An update on the clinical pharmacology of methylphenidate: therapeutic efficacy, abuse potential and future considerations

Response Trajectories and Temporal Trends of Viloxazine Treatment for Young People With ADHD: A Meta-Analysis

Importance

Viloxazine is a novel nonstimulant medication approved for the treatment of attention-deficit/hyperactivity disorder (ADHD).

Objectives

To investigate the whether viloxazine is associated with effective and acceptable outcomes when treating children and adolescents with ADHD and to evaluate these outcomes' associations with viloxazine doses and duration of treatment.

Data Sources

The MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, PsycINFO, and ClinicalTrial.gov databases were searched from database inception to June 23, 2024.

Study Selection

Two reviewers independently screened for double-blind, fixed-dose randomized clinical trials (RCTs) that compared viloxazine with placebo for pediatric patients with ADHD.

Data Extraction and Synthesis

The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline. Data extraction was completed independently by 2 authors and cross-checked for errors. Random-effects pairwise and dose-response meta-analyses were conducted.

Main Outcomes and Measures

The primary outcome was the improvement of ADHD symptoms (measured by ADHD Rating Scale-5), and the secondary outcomes were all-cause discontinuation, dropout due to adverse effects, and serious adverse effects.

Results

A total of 5 dose-response RCTs were included, with 1560 participants (1011 [64.8%] male; mean [SD] age, 10.6 [6.7] years). Viloxazine was associated with better outcomes in ADHD treatment compared with placebo (mean difference, 5.47 points; 95% CI, 4.03-6.91 points). The dose-response curve was bell-shaped, suggesting that doses greater than 400 mg or greater than 7 mg/kg might not be associated with more efficacy. The temporal trends analysis showed ascent curves tapering off at approximately weeks 4 to 6. The curve for 100 mg/d declined more rapidly, while the curves for 200 mg/d and 400 mg/d declined more gradually. The overall discontinuation rate due to adverse effects was 4.15% in the viloxazine group (45 of 1084), while viloxazine compared with placebo was associated with 2.48-fold higher risk of discontinuation due to adverse effects (risk ratio, 2.48; 95% CI, 1.26-4.88).

Conclusions and relevance

In this meta-analysis, viloxazine was associated with better efficacy in treating children and adolescents with ADHD than placebo. A moderate dose (200-400 mg or 6-8 mg/kg) may provide optimal treatment outcomes. Future studies are warranted to assess the long-term effect of viloxazine. Viloxazine was relatively well tolerated for children and adolescents with ADHD.

Balancing acts: The dual faces of fentanyl in medicine and public health

Fentanyl is a potent synthetic opioid widely used in medicine for its effective analgesic properties, particularly in surgical procedures and in the treatment of severe, chronic pain. In recent decades, however, there has been a worrying increase in the illicit use of fentanyl, particularly in North America. This rise in illicit use is concerning because fentanyl is associated with polydrug abuse, which adds layers of complexity and dangerous. This review provides a comprehensive examination of fentanyl, focusing on its synthesis and medical use. It also discusses the significance of the piperidine ring in medicinal chemistry as well as the critical role of fentanyl in pain management and anesthesia. Furthermore, it addresses the challenges associated with the abuse potential of fentanyl and the resulting public health concerns. The study aims to strike a balance between the clinical benefits and risks of fentanyl by advocating for innovative uses while addressing public health issues. It examines the chemistry, pharmacokinetics and pharmacodynamics of fentanyl and highlights the importance of personalized medicine in the administration of opioids. The review underscores the necessity of continuous research and adaptation in both clinical use and public health strategies.

Changes in gut microbiota and metabolites of mice with intravenous graphene oxide-induced embryo toxicity

The expanding applications of graphene oxide (GO) nanomaterials have attracted interest in understanding their potential adverse effects on embryonic and fetal development. Numerous studies have revealed the importance of the maternal gut microbiota in pregnancy. In this study, we established a mouse GO exposure model to evaluate embryo toxicity induced by intravenous administration of GO during pregnancy. We also explored the roles of gut microbiota and fecal metabolites using a fecal microbiota transplantation (FMT) intervention model. We found that administration of GO at doses up to 1.25 mg/kg caused embryo toxicity, characterized by significantly increased incidences of fetal resorption, stillbirths, and decreased birth weight. In pregnant mice with embryo toxicity, the richness of the maternal gut microbiota was dramatically decreased, and components of the microbial community were disturbed. FMT alleviated the decrease in birth weight by remodeling the gut microbiota, especially via upregulation of the Firmicutes/Bacteroidetes ratio. We subsequently used untargeted metabolomics to identify characteristic fecal metabolites associated with GO exposure. These metabolites were closely correlated with the phyla Actinobacteria, Proteobacteria, and Cyanobacteria. Our findings offer new insights into the embryo toxic effects of GO exposure during pregnancy; they emphasize the roles of gut microbiota-metabolite interactions in adverse pregnancy outcomes induced by GO or other external exposures, as demonstrated through FMT intervention.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-024-00242-3.

Effect of ginseng and ginsenosides on attention deficit hyperactivity disorder: A systematic review

Attention deficit hyperactivity disorder (ADHD) is a rapidly increasing neurodevelopmental disorder but currently available treatments are associated with abuse risk, side effects, and incomplete symptom relief. There is growing interest in exploring complementary options, and ginseng has gained attention for its therapeutic potential. This systematic review aimed to assess current evidence on the efficacy of ginseng and its active components, ginsenosides, for ADHD. Eligible studies were identified through searches of PubMed, Embase, Cochrane Library, and Web of Science, up to June 2023. The inclusion criteria included both human and animal studies that investigated the effects of ginseng or ginsenosides on ADHD. The risk of bias was assessed according to study type. Six human studies and three animal studies met the inclusion criteria. The results suggest that ginseng and ginsenosides may have beneficial effects on ADHD symptoms, particularly inattention, through dopaminergic/norepinephrinergicmodulation and BDNF/TrkB signaling. Ginseng and ginsenosides have promising potential for ADHD treatment. Due to limitations in evidence quality, such as the risk of bias and variability in study designs, larger controlled studies are essential. Integrating ginseng into ADHD management may have valuable implications for individuals seeking well-tolerated alternatives or adjunctive therapies.

Methylphenidate Reversal of Dexmedetomidine-Induced Versus Ketamine-Induced Sedation in Rats

BACKGROUND

Dexmedetomidine and ketamine have long elimination half-lives in humans and have no clinically approved reversal agents. Methylphenidate enhances dopaminergic and noradrenergic neurotransmission by inhibiting reuptake transporters for these arousal-promoting neurotransmitters. Previous studies in rats demonstrated that intravenous methylphenidate induces emergence from isoflurane and propofol general anesthesia. These 2 anesthetics are thought to act primarily through enhancement of inhibitory Gamma-aminobutyric acid type A (GABAA) receptors. In this study, we tested the behavioral and neurophysiological effects of methylphenidate in rats after low and high doses of dexmedetomidine (an alpha-2 adrenergic receptor agonist) and ketamine (an N-methyl-D-aspartate [NMDA] receptor antagonist) that induce sedation and unconsciousness, respectively.

