Neuroinflammation as a possible link between attention-deficit/hyperactivity disorder (ADHD) and pain

Abscisic Acid Rescues Behavior in Adult Female Mice in Attention Deficit Disorder with Hyperactivity Model of Dopamine Depletion by Regulating Microglia and Increasing Vesicular GABA Transporter Expression

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental syndrome typically diagnosed in childhood that may persist into adulthood. Its etiology encompasses both genetic and environmental factors, with genetic studies indicating catecholamine dysfunction and epidemiological evidence emphasizing neuroinflammation as a potential trigger. To investigate the roles of inflammation and development processes in ADHD, we conducted a longitudinal behavioral study using female Swiss mice with a dopamine deficit model. We explored the impact of neonatal dopaminergic lesions, treatment with abscisic acid (ABA)-an anti-inflammatory hormone-and developmental changes by comparing behavioral patterns in juvenile and adult mice. Postmortem analyses assessed neuroinflammation through microglial morphology, NLRP3, cytokine expression, and the excitatory/inhibitory (E/I) ratio in specific brain regions. Neonatal dopaminergic lesions induced hyperactivity and hypersensitivity in juvenile mice that persisted into adulthood. In adults, increased social interaction and memory impairment were observed in lesioned mice. Brain development mitigated impulsivity, while ABA treatment reduced locomotor activity, downregulated pain sensitivity, and influenced social interaction, although it did not completely resolve cognitive deficits in lesioned adult mice. In brain regions such as the anterior cingulate cortex (ACC), posterior insular cortex (pIC), and hippocampus, lesions significantly altered microglial morphology. In the ACC, lesions increased IL-1β and TNFα levels, decreased Arg1 mRNA levels, and disrupted the E/I balance. Importantly, ABA treatment restored microglial morphology, normalized IL-1β and Arg1 expression and upregulated vGAT levels. This study demonstrates that dopamine deficits lead to microglia alterations and E/I imbalance, contributing to ADHD symptoms. While some symptoms improve with brain development, targeting microglial health in specific brain regions emerges as a promising therapeutic approach for managing ADHD.

Prone to Stones?: Evaluating the association between food insecurity, psychiatric comorbidity, and pediatric stone management

INTRODUCTION

Pediatric stone disease incidence has increased steadily over the last few decades. Several interrelated factors have been proposed to contribute to these epidemiologic trends including increased ambient temperature, body habitus, and food insecurity.

OBJECTIVE

Given the significant cohort of children living with food insecurity in the United States, the aim of this study is to explore the relationship between food desert residence and obstructing stone disease resulting in surgical intervention in a cohort of pediatric patients.

STUDY DESIGN

Records of pediatric patients who presented to a single tertiary pediatric medical center for urolithiasis between 2009 and 2023 were retrospectively reviewed. Patients were included in the study if they had an obstructing stone; were older than 5 years of age; lacked anatomical predispositions to stone formation; and were regularly consuming a solid diet. Variables studied included demographics, BMI, medical comorbidities and family history, procedures performed, and stone burden. Patients' likelihood of living in a food desert was approximated using the United States Department of Agriculture Food Access Research Atlas.

RESULTS

Of 637 patients reviewed, 199 pediatric patients (90 male and 109 female) were included in our analysis. One hundred and thirty patients (65.3%) had undergone ureteroscopy. Fifty-seven patients (28.6%) had a documented psychiatric comorbidity at time of presentation, with ADHD being the most common psychiatric comorbidity treated via medical management (n = 25, 43.9%). Our analysis demonstrated a significant association between surgical intervention, food desert residence (p = 0.003), and increased stone size (p = 0.001). Additionally, increased time between discharge on medical expulsive therapy and surgery decision was associated with past medical history of stones (p = 0.033) and food desert residence while undergoing stimulant treatment for ADHD (p < 0.001).

CONCLUSION

In this study, we found a significant association between food desert residence and obstructing pediatric stone disease resulting in surgical intervention. We also discuss a potential new association with pediatric stone disease: psychiatric comorbidity and the medical management of such diagnoses. To our knowledge, our study is among the first to assess the association between food insecurity and surgical intervention of pediatric urolithiasis. Given the importance diet plays in medical management of stone development, clinicians should take care to assess food security status of pediatric urolithiasis patients. Limitations to our study include a patient cohort from a singular hospital system, small sample size, and the changing nature of a patients' food security status.

Somatic comorbidities and health related uncertainty among Swedish adolescents with ADHD

Introduction

Attention-deficit/hyperactivity disorder (ADHD) frequently exists alongside psychiatric comorbidities. The coexistence of somatic diseases and ADHD constitutes a growing field of research.

