Age of methylphenidate treatment initiation in children with ADHD and later substance abuse: prospective follow-up into adulthood

Hidden in plain sight: delayed ADHD diagnosis among girls and women - a commentary on Skoglund et al. (2023)

Skoglund et al. (Journal of Child Psychology and Psychiatry, 2023) finds women with ADHD experience a nearly 4-year delay in receiving an ADHD diagnosis compared to men, despite also having high rates of prior contact with the mental health care system. In this commentary, I discuss the findings of Skoglund et al. and how they shed light on possible explanations for this diagnostic delay among women, and the need to consider women-specific issues, like times of hormonal change, in ADHD diagnosis and treatment.

Methylphenidate use and restorative treatment needs in young adults with attention deficit hyperactivity disorder

OBJECTIVE

To assess the effect and dose-response of methylphenidate (MP) use on the restorative treatment needs in young adults with attention deficit hyperactivity disorder.

PARTICIPANTS AND METHODS

This retrospective study comprises a cohort of military recruits aged 18-25 who served for 12 to 48 months between 2005 and 2017. The medical records of 213 604 participants were assessed of which: 6875 participants with ADHD who received treatment with MP, 6729 participants with ADHD who had no prescriptions for MP, and 200 000 healthy participants. The outcome was restorative treatment needs, which served as an indicator of caries: having at least one prescription for restorative treatment during the study period.

RESULTS

Frequency of prescription for restorative treatment among the treated, the untreated and the control groups was 24%, 22%, and 17%, respectively (p < .0001). On multivariate analysis, the dose-response association between MP use and the odds of having at least one restorative treatment was confirmed (OR = 1.006 for each additional 1 gr of MP; 95% CI [1.004:1.009]) CONCLUSIONS: Participants with ADHD who receive chronic treatment with MP have higher restorative treatment needs than participants with untreated ADHD and healthy participants. Our results show that chronic MP medication among young adults leads to an elevated need for restorative treatment and implies a significant impact on oral health (OH).

Is age of onset and duration of stimulant therapy for ADHD associated with cocaine, methamphetamine, and prescription stimulant misuse?

BACKGROUND

To assess whether age of onset and duration of stimulant therapy for attention-deficit/hyperactivity disorder (ADHD) are associated with cocaine, methamphetamine, and prescription stimulant misuse during adolescence.

METHODS

Nationally representative samples of US 10th and 12th grade students (N = 150,395) from the Monitoring the Future study were surveyed via self-administered questionnaires from 16 annual surveys (2005-2020).

RESULTS

An estimated 8.2% of youth received stimulant therapy for ADHD during their lifetime (n = 10,937). More than one in 10 of all youth reported past-year prescription stimulant misuse (10.4%)-past-year cocaine (4.4%) and methamphetamine (2.0%) use were less prevalent. Youth who initiated early stimulant therapy for ADHD (≤9 years old) and for long duration (≥6 years) did not have significantly increased adjusted odds of cocaine or methamphetamine use relative to population controls (ie, non-ADHD and unmedicated ADHD youth). Youth who initiated late stimulant therapy for ADHD (≥10 years old) and for short duration (<1 year) had significantly higher odds of past-year cocaine or prescription stimulant misuse in adolescence than those initiating early stimulant therapy for ADHD (≤9 years old) and for long duration (≥6 years). Youth who initiated late stimulant therapy for ADHD (≥10 years) for short duration (<1 year) had significantly higher odds of past-year cocaine, methamphetamine, and prescription stimulant misuse versus population controls during adolescence. No differences in past-year cocaine, methamphetamine, and prescription stimulant misuse were found between individuals who only used non-stimulant therapy for ADHD relative to youth who initiated early stimulant therapy (≤9 years old) and for long duration (≥6 years).

CONCLUSIONS

An inverse relationship was found between years of stimulant therapy and illicit and prescription stimulant misuse. Adolescents with later initiation and/or shorter duration of stimulant treatment for ADHD should be monitored for potential illicit and prescription stimulant misuse.

Adolescent Cannabis Use, Comorbid Attention-Deficit/Hyperactivity Disorder, and Other Internalizing and Externalizing Disorders

Cannabis use often co-occurs with attention-deficit/hyperactivity disorder and other internalizing and externalizing disorders. Treatment planning, including pharmacologic and psychosocial interventions, for these comorbid disorders require thorough diagnostic evaluation to determine the extent of social, emotional, and behavioral impairments, severity of substance use, and motivation for change. Improved understanding of these comorbid disorders will inform treatment planning that address current symptoms and behaviors and may also prevent the development of mental health and substance use disorders in early adulthood.

Association Between Stimulant Treatment and Substance Use Through Adolescence Into Early Adulthood

Importance

Possible associations between stimulant treatment of attention-deficit/hyperactivity disorder (ADHD) and subsequent substance use remain debated and clinically relevant.

Objective

To assess the association of stimulant treatment of ADHD with subsequent substance use using the Multimodal Treatment Study of ADHD (MTA), which provides a unique opportunity to test this association while addressing methodologic complexities (principally, multiple dynamic confounding variables).

Design, Setting, and Participants

MTA was a multisite study initiated at 6 sites in the US and 1 in Canada as a 14-month randomized clinical trial of medication and behavior therapy for ADHD but transitioned to a longitudinal observational study. Participants were recruited between 1994 and 1996. Multi-informant assessments included comprehensively assessed demographic, clinical (including substance use), and treatment (including stimulant treatment) variables. Children aged 7 to 9 years with rigorously diagnosed DSM-IV combined-type ADHD were repeatedly assessed until a mean age of 25 years. Analysis took place between April 2018 and February 2023.

Exposure

Stimulant treatment of ADHD was measured prospectively from baseline for 16 years (10 assessments) initially using parent report followed by young adult report.

Main Outcomes and Measures

Frequency of heavy drinking, marijuana use, daily cigarette smoking, and other substance use were confidentially self-reported with a standardized substance use questionnaire.

Results

A total of 579 children (mean [SD] age at baseline, 8.5 [0.8] years; 465 [80%] male) were analyzed. Generalized multilevel linear models showed no evidence that current (B [SE] range, -0.62 [0.55] to 0.34 [0.47]) or prior stimulant treatment (B [SE] range, -0.06 [0.26] to 0.70 [0.37]) or their interaction (B [SE] range, -0.49 [0.70] to 0.86 [0.68]) were associated with substance use after adjusting for developmental trends in substance use and age. Marginal structural models adjusting for dynamic confounding by demographic, clinical, and familial factors revealed no evidence that more years of stimulant treatment (B [SE] range, -0.003 [0.01] to 0.04 [0.02]) or continuous, uninterrupted stimulant treatment (B [SE] range, -0.25 [0.33] to -0.03 [0.10]) were associated with adulthood substance use. Findings were the same for substance use disorder as outcome.

Conclusions and Relevance

This study found no evidence that stimulant treatment was associated with increased or decreased risk for later frequent use of alcohol, marijuana, cigarette smoking, or other substances used for adolescents and young adults with childhood ADHD. These findings do not appear to result from other factors that might drive treatment over time and findings held even after considering opposing age-related trends in stimulant treatment and substance use.

Contemporary diagnosis and treatment of conduct disorder in youth

INTRODUCTION

Conduct disorder (CD) is characterized by repetitive and persistent antisocial behaviors, being among the most frequently reported reasons of referral in youth. CD is a highly heterogeneous disorder, with possible specifiers defined according to age at onset, Limited Prosocial Emotions (LPE) otherwise known as Callous-Unemotional (CU) traits, Emotional Dysregulation (ED), and patterns of comorbidity, each with its own specific developmental trajectories.