METHODS

All experiments used adult male and female Sprague-Dawley rats (n = 32 total) and all drugs were administered intravenously in a crossover, blinded experimental design. Locomotion after sedating doses of dexmedetomidine (10 µg/kg) or ketamine (10 mg/kg) with and without methylphenidate (5 mg/kg) was tested using the open field test (n = 16). Recovery of righting reflex after either high-dose dexmedetomidine (50 µg/kg) or high-dose ketamine (50 mg/kg) with and without methylphenidate (1-5 mg/kg) was assessed in a second cohort of rats (n = 8). Finally, in a third cohort of rats (n = 8), frontal electroencephalography (EEG) was recorded for spectral analysis under both low and high doses of dexmedetomidine and ketamine with and without methylphenidate.

RESULTS

Low-dose dexmedetomidine reduced locomotion by 94% in rats. Methylphenidate restored locomotion after low-dose dexmedetomidine (rank difference = 88.5, 95% confidence interval [CI], 70.8-106) and the effect was blocked by coadministration with a dopamine D1 receptor antagonist (rank difference = 86.2, 95% CI, 68.6-104). Low-dose ketamine transiently attenuated mobility by 58% and was not improved with methylphenidate. Methylphenidate did not affect the return of righting reflex latency in rats after high-dose dexmedetomidine nor ketamine. Frontal EEG analysis revealed that methylphenidate reversed spectral changes induced by low-dose dexmedetomidine (F [8,87] = 3.27, P = .003) but produced only transient changes after high-dose dexmedetomidine. Methylphenidate did not induce spectral changes in the EEG after low- or high-dose ketamine.

CONCLUSIONS

Methylphenidate reversed behavioral and neurophysiological correlates of sedation, but not unconsciousness, induced by dexmedetomidine. In contrast, methylphenidate did not affect sedation, unconsciousness, nor EEG signatures in rats after ketamine. These findings suggest that methylphenidate may be efficacious to reverse dexmedetomidine sedation in humans.

Giggle incontinence: a scoping review

Giggle incontinence (GI) is poorly described, defined, and understood. It is considered a bladder storage disorder in which laughter causes an uncontrollable episode of urinary incontinence that cannot be stopped until the bladder is completely emptied. It has been confused with stress urinary incontinence and overactive bladder. A thorough analysis of 26 articles on the subject of "giggle incontinence" and associated terms was performed, including all articles since the phrase first appeared. To date, 351 GI cases have been reported. It occurs mainly in women (69.5%) at 5 years of age, with a prevalence ranging from 8.4 to 16.2 years (average age of 12.4 years), and some cases have a family history of the disease (13-16.7%). This review discusses the historical background, current understanding, and challenges related to GI. It primarily affects females after the age of 5 years, causing complete bladder emptying during uncontrollable laughter. The exact cause is unknown, but hypotheses suggest involvement of the central nervous system. Diagnosis relies on clinical history, physical tests, and urine frequency evaluation. Management involves urotherapy techniques, biofeedback, and methylphenidate. Understanding GI will aid in developing more effective management techniques. IMPACT: Highlights limited awareness among healthcare professionals about giggle incontinence as a distinct condition, emphasizing the need for standardized diagnostic criteria and assessment tools. Addresses insufficient understanding of the underlying mechanisms and contributing factors, providing valuable insights for better diagnosis and treatment. Emphasizes the importance of patient education and support, calling for improved resources and counseling. Urges further research and evidence-based guidelines to enhance treatment strategies.

Methylphenidate, but not citalopram, decreases impulsive choice in rats performing a temporal discounting task

Introduction

Drugs targeting monoamine systems remain the most common treatment for disorders with impulse control impairments. There is a body of literature suggesting that drugs affecting serotonin reuptake and dopamine reuptake can modulate distinct aspects of impulsivity - though such tests are often performed using distinct behavioral tasks prohibiting easy comparisons.

Methods

Here, we directly compare pharmacologic agents that affect dopamine (methylphenidate) vs serotonin (citalopram) manipulations on choice impulsivity in a temporal discounting task where rats could choose between a small, immediate reward or a large reward delayed at either 2 or 10s. In control conditions, rats preferred the large reward at a small (2s) delay and discounted the large reward at a long (10s) delay.

Results

Methylphenidate, a dopamine transport inhibitor that blocks reuptake of dopamine, dose-dependently increased large reward preference in the long delay (10s) block. Citalopram, a selective serotonin reuptake inhibitor, had no effect on temporal discounting behavior. Impulsive behavior on the temporal discounting task was at least partially mediated by the nucleus accumbens shell. Bilateral lesions to the nucleus accumbens shell reduced choice impulsivity during the long delay (10s) block. Following lesions, methylphenidate did not impact impulsivity.

Discussion

Our results suggest that striatal dopaminergic systems modulate choice impulsivity via actions within the nucleus accumbens shell, whereas serotonin systems may regulate different aspects of behavioral inhibition/impulsivity.

Vascular Burden Moderates the Relationship Between ADHD and Cognition in Older Adults

OBJECTIVES

Recent evidence suggests attention-deficit/hyperactivity disorder (ADHD) is a risk factor for cognitive impairment in later life. Here, we investigated cerebrovascular burden, quantified using white matter hyperintensity (WMH) volumes, as a potential mediator of this relationship.

DESIGN

This was a cross-sectional observational study.

SETTING

Participants were recruited from a cognitive neurology clinic where they had been referred for cognitive assessment, or from the community.

PARTICIPANTS

Thirty-nine older adults with clinical ADHD and 50 age- and gender-matched older adults without ADHD.

MEASUREMENTS

A semiautomated structural MRI pipeline was used to quantify periventricular (pWMH) and deep WMH (dWMH) volumes. Cognition was measured using standardized tests of memory, processing speed, visuo-construction, language, and executive functioning. Mediation models, adjusted for sex, were built to test the hypothesis that ADHD status exerts a deleterious impact on cognitive performance via WMH burden.

RESULTS

Results did not support a mediated effect of ADHD on cognition. Post hoc inspection of the data rather suggested a moderated effect, which was investigated as an a posteriori hypothesis. These results revealed a significant moderating effect of WMH on the relationship between ADHD memory, speed, and executive functioning, wherein ADHD was negatively associated with cognition at high and medium levels of WMH, but not when WMH volumes were low.

CONCLUSIONS

ADHD increases older adults' susceptibility to the deleterious cognitive effects of WMH in the brain. Older adults with ADHD may be at risk for cognitive impairment if they have deep WMH volumes above 61 mm3 and periventricular WMH above 260 mm3.

Analyzing the network of parent-rated ADHD symptoms before and 2 weeks after the onset of pharmaceutical treatment

PROBLEM

Via a network analysis approach, following 2 weeks of the medication Ritalin, the present study investigated the quality of symptom interactions and the pattern of behavior changes to identify locations of functional weaknesses in the network interactions of symptomology.

METHODS

Ritalin® prescribed for 112 children (aged 4-14) with attention deficit hyperactivity disorder (ADHD) as diagnosed by five child and adolescent psychiatrists. Their parents completed Swanson, Nolan, and Pelham-IV questionnaire (SNAP-IV) before and after Ritalin® onset as the pre and post-test, respectively. Then, the network analysis approach was used to discover the pattern of changes in symptom interactions.