Method

This study aimed to examine the prevalence of common somatic diseases in adolescents with ADHD and compare them with those in adolescents without any psychiatric diagnoses. A cross-sectional study was conducted among a convenient sample of Swedish upper secondary school students aged 15 to 19 years. Data were collected using an electronic version of the "Mental and Somatic Health without borders" survey. In 2020, 1608 adolescents completed the survey and provided self-reports of their psychiatric and somatic diagnoses.

Results

Among the sample of Swedish adolescents, 5.5% reported having ADHD diagnoses. These adolescents reported more somatic comorbidities than those without any psychiatric diagnosis (comparison group). The most common somatic comorbidities among those with ADHD were allergies (43.4%), asthma (24.7%), and skin diseases (16.7%), which prevalences were significantly higher than those reported by adolescents in the comparison group. However the effect sizes of these differences were negligible (allergies: p=0.002, Cramer's V=0.08; asthma: p=0.041, Cramer's V=0.06; skin diseases: p=0.007, Cramer's V=0.08), raising questions about the practical implications of these findings. Allergies were significantly more common in both genders with ADHD (p=0.038, Cramer's V=0.08 in women and p=0.038, Cramer's V=0.09 in men). Additionally, men with ADHD showed a significant association with skin diseases (p=0.007, Cramer's V=0.12) while women with ADHD were significantly more likely to have migraine (p=0.038, Cramer's V=0.08). Notably, adolescents with ADHD reported significantly higher rates of uncertainty regarding the existence of diabetes, rheumatoid diseases, asthma (with negligible effect sizes), and thyroid diseases (with a small effect size) than those without any psychiatric diagnoses, suggesting heightened health related anxiety within this group.

Conclusions

Adolescents with ADHD reported more somatic comorbidities and greater uncertainty about the potential presence of additional somatic conditions compared to adolescents without psychiatric diagnoses. These findings highlight the importance of addressing both health literacy and access to healthcare. By focusing on this group, we cannot only improve their ability to understand and navigate the healthcare system but also strengthen their confidence in managing their own health.

Parental Perspectives on Eating Disorders of Their School-Age Children with ADHD in Hong Kong: A Qualitative Study

Background: Children with attention deficit hyperactivity disorder (ADHD) frequently encounter eating problems. However, qualitative research on the eating problems of these children and the strategies employed by their parents to manage these issues remains limited. This study aimed to explore the eating problems of school-age children with ADHD and the coping strategies used by parents in urban settings like Hong Kong. Methods: A descriptive qualitative design was utilized, employing semi-structured focus group interviews. Purposive sampling was used to recruit 12 parents who voluntarily participated in five focus group sessions. The interviews were conducted in Cantonese, audio-recorded, and transcribed verbatim. Data were analyzed using template thematic analysis to identify key themes and subthemes. Results: Two major themes emerged: challenges affecting ADHD children's eating behaviors and parental coping strategies in Hong Kong. Children's eating difficulties stemmed from ADHD-specific behaviors, compounded by Hong Kong's demanding educational system and urban environmental constraints. In response, parents developed multifaceted coping approaches, ranging from dietary modifications and behavioral management strategies to healthcare resource utilization, while adapting their urban lifestyle to accommodate their children's needs. Conclusions: Children with ADHD face eating challenges that intersect with Hong Kong's sociocultural environment, where educational pressure, limited living spaces, and parents' work schedules influence their eating patterns. Parents adopt integrated Eastern-Western approaches, supported by Hong Kong's comprehensive healthcare resources spanning professional networks and community programs. Evidence-based dietary guidelines are essential to address ADHD-related nutritional misconceptions.

Neurovascular dysfunction in psychiatric disorders: Underlying mechanisms and therapeutic approaches

BACKGROUND

Neurovascular interfaces, specifically the blood-brain barrier (BBB) and blood-retinal barrier (BRB), play pivotal roles in maintaining the homeostasis of the central nervous system (CNS). For a long time, these structures were seen only as a way of protection, but we currently know that they have a critical role in CNS (dys)function. Several studies have identified neurovascular alterations in early stages of brain and eye diseases, contributing to the pathophysiology of such conditions. More recently, interesting data have also highlighted the importance of neurovasculature in psychiatric disorders.

METHODS

Using the PubMed database, we brought together the evidence concerning the changes in BBB and BRB under psychiatric conditions, with a focus on anxiety, major depressive disorder (MDD), attention-deficit/hyperactivity disorder (ADHD) and drug abuse, specifically related with methamphetamine (METH) and cocaine consumption.

RESULTS

We summarized the main findings obtained from in vitro and animal studies, as well as clinical research that has been undertaken to identify neurovascular abnormalities upon such neuropsychiatric disorders. The drivers of barrier alterations were examined, namely the role of neuroinflammation, while reporting putative barrier-associated biomarkers of these disorders.

CONCLUSION

This review underscores the critical need for a deeper understanding of BBB and BRB function in neuropsychiatric conditions and their potential as therapeutic targets while elucidating the key players involved. The innovative approaches to managing these complex disorders are also addressed while bridging the gap concerning what is currently known regarding the association between neuropsychiatric conditions and their vascular implications.