AREAS COVERED

The authors review the evidence from published literature on the clinical presentations, diagnostic procedures, psychotherapeutic and psychoeducational approaches, and pharmacological interventions from RCT and naturalistic studies in youth. Evidence from studies including youths with LPE/CU traits, ED and aggression are also reviewed, as response moderators.

EXPERT OPINION

Due to its clinical heterogeneity, relevant subtypes of CD should be carefully characterized to gain reliable information on prognosis and treatments. Thus, disentangling this broad category in subtypes is crucial as a first step in diagnosis. Psychosocial interventions are the first option, possibly improving LPE/CU traits and ED, especially if implemented early during development. Instead, limited information, based on low-quality studies, supports pharmacological options. Second-generation antipsychotics, mood stabilizers, and stimulants are first-line medications, according to different target symptoms, such as aggression and emotional reactivity. Developmental pathways including ADHD suggest a specific role of psychostimulants.

Type of medication therapy for ADHD and stimulant misuse during adolescence: a cross-sectional multi-cohort national study

Background

Attention-deficit/hyperactivity disorder (ADHD) is associated with higher substance use rates. Stimulant and non-stimulant pharmacotherapy improve adolescent ADHD, but their associations with prescription stimulant misuse (PSM), cocaine, and methamphetamine use are unclear. Using 2005-2020 US Monitoring the Future data, we investigated relationships between ADHD pharmacotherapy history and PSM, cocaine, or methamphetamine use.

Methods

Secondary students (13-19 years) provided data on pharmacotherapy history (N = 199,560; 86.3% of total sample) between January 1, 2005 and May 31, 2020 in a cross-sectional multi-cohort study; weights assured a nationally representative sample. Participants were grouped by ADHD pharmacotherapy history: none (88.7%; principally non-ADHD controls); stimulant-only (5.8%); non-stimulant-only (3.3%); both stimulant and non-stimulant (2.1%). Outcomes were past-year PSM, cocaine, and methamphetamine use. Logistic regressions examined relationships between pharmacotherapy history and outcomes, controlling for sociodemographics, recent substance use, and stimulant treatment cessation.

Findings

Past-year outcome rates were lowest in adolescents with no pharmacotherapy history: 4.7% for PSM [8310/174,561], 1.6% for cocaine [2858/174,688], and 0.7% for methamphetamine [1036/148,378]. A history of both stimulant and non-stimulant treatment was associated with the highest rates: 22.3% for PSM [940/4098], 10.4% for cocaine [450/4110], and 7.8% for methamphetamine [275/3427]. Adolescents who received monotherapy (stimulant- or non-stimulant-only) had intermediate rates, with no differences between monotherapy groups.

Interpretation

While elevated PSM and illicit stimulant use rates are likely influenced by ADHD, our findings suggested adolescents with a history of both stimulant and non-stimulant pharmacotherapy are at highest risk for these stimulant outcomes. Adolescents receiving ADHD pharmacotherapy should be monitored for PSM and illicit stimulant use.

Funding

National Institute on Drug Abuse/National Institutes of Health (USA) and Food and Drug Administration (USA).

Identification and treatment of individuals with attention-deficit/hyperactivity disorder and substance use disorder: An expert consensus statement

Attention-deficit/hyperactivity disorder (ADHD) often co-occurs with substance use (SU) and/or substance use disorder (SUD). Individuals with concurrent ADHD and SU/SUD can have complex presentations that may complicate diagnosis and treatment. This can be further complicated by the context in which services are delivered. Also, when working with young people and adults with co-existing ADHD and SU/SUD, there is uncertainty among healthcare practitioners on how best to meet their needs. In February 2022, the United Kingdom ADHD Partnership hosted a meeting attended by multidisciplinary experts to address these issues. Following presentations providing attendees with an overview of the literature, group discussions were held synthesizing research evidence and clinical experience. Topics included: (1) A review of substances and reasons for use/misuse; (2) identification, assessment and treatment of illicit SU/SUD in young people and adults with ADHD presenting in community services; and (3) identification, assessment and treatment of ADHD in adults presenting in SU/SUD community and inpatient services. Dis-cussions highlighted inter-service barriers and fragmentation of care. It was concluded that a multimodal and multi-agency approach is needed. The consensus group generated a table of practice recommendations providing guidance on: identification and assessment; pharmacological and psychological treatment; and multi-agency interventions.

Pharmacological strategies for the management of the antisocial personality disorder

INTRODUCTION

Antisocial personality disorder (AsPD) is a pervasive pattern of violation of others' rights, related to the concept of psychopathy. AsPD is stable over time from adolescence, with evidence of conduct disorder (CD) before 15 years. DSM-5 included a specifier 'with limited prosocial emotions' (LPE), which characterizes adolescents with higher developmental vulnerability to develop AsPD. Despite being relatively frequent with considerable societal impact, AsPD is a difficult-to-treat condition with high comorbidity rates and poor evidence for effective pharmacological interventions.

AREAS COVERED

We conducted a narrative review and searched PubMed up to September 2022. We included RCTs and naturalistic studies evaluating pharmacological interventions on AsPD in adults, including those with comorbid substance use disorder or psychopathic traits. Evidence in youths with CD, callous-unemotional (CU) traits and aggression were also reviewed, exploring the role of CU traits as moderators of response.

EXPERT OPINION

Psychosocial interventions are the first option, with possible improvement of CU traits, beyond behavioral and affective symptoms, particularly if implemented early during development. Limited information, based on low-quality studies, supports the pharmacological options. Second-generation antipsychotics, lithium, anti-epileptic drugs, and stimulants are first-line medications, according to different target symptoms. Developmental pathways including ADHD suggest a specific role of psychostimulants.

Triple Diagnosis of Attention-Deficit/Hyperactivity Disorder with Coexisting Bipolar and Alcohol Use Disorders: Clinical Aspects and Pharmacological Treatments

Attention-Deficit/Hyperactivity Disorder (ADHD), Bipolar Disorder (BD) and Alcohol Use Disorder (AUD) are common medical conditions often coexisting and exerting mutual influence on disease course and pharmacological treatment response. Each disorder, when considered separately, relies on different therapeutic approaches, making it crucial to detect the plausible association between them. Treating solely the emerging condition (e.g., alcoholism) and disregarding the patient's whole psychopathological ground often leads to treatment failure and relapse. Clinical experience and scientific evidence rather show that tailoring treatments for these three conditions considering their co-occurrence as a sole complex disorder yields more fulfilling and durable clinical outcomes. In light of the above considerations, the purpose of the present review is to critically discuss the pharmacological strategies in the personalized treatment of complex conditions defined by ADHD-bipolarityalcoholism coexistence.

Adolescent Cannabis Use, Comorbid Attention-Deficit/Hyperactivity Disorder, and Other Internalizing and Externalizing Disorders

Cannabis use often co-occurs with attention-deficit/hyperactivity disorder and other internalizing and externalizing disorders. Treatment planning, including pharmacologic and psychosocial interventions, for these comorbid disorders require thorough diagnostic evaluation to determine the extent of social, emotional, and behavioral impairments, severity of substance use, and motivation for change. Improved understanding of these comorbid disorders will inform treatment planning that address current symptoms and behaviors and may also prevent the development of mental health and substance use disorders in early adulthood.

Age-related clinical characteristics of children and adolescents with ADHD

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) has been associated with difficulties in regulating aversion states, high functional impairment, and a high risk of psychopathology across the lifespan. ADHD is clinically heterogeneous, with a wide spectrum of severity and associated symptoms. Clinical characteristics need to be carefully defined in different periods of life as ADHD course, symptoms, and comorbidities may fluctuate and change over time. Adolescence usually represents the transition from primary to secondary education, with a qualitative and quantitative change in environmental and functional demands, thus driving symptoms' change.