FINDINGS

The results indicated that in 2 weeks following its initiation, Ritalin significantly reduced restlessness and interactions between symptoms of impulsivity. "Inability to follow instructions" and "difficulty waiting their turn" symptoms were the most central symptoms of strength. Three symptoms, "Often has difficulty waiting their turn," "runs and climbs in situations where it is inappropriate" and "does not follow through on instructions," had the most expected influence. In the 14-day period of investigation, Ritalin® was effective in breaking some interactions and components of ADHD, but no significant mitigation of other components of the detected symptomatology network.

CONCLUSION

Follow-up investigations using network analysis can clarify the dynamics of the network changes after initiation of medications.

Management Strategies for Borderline Personality Disorder and Bipolar Disorder Comorbidities in Adults with ADHD: A Narrative Review

This narrative review examines two of the common comorbidities of attention-deficit/hyperactivity disorder, bipolar disorder (BD), and borderline personality disorder (BPD), which each share several common features with ADHD that can make assessment and diagnosis challenging. The review highlights some of the key symptomatic differences between adult ADHD and these disorders, allowing for more careful consideration before establishing a formal diagnosis. When the disorders are found to be comorbid, further complications may arise; thus, the review will also help to provide evidence-based treatment recommendations as well as suggestions on how to minimize adverse events. Incorporating evidence from systematic reviews, journal articles, randomized controlled trials, and case reports, this review highlights that the diagnosis of ADHD and some of its common comorbidities is challenging and requires full, in-depth assessment and management. The management strategies of these comorbidities will also be addressed, with emphasis on achieving mood stabilization for BD prior to initiating appropriate ADHD pharmacotherapy. Medications, specifically mood stabilizers, antipsychotics, and antidepressants, are fundamental in treating symptoms seen in BD and some cases of BPD, alongside psychotherapy and lifestyle modifications when appropriate. The review highlights the effectiveness of specific medications, including psychostimulants, atomoxetine, and bupropion, as add-on therapies to mood-stabilizing treatments for addressing ADHD symptoms in patients with these comorbidities. Despite limited research, the review will address various pharmacological and psychotherapeutic approaches for managing comorbid ADHD and BPD, emphasizing the need for further investigations to better understand the unique needs of this patient population.

The Adverse Effects and Nonmedical Use of Methylphenidate Before and After the Outbreak of COVID-19: Machine Learning Analysis

BACKGROUND

Methylphenidate is an effective first-line treatment for attention-deficit/hyperactivity disorder (ADHD). However, many adverse effects of methylphenidate have been recorded from randomized clinical trials and patient-reported outcomes, but it is difficult to determine abuse from them. In the context of COVID-19, it is important to determine how drug use evaluation, as well as misuse of drugs, have been affected by the pandemic. As people share their reasons for using medication, patient sentiments, and the effects of medicine on social networking services (SNSs), the application of machine learning and SNS data can be a method to overcome the limitations. Proper machine learning models could be evaluated to validate the effects of the COVID-19 pandemic on drug use.

OBJECTIVE

To analyze the effect of the COVID-19 pandemic on the use of methylphenidate, this study analyzed the adverse effects and nonmedical use of methylphenidate and evaluated the change in frequency of nonmedical use based on SNS data before and after the outbreak of COVID-19. Moreover, the performance of 4 machine learning models for classifying methylphenidate use based on SNS data was compared.

METHODS

In this cross-sectional study, SNS data on methylphenidate from Twitter, Facebook, and Instagram from January 2019 to December 2020 were collected. The frequency of adverse effects, nonmedical use, and drug use before and after the COVID-19 pandemic were compared and analyzed. Interrupted time series analysis about the frequency and trends of nonmedical use of methylphenidate was conducted for 24 months from January 2019 to December 2020. Using the labeled training data set and features, the following 4 machine learning models were built using the data, and their performance was evaluated using F-1 scores: naïve Bayes classifier, random forest, support vector machine, and long short-term memory.

RESULTS

This study collected 146,352 data points and detected that 4.3% (6340/146,352) were firsthand experience data. Psychiatric problems (521/1683, 31%) had the highest frequency among the adverse effects. The highest frequency of nonmedical use was for studies or work (741/2016, 36.8%). While the frequency of nonmedical use before and after the outbreak of COVID-19 has been similar (odds ratio [OR] 1.02 95% CI 0.91-1.15), its trend has changed significantly due to the pandemic (95% CI 2.36-22.20). Among the machine learning models, RF had the highest performance of 0.75.

CONCLUSIONS

The trend of nonmedical use of methylphenidate has changed significantly due to the COVID-19 pandemic. Among the machine learning models using SNS data to analyze the adverse effects and nonmedical use of methylphenidate, the random forest model had the highest performance.

Pioglitazone enhances brain mitochondrial biogenesis and phase II detoxification capacity in neonatal rats with 6-OHDA-induced unilateral striatal lesions

The psychostimulant methylphenidate (MPH) is the first-line pharmacological treatment for attention-deficit/hyperactivity disorder (ADHD), but has numerous adverse side effects. The PPARγ receptor agonist pioglitazone (PIO) is known to improve mitochondrial bioenergetics and antioxidant capacity, both of which may be deficient in ADHD, suggesting utility as an adjunct therapy. Here, we assessed the effects of PIO on ADHD-like symptoms, mitochondrial biogenesis and antioxidant pathways in multiple brain regions of neonate rats with unilateral striatal lesions induced by 6-hydroxydopamine (6-OHDA) as an experimental ADHD model. Unilateral striatal injection of 6-OHDA reduced ipsilateral dopaminergic innervation by 33% and increased locomotor activity. This locomotor hyperactivity was not altered by PIO treatment for 14 days. However, PIO increased the expression of proteins contributing to mitochondrial biogenesis in the striatum, hippocampus, cerebellum and prefrontal cortex of 6-OHDA-lesioned rats. In addition, PIO treatment enhanced the expression of the phase II transcription factor Nrf2 in the striatum, prefrontal cortex and cerebellum. In contrast, no change in the antioxidant enzyme catalase was observed in any of the brain regions analyzed. Thus, PIO may improve mitochondrial biogenesis and phase 2 detoxification in the ADHD brain. Further studies are required to determine if different dose regimens can exert more comprehensive therapeutic effects against ADHD neuropathology and behavior.

Athletes With Attention-Deficit/Hyperactivity Disorder: Position Statement of the American Medical Society for Sports Medicine

ABSTRACT

Athletes of all ages may be affected by medical and mental health issues. Sports medicine physicians should be familiar with common conditions that may affect the well-being of athletes, such as attention-deficit/hyperactivity disorder (ADHD). ADHD behaviors have the potential to affect a person's ability to concentrate. It is likely that social and cognitive therapies combined with pharmacotherapy will be the most effective way to treat ADHD in athletes. Medications used for ADHD, especially stimulant types, are known to improve alertness, reaction time, anaerobic performance, and endurance, which would potentially improve athletic performance. Furthermore, stimulant medications may enable student athletes with ADHD to focus on academic studies for longer periods of time, beyond usual levels of fatigue, important for those who may be exhausted after practices and games. The purported performance enhancement effects and potential adverse effects of stimulant medications have prompted many sports governing bodies to ban prescription stimulants or establish strict rules for their use. Athletes taking physician-prescribed stimulants to treat ADHD need to provide the appropriate documentation for approval before competition or risk punitive measures. Physicians should strive to provide a high quality of care to athletes with ADHD through early diagnosis, appropriate and careful multidisciplinary treatment, and complete and timely documentation to facilitate continued sports participation.

