed throughout the course of the MRI scan, termed whole brain flexibility, on and off MPH. We found that whole brain flexibility decreased on MPH. Further, individuals with greater decreases in whole brain flexibility on MPH exhibited greater improvements in task performance. Together, these results provide novel insights into the neurobiological mechanisms underlying the effectiveness of MPH administration for children with ADHD.

Attention-deficit/hyperactivity disorder-related psychomotor activity and altered neuronal activity in the medial prefrontal cortex and striatum in the A53T mouse model of Parkinson's disease and other synucleinopathies: Findings from an "endophenotype" approach

Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with an increased risk of Parkinson's disease (PD) and other synucleinopathies later in life. The severity of the ADHD phenotype may play a significant role in this association. There is no indication that any of the existing animal models can unify these disorders. Using the Open Field Test, amphetamine-challenge test, Western blot and immunohistochemical analysis of neuronal activity markers (c-Fos, FosB and ΔFosB) we performed a deliberate neurobehavioral characterization of 6-month-old hemizygous A53T carriers (A53T+) of the JAX006823 strain, evaluating the utility of this transgenic mouse model of PD and other synucleinopathies in ADHD/PD continuum research. Adhering to the "endophenotype" approach, non-transgenic littermates (A53T-) and C57BL/6J mice (used to maintain the colony) were examined with A53T+ mice, to differentiate between biomarkers of transgenicity and endophenotypic traits related to the genetic background of the strain. Obtained results revealed that increased behavioral and acute striatal response to novelty, increased basal neuronal activity of the ventromedial prefrontal cortex and rate-dependent calming effect of amphetamine were endophenotypic characteristics of the strain. Increased acute response of the medial prefrontal cortex to novelty and chronic increase in neuronal activity of the striatum appeared as the mark of transgenicity. To the best of our knowledge, this is the first study to indicate external validity of a transgenic mouse model of PD and other synucleinopathies with the neurobehavioral pathology associated with ADHD, hinting at its potential in preclinical research of ADHD/PD continuum. The full capacity of the model remains to be explored.

Epigenetic regulation-mediated disorders in dopamine transporter endocytosis: A novel mechanism for the pathogenesis of Parkinson's disease

Mechanisms such as DNA methylation, histone modifications, and non-coding RNA regulation may impact the endocytosis of dopamine transporter (DAT) by influencing processes like neuronal survival, thereby contributing to the initiation and progression of Parkinson's Disease (PD). Some small molecule inhibitors or natural bioactive compounds have the potential to modulate epigenetic processes, thereby reversing induced pluripotent stem cells (iPSCs) reprogramming and abnormal differentiation, offering potential therapeutic effects for PD. Although no specific DNA modification enzyme directly regulates DAT endocytosis, enzymes such as DNA methyltransferases (DNMTs) may indirectly influence DAT endocytosis by regulating the expression of genes associated with this process. DNA modifications impact DAT endocytosis by modulating key signaling pathways, including the (protein kinase C) PKC and D2 receptor (D2R) pathways. Key enzymes involved in RNA modifications that influence DAT endocytosis include m6A methyltransferases and other related enzymes. This regulation impacts the synthesis and function of proteins involved in DAT endocytosis, thereby indirectly affecting the process itself. RNA modifications regulate DAT endocytosis through various indirect pathways, as well as histone modifications. Key enzymes influence the expression of genes associated with DAT endocytosis by modulating the chromatin's accessibility and compaction state. These enzymes control the expression of proteins involved in regulating endocytosis, promoting endosome formation, and facilitating recycling processes. Through the modulation exerted by these enzymes, the speed of DAT endocytosis and recycling patterns are indirectly regulated, establishing a crucial epigenetic control point for the regulation of neurotransmitter transport. Based on this understanding, we anticipate that targeting these processes could lead to favorable therapeutic effects for early PD pathogenesis.

Physical and neurophysiological maturation associated with ADHD among previously institutionalized children: a randomized controlled trial

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental outcome among children with a history of early institutional care. Prior research on institutionalized children suggested that accelerated physical growth in childhood is a risk factor for ADHD outcomes.

METHODS

The current study examined physical and neurophysiological growth trajectories among institutionalized children randomized to foster care treatment (n = 59) or care as usual (n = 54), and never institutionalized children (n = 64) enrolled in the Bucharest Early Intervention Project (NCT00747396, clinicaltrials.gov). Participants completed physical and electroencephalography (EEG) assessments at six time points from infancy through adolescence, as well as structured diagnostic interviews at the 54-month and 12-year time points. A series of multilevel growth models and cross-lagged path models were estimated to examine associations among physical and neurophysiological maturation, treatment group, age of foster care placement, and ADHD diagnostic outcomes.