Frequent Pain is Common Among 10-11-Year-Old Children with Symptoms of Attention Deficit Hyperactivity Disorder

Purpose

Adults with neurodevelopmental disorders have an increased risk for chronic pain. This study aimed to describe the prevalence of frequent and multisite pain among children with symptoms of attention deficit hyperactivity disorder (ADHD) and explore potential sex differences in pain prevalence.

Participants and Methods

Children born in 2008 included in the "Halland Health and Growth Study" were invited to a follow-up (n = 1186) in 2018-19. Parents received a digital screening questionnaire, the Swanson, Nolan and Pelham Rating Scale (SNAP-IV) for ADHD, and the children answered a pain questionnaire that included a pain mannequin. The main outcome was pain experience, and children with symptoms of ADHD were compared to children without these symptoms.

Results

In this general population of 10-11-year-old Swedish children, weekly pain was reported in 52.5% of children with symptoms of ADHD combined type, compared to 36.2% of children without these symptoms (p < 0.05). Hyperactivity and impulsivity were significant contributors to the increased risk for frequent pain (OR 2.33 95% CI 1.30 to 4.17, p = 0.004), but inattention was not a significant contributor (OR 1.17 95% CI 0.74 to 1.87, p = 0.497). Multisite pain was more common among girls with hyperactivity compared to boys with hyperactivity (51.4 vs 27.9%, p = 0.036). Weekly headache and/or abdominal pain was reported by a quarter of girls with symptoms of ADHD combined type, and up to a fifth of boys, compared to 11-13% of children without these symptoms.

Conclusion

Frequent pain was more common for children with symptoms of ADHD compared to children without symptoms of ADHD. Hyperactivity and impulsivity had a stronger association to pain than had inattention-related problems. Clinicians should be aware of the frequent occurrence and the association between pain and neurodevelopmental disorders among children, and that it could complicate both the clinical picture and the treatment.

Pain-Associated Diagnoses in Childhood Before the Diagnosis of Attention-Deficit/Hyperactivity Disorder: A Population-Based Study

Background: Pediatric pain significantly affects children's lives, leading to school absenteeism, impaired social interactions, and psychological distress. The perception of sensory signals as pain is influenced by the brain's noradrenergic system, and recent evidence suggests that chronic pain may impact cognitive functioning and emotional regulation. Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with alterations in the dopaminergic/noradrenergic systems, which could affect pain perception. Pain-associated conditions and frequent analgesic use in childhood may be linked to ADHD development and could serve as early indicators, yet data on this potential association remain limited. Study Aim: This population-based case-control study in Israel aimed to assess the prevalence of pain-related diagnoses prior to ADHD diagnosis in children aged 5 to 18. The study included children registered with Leumit Health Services (LHS) between 1 January 2006, and 30 June 2021. Children diagnosed with ADHD were compared to matched controls, selected based on age, gender, socioeconomic status, and other sociodemographic factors, who were never diagnosed with ADHD during the study period. Results: Children with ADHD (N = 18,756) and controls (N = 37,512) were precisely matched for sociodemographic characteristics. Individuals with ADHD exhibited significantly higher frequencies of diverse pain conditions, including those associated with illness [headache, earaches, and throat pain (odds ratios [OR] = 1.156 [95%CI 1.085, 1.232], 1.295 [95%CI 1.217, 1.377], and 1.080 [95%CI 1.019, 1.145], respectively; p < 0.01)] and injury [sprains and strains (OR = 1.233 [95% CI 1.104,1.376)]. Analgesics were more frequently purchased by individuals with ADHD, particularly paracetamol (OR = 1.194 [95%CI 1.152, 1.237], p < 0.001) and ibuprofen (OR = 1.366 [95%CI 1.318, 1.416], p = 0.001). Conclusions: This study highlights a potential connection between ADHD and pediatric pain. The elevated rates of pain diagnoses and analgesic usage among children with ADHD underscore the need for further research.

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.

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.

Fascia as a regulatory system in health and disease

Neurology and connective tissue are intimately interdependent systems and are critical in regulating many of the body's systems. Unlocking their multifaceted relationship can transform clinical understanding of the mechanisms involved in multisystemic regulation and dysregulation. The fascial system is highly innervated and rich with blood vessels, lymphatics, and hormonal and neurotransmitter receptors. Given its ubiquity, fascia may serve as a "watchman," receiving and processing information on whole body health. This paper reviews what constitutes fascia, why it is clinically important, and its contiguous and interdependent relationship with the nervous system. Unquestionably, fascial integrity is paramount to human locomotion, interaction with our environment, bodily sense, and general physical and emotional wellbeing, so an understanding of the fascial dysregulation that defines a range of pathological states, including hypermobility syndromes, autonomic dysregulation, mast cell activation, and acquired connective tissue disorders is critical in ensuring recognition, research, and appropriate management of these conditions, to the satisfaction of the patient as well as the treating practitioner.