Oxytocin receptors mediate oxytocin potentiation of methylphenidate-induced stimulation of accumbens dopamine in rats

While the illicit use and misuse of stimulants like cocaine and methylphenidate (MP) has increased, there remains no FDA-approved treatments for psychostimulant use disorders (PSUD). Oxytocin (OT) has shown promise as a potential pharmacotherapy for PSUD. Dopamine (DA) neurotransmission plays a significant role in PSUD. We have recently shown that OT blunts the reinforcing effects of MP but, surprisingly, enhanced MP-induced stimulation of DA levels. Such effects have been suggested as a result of activation of OT receptors or, alternatively, could be mediated by direct actions of OT on MP blockade of the DA transporter. Here, we employed fast scan cyclic voltammetry (FSCV) to investigate the effects of systemic OT on MP-induced changes in the dynamics of DA, phasic release and uptake, in the nucleus accumbens shell (NAS) of Sprague-Dawley rats. We also tested the systemic effects of an antagonist of OT receptors, atosiban, to counteract the OT enhancement of dopaminergic effects of MP under microdialysis procedures in the NAS in rats. Administration of OT alone (2 mg/kg; i.p.) did not significantly modify evoked NAS DA dynamics measured by FSCV, and when administered 10 min before MP (0.1, 0.3, 1.0 mg/kg; i.v.), OT did not potentiate MP-induced increases in phasic DA release and did not alter DA clearance rate, suggesting no direct interactions of OT with the MP-induced blockade of DA uptake. Also, OT alone did not elicit significant changes in tonic, extracellular NAS DA levels measured by microdialysis. However, consistent with previous studies, we observed that OT pretreatments (2 mg/kg; i.p.) potentiated MP-induced (0.1, 0.3, 1.0 mg/kg; i.v.) efflux of extracellular NAS DA levels. This effect was abolished when rats were pretreated with atosiban (2 mg/kg; i.p.), suggesting that OT receptors mediate this OT action. Overall, our results suggest that OT receptors mediated OT potentiation of MP-induced stimulation of extracellular NAS DA levels, likely driven by modulation of DA receptor signaling pathways, without affecting MP blockade of DAT.

The current state of ayahuasca research in animal models: A systematic review

RATIONALE

The psychedelic brew ayahuasca is increasingly being investigated for its therapeutic potential. Animal models are essential to investigate the pharmacological effects of ayahuasca since they can control important factors influencing it, such as the set and setting.

OBJECTIVE

Review and summarise data available on ayahuasca research using animal models.

METHODS

We systematically searched five databases (PubMed, Web of Science, EMBASE, LILACS and PsycInfo) for peer-reviewed studies in English, Portuguese or Spanish published up to July 2022. The search strategy included ayahuasca- and animal model-related terms adapted from the SYRCLE search syntax.

RESULTS

We identified 32 studies investigating ayahuasca effects on toxicological, behavioural and (neuro)biological parameters in rodents, primates and zebrafish. Toxicological results show that ayahuasca is safe at ceremonial-based doses but toxic at high doses. Behavioural results indicate an antidepressant effect and a potential to reduce the reward effects of ethanol and amphetamines, while the anxiety-related outcomes are yet inconclusive; also, ayahuasca can influence locomotor activity, highlighting the importance of controlling the analysis for locomotion when using tasks depending on it. Neurobiological results show that ayahuasca affects brain structures involved in memory, emotion and learning and that other neuropathways, besides the serotonergic action, are important in modulating its effects.

CONCLUSIONS

Studies using animal models indicate that ayahuasca is toxicologically safe in ceremonial-comparable doses and indicates a therapeutic potential for depression and substance use disorder while not supporting an anxiolytic effect. Essential gaps in the ayahuasca field can still be sufficed using animal models.

A Potential Role for Neuroinflammation in ADHD

Attention deficit hyperactivity disorder (ADHD) is a neurobehavioural disorder in children and adolescents. Although increases in oxidative stress and disturbances of neurotransmitter system such as the dopaminergic and abnormalities in several brain regions have been demonstrated, the pathophysiology of ADHD is not fully understood. Nevertheless, ADHD involves several factors that have been associated with an increase in neuroinflammation. This chapter presents an overview of factors that may increase neuroinflammation and play a potential role in the development and pathophysiology of ADHD. The altered immune response, polymorphisms in inflammatory-related genes, ADHD comorbidity with autoimmune and inflammatory disorders and prenatal exposure to inflammation are associated with alterations in offspring brain development and are a risk factor; genetic and environmental risk factors that may increase the risk for ADHD and medications can increase neuroinflammation. Evidence of an association between these factors has been an invaluable tool for research on inflammation in ADHD. Therefore, evidence studies have made it possible to generate alternative therapeutic interventions using natural products as anti-inflammatories that could have great potential against neuroinflammation in ADHD.

Características das prescrições de metilfenidato em ambulatório de neuropediatria

RESUMO O metilfenidato não é disponibilizado pelo Sistema Único de Saúde (SUS), pois não faz parte da Relação Nacional de Medicamentos Essenciais. Todavia, o metilfenidato 10 mg é disponibilizado pela rede pública em Maringá-PR de acordo com a Política da Assistência Farmacêutica do município. Objetivou-se analisar as características das prescrições médicas de metilfenidato para crianças em ambulatório de neuropediatria vinculado ao SUS no município. Estudo transversal observacional retrospectivo de caráter quantitativo, realizado por meio da coleta de dados dos prontuários cadastrados no Sistema Gestor da rede pública de saúde do município, pelo ambulatório de neuropediatria na Unidade Básica de Saúde, Zona 7, entre janeiro de 2017 e novembro de 2019. Analisaram-se os dados por frequência relativa e absoluta. Emitiram-se 339 prescrições pelo neuropediatra responsável do ambulatório para 107 pacientes de 6 a 11 anos. Notou-se distribuição geográfica desigual das crianças atendidas conforme bairro da cidade, o que denota influência socioeconômica na prescrição de medicamentos. Ressaltam-se picos de prescrições coincidindo com o período do ano letivo escolar. Concluiu-se que o acompanhamento especializado adequado é premissa para o tratamento, não dispensando a rede longitudinal de assistência. Ademais, evidencia-se o impacto das condições socioeconômicas, tanto na prescrição como na aquisição do medicamento.

Potential Targets and Action Mechanism of Gastrodin in the Treatment of Attention-Deficit/Hyperactivity Disorder: Bioinformatics and Network Pharmacology Analysis

Objective

Gastrodin is a main medicinal component of traditional Chinese medicine (TCM) Gastrodia elata Blume (G. elata), presenting the potential for the treatment of attention-deficit/hyperactivity disorder (ADHD). However, the underlying targets and action mechanisms of the treatment have not been identified.

Methods

The gastrodin-related microarray dataset GSE85871 was obtained from the GEO database and analyzed by GEO2R to obtain differentially expressed genes (DEGs). Subsequently, the targets of gastrodin were supplemented by the Encyclopedia of Traditional Chinese Medicine (ETCM), PubChem, STITCH, and SwissTargetPrediction databases. ADHD-associated genes were collected from six available disease databases (i.e., TTD, DrugBank, OMIM, PharmGKB, GAD, and KEGG DISEASE). The potential targets of gastrodin during ADHD treatment were obtained by mapping gastrodin-related targets with ADHD genes, and their protein–protein interaction (PPI) relationship was constructed by the STRING database. The GO function and KEGG pathway enrichment analyses were performed using the ClueGO plug-in in the Cytoscape software and DAVID database, respectively. Finally, the binding affinity between gastrodin and important targets was verified by molecular docking.