RESULTS

Twenty-seven percent of the institutionalized children met research criteria for ADHD at one or both time points. Slowed, prolonged growth of height and head circumference were associated with both ADHD and delayed foster care placement. Placement in foster care versus care as usual, but not ADHD, was associated with maturation of the peak alpha frequency. Among children randomized to foster care, average theta-beta ratio was lower among those with ADHD. There was no evidence that rapid physical maturation led to atypical cortical activity.

CONCLUSIONS

Delayed, prolonged physical growth and atypical neurophysiology from infancy through adolescence is associated with ADHD among institutionalized children, over and above the protective effects of foster care.

Pharmacological target sites for restoration of age-associated deficits in NMDA receptor-mediated norepinephrine release in brain

Aging affects virtually all organs of the body, but perhaps it has the most profound effects on the brain and its neurotransmitter systems, which influence a wide range of crucial functions, such as attention, focus, mood, neuroendocrine and autonomic functions, and sleep cycles. All of these essential functions, as well as fundamental cognitive processes such as memory, recall, and processing speed, utilize neuronal circuits that depend on neurotransmitter signaling between neurons. Glutamate (Glu), the main excitatory neurotransmitter in the CNS, is involved in most neuronal excitatory functions, including release of the neurotransmitter norepinephrine (NE). Previous studies from our lab demonstrated that the age-associated decline in Glu-stimulated NE release in rat cerebral cortex and hippocampus mediated by NMDA glutamate receptors, as well as deficits in dendritic spines, and cognitive functions are fully rescued by the CNS stimulant amphetamine. Here we further investigated Glu-stimulated NE release in the cerebral cortex to identify additional novel target sites for restoration of Glu-stimulated NE release. We found that blockade of alpha-2 adrenergic receptors fully restores Glu-stimulated NE release to the levels of young controls. In addition, we investigated the density and responsiveness of NMDA receptors as a potential underlying neuronal mechanism that could account for the observed age-associated decline in Glu-stimulated NE release. In the basal state of the receptor (no added glutamate and glycine) the density of NMDA receptors in the cortex from young and aged rats was similar. However, in contrast, in the presence of 10 μM added glutamate, which opens the receptor channel and increases the number of available [3H]-MK-801 binding sites within the channel, the density of [3H]-MK-801 binding sites was significantly less in the cortex from aged rats.

Safety and efficacy of dasotraline for patients with attention deficit/hyperactivity disorder: a systematic review and meta-analysis of 1594 patients including GRADE qualifications

INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is a complex neurodevelopmental disorder. It is one of the most common mental disorders in youth worldwide characterized by persistent overactivity and impulsivity/inattention symptoms associated with social and academic impairment. dasotraline has been suggested to play a pivotal role as a serotonin, norepinephrine, and dopamine reuptake inhibitor. This study aimed to create evidence from published randomized clinical trials (RCTs) about the benefits of dasotraline for ADHD patients.

METHODS

A computer literature search (PubMed, Scopus, Web of Science, and Cochrane CENTRAL) was conducted. We included RCTs comparing dasotraline versus placebo. The primary outcome measure was the ADHD Rating Scale-IV score, pooled as the mean difference between the two groups from baseline to the endpoint. The secondary outcome measures were the ADHD Rating Scale-IV Inattention score, ADHD Rating Scale-IV Hyperactivity score.

RESULTS

Five RCTs with a total of 1594 patients were included in this study. dasotraline showed a significant improvement in the primary outcome (MD -2.65, 95% CI [-4.14 to -1.17], P= 0.0004 CONCLUSION: The results showed that dasotraline demonstrated a significant improvement in both primary and secondary outcomes, establishing its efficacy as a novel treatment for ADHD symptoms. However, mild to moderate side effects were observed.

The Impact of Dexamphetamine Treatment for Obesity on Executive Function: A Double-Blind Randomised Controlled Pilot Study

BACKGROUND

Amphetamines increase dopamine levels in mid-brain regions which, in turn, impact top-down executive function. Repeated exposure is linked to substance use disorders. Nonetheless, amphetamines are used to manage attention-deficit/hyperactivity disorder (ADHD) and eating-related disorders. In ADHD, amphetamines upregulate a system characterised by low dopaminergic tone, assisting to improve executive function. A similar process might be at play with eating disorders; however, the effect of amphetamine treatment on executive function in this case has not been thoroughly considered.

METHODS

Participants (N = 52, Mage = 47.06, SD = 12.29) with a body mass index of 25-60 were randomised to treatment (6-week dexamphetamine titration) or control (placebo) groups. They completed an executive function measure-Barkley Deficits in Executive Functioning Scale (BDEFS-SF)-and response inhibition task-Stop-Signal Task (SST)-at Baseline, throughout titration, at Maintenance, and at Follow-up. Mixed effects models examined whether BDEFS-SF score or the SST variable, stop-signal reaction time (SSRT), changed across sessions as a function of treatment.