Childhood neurodivergent traits, inflammation and chronic disabling fatigue in adolescence: a longitudinal case-control study

OBJECTIVES

To test whether inflammatory processes link the expression of childhood neurodivergent traits to chronic disabling fatigue in adolescence.

DESIGN

Longitudinal case-control study.

SETTING

We analysed data from The Avon Longitudinal Study of Parents and Children (ALSPAC).

PARTICIPANTS

8115 and 8036 children of the ALSPAC cohort at ages 7 and 9 years, respectively, 4563 of whom also completed self-report measures at age 18 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

We assessed if children scoring above screening threshold for autism/attention deficit hyperactivity disorder (ADHD) at ages 7 and 9 years had increased risk of chronic disabling fatigue at age 18 years, computing ORs and CIs for effects using binary logistic regression. Mediation analyses were conducted to test if an inflammatory marker (interleukin 6 (IL-6)) at age 9 years linked neurodivergent traits to chronic disabling fatigue at age 18 years.

RESULTS

Children with neurodivergent traits at ages 7 and 9 years were two times as likely to experience chronic disabling fatigue at age 18 years (likely ADHD OR=2.18 (95% CI=1.33 to 3.56); p=0.002; likely autism OR=1.78 (95% CI=1.17 to 2.72); p=0.004). Levels of IL-6 at age 9 were associated with chronic disabling fatigue at age 18 (OR=1.54 (95% CI=1.13 to 2.11); p=0.006). Inflammation at age 9 years mediated effects of neurodivergent traits on chronic disabling fatigue (indirect effect via IL-6: ADHD b=1.08 (95% CI=1.01 to 1.15); autism b=1.06; (95% CI=1.03 to 1.10)). All effects remained significant when controlling for the presence of depressive symptoms.

CONCLUSIONS

Our results indicate higher risk of chronic disabling fatigue for children with neurodivergent traits, likely linked to higher levels of inflammation. The implementation of transdiagnostic screening criteria to inform support strategies to counteract risk early in life is recommended.

Prevalence of chronic and multisite pain in adolescents and young adults with ADHD: a comparative study between clinical and general population samples (the HUNT study)

Attention-deficit/hyperactivity disorder (ADHD) and chronic pain are prevalent and associated. We examined the prevalence and distribution of chronic pain in adolescents and young adults with ADHD using 9-years longitudinal data (from T1:2009-2011 to T3:2018-2019) with three time points from a clinical health survey compared to two age-matched reference population-based samples. Mixed-effect logistic regression and binary linear regression were used to estimate the probability for chronic and multisite pain at each time point and to compare the prevalence of chronic pain with the reference populations. The prevalence of chronic and multisite pain was high in those with ADHD, especially in female young adults, with highly prevalent chronic pain at 9 years of follow-up (75.9%) compared to 45.7% in females in the reference population. The probability of having pain was only statistically significant for chronic pain in males at 3 years of follow-up (41.9%, p = 0.021). Those with ADHD were at higher risk of reporting single-site and multisite pain compared to the general population at all measurement points. Longitudinal studies should be tailored to further understand the complex sex differences of comorbid chronic pain and ADHD in adolescents, exploring predictive factors of pain assessing long-term associations with bodyweight, psychiatric comorbidities, and possible mechanisms of stimulant use effects on pain.

Safety and efficacy of antioxidant therapy in children and adolescents with attention deficit hyperactivity disorder: A systematic review and network meta-analysis

OBJECTIVE

To systematically evaluate the safety and efficacy of antioxidant therapy in children and adolescents with attention deficit hyperactivity disorder (ADHD).

METHODS

Randomized controlled trials and prospective studies on antioxidant therapy in children and adolescents with ADHD were searched in PubMed, Embase, and Cochrane Library from the inception of databases to November 12, 2022. Two investigators independently screened the literature, extracted data, and evaluated the quality of the included studies. Network meta-analysis (PROSPERO registration number CRD 42023382824) was carried out by using R Studio 4.2.1.