METHODS

In order to characterize age-related clinical features of children (<11 years) and adolescents (≥11 years) with ADHD, we conducted a naturalistic study on 750 children and adolescents assessed for ADHD at our Neuropsychiatry Unit over the course of 3 years (2018-2020).

RESULTS

We found that ADHD symptoms were significantly higher in children than adolescents. More importantly, we found worse global functioning, lower adaptive skills, higher levels of anxiety and depressive symptoms, somatic complaints, emotional dysregulation, social problems, and aggression in adolescents, despite a lower severity of ADHD-specific symptoms.

CONCLUSION

These results should be confirmed in longitudinal observational studies of adequate sample size in order to reliably describe a potential course characterized by worsening of functioning, reduction in ADHD-specific symptoms and increase in general psychopathology during the transition from childhood to adolescence.

Cerebro-cerebellar Dysconnectivity in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Abnormal cerebellar development has been implicated in attention-deficit/hyperactivity disorder (ADHD), although cerebro-cerebellar functional connectivity (FC) has yet to be examined in ADHD. Our objective is to investigate the disturbed cerebro-cerebellar FC in children and adolescents with ADHD.

METHOD

We analyzed a dataset of 106 individuals with ADHD (68 children, 38 adolescents) and 62 healthy comparison individuals (34 children, 28 adolescents) from the publicly available ADHD-200 dataset. We identified 7 cerebellar subregions based on cerebro-cerebellar FC and subsequently obtained the FC maps of cerebro-cerebellar networks. The main effects of ADHD and age and their interaction were examined using 2-way analysis of variance.

RESULTS

Compared to comparisons, ADHD showed higher cerebro-cerebellar FC in the superior temporal gyrus within the somatomotor network. Interactions of diagnosis and age were identified in the supplementary motor area and postcentral gyrus within the somatomotor network and middle temporal gyrus within the ventral attention network. Follow-up Pearson correlation analysis revealed decreased cerebro-cerebellar FC in these regions with increasing age in comparisons, whereas the opposite pattern of increased cerebro-cerebellar FC occurred in ADHD.

CONCLUSION

Increased cerebro-cerebellar FC in the superior temporal gyrus within the somatomotor network could underlie impairments in cognitive control and somatic motor function in ADHD. In addition, increasing cerebro-cerebellar FC in older participants with ADHD suggests that enhanced cerebellar involvement may compensate for dysfunctions of the cerebral cortex in ADHD.

Effects of Methylphenidate on the Dopamine Transporter and Beyond

The dopamine transporter (DAT) is the main target of methylphenidate (MPH), which remains the number one drug prescribed worldwide for the treatment of Attention-Deficit Hyperactivity Disorder (ADHD). In addition, abnormalities of the DAT have been widely associated with ADHD. Based on clinical and preclinical studies, the direction of DAT abnormalities in ADHD are, however, still unclear. Moreover, chronic treatment of MPH has been shown to increase brain DAT expression in both animals and ADHD patients, suggesting that findings of overexpressed levels of DAT in ADHD patients are possibly attributable to the effects of long-term MPH treatment rather than the pathology of the condition itself. In this chapter, we will discuss some of the effects exerted by MPH, which are related to its actions on catecholamine protein targets and brain metabolites, together with genes and proteins mediating neuronal plasticity. For this purpose, we present data from biochemical, proton nuclear magnetic resonance spectroscopy (¹H-NMR) and gene/protein expression studies. Overall, results of the studies discussed in this chapter show that MPH has a complex biological/pharmacological action well beyond the DAT.

The effect of environment on cross-sensitization between methylphenidate and amphetamine in female rats

Methylphenidate (MPD) and amphetamine (AMP) are both psychostimulants that are often used to treat behavioral disorders. More recently, it has also been increasingly used illicitly for recreation as well as to improve intellectual performance. Many factors such as age, gender, genetic background, and environment govern the development of behavioral sensitization to MPD and cross-sensitization with other drugs, which are experimental behavioral markers indicating potential of substance dependence and abuse. This study examines the effects of the environment and age when MPD was exposed in adulthood alone as well as in adolescence into adulthood on cross-sensitization with AMP in female SD rats by randomizing animals to either receive the drug in a home cage or a test cage during adolescence, adulthood, or both. In a 34 day experiment, 16 groups of animals starting in adolescence were treated with saline on experimental day one (ED1), followed by a 6 day (ED2-ED7) treatment with either saline, 0.6 mg/kg AMP, 0.6, 2.5, or 10.0 mg/kg MPD. Experimental groups were then subject to a 3-day washout period (ED8-ED10) and then a retreatment with the respective drug on ED11 in adolescence (P-38 to P-49). Experiments continued in the same animal groups now in adulthood (P-60) with a saline treatment (ED1), followed by the same sequence of treatments in adolescence (ED2-ED11;P-61 to P-69). A rechallenge with the same AMP or MPD dose was performed on ED11 (P-70) followed by a single exposure to 0.6 mg/kg AMP on ED12 (P-71) to assess for cross sensitization between MPD and AMP. Animals treated with MPD in both adolescence and adulthood and in the last experimental day of AMP (ED12) showed higher intensity of cross-sensitivity between MPD and AMP as compared to animals treated with MPD only in adulthood. AMP and MPD treatment in adolescence and into adulthood in the home or test cage resulted in significantly higher responses to the drug as compared to those treated only in adulthood. Overall, we conclude that environmental alteration and adolescent exposure to MPD appeared to increase the risk of cross-sensitization to AMP in female SD rats i.e, using MPD in adolescence may increase the probability of becoming dependent on drugs of abuse. This further indicates that age, sex, and environment all influence the response to MPD and AMP, and further work is needed to elucidate the risks associated with MPD and AMP use.

Sex Differences in Substance Use, Prevalence, Pharmacological Therapy, and Mental Health in Adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD)

Sex differences are poorly studied within the field of mental health, even though there is evidence of disparities (with respect to brain anatomy, activation patterns, and neurochemistry, etc.) that can significantly influence the etiology and course of mental disorders. The objective of this work was to review sex differences in adolescents (aged 13–18 years) diagnosed with ADHD (according to the DSM-IV, DSM-IV-TR and DSM-5 criteria) in terms of substance use disorder (SUD), prevalence, pharmacological therapy and mental health. We searched three academic databases (PubMed, Web of Science, and Scopus) and performed a narrative review of a total of 21 articles. The main conclusions of this research were (1) girls with ADHD are more at risk of substance use than boys, although there was no consensus on the prevalence of dual disorders; (2) girls are less frequently treated because of underdiagnosis and because they are more often inattentive and thereby show less disruptive behavior; (3) together with increased impairment in cognitive and executive functioning in girls, the aforementioned could be related to greater substance use and poorer functioning, especially in terms of more self-injurious behavior; and (4) early diagnosis and treatment of ADHD, especially in adolescent girls, is essential to prevent early substance use, the development of SUD, and suicidal behavior.