RESULTS

There was no effect of group (p = 0.440), but an effect of session (p = 0.024) on BDEFS-SF, with scores at Time 2 (p = 0.011, 95% CI [0.47, 3.49]) and Maintenance (p = 0.022, 95% CI [-4.89, -0.39]), respectively, higher and lower than other timepoints. There was no group by session interaction (p = 0.659). R2 (conditional) = 0.74; ICC = 0.73. There was an effect of group (p = 0.039) and session (p < 0.001) on SSRT, but no interaction (p = 0.707). Baseline SSRT was significantly longer than the mean of all subsequent timepoints (p < 0.001, 95% CI [16.29, 33.84]). R2 (conditional) = 0.47; ICC = 0.39.

CONCLUSIONS

There was no discernible impact of amphetamine treatment for obesity on executive function. Our results suggest some variation related to sample size and/or practice effects. Thus, while treatment appears unlikely to render individuals susceptible to substance use disorders, parallels with ADHD might be overstated.

Neurobiology of attention-deficit hyperactivity disorder: historical challenges and emerging frontiers

Extensive investigations spanning multiple levels of inquiry, from genetic to behavioural studies, have sought to unravel the mechanistic foundations of attention-deficit hyperactivity disorder (ADHD), with the aspiration of developing efficacious treatments for this condition. Despite these efforts, the pathogenesis of ADHD remains elusive. In this Review, we reflect on what has been learned about ADHD while also providing a framework that may serve as a roadmap for future investigations. We emphasize that ADHD is a highly heterogeneous disorder with multiple aetiologies that necessitates a multifactorial dimensional phenotype, rather than a fixed dichotomous conceptualization. We highlight new findings that suggest a more brain-wide, 'global' view of the disorder, rather than the traditional localizationist framework, which asserts that a limited set of brain regions or networks underlie ADHD. Last, we underscore how underpowered studies that have aimed to associate neurobiology with ADHD phenotypes have long precluded the field from making progress. However, a new age of ADHD research with refined phenotypes, advanced methods, creative study designs and adequately powered investigations is beginning to put the field on a good footing. Indeed, the field is at a promising juncture to advance the neurobiological understanding of ADHD and fulfil the promise of clinical utility.

Evaluating experimental, knowledge-based and computational cocrystal screening methods to advance drug-drug cocrystal fixed-dose combination development

Fixed-dose combinations (FDCs) offer significant advantages to patients and the pharmaceutical industry alike through improved dissolution profiles, synergistic effects and extended patent lifetimes. Identifying whether two active pharmaceutical ingredients have the potential to form a drug-drug cocrystal (DDC) or interact is an essential step in determining the most suitable type of FDC to formulate. The lack of coherent strategies to determine if two active pharmaceutical ingredients that can be co-administered can form a cocrystal, has significantly impacted DDC commercialisation. This review aims to accelerate the development of FDCs and DDCs by evaluating existing experimental, knowledge-based and computational cocrystal screening methods; the background of their development, their application in screening for cocrystals and DDCs, and their limitations are discussed. The evaluation provided in this review will act as a guide for selecting suitable screening methods to accelerate FDC development.

The Relationship Between Prenatal, Perinatal, and Postnatal Factors and ADHD: The Role of Nutrition, Diet, and Stress

Attention-Deficit Hyperactive Disorder (ADHD) is a neurobehavioral syndrome affecting children aged 6-17 with symptoms manifesting before age 12. ADHD presents heterogeneously and is associated with various psychiatric disorders. The cause remains elusive, but genetic and environmental factors, brain region maturation delays, and neurotransmitter dysregulation are implicated. Effective treatment requires a multi-disciplinary approach, primarily involving pharmacological and behavioral intervention. Stimulants like methylphenidate and amphetamines are first-line medications, but non-stimulants may be considered for some patients. However, stimulants face challenges related to misuse, dependence, and long-term tolerability issues. The etiology of ADHD involved genetic predisposition, environmental influences, and prenatal, perinatal, and postnatal factors. Prenatal causes encompass maternal diet, alcohol consumption, viral infections, and stress. Postnatal factors include head trauma, meningitis, toxin, nutritional deficiencies, as well as iodine deficiency and hypothyroidism. The gut microbiome's role in ADHD is emerging, influencing neurodevelopment through microbiota-gut-brain axis. Understanding these diverse etiological factors is essential for comprehensive ADHD management.