RESULTS

48 studies involving 12 antioxidant drugs (resveratrol, pycnogenol, omega-3, omega-6, quercetin, phosphatidylserine, almond, vitamin D, zinc, folic acid, ginkgo biloba, Acetyl-L-carnitine) were finally included, with 3,650 patients. Network meta-analysis showed that omega-6 (0.18), vitamin D (0.19), and quercetin (0.24) were the top three safest drugs according to SUCRA. The omega-3 (SUCRA 0.35), pycnogenol (SUCRA 0.36), and vitamin D (SUCRA 0.27) were the most effective in improving attention, hyperactivity, and total score of Conners' parent rating scale (CPRS), respectively. In terms of improving attention, hyperactivity, and total score of Conners' teacher rating scale (CTRS), pycnogenol (SUCRA 0.32), phosphatidylserine+omega-3 (SUCRA 0.26), and zinc (SUCRA 0.34) were the most effective, respectively. In terms of improving attention, hyperactivity and total score of ADHD Rating Scale-Parent, the optimal agents were phosphatidylserine (SUCRA 0.39), resveratrol+MPH (SUCRA 0.24), and phosphatidylserine (SUCRA 0.34), respectively. In terms of improving attention, hyperactivity and total score of ADHD Rating Scale-Teacher, pycnogenol (SUCRA 0.32), vitamin D (SUCRA 0.31) and vitamin D (SUCRA 0.18) were the optimal agents, respectively. The response rate of omega-3+6 was the highest in CGI (SUCRA 0.95) and CPT (SUCRA 0.42).

CONCLUSION

The rankings of safety and efficacy of the 12 antioxidants vary. Due to the low methodological quality of the included studies, the probability ranking cannot fully explain the clinical efficacy, and the results need to be interpreted with caution. More high-quality studies are still needed to verify our findings.

Complex interplay of neurodevelopmental disorders (NDDs), fractures, and osteoporosis: a mendelian randomization study

BACKGROUND

Neurodevelopmental disorders (NDDs), such as Attention-Deficit/Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD), and Tourette Syndrome (TS), have been extensively studied for their multifaceted impacts on social and emotional well-being. Recently, there has been growing interest in their potential relationship with fracture risks in adulthood. This study aims to explore the associations between these disorders and fracture rates, in order to facilitate better prevention and treatment.

METHODS

Employing a novel approach, this study utilized Mendelian randomization (MR) analysis to investigate the complex interplay between ADHD, ASD, TS, and fractures. The MR framework, leveraging extensive genomic datasets, facilitated a systematic examination of potential causal relationships and genetic predispositions.

RESULTS

The findings unveil intriguing bidirectional causal links between ADHD, ASD, and specific types of fractures. Notably, ADHD is identified as a risk factor for fractures, with pronounced associations in various anatomical regions, including the skull, trunk, and lower limbs. Conversely, individuals with specific fractures, notably those affecting the femur and lumbar spine, exhibit an increased genetic predisposition to ADHD and ASD. In this research, no correlation was found between TS and fractures, or osteoporosis.These results provide a genetic perspective on the complex relationships between NDDs and fractures, emphasizing the importance of early diagnosis, intervention, and a holistic approach to healthcare.

CONCLUSION

This research sheds new light on the intricate connections between NDDs and fractures, offering valuable insights into potential risk factors and causal links. The bidirectional causal relationships between ADHD, ASD, and specific fractures highlight the need for comprehensive clinical approaches that consider both NDDs and physical well-being.

Unraveling the Interplay of Dopamine, Carbon Monoxide, and Heme Oxygenase in Neuromodulation and Cognition

The dopaminergic system plays important roles in neuromodulation, including prominent roles in complex neurological functions such as cognition, reward, motivation, and memory. Understandably, the highly complex nature of such physiological functions means that their regulation is intertwined with other signaling pathways, as has been demonstrated by numerous studies. Contrary to its public perception of being poisonous at all concentrations, carbon monoxide (CO) is produced endogenously from heme degradation by heme oxygenase (HO) as part of the physiological process of red blood cell turnover. Physiological concentrations of CO can reach high micromolar ranges in the hemoglobin bound form. Low-dose CO has shown therapeutic effects in numerous animal models, including traumatic brain injury via engaging various hemoprotein targets. As such, the HO-CO axis has been shown to offer beneficial effects in organ protection, anti-inflammation, and neuroprotection, among many others. Further, a large number of publications have shown the interactions among CO, HO, and the dopaminergic system. In this review, we critically examine such experimental evidence in a holistic fashion and in the context of a possible dopamine-HO-CO signaling axis. We hope that this Perspective will stimulate additional investigations into the molecular connectivity related to this possible axis and open doors to the development of novel therapeutics that impact the dopaminergic system.

ADHD-pain: Characteristics of chronic pain and association with muscular dysregulation in adults with ADHD

OBJECTIVES

A high incidence of attention-deficit hyperactivity disorder (ADHD) has been reported in chronic pain (ChP) patients. Furthermore, an association between ChP and muscular dysregulation has been reported in adults with ADHD. The present study investigated whether ADHD was more prevalent among psychiatric outpatients with ChP than those without ChP, and if there was an association between ChP, muscular dysregulation and characteristics of pain in patients with ADHD.