The Impact of Pharmacotherapy of Childhood-Onset Psychiatric Disorders on the Development of Substance Use Disorders

Background and Objective: Child- and adolescent-onset psychopathology is known to increase the risk for developing substance use and substance use disorders (SUDs). While pharmacotherapy is effective in treating pediatric psychiatric disorders, the impact of medication on the ultimate risk to develop SUDs in these youth remains unclear. Methods: We conducted a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) systematic review of peer-reviewed literature published on PubMed through November 2021, examining pharmacological treatments of psychiatric disorders in adolescents and young adults and their effect on substance use, misuse, and use disorder development. Results: Our search terms yielded 21 studies examining the impact of pharmacotherapy and later SUD in attention-deficit/hyperactivity disorder (ADHD), two studies on Major Depressive Disorder, and three studies on psychotic disorders. The majority of these studies reported reductions in SUD (N = 14 sides) followed by no effects (N = 10) and enhanced rates of SUD (N = 2). Studies in ADHD also reported that earlier-onset and longer-duration treatment was associated with the largest risk reduction for later SUD. Conclusions: Overall, pharmacological treatments for psychiatric disorders appear to mitigate the development of SUD, especially when treatment is initiated early and for longer durations. More studies on the development of SUD linked to the effects of psychotherapy alone and in combination with medication, medication initiation and duration, adequacy of treatment, non-ADHD disorders, and psychiatric comorbidity are necessary.

Sensitization-based risk for substance abuse in vulnerable individuals with ADHD: Review and re-examination of evidence

Evidence of sensitization following stimulants administration in humans is just emerging, which prevents reaching more definitive conclusions in favor or against a purported protective role of stimulant treatments for ADHD for the development of substance use disorders. Existing evidence from both animal and human research suggest that stimulants produce neurophysiological changes in the brain reward system, some of which could be persistent. This could be relevant in choosing optimal treatments for young patients with ADHD who have additional clinical risk factors for substance abuse (e.g. conduct disorder (CD) and/or familial addictions). Here we stipulate that, while the majority of youth with ADHD greatly benefit from treatments with stimulants, there might be a subpopulation of individuals whose neurobiological profiles may confer risk for heightened vulnerability to the effects of stimulants on the responsiveness of the brain reward system. We propose that focused human research is needed to elucidate the unknown effects of prolonged stimulant exposure on the neurophysiology of the brain reward system in young patients with ADHD.

Risk and resilience for alcohol use disorder revealed in brain functional connectivity

A family history of alcoholism (FH) increases risk for alcohol use disorder (AUD), yet many at-risk individuals never develop alcohol use problems. FH is associated with intermediate levels of risk phenotypes, whereas distinct, compensatory brain changes likely promote resilience. Although several cognitive, behavioral, and personality factors have been associated with AUD, the relative contributions of these processes and their neural underpinnings to risk or resilience processes remains less clear. We examined whole-brain resting-state functional connectivity (FC) and behavioral metrics from 841 young adults from the Human Connectome Project, including healthy controls, individuals with AUD, and their unaffected siblings. First, we identified functional connections in which unaffected siblings were intermediate between controls and AUD, indicating AUD risk, and those in which siblings diverged, indicating resilience. Canonical correlations relating brain risk and resilience FC to behavioral patterns revealed AUD risk and resilience phenotypes. Risk phenotypes primarily implicated frontal-parietal networks corresponding with executive function, impulsivity, externalizing behaviors, and social-emotional intelligence. Conversely, resilience-related phenotypes were underpinned by networks of medial prefrontal, striatal, temporal, brainstem and cerebellar connectivity, which associated with high trait attention and low antisocial behavior. Additionally, we calculated "polyphenotypic" risk and resilience scores, to investigate how the relative load of risk and resilience phenotypes influenced the probability of an AUD diagnosis. Polyphenotypic scores predicted AUD in a dose-dependent manner. Moreover, resilience phenotypes interacted with risk phenotypes, reducing their effects. The hypothesis-generating results revealed interpretable AUD-related phenotypes and offer brain-informed targets for developing more effective interventions.

Alcohol use disorders and ADHD

Despite a growing literature on the complex bidirectional relationship of ADHD and substance use, reviews specifically focusing on alcohol are scarce. ADHD and AUD show a significant genetic overlap, including genes involved in gluatamatergic and catecholaminergic neurotransmission. ADHD drives risky behavior and negative experiences throughout the lifespan that subsequently enhance a genetically increased risk for Alcohol Use Disorders (AUD). Impulsive decisions and a maladaptive reward system make individuals with ADHD vulnerable for alcohol use and up to 43 % develop an AUD; in adults with AUD, ADHD occurs in about 20 %, but is vastly under-recognized and under-treated. Thus, routine screening and treatment procedures need to be implemented in AUD treatment. Long-acting stimulants or non-stimulants can be used to treat ADHD in individuals with AUD. However, it is crucial to combine medical treatment for ADHD with pharmacotherapy and psychotherapy for AUD, and other comorbid disorders. Identification of individuals at risk for AUD, especially those with ADHD and conduct disorder or oppositional defiant disorder, is a key factor to prevent negative outcomes.

Do effects of methylphenidate on cognitive performance last beyond treatment? A randomized placebo-controlled trial in boys and men with ADHD

Methylphenidate (MPH) is the first-choice pharmacological treatment for treatment of Attention-Deficit/Hyperactivity Disorder (ADHD) across the lifespan. However, it is unclear whether MPH affects cognitive development, while recent (pre-) clinical studies suggest effects on the developing brain. The present randomized, placebo-controlled trial aims to determine whether MPH has short-term, age-dependent effects on cognitive performance in ADHD after a 1-week washout. Effects of 16 weeks MPH treatment were assessed after a one-week washout on cognitive functioning. Boys (age=10-12) and men (age=23-40) with ADHD were assigned to MPH treatment (boys n=25, men n=24) or placebo (boys n=25, men n=24). Outcome measures were working memory, response inhibition, response speed, episodic memory, and delay aversion. Differences in task performances over time (pre-, mid-, and post-treatment, following a 1-week wash-out) were compared between age and treatment conditions with mixed ANOVAs. MPH improved working memory and response speed, but only during treatment. No lasting age*treatment effects were observed post intervention. Overall, the results from the present randomized, placebo-controlled trial show that the effects of MPH on cognition do not extend past treatment in children or adults. While treatment with MPH improves cognition during treatment, these effects appear transient after 16-weeks of treatment. (Title trial: "Effects of methylphenidate on the developing brain"; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=3103).

Overdiagnosis of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents: A Systematic Scoping Review

IMPORTANCE

Reported increases in attention-deficit/hyperactivity disorder (ADHD) diagnoses are accompanied by growing debate about the underlying factors. Although overdiagnosis is often suggested, no comprehensive evaluation of evidence for or against overdiagnosis has ever been undertaken and is urgently needed to enable evidence-based, patient-centered diagnosis and treatment of ADHD in contemporary health services.

OBJECTIVE

To systematically identify, appraise, and synthesize the evidence on overdiagnosis of ADHD in children and adolescents using a published 5-question framework for detecting overdiagnosis in noncancer conditions.

EVIDENCE REVIEW

This systematic scoping review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Extension for Scoping Reviews and Joanna Briggs Methodology, including the PRISMA-ScR Checklist. MEDLINE, Embase, PsychINFO, and the Cochrane Library databases were searched for studies published in English between January 1, 1979, and August 21, 2020. Studies of children and adolescents (aged ≤18 years) with ADHD that focused on overdiagnosis plus studies that could be mapped to 1 or more framework question were included. Two researchers independently reviewed all abstracts and full-text articles, and all included studies were assessed for quality.

FINDINGS

Of the 12 267 potentially relevant studies retrieved, 334 (2.7%) were included. Of the 334 studies, 61 (18.3%) were secondary and 273 (81.7%) were primary research articles. Substantial evidence of a reservoir of ADHD was found in 104 studies, providing a potential for diagnoses to increase (question 1). Evidence that actual ADHD diagnosis had increased was found in 45 studies (question 2). Twenty-five studies showed that these additional cases may be on the milder end of the ADHD spectrum (question 3), and 83 studies showed that pharmacological treatment of ADHD was increasing (question 4). A total of 151 studies reported on outcomes of diagnosis and pharmacological treatment (question 5). However, only 5 studies evaluated the critical issue of benefits and harms among the additional, milder cases. These studies supported a hypothesis of diminishing returns in which the harms may outweigh the benefits for youths with milder symptoms.