Dopamine Transporter and CYP2D6 Gene Relationships with Attention-Deficit/Hyperactivity Disorder Treatment Response in the Methylphenidate and Atomoxetine Crossover Study

Background: Few biological or clinical predictors guide medication selection and/or dosing for attention-deficit/hyperactivity disorder (ADHD). Accumulating data suggest that genetic factors may contribute to clinically relevant pharmacodynamic (e.g., dopamine transporter-SLC6A3 also commonly known as DAT1) or pharmacokinetic (e.g., the drug metabolizing enzyme Cytochrome P450 2D6 CYP2D6) effects of methylphenidate (stimulant) and atomoxetine (non-stimulant), which are commonly prescribed medications. This is the first study of youth with ADHD exposed to both medications examining the clinical relevance of genetic variation on treatment response. Methods: Genetic variations in DAT1 and CYP2D6 were examined to determine how they modified time relationships with changes in ADHD symptoms over a 4-week period in 199 youth participating in a double-blind crossover study following a stepped titration dose optimization protocol. Results: Our results identified trends in the modification effect from CYP2D6 phenotype and the time-response relationship between ADHD total symptoms for both medications (atomoxetine [ATX]: p = 0.058, Methylphenidate [MPH]: p = 0.044). There was also a trend for the DAT1 3' untranslated region (UTR) variable number of tandem repeat (VNTR) genotype to modify dose relationships with ADHD-RS total scores for atomoxetine (p = 0.029). Participants with DAT1 9/10 repeat genotypes had a more rapid dose-response to ATX compared to 10/10, while those with 9/9 genotypes did not respond as doses were increased. Regardless of genotype, ADHD symptoms and doses were similar across CYP2D6 metabolizer groups after 4 weeks of treatment. Conclusions: Most children with ADHD who were CYP2D6 normal metabolizers or had DAT1 10/10 or 9/10 genotypes responded well to both medications. While we observed some statistically significant effects of CYP2D6 and DAT1 with treatment response over time, our data indicate that genotyping for clinical purposes may have limited utility to guide treatment decisions for ATX or MPH because both medications were generally effective in the studied cohort after 3 weeks of titration to higher doses. The potential DAT1 association with ATX treatment is a novel finding, consistent with prior reports suggesting an association of the DAT1 in 9/9 genotypes with lower responsive rates to treatment at low and moderate doses.

Prediction of methylphenidate treatment response for ADHD using conventional and radiomics T1 and DTI features: Secondary analysis of a randomized clinical trial

BACKGROUND

Attention-Deficit/Hyperactivity Disorder (ADHD) is commonly treated with methylphenidate (MPH). Although highly effective, MPH treatment still has a relatively high non-response rate of around 30%, highlighting the need for a better understanding of treatment response. Radiomics of T1-weighted images and Diffusion Tensor Imaging (DTI) combined with machine learning approaches could offer a novel method for assessing MPH treatment response.

PURPOSE

To evaluate the accuracy of both conventional and radiomics approaches in predicting treatment response based on baseline T1 and DTI data in stimulant-naive ADHD participants.

METHODS

We performed a secondary analysis of a randomized clinical trial (ePOD-MPH), involving 47 stimulant-naive ADHD participants (23 boys aged 11.4 ± 0.4 years, 24 men aged 28.1 ± 4.3 years) who underwent 16 weeks of treatment with MPH. Baseline T1-weighted and DTI MRI scans were acquired. Treatment response was assessed at 8 weeks (during treatment) and one week after cessation of 16-week treatment (post-treatment) using the Clinical Global Impressions - Improvement scale as our primary outcome. We compared prediction accuracy using a conventional model and a radiomics model. The conventional approach included the volume of bilateral caudate, putamen, pallidum, accumbens, and hippocampus, and for DTI the mean fractional anisotropy (FA) of the entire brain white matter, bilateral Anterior Thalamic Radiation (ATR), and the splenium of the corpus callosum, totaling 14 regional features. For the radiomics approach, 380 features (shape-based and first-order statistics) were extracted from these 14 regions. XGBoost models with nested cross-validation were used and constructed for the total cohort (n = 47), as well as children (n = 23) and adults (n = 24) separately. Exact binomial tests were employed to compare model performance.

RESULTS

For the conventional model, balanced accuracy (bAcc) in predicting treatment response during treatment was 63 % for the total cohort, 32 % for children, and 36 % for adults (Area Under the Receiver Operating Characteristic Curve (AUC-ROC): 0.69, 0.33, 0.41 respectively). Radiomics models demonstrated bAcc's of 68 %, 64 %, and 64 % during treatment (AUC-ROCs of 0.73, 0.62, 0.69 respectively). These predictions were better than chance for both conventional and radiomics models in the total cohort (p = 0.04, p = 0.003 respectively). The radiomics models outperformed the conventional models during treatment in children only (p = 0.02). At post-treatment, performance was markedly reduced.