METHODS

One-hundred and twenty-one individuals remitted to an outpatient psychiatry unit took part in this naturalistic epidemiological cross-sectional study. They were assessed with a pain self-report form (localization, intensity, and onset) and a test of muscle dysregulation (the Motor Function Neurological Assessment). Prevalence of ADHD among patients with ChP, as well as the qualitative characteristics of ChP within the ADHDgroup are reported. Both ChP and pain intensity correlated with muscular dysregulation through Spearman's rho analysis. Additionally, the relationship between various diagnostic categories (ADHD, affective disorders, anxiety, or personality disorders) and incidence of axial pain was evaluated in logistic regression.

RESULTS

ADHD was significantly more prevalent in patients with ChP, than in patients without ChP. In the ADHD group, ChP and pain intensity was associated with muscular dysregulation, particularly with high muscle tone. ChP was more axial and widespread, than for the patients without ADHD, and started at an early age. ADHD diagnosis predicted axial pain, whereas affective-, anxiety-, or personality disorders did not.

CONCLUSIONS

The study suggests that ChP in ADHD is associated with muscular dysregulation and is qualitatively different from ChP in psychiatric patients without ADHD. These findings may lead to further understanding of potential mechanisms involved in ADHD and ChP, and in turn to new treatment strategies for both disorders.

Armodafinil as a Potential Pharmacological Treatment for Attention Deficit Hyperactivity Disorder in Adults: A Review

INTRODUCTION

Armodafinil is a psychostimulant that promotes alertness, and it has been shown to improve attention, memory, and fatigue in healthy adults and adults with neurodevelopmental conditions that share symptoms with Attention Deficit Hyperactivity Disorder (ADHD). It is generally well tolerated and safe, and most of the adverse events reported are considered not serious. However, the available evidence on the efficacy of armodafinil for the treatment of ADHD in adults is scarce.

OBJECTIVE

The present review aims to perform a systematized search of the available evidence on the possible therapeutic benefit of armodafinil treatment in adult patients with ADHD.

METHODS

A literature review using PubMed was conducted to compile and summarize the available clinical and scientific evidence on the possible use of armodafinil as a pharmacological treatment in adult patients with ADHD.

RESULTS

From the 86 articles reviewed, the available evidence showed that both acute and chronic treatment with armodafinil can improve wakefulness, memory, impulse control, and executive functions in adults with sleep disorders and other conditions. In addition, evidence of improvement in cognitive functions and mood alterations in other neuropsychiatric conditions was shown.

CONCLUSION

Armodafinil could be useful for the treatment of ADHD in adults, according to the review of the literature from both pre-clinical and clinical studies.

A cholinergic circuit that relieves pain despite opioid tolerance

Chronic pain is a tremendous burden for afflicted individuals and society. Although opioids effectively relieve pain, significant adverse outcomes limit their utility and efficacy. To investigate alternate pain control mechanisms, we explored cholinergic signaling in the ventrolateral periaqueductal gray (vlPAG), a critical nexus for descending pain modulation. Biosensor assays revealed that pain states decreased acetylcholine release in vlPAG. Activation of cholinergic projections from the pedunculopontine tegmentum to vlPAG relieved pain, even in opioid-tolerant conditions, through ⍺7 nicotinic acetylcholine receptors (nAChRs). Activating ⍺7 nAChRs with agonists or stimulating endogenous acetylcholine inhibited vlPAG neuronal activity through Ca2+ and peroxisome proliferator-activated receptor α (PPAR⍺)-dependent signaling. In vivo 2-photon imaging revealed that chronic pain induces aberrant excitability of vlPAG neuronal ensembles and that ⍺7 nAChR-mediated inhibition of these cells relieves pain, even after opioid tolerance. Finally, pain relief through these cholinergic mechanisms was not associated with tolerance, reward, or withdrawal symptoms, highlighting its potential clinical relevance.

Dysmenorrhea and psychological wellbeing among females with attention deficit hyperactivity disorder

Although rarely examined together, ADHD, emotional regulation (ER), and dysmenorrhea may be associated, which could create additive burdens on psychological well-being (PWB). Clinicians working with ADHD populations may need to take these challenges into consideration to maximize treatment outcomes. This study investigated the relationships among ADHD, dysmenorrhea, ER, and PWB within a sample of 266 adult females with a self-reported ADHD diagnosis. ADHD symptom severity was positively correlated with dysmenorrhea severity, but ER skills were not a significant moderator of this relationship. ADHD symptom severity was negatively correlated with PWB; however, this relationship was not moderated by dysmenorrhea severity nor ER ability. Overall, a positive association between ADHD symptom severity and dysmenorrhea severity was found in our sample. Further research is needed to understand the nature of this association, as well as factors that may contribute to PWB among individuals with these comorbid conditions.

Case report: Methylphenidate improved chronic pain in an adult patient with attention deficit hyperactivity disorder

Introduction

Chronic pain remains a health problem that is difficult to treat adequately. Its unknown cause and complex comorbidity with other illnesses, including mental disorders, amplify the severity of symptoms, which consequently decreases the quality of life of patients long term. In our clinical practice, we coincidentally found evidence that methylphenidate (MPH) effectively managed chronic pain in an adult patient with attention deficit hyperactivity disorder (ADHD). The effectiveness of MPH in the treatment of ADHD is well-established; however, its utility in treating pain remains unclear.

