Methylphenidate significantly improves neurocognitive impairments in children with ADHD

Differentiating pure cognitive disengagement syndrome and attention-deficit/hyperactivity disorder-restrictive inattentive presentation with respect to depressive symptoms, autistic traits, and neurocognitive profiles

This study aimed to differentiate "pure" cognitive disengagement syndrome (CDS) from attention-deficit/hyperactivity disorder-restrictive inattentive presentation (ADHD-RI) by examining their neurocognitive profiles and associations with autistic traits (ATs) and depressive symptoms. A cross-sectional study was conducted involving three groups: pure CDS (n = 24), ADHD-RI (n = 32), and controls (n = 31). Participants underwent neuropsychological assessments using Computerized Neurocognitive Assessment Software (CNS) Vital Signs, alongside evaluations for ATs with the Autism Spectrum Screening Questionnaire, depressive symptoms with the Children's Depression Inventory, and CDS symptoms with the Barkley Child Attention Scale. A semi-structured interview was also conducted with all participants and their parents to ensure the diagnostic validity of the groups. Findings indicated no dimensional symptomatological distinctions between CDS and ADHD-RI, except for CDS symptoms, and demonstrated no significant differences in neurocognitive test profiles between CDS and ADHD-RI, except for the neurocognition index and reaction time. ATs and depressive symptoms did not significantly differ between the pure CDS and ADHD-RI groups but were significantly elevated in both groups compared to controls. The ADHD-RI group exhibited significantly worse performance than CDS concerning the neurocognition index and reaction time, and worse than controls regarding the neurocognition index, reaction time, psychomotor speed, and complex attention. This study elucidates that ADHD-RI and "pure" CDS have substantially overlapping neurocognitive and phenotypic profiles despite certain minor differences, which is detrimental to subjects with ADHD-RI in terms of overall neurocognition and reaction time. It can be argued that, compared to "pure" CDS, executive dysfunction might be slightly more specific to ADHD-RI, while depressive symptoms and ATs are common in both psychological constructs.

Methylphenidate differentially alters corticostriatal connectivity after traumatic brain injury

Traumatic brain injury commonly impairs attention and executive function and disrupts the large-scale brain networks that support these cognitive functions. Abnormalities of functional connectivity are seen in corticostriatal networks, which are associated with executive dysfunction and damage to neuromodulatory catecholaminergic systems caused by head injury. Methylphenidate, a stimulant medication that increases extracellular dopamine and noradrenaline, can improve cognitive function following traumatic brain injury. In this experimental medicine add-on study to a randomized, double-blind, placebo-controlled clinical trial, we test whether administration of methylphenidate alters corticostriatal network function and influences drug response. Forty-three moderate-severe traumatic brain injury patients received 0.3 mg/kg of methylphenidate or placebo twice a day in 2-week blocks. Twenty-eight patients were included in the neuropsychological and functional imaging analysis (four females, mean age 40.9 ± 12.7 years, range 20-65 years) and underwent functional MRI and neuropsychological assessment after each block. 123I-Ioflupane single-photon emission computed tomography dopamine transporter scans were performed, and specific binding ratios were extracted from caudate subdivisions. Functional connectivity and the relationship to cognition were compared between drug and placebo conditions. Methylphenidate increased caudate to anterior cingulate cortex functional connectivity compared with placebo and decreased connectivity from the caudate to the default mode network. Connectivity within the default mode network was also decreased by methylphenidate administration, and there was a significant relationship between caudate functional connectivity and dopamine transporter binding during methylphenidate administration. Methylphenidate significantly improved executive function in traumatic brain injury patients, and this was associated with alterations in the relationship between executive function and right anterior caudate functional connectivity. Functional connectivity is strengthened to brain regions, including the anterior cingulate, that are activated when attention is focused externally. These results show that methylphenidate alters caudate interactions with cortical brain networks involved in executive control. In contrast, caudate functional connectivity reduces to default mode network regions involved in internally focused attention and that deactivate during tasks that require externally focused attention. These results suggest that the beneficial cognitive effects of methylphenidate might be mediated through its impact on the caudate. Methylphenidate differentially influences how the caudate interacts with large-scale functional brain networks that exhibit co-ordinated but distinct patterns of activity required for attentionally demanding tasks.

The relationships of neuropsychological factors and loneliness preference in children with attention deficit hyperactivity disorder and cognitive disengagement syndrome

This study aimed to examine emotion dysregulation and internalizing disorders mediating the relationship between selective and sustained attention and loneliness preference in children diagnosed with attention deficit hyperactivity disorder (ADHD) and Cognitive Disengagement Syndrome (CDS). This study included 176 children and adolescents between ages 8 and 12. The solitude scale for children, Difficulties in Emotion Regulation Scale, Child Behavior Checklist, Barkley Sluggish Cognitive Tempo Scale, and CNS Vital Signs test were used. The results suggest that difficulties in emotion regulation and having an internalizing disorder had a mediating effect between difficulties in selective attention and preference for the loneliness of children with ADHD + CDS. Also, it was likely that the association between sustained attention and preference for loneliness is mediated by internalizing disorders. The results suggest that the social problems commonly exhibited by children with ADHD + CDS may be related to deficits in sustained and selective attention.

Commentary: Using QbTest for monitoring pharmacological treatment response in ADHD - are we there yet?

Individuals with attention-deficit/hyperactivity disorder (ADHD) exhibit varied responses to pharmacological treatments (e.g. stimulants and non-stimulants). Accurately and promptly detecting treatment-related improvements, response failure, or deterioration poses significant challenges, as current monitoring primarily relies on subjective ratings. In this commentary, we critically evaluate the evidence supporting the use of QbTest for objectively monitoring ADHD treatment response in clinical practice. We also offer recommendations for future research, advocating for rigorous clinical trials and longitudinal studies to further explore the potential utilisation of QbTest and other tools for monitoring treatment responses in individuals with ADHD.