CONCLUSION

While conventional and radiomics models performed equally well in predicting clinical improvement across children and adults during treatment, radiomics features offered enhanced structural information beyond conventional region-based volume and FA averages in children. Prediction of symptom improvement one week after treatment cessation was poor, potentially due to the transient effects of stimulant treatment on symptom improvement.

Charting brain GABA and glutamate levels across psychiatric disorders by quantitative analysis of 121 1H-MRS studies

BACKGROUND

Psychiatric diagnosis is based on categorical diagnostic classification, yet similarities in genetics and clinical features across disorders suggest that these classifications share commonalities in neurobiology, particularly regarding neurotransmitters. Glutamate (Glu) and gamma-aminobutyric acid (GABA), the brain's primary excitatory and inhibitory neurotransmitters, play critical roles in brain function and physiological processes.

METHODS

We examined the levels of Glu, combined glutamate and glutamine (Glx), and GABA across psychiatric disorders by pooling data from 121 1H-MRS studies and further divided the sample based on Axis I disorders.

RESULTS

Statistically significant differences in GABA levels were found in the combined psychiatric group compared with healthy controls (Hedge's g = -0.112, p = 0.008). Further analyses based on brain regions showed that brain GABA levels significantly differed across Axis I disorders and controls in the parieto-occipital cortex (Hedge's g = 0.277, p = 0.019). Furthermore, GABA levels were reduced in affective disorders in the occipital cortex (Hedge's g = -0.468, p = 0.043). Reductions in Glx levels were found in neurodevelopmental disorders (Hedge's g = -0.287, p = 0.022). Analysis focusing on brain regions suggested that Glx levels decreased in the frontal cortex (Hedge's g = -0.226, p = 0.025), and the reduction of Glu levels in patients with affective disorders in the frontal cortex is marginally significant (Hedge's g = -0.172, p = 0.052). When analyzing the anterior cingulate cortex and prefrontal cortex separately, reductions were only found in GABA levels in the former (Hedge's g = - 0.191, p = 0.009) across all disorders.

CONCLUSIONS

Altered glutamatergic and GABAergic metabolites were found across psychiatric disorders, indicating shared dysfunction. We found reduced GABA levels across psychiatric disorders and lower Glu levels in affective disorders. These results highlight the significance of GABA and Glu in psychiatric etiology and partially support rethinking current diagnostic categories.

Overactive PKA signaling underlies the hyperalgesia in an ADHD mouse model

There is an intimate relationship between pain hypersensitivity and attention deficit hyperactivity disorder (ADHD); however, the underlying mechanisms are still elusive. Individuals carrying the mutation in CRY1 (c. 1657 + 3A > C), which leads to deletion of exon 11 expression in the CRY1 protein (CRY1Δ11), exhibit ADHD symptoms. Here, we demonstrate that the responses to thermal and mechanical stimuli were amplified in the Cry1Δ11 mice. RNA-sequencing analysis identified protein kinase A (PKA) signaling as being overactive in the spinal cords of Cry1Δ11 mice. The neuronal excitability was significantly enhanced in the spinal cords of Cry1Δ11 mice as determined by in vitro electrophysiology. The PKA inhibitor H89 normalized hyperalgesia in Cry1Δ11 mice, underscoring the causative effect of overactive PKA signaling. Our results thus point to the PKA signaling pathway as the underlying mechanism and a potential therapeutic target for pain hypersensitivity in a validated ADHD mouse model.

Change in striatal functional connectivity networks across 2 years due to stimulant exposure in childhood ADHD: results from the ABCD sample

Widely prescribed for Attention-Deficit/Hyperactivity Disorder (ADHD), stimulants (e.g., methylphenidate) have been studied for their chronic effects on the brain in prospective designs controlling dosage and adherence. While controlled approaches are essential, they do not approximate real-world stimulant exposure contexts where medication interruptions, dosage non-compliance, and polypharmacy are common. Brain changes in real-world conditions are largely unexplored. To fill this gap, we capitalized on the observational design of the Adolescent Brain Cognitive Development (ABCD) study to examine effects of stimulants on large-scale bilateral cortical networks' resting-state functional connectivity (rs-FC) with 6 striatal regions (left and right caudate, putamen, and nucleus accumbens) across two years in children with ADHD. Bayesian hierarchical regressions revealed associations between stimulant exposure and change in rs-FC of multiple striatal-cortical networks, affiliated with executive and visuo-motor control, which were not driven by general psychotropic medication. Of these connections, three were selective to stimulants versus stimulant naive: reduced rs-FC between caudate and frontoparietal network, and between putamen and frontoparietal and visual networks. Comparison with typically developing children in the ABCD sample revealed stronger rs-FC reduction in stimulant-exposed children for putamen and frontoparietal and visual networks, suggesting a normalizing effect of stimulants. 14% of stimulant-exposed children demonstrated reliable reduction in ADHD symptoms, and were distinguished by stronger rs-FC reduction between right putamen and visual network. Thus, stimulant exposure for a two-year period under real-world conditions modulated striatal-cortical functional networks broadly, had a normalizing effect on a subset of networks, and was associated with potential therapeutic effects involving visual attentional control.