Case presentation

We present a rare case of a 43-year-old male patient with 15 years of chronic idiopathic pain symptoms that did not adequately respond to standard pain management, such as acetaminophen, non-opioid analgesics, and muscle relaxers. Pain also persisted after treatments with antidepressants and an epidural block. Furthermore, symptoms worsened following several sessions of modified electroconvulsive therapy. After a thorough assessment at our child and adolescent psychiatric outpatient clinic, we confirmed a diagnosis of adult ADHD with a predominantly inattentive type. Considering this newly established diagnosis, we prescribed osmotic-release oral system (OROS) methylphenidate. Within 1 month of treatment at a dose of 18 mg/day of OROS-MPH, the patient’s chronic pain unexpectedly improved dramatically, and the patient no longer experienced pain symptoms. The dosage of OROS-MPH was titrated monthly, reaching 72 mg/day as a maintenance dose, and ADHD symptoms improved after 4 months of treatment. The patient was followed up regularly for 7 years during his OROS-MPH treatment. No adverse effects were reported, including stimulant addiction. He was stable overall and functioned well in his daily activities. His pain never recurred.

Conclusion

This case report suggests that MPH may be potentially effective in treating chronic pain. Further studies are needed to confirm whether MPH improved chronic pain simultaneously with or separately from the improvement in ADHD. Moreover, elucidating the anatomical sites and molecular pharmacological mechanisms related to the action of MPH in pain modulation and perception is essential. Such sites include the descending dopaminergic pain pathway and higher cortical areas. Furthering our understanding may reinforce the justification for treating chronic pain using MPH.

Targeting Neuroinflammation with Abscisic Acid Reduces Pain Sensitivity in Females and Hyperactivity in Males of an ADHD Mice Model

Attention deficit/hyperactivity disorder (ADHD) is a neurodevelopmental syndrome characterized by dopaminergic dysfunction. In this study, we aimed to demonstrate that there is a link between dopaminergic deficit and neuroinflammation that underlies ADHD symptoms. We used a validated ADHD mice model involving perinatal 6-OHDA lesions. The animals received abscisic acid (ABA), an anti-inflammatory phytohormone, at a concentration of 20 mg/L (drinking water) for one month. We tested a battery of behavior tests, learning and memory, anxiety, social interactions, and pain thresholds in female and male mice (control and lesioned, with or without ABA treatment). Postmortem, we analyzed microglia morphology and Ape1 expression in specific brain areas related to the descending pain inhibitory pathway. In females, the dopaminergic deficit increased pain sensitivity but not hyperactivity. In contrast, males displayed hyperactivity but showed no increased pain sensitivity. In females, pain sensitivity was associated with inflammatory microglia and lower Ape1 levels in the anterior cingulate cortex (ACC) and posterior insula cortex (IC). In addition, ABA treatment alleviated pain sensitivity concomitant with reduced inflammation and normalized APE1. In males, ABA reduced hyperactivity but had no significant effect on inflammation in these areas. This is the first study proving a sex-dependent association between dopamine dysfunction and inflammation in specific brain areas, hence leading to different behavioral outcomes in a mouse model of ADHD. These findings provide new clues for potential treatments for ADHD.

Associations between Chronic Pain and Attention-Deficit Hyperactivity Disorder (ADHD) in Youth: A Scoping Review

Background: Chronic pain and ADHD are common conditions among youth that negatively impact functioning. This review fills a critical gap by summarizing current research on chronic pain and ADHD comorbidity, and it proposes a conceptual model of shared associations and underlying mechanisms. Objective: The aims of the current study were to: (1) review the extant literature and present estimates of the prevalence of comorbid non-headache chronic pain and ADHD in youth and (2) describe potential shared mechanisms for ADHD and chronic non-headache pain in youth. We also outline future directions to inform future research and interventions directed to youth with comorbid pain and ADHD. Design: A scoping review of the literature was performed in MEDLINE, PsycInfo, and Cochrane Database of Systematic Reviews using a wide range of search terms related to pain, Attention Deficit-Hyperactivity Disorder, childhood, adolescence, and young adulthood. Results: Eleven published studies were included in the review. These studies examined the prevalence of chronic pain among youth with ADHD, the prevalence of ADHD in chronic pain samples, and the association between chronic pain and ADHD among youth. Findings revealed results from studies indicating a higher prevalence of ADHD among youth with chronic pain and a higher prevalence of chronic pain in samples of youth with ADHD. Conclusions: Findings from this scoping review suggest an association between chronic pain and ADHD among youth. Little research was found to examine the etiology of this association. Future studies should examine underlying mechanisms of comorbid chronic pain and ADHD.