CONCLUSIONS AND RELEVANCE

This review found evidence of ADHD overdiagnosis and overtreatment in children and adolescents. Evidence gaps remain and future research is needed, in particular research on the long-term benefits and harms of diagnosing and treating ADHD in youths with milder symptoms; therefore, practitioners should be mindful of these knowledge gaps, especially when identifying these individuals and to ensure safe and equitable practice and policy.

ADHD stimulant medication misuse and considerations for current prescribing practice: a literature review

BACKGROUND

Stimulant medications have been prescribed to effectively treat childhood Attention Deficit Hyperactivity Disorder (ADHD) since the 1960's, with improved outcomes observed in the three core symptom domains. Over the course of these decades researchers and clinicians have debated the issue of negative outcomes with regard to later development of substance use disorders (SUD) for these children.

AIMS

To chronicle the development of medical and scientific opinion on the subject of SUD outcomes in ADHD and to appraise most recently published research in this sphere.

METHODS

A systematic search of the literature was conducted over 4 databases. Removal of duplicates, application of exclusion criteria and inclusion of publications identified through manual and citation-based search yielded 9 papers.

RESULTS

Prescriptions for stimulant medications are increasing worldwide and in tandem the prevalence of stimulant misuse. Much research focuses on non-medical stimulant misuse as a study aid; however, they are also used as recreational drugs with action on dopaminergic neurotransmitter pathways implicated in addiction disorders. Considering the risks and benefits of stimulant prescribing on later SUD development research in recent decades has produced inconsistent results. Current research supports the hypothesis of improved SUD outcomes for young people treated early and intensely, with poorer outcomes for those with less robust treatment histories.

CONCLUSIONS

Consideration of the impact that variable treatment trajectories may have on the risk of later SUD development is recommended, with further research potentially leading to the development of different management pathways based on an individual's multivariate treatment profile.

High Trait Attention Promotes Resilience and Reduces Binge Drinking Among College Students With a Family History of Alcohol Use Disorder

Binge patterns of alcohol use among post-high school emerging adults are associated with both immediate negative consequences and increased risk of long-term drinking problems, particularly among individuals with a family history (FH) of alcohol use disorder (AUD). Therefore, the developmental time period of emerging adulthood, paired with the high-risk environment of college campuses, represents an important target for interventions. Attentional ability has recently emerged as a mediator of resilience to stress-related psychopathology and offers a potential neurocognitive target for interventions. We tested the hypothesis that attentional ability promotes resilience to binge drinking in a sample of 464 college students with (n = 221) or without (n = 243) familial risk for AUD. Two-way analyses of covariance (ANCOVA) tested effects of FH and self-reported binge drinking on attention scores from the Barratt Impulsiveness Scale (BIS). In addition, mediation analyses tested whether BIS attention scores mediated the relationship between Conner-Davidson Resilience Scale scores and binge drinking. ANCOVA results indicated a significant FH-by-binge drinking interaction (p = 0.008) in which FH positive subjects who did not binge drink had the fewest attention problems, consistent with a marker of resilience. Furthermore, BIS attention scores significantly mediated the effect of Conner-Davidson Resilience Scale scores on binge drinking, with stronger effects in FH positive subjects (p < 0.001) than FH negative subjects (p = 0.49). The findings suggest that attention promotes resilience to binge drinking in individuals with familial risk for AUD. Interventions targeting attentional ability in this high-risk population, particularly FH positive individuals with attention deficits, may serve to reduce binge drinking and its consequences.

Integrating data science into the translational science research spectrum: A substance use disorder case study

The availability of large healthcare datasets offers the opportunity for researchers to navigate the traditional clinical and translational science research stages in a nonlinear manner. In particular, data scientists can harness the power of large healthcare datasets to bridge from preclinical discoveries (T0) directly to assessing population-level health impact (T4). A successful bridge from T0 to T4 does not bypass the other stages entirely; rather, effective team science makes a direct progression from T0 to T4 impactful by incorporating the perspectives of researchers from every stage of the clinical and translational science research spectrum. In this exemplar, we demonstrate how effective team science overcame challenges and, ultimately, ensured success when a diverse team of researchers worked together, using healthcare big data to test population-level substance use disorder (SUD) hypotheses generated from preclinical rodent studies. This project, called Advancing Substance use disorder Knowledge using Big Data (ASK Big Data), highlights the critical roles that data science expertise and effective team science play in quickly translating preclinical research into public health impact.

Methylphenidate and mortality in children with attention-deficit hyperactivity disorder: population-based cohort study

BACKGROUND

Little is known about methylphenidate (MPH) use and mortality outcomes.

AIMS

To investigate the association between MPH use and mortality among children with an attention-deficit hyperactivity disorder (ADHD) diagnosis.

METHOD

This population-based cohort study analysed data from Taiwan's National Health Insurance Research Database (NHIRD). A total of 68 096 children and adolescents aged 4-17 years with an ADHD diagnosis and prescribed MPH between 2000 and 2010 were compared with 68 096 without an MPH prescription, matched on age, gender and year of first ADHD diagnosis. All participants were followed to death, migration, withdrawal from the National Health Insurance programme or 31 December 2013. MPH prescriptions were measured on a yearly basis during the study period, and the association between MPH use and mortality was analysed using a repeated-measures time-dependent Cox regression model. The outcome measures included all-cause, unnatural-cause (including suicide, accident and homicide) and natural-cause mortality, obtained from linkage to the National Mortality Register in Taiwan.

RESULTS

The MPH group had lower unadjusted all-cause, natural-, unnatural- and accident-cause mortality than the comparison group. After controlling for potential confounders, MPH use was associated with a significantly lower all-cause mortality (adjusted hazard ratio AHR = 0.81, 95% CI 0.67-0.98, P = 0.027), delayed use of MPH was associated with higher mortality (AHR = 1.05, 95% CI 1.01-1.09) and longer MPH use was associated with lower mortality (AHR = 0.83, 95% CI 0.70-0.98).

CONCLUSIONS

MPH use is associated with a reduced overall mortality in children with ADHD in this cohort study, but unmeasured confounding cannot be excluded absolutely.

Neurobehavioral changes arising from early life dopamine signaling perturbations

Dopamine (DA) signaling is critical to the modulation of multiple brain functions including locomotion, reinforcement, attention and cognition. The literature provides strong evidence that altered DA availability and actions can impact normal neurodevelopment, with both early and enduring consequences on anatomy, physiology and behavior. An appreciation for the developmental contributions of DA signaling to brain development is needed to guide efforts to preclude and remedy neurobehavioral disorders, such as attention-deficit/hyperactivity disorder, addiction, bipolar disorder, schizophrenia and autism spectrum disorder, each of which exhibits links to DA via genetic, cellular and/or pharmacological findings. In this review, we highlight research pursued in preclinical models that use genetic and pharmacological approaches to manipulate DA signaling at sensitive developmental stages, leading to changes at molecular, circuit and/or behavioral levels. We discuss how these alterations can be aligned with traits displayed by neuropsychiatric diseases. Lastly, we review human studies that evaluate contributions of developmental perturbations of DA systems to increased risk for neuropsychiatric disorders.