Results

A total of 460 gastrodin-related DEGs were identified from GSE85871, and 124 known gastrodin targets were supplemented from 4 databases, including ETCM. A total of 440 genes were collected from the above 6 disease databases, and 267 ADHD-relevant genes were obtained after duplicate removal. Through mapping the 584 gastrodin targets to the 267 ADHD genes, 16 potential therapeutic targets were obtained, among which the important ones were DRD2, DRD4, CHRNA3, CYP1A1, TNF, IL6, and KCNJ3. The enrichment analysis results indicated that 16 potential targets were involved in 25 biological processes (e.g., dopamine (DA) transport) and 22 molecular functions (e.g., postsynaptic neurotransmitter receptor activity), which were mainly localized at excitatory synapses. The neuroactive ligand-receptor interaction, cholinergic synapse, and dopaminergic synapse might be the core pathways of gastrodin in ADHD treatment. Through molecular docking, it was preliminarily verified that gastrodin showed good binding activity to seven important targets and formed stable binding conformations.

Conclusions

Gastrodin might exert an anti-ADHD effect by upgrading the dopaminergic system and central cholinergic system, inhibiting the inflammatory response and GIRK channel, and exerting a synergistic effect with other drugs on ADHD. For this reason, gastrodin should be considered a multitarget drug for ADHD treatment.

Physiologically-Based Pharmacokinetic Modeling to Predict Methylphenidate Exposure Affected by Interplay Among Carboxylesterase 1 Pharmacogenetics, Drug-Drug Interactions, and Sex

BACKGROUND AND OBJECTIVE

The pharmacokinetics (PK) of methylphenidate (MPH) differ significantly among individuals. Carboxylesterase 1 (CES1) is the primary enzyme metabolizing MPH, and its function is affected by genetic variants, drug-drug interaction (DDI), and sex. The object of this study is to evaluate CES1 pharmacogenetics as related to MPH metabolism using human liver samples and develop a physiologically-based pharmacokinetic (PBPK) modeling approach to investigate the influence of CES1 genotypes and other factors on MPH PK.

METHODS

The effect of the CES1 variant G143E (rs71647871) on MPH metabolism was studied utilizing 102 individual human liver S9 (HLS9) fraction samples. PBPK models were developed using the population-based PBPK software PK-Sim® by incorporating the HLS9 incubation data. The established models were applied to simulate MPH PK profiles under various clinical scenarios, including different genotypes, drug-alcohol interactions, and the difference between males and females.

RESULTS

The HLS9 incubation study showed that subjects heterozygous for the CES1 variant G143E metabolized MPH at a rate of approximately 50% of that in non-carriers. The developed PBPK models successfully predicted the exposure alteration of MPH from the G143E genetic variant, ethanol-MPH DDI, and sex. Importantly, the study suggests that male G143E carriers who are alcohol consumers are at a higher risk of MPH overexposure.

CONCLUSION

PBPK modeling provides a means for better understanding the mechanisms underlying interindividual variability in MPH PK and PD and could be utilized to develop a safer and more effective MPH pharmacotherapy regimen.

Increased sperm DNA damage leads to poor embryo quality and subfertility of male rats treated with methylphenidate hydrochloride in adolescence

BACKGROUND

Methylphenidate hydrochloride (MPH) is a psychostimulant widely used in the treatment of attention deficit hyperactive disorder (ADHD), as well as a performance enhancer, for at least 60 years. Despite the notable effectiveness as a psychostimulant, ADHD is a chronic disorder and has a two-third chance of accompanying the individual throughout life. Long-term use of MPH has been associated not only with an increase in the development of neurodegenerative diseases, but it also has side effects on male fertility in experimental animals.

OBJECTIVES

To investigate whether methylphenidate poses a risk to sperm DNA structure and to the quality of embryos conceived after treatment during adolescence in rats.

MATERIALS AND METHODS

Wistar rats at 38 days of age were treated either with 5 mg/kg body weight of MPH, in a single daily dose for 30 days, via gavage or with distilled water-only protocol. Levels of oxidative stress in testicular and epididymal tissues were evaluated. Sperm chromatin quality and acrosome integrity was assessed under flow cytometry. From 107 days of age, animals were mated with untreated females. The effects of the paternal contribution at two different embryo development moments - cleavage stage (2.5 days post coitum) and late gestation (20 days post coitum) - were analyzed.

RESULTS

MPH caused high levels of sperm DNA damage, which was reflected in 40% of decrease in early embryo quality and a lower number of live pups at 20 dpc.

DISCUSSION

The high level of fragmentation seen in the embryos sired from the MPH group is consistent with the poor chromatin structure of the sperm, and does not seem to be a result of oxidative stress in the reproductive tissues.

CONCLUSIONS

The results presented here suggest that the subchronic use of MPH during male prepubertal phase may cause long term subfertility and compromise embryo survival. This article is protected by copyright. All rights reserved.

Time-dependent affective disturbances in abstinent patients with methylphenidate use disorder

BACKGROUND

Methylphenidate (MPH), also called Ritalin, is used to treat attention-deficit hyperactivity disorder (ADHD) patients. With occasional reports of subjects suffering from Methylphenidate use disorder (MPHUD), few studies analyzed the neuropsychological changes in this population.

PURPOSE

This study aims to evaluate the clinical outcomes of individuals with MPHUD.

METHODS

We retrospectively analyzed 61 MPH patients (aged 16-27 years) admitted to the Beijing Gaoxin Hospital drug rehabilitation program from Jan 2017 to Mar 2019. The drug use history and drug abuse motivation scale were collected at admission. Clinicians rated the Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, and DSM-5 Stimulant use disorder criteria each week during the 4 weeks rehabilitation program. Correlation analyses were conducted between drug use history and affective disturbances.

RESULTS

The results showed that the adolescent period is the peak for MPH exposure, and 1/3 of patients got their first exposure to MPH from their parents. MPH abstinence accompanies severe anxiety and depression symptoms, significantly alleviating after four weeks of treatment.

CONCLUSIONS

MPHUD is associated with substantial affective disturbances, which warrants a more considerable sample investigation.

Rosmarinus officinalis and Methylphenidate Exposure Improves Cognition and Depression and Regulates Anxiety-Like Behavior in AlCl3-Induced Mouse Model of Alzheimer’s Disease

Alzheimer’s disease (AD) is a neurological illness that causes severe cognitive impairment. AD patients also experience at least one of the neuropsychiatric symptoms including apathy, depression, and anxiety during the course of their life. Acetylcholine esterase inhibitors are the available treatment options to alleviate cognitive deficits, whereas methylphenidate (MPH), a psychostimulant, is considered for the treatment of apathy in AD patients. Rosmarinus officinalis, a perennial herb, has been potentially known to have antioxidant and anti-inflammatory properties. The present study investigated the potential effects of MPH and R. officinalis in comparison with the standard drug, Donepezil, on cognition, anxiety, and depression in the AlCl₃-induced mouse model of AD. The animals were divided into eight groups (n = 8, each). The results revealed that the MPH- and R. officinalis-treated groups significantly improved memory impairment, whereas R. officinalis substantially reduced depression and anxiety as compared with other treatment groups. MPH treatment induced an antidepressant effect and increased anxiety-like behavior. Moreover, the AlCl₃ exposure led to the formation of amyloid beta (Aβ) plaques in mice hippocampus; however, none of the tested drugs caused a significant reduction in amyloid burden at the selected doses. The present study suggested the potential of R. officinalis to improve memory as well as neuropsychiatric symptoms in AD. Although R. officinalis improved cognitive abilities, it did not reduce the amyloid plaque burden, which indicates that the memory-enhancing effects of R. officinalis are due to some alternate mechanism that needs to be explored further.