Chronic Pain and Psychiatric Conditions

Introduction

Chronic pain is a common condition with high socioeconomic and public health burden. A wide range of psychiatric conditions are often comorbid with chronic pain and chronic pain conditions, negatively impacting successful treatment of either condition. The psychiatric condition receiving most attention in the past with regard to chronic pain comorbidity has been major depressive disorder, despite the fact that many other psychiatric conditions also demonstrate epidemiological and genetic overlap with chronic pain. Further understanding potential mechanisms involved in psychiatric and chronic pain comorbidity could lead to new treatment strategies both for each type of disorder in isolation and in scenarios of comorbidity.

Methods

This article provides an overview of relationships between DSM-5 psychiatric diagnoses and chronic pain, with particular focus on PTSD, ADHD, and BPD, disorders which are less commonly studied in conjunction with chronic pain. We also discuss potential mechanisms that may drive comorbidity, and present new findings on the genetic overlap of chronic pain and ADHD, and chronic pain and BPD using linkage disequilibrium score regression analyses.

Results

Almost all psychiatric conditions listed in the DSM-5 are associated with increased rates of chronic pain. ADHD and BPD are significantly genetically correlated with chronic pain. Psychiatric conditions aside from major depression are often under-researched with respect to their relationship with chronic pain.

Conclusion

Further understanding relationships between psychiatric conditions other than major depression (such as ADHD, BPD, and PTSD as exemplified here) and chronic pain can positively impact understanding of these disorders, and treatment of both psychiatric conditions and chronic pain.

The associations between ADHD, pain, inflammation, and quality of life in children and adolescents-a clinical study protocol

New research shows that the prevalence of neurodevelopmental disorders, such as attention-deficit/hyperactivity disorder (ADHD), is increased in children and adolescents as well as in adults with chronic pain, compared to those without chronic pain. Children and adolescents with ADHD also have an increased incidence of various physical conditions associated with pain, and they more frequently suffer from inflammatory diseases. Moreover, parents of children with ADHD can often suffer from pain conditions. These epidemiological and clinical observations form the scientific basis of our study, which aims to map the relationships between ADHD, altered pain experiences/central sensitization, and inflammation in children and adolescents. We will investigate the presence of central sensitization in children and adolescents with newly diagnosed ADHD and compare it with those who have not been diagnosed with ADHD. Participants (and their biological parents) will complete surveys about their somatic health, pain experience, and quality of life. Biological samples (saliva and stool) will be collected, aiming to utilize proteome and metabolome data to discover disease mechanisms and to predict, prevent and treat them. The results from our investigation should enable an expanded understanding of the pathophysiology behind both ADHD and pain/central sensitization. Presently, there are no established protocols for addressing psychiatric symptoms when examining patients with pain conditions in a somatic care setting, nor is there any knowledge of offering patients with ADHD or other neurodevelopmental disorders adapted treatments for pain conditions. Our results, therefore, can contribute to the development of new treatment strategies for pathological pain conditions in children and adolescents with ADHD. They may also increase awareness about and provide opportunities for the treatment of attention and impulse control problems in children and adolescents with pain syndromes.

Attention-Deficit Hyperactivity Disorder and Therapeutic Cannabis Use Motives

Rates of cannabis use have been rising in the US due to the increasing legalization/decriminalization of cannabis products for medical and recreational use. Individuals with attention-deficit hyperactivity disorder (ADHD) may be at an increased risk of experiencing cannabis use problems due to deficits in self-regulation. This article explores motivations for cannabis use in ADHD populations. Research on the neural correlates and therapeutic potential of cannabis use are reviewed.

Peridontitis as a Risk Factor for Attention Deficit Hyperactivity Disorder: Possible Neuro-inflammatory Mechanisms

Periodontitis is a condition caused mostly by the creation of a biofilm by the bacterium P. gingivalis, which releases toxins and damages the tooth structure. Recent research studies have reported association between dental health and neuropsychiatric illnesses. Neuroinflammation triggered by the first systemic inflammation caused by the bacterium present in the oral cavities is a plausible explanation for such a relationship. Substantial amount of evidence supports the role of neuroinflammation and dysfunction of the dopaminergic system in the pathology of ADHD (Attention deficit hyperactivity disorders). Recent epidemiological, microbiological and inflammatory findings strengthen that, periodontal bacteria, which cause systemic inflammation can contribute to neuroinflammation and finally ADHD. Although both diseases are characterized by inflammation, the specific pathways and crosslink's between periodontitis and ADHD remain unknown. Here, the authors describe the inflammatory elements of periodontitis, how this dental illness causes systemic inflammation, and how this systemic inflammation contributes to deteriorating neuroinflammation in the evolution of ADHD. Therefore, the aim of this review is to present possible links and mechanisms that could confirm the evidence of this association.