Review of Clinical Considerations in the Management of Adolescents with ADHD During Ramadan

Background:

Fasting in Ramadan, a holy month in Islam, is considered a religious obligation to Muslims after puberty. Fasting during Ramadan entails abstinence from consuming food and liquids, as well as abstaining from other activities, including smoking and sexual activity, from dawn until sunset. Literature exists regarding the management of multiple medical conditions impacted by the month of fasting; however, limited literature exists to guide the management of Attention-Deficit/Hyperactivity Disorder (ADHD) during Ramadan.

Methods:

This systematic review employed a PUBMED search which was conducted using keywords ((ADHD) AND (Muslims)) OR ((ADHD) AND (FASTING)) OR ((ADHD) AND (RAMADAN)) OR ((RAMADAN) AND (MANAGEMENT)) and search strategies to find existing literature on ADHD management during Ramadan or while fasting.

Results:

Eight hundred and sixty-one results were obtained. Of these, full texts of clinical trials, systematic reviews, reviews, randomized control trials, and metaanalyses resulted in 303 results that were screened by title or abstract for relevance to the topic. The duplicate articles were removed. Eighty-nine results were incorporated into this paper, including full articles, book excerpts, and online articles.

Discussion:

Muslim adolescents may face challenges with academic and social functioning as they navigate psychosocial changes in the context of Ramadan. ADHD management options should be discussed with individuals who are planning to fast. Pharmacologic management options include continuing on the current regimen, dose adjustment to mitigate side effect exacerbation, a change in medication class, or a change in medication formulation. For severe cases or cases with comorbid conditions, continued fasting may not be recommended. In these cases, the patient should attempt to seek counsel with their community’s religious scholar in collaboration with their medication provider. Ultimately, there are limitations in the available data, and there is a need for further investigation into the impacts of fasting during Ramadan on individuals with ADHD and the effectiveness of interventions to promote treatment adherence.

Rhynchophylline Alleviates Hyperactivity and Cognitive Flexibility Impairment Associated With Inhibition of Inflammatory Responses in Mice That Partly Lack the Dopamine Transporter Protein

BACKGROUND AND AIMS

Rhynchophylline (RHY) can alleviate some cognitive flexibility impairment and stereotyped behavior for attention-deficit hyperactivity disorder (ADHD) and Tourette syndrome (TS) patients as one of a key extract and an active ingredient in Ningdong granule (NDG), which is a Traditional Chinese medicine (TCM) preparation widely used in the treatment of ADHD and TS children in China; however, the underlying mechanism is not well understood. Therefore, this study aimed to evaluate how RHY alleviates hyperactivity and cognitive flexibility impairment while inhibiting inflammatory responses in mice that partly lack dopamine transporter protein (DAT- mice).

METHODS

Male DAT- mice were randomly divided into the RHY group (n = 8) and administered RHY (30 mg/kg) in the DAT- group (n = 8) and administered saline (i.p., 10 mL/kg) in wild-type (WT) mice as the WT control group (n = 8). Hyperactivity and cognitive flexibility impairment were evaluated by the open field test (OFT) and the Morris water maze (MWM) test. The levels of the inflammatory factors of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in cortical homogenates were tested by enzyme-linked immunosorbent assays (ELISA) after 8 weeks of treatment with RHY. In vitro, primary microglia and astrocytes extracted from the cortices of DAT- neonatal mice and WT neonatal mice were treated with lipopolysaccharide (LPS) (1 mg/mL) to induce neuroinflammatory responses and with RHY (20 mM) for 48 h. The levels of the inflammatory factors TNF-α, IL-1β, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX2) in the culture medium were measured at 6 h, 24 h, and 48 h after treatment with LPS and RHY.

RESULTS

RHY ameliorated hyperactivity and cognitive flexibility impairment in DAT- mice and inhibited the expression of the inflammatory factors TNF-α, IL-1β, iNOS, and COX-2 in microglia and astrocytes in vitro, and also inhibited the expression of TNF-α and IL-1β in cortical homogenates after 8 weeks of treatment.

CONCLUSION

RHY improved hyperactivity and cognitive flexibility impairment through inhibiting inflammatory responses in DAT- mice.

Comparative pharmacology and abuse potential of oral dexamphetamine and lisdexamfetamine-A literature review

OBJECTIVE

To compare the pharmacology and abuse potential of oral dexamphetamine and lisdexamfetamine (LDX).