Role of adenosine in the pathophysiology and treatment of attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a complex neurodevelopmental condition characterized by persistent inattention, hyperactivity, and impulsivity. Although its precise etiology remains unclear, current evidence suggests that dysregulation within the neurotransmitter system plays a key role in the pathogenesis of ADHD. Adenosine, an endogenous nucleoside widely distributed throughout the body, modulates various physiological processes, including neurotransmitter release, sleep regulation, and cognitive functions through its receptors. This review critically examines the role of the adenosine system in ADHD, focusing on the links between adenosine receptor function and ADHD-related symptoms. Additionally, it explores how adenosine interacts with dopamine and other neurotransmitter pathways, shedding light on its involvement in ADHD pathophysiology. This review aims to provide insights into the potential therapeutic implications of targeting the adenosine system for ADHD management.

The Comparison of Psychological Factors and Executive Functions of Children with Attention Deficit Hyperactivity Disorder and Cognitive Disengagement Syndrome to ADHD and ADHD Comorbid with Oppositional Defiant Disorder

OBJECTIVE

The study aims to examine family functionality, emotion regulation difficulties, preference for loneliness, social exclusion, internalizing and externalizing disorders, and executive functions in children with Attention Deficit Hyperactivity Disorder (ADHD) and Cognitive Disengagement Syndrome (CDS) and compare with ADHD, and ADHD+ Oppositional Defiant Disorder (ODD).

METHOD

This study included 842 children aged 8-12 years. The subjects were categorized according to DSM-V as ADHD (n = 246), ADHD + ODD (n = 212), ADHD + CDS (n = 176), and Control group (n = 207). The solitude and social exclusion, difficulties in emotion dysregulation and Barkley SCT scales, Child Behavior Checklist, family assessment device, and Central Vital Signs (CNSVS) test were used.

RESULTS

According to the study, children with ADHD + CDS had higher rates of internalizing disorders. They also preferred being alone and experienced more difficulty communicating with their parents and solving problems within the family. Additionally, these children had difficulty recognizing and understanding the emotional reactions of others. The ADHD + ODD group presented a poorer performance on CNSVS domain tests except for the psychomotor speed test than other groups. Also, ADHD + CDS children had the lowest psychomotor speed scores and lower scores on reaction time and cognitive flexibility than pure ADHD children.

CONCLUSION

This study will contribute to the etiology, treatment, and clinical discrimination of ADHD + CDS.

Assessing the mediating relationships between psychological factors in children with attention deficit hyperactivity disorder and cognitive disengagement syndrome

This study aims to investigate the predictive and mediating relationships between emotion dysregulation, internalizing disorders, family functionality, loneliness preference, and executive functions (EF) in children with attention deficit hyperactivity disorder and cognitive disengagement syndrome (ADHD + CDS). This study included 176 children and adolescents (92 boys, 84 girls) who were diagnosed with ADHD + CDS according to the Diagnostic and Statistical Manual of Mental Disorders, the Fifth Edition criteria by a fellowship-trained child and adolescent psychiatrist, between ages 8 -12 (M = 10, SD = 1.52) with a convenience sampling method. The solitude scale for children, difficulties in emotion dysregulation scale, Child Behavior Checklist, Barkley Sluggish Cognitive Tempo Scale, Family assessment device, and CNS Vital Signs test were used. The results showed that difficulty in emotion regulation, preference for loneliness, internalizing disorders and CDS symptom severity did not have a mediating effect between family functionality and EF. Still, emotion dysregulation mediates the relationship between EF and internalizing disorders by itself and through loneliness preference. Also, preference for loneliness and emotion dysregulation had a mediating effect between family functionality and internalizing disorders. Finally, it was found that the effect of emotion regulation difficulty, loneliness preference, and internalizing disorders had a mediating role between CDS symptom severity and family functionality. In conclusion, the information obtained from this study on the etiology of CDS may guide future studies.

Investigating the effects of age, IQ, dosing, and anthropometric measures on the treatment persistence in long-term methylphenidate use

OBJECTIVES

This study aimed to determine anthropometric and clinical correlates of persistence to methylphenidate (MPH) treatment in Turkish youth with attention-deficit hyperactivity disorder (ADHD).

METHODS

Data from medical records of 518 children and adolescents with ADHD were recorded between March 2012 and January 2022. Clinical variables of patients persistent to MPH ≥ 2 years were compared with those of the non-persistent group. Children and adolescent age groups were compared using Kaplan-Meier estimates for treatment drop-outs. Cox regression analysis until the treatment drop-out was implemented to calculate hazard ratios (HRs) for gender, age, full-scale IQ, and anthropometric measures. Weight, height, and body mass index (BMI) z-scores were calculated per national guidelines.

RESULTS

Persistent and non-persistent study groups had similar full-scale IQ, weight, height, and BMI z-scores at treatment onset. The mean MPH dose was significantly higher in the persistent group compared to the non-persistent counterparts (31.43 ± 10.70 vs. 24.28 ± 9.60 mg/d, p < 0.001, d = 0.70). Compared to children, the adolescents showed earlier treatment drop-outs in males (p < 0.001) but not in females (p = 0.110). Younger age showed a positive effect on treatment persistence. Conversely, baseline BMI and IQ scores were not associated with long-term persistence.

DISCUSSION

Our study demonstrated lower daily doses and older age-onset were associated with early drop-outs in MPH treatment. These findings supported the notion that effective dosing strategies at younger ages could increase the sustainability of the treatment with MPH in the Turkish population.