Stimulants

Stimulants have been available for the treatment of attention-deficit/hyperactivity disorder (ADHD) for more than 70 years and are the most effective medications available. During the past 2 decades, several new immediate-release (IR) and extended-release methylphenidate (MPH) and amphetamine (AMPH) formulations have become available. These products differ by dose form (capsules, tablets, oral suspensions, oral disintegrating tablets, and patch), by onset and duration of effect, and by bioavailability. The side effect profile is generally similar for all compounds. Although the products are similar, individual patients may have a better response or tolerability to a particular class (MPH or AMPH) or formulation.

Evidence of methylphenidate effect on mitochondria, redox homeostasis, and inflammatory aspects: Insights from animal studies

Methylphenidate (MPH) is a central nervous system (CNS) stimulant known for its effectiveness in the treatment of Attention Deficit Hyperactivity Disorder (ADHD), a neuropsychiatric condition that has a high incidence in childhood and affects behavior and cognition. However, the increase in its use among individuals who do not present all the diagnostic criteria for ADHD has become a serious public health problem since the neurological and psychiatric consequences of this unrestricted use are not widely known. In addition, since childhood is a critical period for the maturation of the CNS, the high prescription of MPH for preschool children also raises several concerns. This review brings new perspectives on how MPH (in different doses, routes of administration and ages) affects the CNS, focusing on animal studies that evaluated changes in mitochondrial (bioenergetics), redox balance and apoptosis, as well as inflammatory parameters. MPH alters brain energy homeostasis, increasing glucose consumption and impairing the activity of enzymes in the Krebs cycle and electron transport chain, as well as ATP levels and Na⁺,K⁺-ATPase activity. MPH induces oxidative stress, increasing the levels of reactive oxygen and nitrogen species and altering enzymatic and non-enzymatic antioxidant defenses, which, consequently, is related to damage to proteins, lipids, and DNA. Among the harmful effects of MPH, studies also demonstrate its ability to induce inflammation as well as alter the apoptosis pathway. It is important to highlight that age, treatment time, administration route, and dose are factors that can influence MPH effects. However, young animals seem to be more susceptible to damage caused by MPH. It is possible that changes in mitochondrial function and markers of status oxidative, apoptosis and inflammation may be exerting important mechanisms associated with MPH toxicity and, therefore, the unrestricted use of this drug can cause brain damage.

D-serine metabolism in the medial prefrontal cortex, but not the hippocampus, is involved in AD/HD-like behaviors in SHRSP/Ezo

Attention-deficit/hyperactivity disorder (AD/HD) is a mild neurodevelopmental disorder with inattention, hyperactivity, and impulsivity as its core symptoms. We previously revealed that an AD/HD animal model, juvenile stroke-prone spontaneously hypertensive rats (SHRSP/Ezo) exhibited functional abnormalities in N-methyl-D-aspartate (NMDA) receptors in the prefrontal cortex. D-serine is an endogenous co-ligand that acts on the glycine-binding site of NMDA receptors, which is essential for the physiological activation of NMDA receptors. We herein performed neurochemical and pharmacological behavioral experiments to elucidate dysfunctions in D-serine metabolism (namely, biosynthesis and catabolism) associated to AD/HD. The serine enantiomers ratio (D-serine/D-serine + L-serine, DL ratio) in the medial prefrontal cortex (mPFC) and hippocampus (HIP) was lower in SHRSP/Ezo than in its genetic control. The level of D-amino acid oxidase (DAAO, D-serine degrading enzyme) was higher in the mPFC, and the level of serine racemase (SR, D-serine biosynthetic enzyme), was lower in the HIP in SHRSP/Ezo. Thus, changes in these enzymes may contribute to the lower DL ratio of SHRSP/Ezo. Moreover, a microinjection of a DAAO inhibitor into the mPFC in SHRSP/Ezo increased DL ratio and attenuated AD/HD-like behaviors, such as inattention and hyperactivity, in the Y-maze test. Injection into the HIP also increased the DL ratio, but had no effect on behaviors. These results suggest that AD/HD-like behaviors in SHRSP/Ezo are associated with an abnormal D-serine metabolism underlying NMDA receptor dysfunction in the mPFC. These results will contribute to elucidating the pathogenesis of AD/HD and the development of new treatment strategies for AD/HD.

Human behavioral pharmacology of stimulant drugs: An update and narrative review

Stimulant use disorders present an enduring public health concern. Chronic stimulant use is associated with a range of health problems, with notable increases in stimulant overdose that disproportionately affect marginalized populations. With these persistent problems, it is important to understand the behavioral and pharmacological factors that contribute to stimulant use in humans. The purpose of this chapter is to provide an update and narrative review on recent human laboratory research that has evaluated the behavioral pharmacology of stimulant drugs. We focus on two prototypic stimulants: cocaine as a prototype monoamine reuptake inhibitor and d-amphetamine as a prototype monoamine releaser. As such, placebo controlled human laboratory studies that involved administration of doses of cocaine or d-amphetamine and were published in peer reviewed journals within the last 10 years (i.e., since 2011) are reviewed. Primary outcomes from these studies are subjective effects, reinforcing effects, cognitive/behavioral effects, and discriminative stimulus effects. Both cocaine and d-amphetamine produce classical stimulant-like behavioral effects (e.g., increase positive subjective effects, function as reinforcers), but there are notable gaps in the literature including understanding sex differences in response to stimulant drugs, cognitive-behavioral effects of stimulants, and influence of use history (e.g., relatively drug naïve vs drug experienced) on stimulant effects.

Neuroprotective Properties of Minocycline Against Methylphenidate-Induced Neurodegeneration: Possible Role of CREB/BDNF and Akt/GSK3 Signaling Pathways in Rat Hippocampus