METHODS

A search of Medline and Embase was conducted to identify relevant articles for this literature review.

RESULTS

Dexamphetamine and LDX, a prodrug of dexamphetamine, are indicated for the treatment of attention-deficit/hyperactivity disorder. It has been suggested that LDX may have a reduced potential for oral abuse compared to immediate-release dexamphetamine. As a prodrug, LDX has the same pharmacodynamic properties as dexamphetamine. A study in healthy adults showed that the pharmacokinetic profile of dexamphetamine following oral administration of LDX is essentially identical to that of an equimolar dose of dexamphetamine administered 1 h later. In addition, dexamphetamine produced subjective drug liking effects comparable to those produced by LDX. LDX showed linear dose proportional pharmacokinetics up to a dose of 250 mg, indicating a lack of overdose protection at supratherapeutic doses. Furthermore, the exposure to dexamphetamine released from LDX may be prolonged by the consumption of alkalizing agents.

CONCLUSIONS

The available evidence from pharmacodynamic, pharmacokinetic and abuse liability studies suggests a comparable potential for oral abuse of dexamphetamine and LDX.

Driving performance and ocular activity following acute administration of 10 mg methylphenidate: A randomised, double-blind, placebo-controlled study

BACKGROUND

Methylphenidate is a routinely prescribed treatment for attention-deficit/hyperactivity disorder with misuse potential owing to its perceived performance-enhancing and euphoric properties. Although clinically effective, there is limited understanding of how methylphenidate affects safety-sensitive tasks such as driving when used by healthy individuals.

AIM

Explore the acute effects of 10 mg methylphenidate on driving performance and gaze behaviour.

METHODS

Twenty-five fully licensed, healthy adults (mean age = 33.5 ± 7.8 years, 64% male) took part in two 40-min simulated highway drives with simultaneous eye movements monitored using a proprietary automotive-grade driver monitoring system (Seeing Machines). Driving performance was assessed using the standard deviation of lateral position, standard deviation of speed and steering variability. Visual scanning efficiency was determined using ocular metrics, such as fixation duration and rate, gaze transition entropy, and stationary gaze entropy, were assessed to determine visual scanning efficiency.

RESULTS

Methylphenidate significantly improved driving performance by reducing lane weaving and speed variation, particularly in the latter half of the drive. Although a significant reduction in fixation duration was observed, all other ocular metrics remained unchanged.

CONCLUSIONS

Methylphenidate mitigates performance decrements typically associated with prolonged and monotonous driving. The absence of pronounced oculomotor effects suggests that a single 10 mg dose of methylphenidate has no deleterious impact on visual scanning behaviour during driving tasks with low-to-moderate cognitive demand. Future research should investigate the effects of methylphenidate under various dosing and driving conditions to better understand its impact.

TRIAL REGISTRATION

ACTRN12620000499987.

Investigating the impact of an AI-based play activities intervention on the quality of life of school-aged children with ADHD

BACKGROUND

Attention-Deficit/Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental disorder that not only impacts children's behavior, learning, and social interactions but also their quality of life. Advances in artificial intelligence (AI) may provide new opportunities to improve the ADHD symptoms and quality of life of children with ADHD, especially through customized play activities that address their specific needs.

AIMS

This study examined the impact of AI-based play activities on the quality of life of 61 Saudi children aged between 8 and 12 years who had an ADHD diagnosis.

METHODS

AI-based play activities intervention consisted of twelve 45-minute sessions, delivered to the experimental group over four weeks (three sessions per week). The control group did not receive any intervention. Children and parents completed the Pediatric Quality of Life Inventory (PedsQL) at pre-test, post-test and follow-up.

RESULTS AND OUTCOMES

The experimental group exhibited significant improvements in all dimensions and total scores of PedsQL, with moderate to large effect sizes. These improvements were not observed in the control group. The beneficial effects of the AI-based play activities were maintained at the 7-weeks follow-up.

CONCLUSIONS

AI-based play interventions may enhance quality of life for children with ADHD, with sustained improvements observed after 7-weeks. Incorporating such interventions into educational and therapeutic settings could improve behavioral, social, and cognitive ADHD symptoms. Future research should explore broader applications and long-term effects of AI-based play activities interventions.