Time to Stable Dose of Psychostimulants in Pediatric Patients With ADHD

OBJECTIVES The prevalence of attention-deficit/hyperactivity disorder (ADHD) is increasing and psychostimulants are the pharmacological standard of care. Patients benefit most when there is efficient titration to a stable dose of medication as defined by maintaining that same dose for 6 months. The aims of this study were to describe time to stable dose in a cohort of children with ADHD and examine the impact of demographic factors.

METHODS A list of pediatric patients with a diagnosis of ADHD in the electronic health record was generated, and a retrospective chart review of stimulant use was conducted on 500 patients randomly selected from 2010 to 2015 who met inclusion criteria. Time to stable dosing and its association with demographic characteristics were assessed.

RESULTS Patients were predominantly male (72%), white (81%), and privately insured (67%). Fifty-five percent of patients achieved a stable dose of medication on first attempt; therefore, the median time to stable dosing for the cohort was 0 days with the interquartile range being 0 to 133.8 days. There was significant increase in time to stable dose for patients younger than 10 years compared with those ≥10 years of age (p = 0.01). Time to stable dose was not significantly associated with race (p = 0.13), sex (p = 0.72), type of insurance (p = 0.56), or formulation being immediate or extended release (p = 0.56).

CONCLUSIONS Many patients had long titration periods when trying to reach a stable dose. Given that medication switching can be challenging for patients and families, more frequent contact with providers during titration may be necessary.

Oral Methylphenidate Treatment of an Adolescent ADHD Rat Model Does Not Alter Cocaine-Conditioned Place Preference during Adulthood: A Negative Report

The stimulant, methylphenidate (MPH), is commonly used to treat attention deficit hyperactivity disorder (ADHD) and has been increasingly prescribed for school age children and adolescents. Concerns regarding its long-term effects on later substance use disorders (SUDs) have been raised. Previous animal studies have produced contradictory results regarding whether early exposure to MPH increases or protects against SUD in adulthood. The goal of our study was to determine if clinically relevant doses of MPH during adolescence alter cocaine responsiveness in adulthood in a rat model of ADHD, the spontaneous hypertensive rat (SHR). We pretreated SHRs with saline or MPH (2.5 mg/kg once or twice day) via oral gavage during their dark cycle from postnatal day 35 (p35) to p44. Adult rats (p80) were assessed in an eight-session cocaine-conditioned place preference test (CPP). Four doses of cocaine were administered via intraperitoneal injection (i.p.) during the conditioning sessions: 1, 5, 10 and 20 mg/kg. Once per day MPH treatment had a small sensitizing effect on baseline general locomotor activity in a novel environment at p80 as well as a limited suppressive effect on reward-specific locomotor activity as measured by the decreased preference to enter the cocaine-paired chamber. This treatment did not have any effect on the amount of time that rats chose to spend in the cocaine-paired chamber. Twice per day MPH treatment had no effect on locomotion or drug-preference. Our results suggest that MPH treatment of ADHD rats during adolescence does not alter preference for cocaine in adulthood.

Childhood methylphenidate adherence as a predictor of antidepressants use during adolescence

Methylphenidate (MPH) is a common and effective treatment for attention deficit hyperactivity disorder (ADHD), but little is known about the relationship between early childhood intake of MPH and onset of antidepressant treatment during adolescence. The study aimed to examine whether adherence to MPH during early childhood predicts the initiation of antidepressants during adolescence. This is a 12-year historical prospective nationwide cohort study of children enrolled in an integrated care system who were first prescribed MPH between the ages of 6 and 8 years (N = 6830). We tested for an association between their adherence to MPH during early childhood (as indicated by medication possession ratio from MPH onset through the age of twelve) and the likelihood of being prescribed any antidepressant during adolescence (age 13-18). As all country citizens are covered by mandatory health insurance, and full services are provided by one of the four integrated care systems, data regarding patients' diagnoses, prescriptions, and medical purchases are well documented. Logistic regression analysis indicated that those with higher adherence to MPH had a 50% higher risk (95% CI 1.16-1.93) of receiving antidepressants during adolescence when controlling for other comorbid psychiatric conditions and parental use of antidepressants. In this large-scale longitudinal study, MPH adherence during early childhood emerged as a predictor for antidepressant treatment during adolescence, which may reflect increased emotional and behavioral dysregulation in this group. The highly adherent patients are at higher risk and should be clinically monitored more closely, particularly into adolescence.

Neurological and psychiatric adverse effects of long-term methylphenidate treatment in ADHD: A map of the current evidence

Methylphenidate (MPH), the most common medication for children with Attention Deficit/Hyperactivity Disorder (ADHD) in many countries, is often prescribed for long periods of time. Any long-term psychotropic treatment in childhood raises concerns about possible adverse neurological and psychiatric outcomes. We aimed to map current evidence regarding neurological and psychiatric outcomes, adverse or beneficial, of long-term MPH (> 1 year) treatment in ADHD. We coded studies using a "traffic light" system: Green: safe/favours MPH; Amber: warrants caution; Red: not safe/not well-tolerated. Un-categorisable study findings were coded as "Unclear". Although some evidence suggests an elevated risk of psychosis and tics, case reports describe remission on discontinuation. Several studies suggest that long-term MPH may reduce depression and suicide in ADHD. Evidence suggests caution in specific groups including pre-school children, those with tics, and adolescents at risk for substance misuse. We identified a need for more studies that make use of large longitudinal databases, focus on specific neuropsychiatric outcomes, and compare outcomes from long-term MPH treatment with outcomes following shorter or no pharmacological intervention.

Experience during adolescence shapes brain development: From synapses and networks to normal and pathological behavior

Adolescence is a period of dramatic neural reorganization creating a period of vulnerability and the possibility for the development of psychopathology. The maturation of various neural circuits during adolescence depends, to a large degree, on one's experiences both physical and psychosocial. This occurs through a process of plasticity which is the structural and functional adaptation of the nervous system in response to environmental demands, physiological changes and experiences. During adolescence, this adaptation proceeds upon a backdrop of structural and functional alterations imparted by genetic and epigenetic factors and experiences both prior to birth and during the postnatal period. Plasticity entails an altering of connections between neurons through long-term potentiation (LTP) (which alters synaptic efficiency), synaptogenesis, axonal sprouting, dendritic remodeling, neurogenesis and recruitment (Skaper et al., 2017). Although most empirical evidence for plasticity derives from studies of the sensory systems, recent studies have suggested that during adolescence, social, emotional, and cognitive experiences alter the structure and function of the networks subserving these domains of behavior. Each of these neural networks exhibits heightened vulnerability to experience-dependent plasticity during the sensitive periods which occur in different circuits and different brain regions at specific periods of development. This report will summarize some examples of adaptation which occur during adolescence and some evidence that the adolescent brain responds differently to stimuli compared to adults and children. This symposium, "Experience during adolescence shapes brain development: from synapses and networks to normal and pathological behavior" occurred during the Developmental Neurotoxicology Society/Teratology Society Annual Meeting in Clearwater Florida, June 2018. The sections will describe the maturation of the brain during adolescence as studied using imaging technologies, illustrate how plasticity shapes the structure of the brain using examples of pathological conditions such as Tourette's' syndrome and attention deficit hyperactivity disorder, and a review of the key molecular systems involved in this plasticity and how some commonly abused substances alter brain development. The role of stimulants used in the treatment of attention deficit hyperactivity disorder (ADHD) in the plasticity of the reward circuit is then described. Lastly, clinical data promoting an understanding of peer-influences on risky behavior in adolescents provides evidence for the complexity of the roles that peers play in decision making, a phenomenon different from that in the adult. Imaging studies have revealed that activation of the social network by the presence of peers at times of decision making is unique in the adolescent. Since normal brain development relies on experiences which alter the functional and structural connections between cells within circuits and networks to ultimately alter behavior, readers can be made aware of the myriad of ways normal developmental processes can be hijacked. The vulnerability of developing adolescent brain places the adolescent at risk for the development of a life time of abnormal behaviors and mental disorders.