Neurodegeneration is a side effect of methylphenidate (MPH), and minocycline possesses neuroprotective properties. This study aimed to investigate the neuroprotective effects of minocycline against methylphenidate-induced neurodegeneration mediated by signaling pathways of CREB/BDNF and Akt/GSK3. Seven groups of seventy male rats were randomly distributed in seven groups (n = 10). Group 1 received 0.7 ml/rat of normal saline (i.p.), and group 2 was treated with MPH (10 mg/kg, i.p.). Groups 3, 4, 5, and 6 were simultaneously administered MPH (10 mg/kg) and minocycline (10, 20, 30, and 40 mg/kg, i.p.) for 21 days. Minocycline alone (40 mg/kg, i.p.) was administrated to group 7. Open field test (OFT) (on day 22), forced swim test (FST) (on day 24), and elevated plus maze (on day 26) were conducted to analyze the mood-related behaviors; hippocampal oxidative stress, inflammatory, and apoptotic parameters, as well as the levels of protein kinase B (Akt-1), glycogen synthase kinase 3 (GSK3), cAMP response element-binding protein (CREB), and brain-derived neurotrophic factor (BDNF), were also assessed. Furthermore, localization of total CREB, Akt, and GSK3 in the DG and CA1 areas of the hippocampus were measured using immunohistochemistry (IHC). Histological changes in the mentioned areas were also evaluated. Minocycline treatment inhibited MPH-induced mood disorders and decreased lipid peroxidation, oxidized form of glutathione (GSSG), interleukin 1 beta (IL-1β), alpha tumor necrosis factor (TNF-α), Bax, and GSK3 levels. In the contrary, it increased the levels of reduced form of glutathione (GSH), Bcl-2, CREB, BDNF, and Akt-1 and superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in the experimental animals' hippocampus. IHC data showed that minocycline also improved the localization and expression of CREB and Akt positive cells and decreased the GSK3 positive cells in the DG and CA1 regions of the hippocampus of MPH-treated rats. Minocycline also inhibited MPH-induced changes of hippocampal cells' density and shape in both DG and CA1 areas of the hippocampus. According to obtained data, it can be concluded that minocycline probably via activation of the P-CREB/BDNF or Akt/GSK3 signaling pathway can confer its neuroprotective effects against MPH-induced neurodegeneration.

Attention Deficit Hyperactivity Disorder and Substance Use Disorder: A Narrative Review

Attention deficit hyperactivity disorder (ADHD) has a growing incidence and prevalence in the United States and throughout the world, much of which is contributed to increased awareness of the condition and solidified diagnostic criteria. Substance use disorder (SUD) similarly has seen a sharp increase, particularly with the rising cases of opioid abuse. Management of ADHD is done primarily with pharmacologic therapy, often stimulants and with psychosocial interventions (i.e., exercise, meditation, peer-to-peer intervention, etc.) for adjunctive management. Management of SUD involves cessation and treatment based on the underlying drug of abuse. Many clinicians are uncomfortable treating ADHD in patients with SUD based on concerns the intervention may lead to an adverse event, including drug relapse, and the development of other psychiatric comorbidities. Concerns also arise about stimulants acting as a gateway drug in adolescents leading to the onset of SUD. Thus, in this narrative review, we aim to shed light on ADHD in relation to SUD and to provide clinical insight based on the current scientific literature on the topic. ADHD causes lesions in subcortical structures in the basal ganglia and limbic system. Treatment of ADHD with stimulants has been shown to normalize malformed neuroanatomical variations and lead to improved long-term outcomes compared to non-treatment of ADHD. Based on current scientific literature, it is recommended to treat ADHD with guideline-directed pharmacologic agents including stimulants along with non-pharmacologic interventions primarily exercise. There may be some improvement in reducing risky behavior, such as substance abuse, and may even help prevent the development of SUD.

Effect of Atomoxetine on Behavioral Difficulties and Growth Development of Primary School Children with Attention-Deficit/Hyperactivity Disorder: A Prospective Study

(1) Objective: Atomoxetine is a selective norepinephrine reuptake inhibitor used to treat attention-deficit/hyperactivity disorder (ADHD) in children over six years old. Although it is common knowledge that primary school children with ADHD often present with difficulties in the morning prior to school and in the evening, these two periods, and the family interactions they involve, are often neglected in studies of ADHD. Questionnaire–Children with Difficulties (QCD) has been widely used in China to evaluate parents’ perceptions of ADHD and patients’ daily behaviors during different times. In the long term, the efficacy and safety of atomoxetine have been well established in previous studies. Still, the short-term effects of atomoxetine treatment on serum growth parameters, such as IGF-1, IGFBP-3, and thyroid function, are not well documented. Therefore, this study was the first one using the QCD to quantify the efficacy of atomoxetine treatment in the morning prior to school and in the evening, and has investigated the possible influence on the growth parameters of Chinese primary school children with ADHD. (2) Method: This prospective study was conducted at the Department of Pediatrics at the Affiliated Hospital of Jiangnan University from August 2019 to February 2021. Changes in the children’s behavior and core ADHD symptoms following treatment were assessed using three parent-reported questionnaires, including Children with Difficulties (QCD), the Swanson, Nolan, and Pelham IV scale (SNAP-IV), and the Conners’ parents rating scales (CPRS). The height, weight, and body mass index (BMI) were measured and corrected to reflect the standard deviations (SDS) in Chinese children based on age and gender. Serum growth parameters, such as insulin-like growth factor 1 (IGF-1), insulin-like growth factor-binding protein 3 (IGFBP-3), and thyroid function, were also measured to assess the children’s growth development. Any adverse drug reactions were assessed every three weeks. (3) Result: Finally, 149 children were enrolled in this study, and they completed 12 weeks of atomoxetine treatment. The QCD results indicated that the atomoxetine treatment could significantly alleviate behavioral difficulties in primary children with ADHD, especially in the morning prior to school (p < 0.001, r = 0.66) and in the evening (p < 0.001, r = 0.73). A statically significant decrease in weight SDS (p < 0.05) was noted during treatment, but the effect size was slight (r = 0.09). The atomoxetine treatment had no significant impact on height SDS, BMI SDS, and serum growth parameters, such as the levels of IGF-1, IGFBP-3, and thyroid function. The SNAP-IV results showed a significant improvement in the core symptoms of ADHD, while the CPRS results indicated a significant improvement in controlling ADHD symptoms across two different domains, learning problems (r = 0.81) and hyperactivity (r = 0.86). No severe adverse reactions were observed in the course of treatment, and the most common adverse reactions were gastrointestinal symptoms. (4) Conclusions: Atomoxetine is an effective and safe treatment for primary school children with ADHD. In China, it may be an excellent choice to alleviate parenting stress and improve the condition of primary school children with ADHD. Moreover, our study indicated that the serum levels of IGF-1 and IGFBP-3 were within the normal range in newly diagnosed ADHD children, and atomoxetine will not affect the serum concentration of growth parameters, such as IGF-1, IGFBP-3, and thyroid function, in the short term. However, the treatment may reduce appetite, resulting in a reduction in the Children’s weight for a short period. Further observational studies to monitor the long-term effects of atomoxetine on primary school children are recommended.

Pharmacotherapy of residual excessive sleepiness among continuous positive airway pressure (CPAP) treated patients with sleep apnea

INTRODUCTION

Patients with persistent sleepiness after adequate treatment of obstructive sleep apnea (OSA) with nasal continuous positive airway pressure (nCPAP) experience impaired cognition, reduced productivity, and worse quality of life. Although the mechanisms responsible for this phenomenon are not completely understood, neuroimaging studies have identified reduced gray matter in the frontal cortex and alterations in white matter integrity suggestive of axonal and myelin damage. The intermittent hypoxia with resulting oxidative injury is considered a prime culprit behind the loss of wake-promoting catecholaminergic neurons.

AREAS COVERED

This narrative review gives an overview of the pathophysiology and approaches to managing patients with residual sleepiness. The authors explore different targeted strategies aimed at improving selection of appropriate pharmacotherapy.

EXPERT OPINION

Wake-stimulant medications (modafinil and armodafinil) have demonstrated efficacy in reducing sleepiness in adequately treated OSA. The recent FDA approval of pitolisant and solriamfetol complements the use of modafinil by substituting for direct sympathomimetic agents. The distinctive pharmacologic profile and mode of action of each of these agents offer the opportunity of a personalized approach to the management of this disorder. Further studies should be conducted on the long-term effect of these agents alone or in combination on brain structural and functional changes.