Amphetamine and methylphenidate potential on the recovery from stroke and traumatic brain injury: a review

The prevalence of stroke and traumatic brain injury is increasing worldwide. However, current treatments do not fully cure or stop their progression, acting mostly on symptoms. Amphetamine and methylphenidate are stimulants already approved for attention deficit hyperactivity disorder and narcolepsy treatment, with neuroprotective potential and benefits when used in appropriate doses. This review aimed to summarize pre-clinical and clinical trials testing either amphetamine or methylphenidate for the treatment of stroke and traumatic brain injury. We used PubMed as a database and included the following keywords ((methylphenidate) OR (Ritalin) OR (Concerta) OR (Biphentin) OR (amphetamine) OR (Adderall)) AND ((stroke) OR (brain injury) OR (neuroplasticity)). Overall, studies provided inconsistent results regarding cognitive and motor function. Neurite outgrowth, synaptic proteins, dendritic complexity, and synaptic plasticity increases were reported in pre-clinical studies along with function improvement. Clinical trials have demonstrated that, depending on the brain region, there is an increase in motor activity, attention, and memory due to the stimulation of the functionally depressed catecholamine system and the activation of neuronal remodeling proteins. Nevertheless, more clinical trials and pre-clinical studies are needed to understand the drugs' full potential for their use in these brain diseases namely, to ascertain the treatment time window, ideal dosage, long-term effects, and mechanisms, while avoiding their addictive potential.

Molecular Docking, Bioinformatic Analysis, and Experimental Verification for the Effect of Naringin on ADHD: Possible Inhibition of GSK-3β and HSP90

Background/Objectives: One of the most abundant and growing neurodevelopmental disorders in recent decades is attention deficit hyperactivity disorder (ADHD). Many trials have been performed on using drugs for the improvement of ADHD signs. This study aimed to detect the possible interaction of naringin with Wnt/β-catenin signaling and its putative anti-inflammatory and protective effects in the mouse ADHD model based on bioinformatic, behavioral, and molecular investigations. Furthermore, molecular docking was applied to investigate possible interactions with the GSK-3β and HSP90 proteins. Methods: Male Swiss albino mice were divided into four groups, a normal control group, monosodium glutamate (SGL) control, SGL + naringin 50 mg/kg, and SGL + naringin 100 mg/kg. The psychomotor activity of the mice was assessed using the self-grooming test, rope crawling test, and attentional set-shifting task (ASST). In addition, biochemical analyses were performed using brain samples. Results: The results of the SGL group showed prolonged grooming time (2.47-folds), a lower percentage of mice with successful crawling on the rope (only 16.6%), and a higher number of trials for compound discrimination testing in the ASST (12.83 ± 2.04 trials versus 5.5 ± 1.88 trials in the normal group). Treatment with naringin (50 or 100 mg per kg) produced significant shortening in the grooming time (31% and 27% reductions), as well as a higher percentage of mice succeeding in crawling with the rope (50% and 83%, respectively). Moreover, the ELISA assays indicated decreased dopamine levels (0.36-fold) and increased TNF-α (2.85-fold) in the SGL control group compared to the normal mice, but an improvement in dopamine level was observed in the naringin (50 or 100 mg per kg)-treated groups (1.58-fold and 1.97-fold). Similarly, the PCR test showed significant declines in the expression of the Wnt (0.36), and β-catenin (0.33) genes, but increased caspase-3 (3.54-fold) and BAX (5.36-fold) genes in the SGL group; all these parameters were improved in the naringin 50 or 100 mg/kg groups. Furthermore, molecular docking indicated possible inhibition for HSP90 and GSK-3β. Conclusions: Overall, we can conclude that naringin is a promising agent for alleviating ADHD symptoms, and further investigations are required to elucidate its mechanism of action.

ADHD and Risk of Precocious Puberty: Considering the Impact of MPH

BACKGROUND/OBJECTIVES

The complex association between attention-deficit/hyperactivity disorder (ADHD) and methylphenidate (MPH) with precocious puberty (PP) is still unclear. This study aims to investigate the association between ADHD, MPH, and PP.

METHODS

This is a nationwide cohort study including a total of 3,342,077 individuals, 186,681 with ADHD and 3,155,396 without. First, we compared the risk of PP between ADHD cases and non-ADHD cases. Second, we compared the risk of PP between MPH users and non-MPH users in patients with ADHD.

RESULTS

Patients with ADHD were at a greater risk of PP (adjusted hazard ratio [aHR], 2.01 [95% CI, 1.91-2.11]). In our moderation analyses, the female gender was a positive additive effect modifier of the association between ADHD and PP, whereas tics and intellectual disability were negative effect modifiers. In patients with ADHD, MPH users had a significantly lower risk of PP (aHR, 0.63 [95% CI 0.57-0.70]), and females had a negative effect modification on the association between MPH and PP.

CONCLUSIONS

Our study found that children with ADHD were at a greater risk of PP. Girls with ADHD were a group particularly vulnerable to PP. Comorbid tics or intellectual disability was associated with a lower risk of PP. Among patients with ADHD, MPH was protective against PP, especially in girls. However, these preliminary results need further validation due to the nature of them being from an electronic database study. Unmeasured confounding factors might affect the association between MPH and PP.