Glutaminergic signaling in the caudate nucleus is required for behavioral sensitization to methylphenidate

Methylphenidate (MPD) is a widely prescribed psychostimulant for the treatment of attention deficit hyperactivity disorder, and is growing in use as a recreational drug and academic enhancer. MPD acts on the reward/motive and motor circuits of the CNS to produce its effects on behavior. The caudate nucleus (CN) is known to be a part of these circuits, so a lesion study was designed to elucidate the role of the CN in response to acute and chronic MPD exposure. Five groups of n = 8 rats were used: control, sham CN lesions, non-specific electrolytic CN lesions, dopaminergic-specific (6-OHDA toxin) CN lesion, and glutaminergic-specific (ibotenic acid toxin) CN lesions. On experimental day (ED) 1, all groups received saline injections. On ED 2, surgeries took place, followed by a 5-day recovery period (ED 3-7). Groups then received six daily MPD 2.5 mg/kg injections (ED 9-14), then three days of washout with no injection (ED 15-17), followed by a re-challenge with the previous 2.5 mg/kg MPD dose (ED 18). Locomotive activity was recorded for 60 min after each injection by a computerized animal activity monitor. The electrolytic CN lesion group responded to the MPD acute and chronic exposures similarly to the control and sham groups, showing an increase in locomotive activity, i.e. sensitization. The dopaminergic-specific CN lesion group failed to respond to MPD exposure both acute and chronically. The glutaminergic-specific CN lesion group responded to MPD exposure acutely but failed to manifest chronic effects. This confirms the CN's dopaminergic system is necessary for MPD to manifest its acute and chronic effects on behavior, and demonstrates that the CN's glutaminergic system is necessary for the chronic effects of MPD such as sensitization. Thus, the dopaminergic and glutaminergic components of the CN play a significant role in differentially modulating the acute and chronic effects of MPD respectively.

A neurocomputational account of reward and novelty processing and effects of psychostimulants in attention deficit hyperactivity disorder

Computational models of reinforcement learning have helped dissect discrete components of reward-related function and characterize neurocognitive deficits in psychiatric illnesses. Stimulus novelty biases decision-making, even when unrelated to choice outcome, acting as if possessing intrinsic reward value to guide decisions toward uncertain options. Heightened novelty seeking is characteristic of attention deficit hyperactivity disorder, yet how this influences reward-related decision-making is computationally encoded, or is altered by stimulant medication, is currently uncertain. Here we used an established reinforcement-learning task to model effects of novelty on reward-related behaviour during functional MRI in 30 adults with attention deficit hyperactivity disorder and 30 age-, sex- and IQ-matched control subjects. Each participant was tested on two separate occasions, once ON and once OFF stimulant medication. OFF medication, patients with attention deficit hyperactivity disorder showed significantly impaired task performance (P = 0.027), and greater selection of novel options (P = 0.004). Moreover, persistence in selecting novel options predicted impaired task performance (P = 0.025). These behavioural deficits were accompanied by a significantly lower learning rate (P = 0.011) and heightened novelty signalling within the substantia nigra/ventral tegmental area (family-wise error corrected P < 0.05). Compared to effects in controls, stimulant medication improved attention deficit hyperactivity disorder participants' overall task performance (P = 0.011), increased reward-learning rates (P = 0.046) and enhanced their ability to differentiate optimal from non-optimal novel choices (P = 0.032). It also reduced substantia nigra/ventral tegmental area responses to novelty. Preliminary cross-sectional evidence additionally suggested an association between long-term stimulant treatment and a reduction in the rewarding value of novelty. These data suggest that aberrant substantia nigra/ventral tegmental area novelty processing plays an important role in the suboptimal reward-related decision-making characteristic of attention deficit hyperactivity disorder. Compared to effects in controls, abnormalities in novelty processing and reward-related learning were improved by stimulant medication, suggesting that they may be disorder-specific targets for the pharmacological management of attention deficit hyperactivity disorder symptoms.

A Neurodevelopmental Model of Combined Pyrethroid and Chronic Stress Exposure

Attention-deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders of childhood and previous studies indicate the dopamine system plays a major role in ADHD pathogenesis. Two environmental exposures independently associated with dopaminergic dysfunction and ADHD risk include exposure to deltamethrin, a pyrethroid insecticide, and chronic stress. We hypothesized that combined neurodevelopmental exposure to both deltamethrin and corticosterone (CORT), the major stress hormone in rodents, would result in additive changes within the dopamine system. To study this, we developed a novel dual exposure paradigm and exposed pregnant C57BL/6 dams to 3 mg/kg deltamethrin through gestation and weaning, and their offspring to 25 μg/mL CORT dissolved in the drinking water through adulthood. Midbrain RNA expression as well as striatal and cortical protein expression of key dopaminergic components were investigated, in addition to ADHD-like behavioral tasks and electrochemical dopamine dynamics via fast-scan cyclic voltammetry. Given the well-described sexual dimorphism of ADHD, males and females were assessed separately. Males exposed to deltamethrin had significantly decreased midbrain Pitx3 expression, decreased cortical tyrosine hydroxylase (TH) expression, increased activity in the Y maze, and increased dopamine uptake rate in the dorsal striatum. These effects did not occur in males exposed to CORT only, or in males exposed to both deltamethrin and CORT, suggesting that CORT may attenuate these effects. Additionally, deltamethrin- and CORT-exposed females did not display these dopaminergic features, which indicates these changes are sex-specific. Our results show dopaminergic changes from the RNA through the functional level. Moreover, these data illustrate the importance of testing multiple environmental exposures together to better understand how combined exposures that occur in certain vulnerable populations could affect similar neurodevelopmental systems, as well as the importance of studying sex differences of these alterations.

Sex Differences in Comorbidity Patterns of Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

To investigate sex differences in associations between attention-deficit/hyperactivity disorder (ADHD) and a spectrum of comorbid disorders.

METHOD

The study population included all children born in Denmark from 1981 through 2013 (N = 1,665,729). Data were merged from Danish registers and information was obtained on birth characteristics, socioeconomic status, familial psychiatric history, and diagnoses of ADHD (n = 32,308) and comorbid disorders. To estimate absolute and relative risks of comorbid disorders, incidence rates and adjusted hazard ratios (HRs) with 95% CIs were calculated for female and male individuals. In addition, interactions between ADHD and sex in association with comorbid disorders were estimated as HR ratios (HRRs) in female and male individuals (95% CIs).

RESULTS

Individuals diagnosed with ADHD had significantly increased absolute and relative risks of all 12 comorbid psychiatric disorders investigated. ADHD-sex interactions were found for some comorbid disorders. Compared with male individuals, ADHD in female individuals showed a stronger association with autism spectrum disorder (HRR 1.86, 95% CI 1.62-2.14), oppositional defiant/conduct disorder (HRR 1.97, 95% CI 1.68-2.30), intellectual disability (HRR 1.79, 95% CI 1.54-2.09), personality disorders (HRR 1.23, 95% CI 1.06-1.43), schizophrenia (HRR 1.21, 95% CI 1.02-1.43), substance use disorders (HRR 1.21, 95% CI 1.07-1.38), and suicidal behavior (1.28, 95% CI 1.12-1.47). The remaining disorders showed no significant sex differences in association with ADHD.