Childhood ADHD, Going Beyond the Brain: A Meta-Analysis on Peripheral Physiological Markers of the Heart and the Gut

Attention-Deficit/Hyperactivity Disorder (ADHD) is the most common neurodevelopmental disorder diagnosed in children. Questions regarding its increased diagnostic rates and pharmacological treatments in developing children have led to a more holistic review of the multi-system pathophysiology observed in ADHD. The dopaminergic neurotransmitter system, known for its influence on reward-motivated behaviors and motor control, and the frontostriatal systems, that mediate motor, cognition, and behavior, are associated with ADHD's development. However, studies have shown that these neural systems do not wholly account for ADHD's multilayered and heterogeneous symptom presentation. For instance, the literature suggests that emotional dysregulation, the inability to regulate one's emotional responses to provoking stimuli, is associated with increased risk for social impairment in ADHD. A broader examination of physiological systems in children with ADHD has found potential markers in the heart-brain and gut-brain axes that correspond with certain behaviors associated with emotional dysregulation in recent studies. Hence, the purpose of this meta-analysis is to aggregate ten applicable published case studies and analyze task-related heart rate reactivity (HRR; n = 5 studies) and gut microbiota (n = 5 studies) data in children with and without ADHD. Data from a total of 531 youth with ADHD and 603 youth without ADHD revealed significant small and medium effect sizes for higher Chao1 levels and Actinobacteria levels in the ADHD group, respectively, but no evidence of altered task-related HRR. Thus, further research into multi-system psychophysiological measures of emotional dysregulation and ADHD is warranted. The clinical, empirical, and educational implications of these findings are discussed.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier PROSPERO (CRD42021236819).

Fifteen years' experience with methylphenidate for attention-deficit disorder during pregnancy: Effects on birth weight, Apgar score and congenital malformation rates

BACKGROUND

Methylphenidate (MPD) is increasingly prescribed to fertile women with Attention-Deficit Disorder (AD(H)D), with or without hyperactivity, despite advice for discontinuation during pregnancy. Few studies report on results concerning safety after methylphenidate exposure during pregnancy for the offspring.

AIM

Safety for the offspring of exposure to MPD during pregnancy.

METHODS

This is an observational retrospective cohort study in a population of pregnant women and their offspring, treated with MPD for ADHD in the Psychiatry-Gynaecology-Pediatrics outpatient clinic between 1 January 2005 and 1 June 2020 at Isala hospital. The primary endpoints were birth weight and Apgar score in offspring exposed to MPD during pregnancy, compared to offspring unexposed to MPD. Birth weight was analysed using linear mixed model analysis. Apgar score and (secondary endpoint) neonatal malformations, at 20 week ultrasound, were analysed using basic univariate statistical analysis.

RESULTS

MPD continuation, compared to discontinuation, was associated with higher neonatal birth weight (p = 0.049), but lost statistical significance after incorporating covariates (p = 0.079). There were no significant differences in Apgar scores and congenital malformations between neonates exposed and unexposed to MPD.

CONCLUSIONS

MPD does not seem to affect birth weight, Apgar score and the frequency of neonatal malformations at the 20 week ultrasound.

MicroPET/CT assessment of neurochemical effects in the brain after long-term methylphenidate treatment in nonhuman primates

Methylphenidate (MPH) is a psychostimulant approved by the FDA to treatment Attention-Deficit Hyperactivity Disorder (ADHD). MPH is believed to exert its pharmacological effects via preferential blockade of the dopamine transporter (DAT) and the norepinephrine transporter (NET), resulting in increased monoamine levels in the synapse. We used a quantitative non-invasive PET imaging technique to study the effects of long-term methylphenidate use on the central nervous system (CNS). We conducted microPET/CT scans on young adult male rhesus monkeys to monitor changes in the dopaminergic system. We used [¹⁸F] AV-133, a ligand for the vesicular monoamine transporter 2 (VMAT2), and [¹⁸F]FESP a ligand for the D₂ and 5HT₂ receptors. In this study we evaluated the effects if chronic MPH treatment in the nonhuman primates (NHP). Two-year-old, male rhesus monkeys were orally administered MPH diluted in the electrolyte replenisher, Prang, twice a day, five days per week (M-F) over an 8-year period. The dose of MPH was gradually escalated from 0.15 mg/kg initially to 2.5 mg/kg/dose for the low dose group, and 1.5 mg/kg to 12.5 mg/kg/dose for the high dose group (Rodriguez et al., 2010). Scans were performed on Mondays, about 60 h after their last treatment, to avoid the acute effects of MPH. Tracers were injected intravenously ten minutes before microPET/CT scanning. Sessions lasted about 120 min. The Logan reference tissue model was used to determine the Binding Potential (BP) of each tracer in the striatum with the cerebellar cortex time activity curve as an input function. Both MP treatment groups had a lower [¹⁸F] AV-133 BP, although this failed to reach statistical significance. MPH treatment did not have a significant effect on The BP of [¹⁸F] FESP in the striatum. Long-term administration of MPH did not significant change any of the marker of monoamine function used here. These data suggest that, despite lingering concerns, long-term use of methylphenidate does not negatively impact monoamine function. This study also demonstrates that microPET imaging can distinguish differences in binding potentials of a variety of radiotracers in the CNS of NHPs. This approach may provide minimally-invasive biomarkers of neurochemical processes associated with chronic exposure to CNS medications. (Supported by NCTR).

Serum Levels of Vitamin A and Vitamin D and Their Association With Symptoms in Children With Attention Deficit Hyperactivity Disorder

Objective: To measure levels of vitamin A (VA) and vitamin D (VD) and the symptomatic association of their co-deficiencies on attention deficit hyperactivity disorder (ADHD) in Chinese children (6-9 years). Methods: Eighty-two children (69 boys and 13 girls; mean age = 7.1 ± 0.9 years at the time of the diagnosis) with ADHD were recruited as ADHD group. A total of 106 healthy children were recruited as the healthy control (HC) group. Serum levels of retinol and 25-hydroxyvitamin D (25(OH)D) of all children were evaluated using high-performance liquid chromatography (HPLC) and HPLC-tandem mass spectrometry. The Swanson, Nolan, and Pelham IV Rating Scale (SNAP-IV) was employed to assess the clinical symptoms of ADHD. Results: Children suffering from ADHD had significantly reduced serum levels of retinol and 25(OH)D compared with those of HCs, and the prevalence of VA deficiency and VD deficiency were higher in children suffering from ADHD. Serum concentrations of 25(OH)D and retinol were linked closely with the presence or absence of ADHD after adjustment for age, body mass index, season of blood sampling, and sun exposure. Serum concentrations of 25(OH)D and retinol showed a negative correlation with the total scores of SNAP-IV. Children with ADHD as well as VA and VD co-deficiency had increased SNAP-IV total scores and ADHD inattention subscale scores. Conclusion: VA deficiency and VD deficiency in children with ADHD were increased in comparison with that in HCs. VA and VD co-deficiency associated with ADHD symptom severity. Attention should be paid to regular testing of VA levels and VD levels. However, the mechanism of VA and VD in ADHD needs to be further studied. Interventional studies on VA and VD supplementation are recommended to further verify the relationship between VA and VD co-deficiency and ADHD.