CONCLUSION

This study indicates that the association between ADHD and several comorbid disorders is stronger in female than in male individuals. These important findings add to the literature on sex differences in ADHD and suggest that female individuals diagnosed with ADHD are a more vulnerable group of patients.

Crocus sativus L. Versus Methylphenidate in Treatment of Children with Attention-Deficit/Hyperactivity Disorder: A Randomized, Double-Blind Pilot Study

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neuropsychiatric disorders of childhood and adolescence. About 30% of patients do not respond to stimulants or cannot tolerate their side effects. Thus, alternative medication, like herbal medicine, should be considered. The aim of this trial is to compare the safety and efficacy of Crocus sativus (saffron) versus methylphenidate in improving symptoms of children with ADHD.

METHODS

In a 6-week randomized double-blind study, 54 patients (children 6-17 years old) with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis of ADHD were randomly assigned to receive either 20-30 mg/d (20 mg/d for <30 kg and 30 mg/d for >30 kg) methylphenidate (MPH) or 20-30 mg/d saffron capsules depending on weight (20 mg/d for <30 kg and 30 mg/d for >30 kg). Symptoms were assessed using the Teacher and Parent Attention-Deficit/Hyperactivity Disorder Rating Scale-IV (ADHD-RS-IV) at baseline and weeks 3 and 6.

RESULTS

Fifty patients completed the trial. General linear model repeated measures showed no significant difference between the two groups on Parent and Teacher Rating Scale scores (F = 0.749, df = 1.317, p = 0.425, and F = 0.249, df = 1.410, p = 0.701, respectively). Changes in Teacher and Parent ADHD Rating Scale scores from baseline to the study end were not significantly different between the saffron group and the MPH group (p = 0.731 and p = 0.883, respectively). The frequency of adverse effects was similar between saffron and MPH groups.

CONCLUSION

Short-term therapy with saffron capsule showed the same efficacy compared with methylphenidate. Nevertheless, larger controlled studies with longer treatment periods are necessary for future studies.

Long-term effects of stimulant exposure on cerebral blood flow response to methylphenidate and behavior in attention-deficit hyperactivity disorder

Stimulant prescription rates for attention deficit hyperactivity disorder (ADHD) are increasing, even though potential long-term effects on the developing brain have not been well-studied. A previous randomized clinical trial showed short-term age-dependent effects of stimulants on the DA system. We here assessed the long-term modifying effects of age-of-first-stimulant treatment on the human brain and behavior. 81 male adult ADHD patients were stratified into three groups: 1) early stimulant treatment (EST; <16 years of age) 2) late stimulant treatment (LST: ≥23 years of age) and 3) stimulant treatment naive (STN; no history of stimulant treatment). We used pharmacological magnetic resonance imaging (phMRI) to assess the cerebral blood flow (CBF) response to an oral methylphenidate challenge (MPH, 0.5 mg/kg), as an indirect measure of dopamine function in fronto-striatal areas. In addition, mood and anxiety scores, and recreational drug use were assessed. Baseline ACC CBF was lower in the EST than the STN group (p = 0.03), although CBF response to MPH was similar between the three groups (p = 0.23). ADHD symptom severity was higher in the STN group compared to the other groups (p < 0.01). In addition, the EST group reported more depressive symptoms (p = 0.04), but not anxiety (p = 0.26), and less recreational drug use (p = 0.04). In line with extensive pre-clinical data, our data suggest that early, but not late, stimulant treatment long-lastingly affects the human brain and behavior, possibly indicating fundamental changes in the dopamine system.

Treatment strategies for ADHD: an evidence-based guide to select optimal treatment

Attention-deficit/hyperactivity disorder (ADHD) is a common and impairing disorder affecting children, adolescents, and adults. Several treatment strategies are available that can successfully ameliorate symptoms, ranging from pharmacological to dietary interventions. Due to the increasing range of available options, an informed selection or prioritization of treatments is becoming harder for clinicians. This review aims to provide an evidence-based appraisal of the literature on ADHD treatment, supplemented by expert opinion on plausibility. We outline proposed mechanisms of action of established pharmacologic and non-pharmacologic treatments, and we review targets of novel treatments. The most relevant evidence supporting efficacy and safety of each treatment strategy is discussed. We review the individualized features of the patient that should guide the selection of treatments in a shared decision-making continuum. We provide guidance for optimizing initiation of treatment and follow-up of patients in clinical settings.

Psychiatric comorbid patterns in adults with attention-deficit hyperactivity disorder: Treatment effect and subtypes

Psychiatric comorbidities are common in individuals with attention-deficit/hyperactivity disorder (ADHD). In this study, we sought to evaluate the effects of medication and childhood ADHD subtypes on psychiatric comorbidities among adults with ADHD as compared to healthy adult controls. We assessed 121 drug-naïve adults with ADHD, 93 treated adults with ADHD, and 145 healthy controls (age 18–36 years) using semi-structured psychiatric interviews, intelligence tests, and medical records. Drug-naïve adults with ADHD had more comorbidities than treated adults with ADHD and controls. Childhood ADHD-combined subtype, relative to ADHD-inattentive subtype, was associated with higher risks of comorbidities. Current medication treatment was associate with a higher risk for anxiety disorders, and longer treatment duration was associated with lower risks of mood disorders and sleep disorders. Our results indicate that no medication treatment, short treatment duration, and childhood ADHD-combined subtype are associated with increased risks for psychiatric comorbidities among adults with ADHD.

Juvenile exposure to methylphenidate and guanfacine in rats: effects on early delay discounting and later cocaine-taking behavior

RATIONALE

Both methylphenidate (MPH), a catecholamine reuptake blocker, and guanfacine, an alpha2A agonist, are used to treat attention-deficit hyperactivity disorder (ADHD). Childhood impulsivity, including delay discounting, is associated with increased substance use during adolescence. These effects can be mitigated by juvenile exposure to MPH, but less is known about the long-term effects of developmental exposure to guanfacine in males and females.

OBJECTIVE

This study aims to determine sex differences and dose-dependent effects of juvenile exposure to MPH or guanfacine on delay-discounting and later cocaine self-administration.

METHODS

The dose-dependent effects of vehicle, MPH (0.5, 1, and 2 mg/kg p.o.) or guanfacine (0.003, 0.03, and 0.3 mg/kg, i.p.) on discounting were determined in male and female Sprague-Dawley rats beginning at postnatal day (P)20. At P90, the amount, motivation, and sensitivity to cocaine following early drug exposure were determined with self-administration.

RESULTS

Guanfacine, but not MPH, significantly reduced weight by 22.9 ± 4.6% in females. MPH dose dependently decreased delay discounting in both juvenile males and females, while guanfacine was only effective in males. Discounting was associated with cocaine self-administration in vehicle males (R² = -0.4, P < 0.05) and self-administration was reduced by guanfacine treatment (0.3 mg/kg). Guanfacine significantly decreased cocaine sensitivity in both sexes.

CONCLUSIONS

These data suggest that MPH is effective in reducing delay discounting in both sexes. Due to both weight loss and ineffectiveness on discounting in females, guanfacine should be used only in males to reduce delay discounting and later cocaine use.

Stress, sensitive periods, and substance abuse

Research on the inter-relationship between drug abuse and social stress has primarily focused on the role of stress exposure during adulthood and more recently, adolescence. Adolescence is a time of heightened reward sensitivity, but it is also a time when earlier life experiences are expressed. Exposure to stress early in postnatal life is associated with an accelerated age of onset for drug use. Lifelong addiction is significantly greater if drug use is initiated during early adolescence. Understanding how developmental changes following stress exposure interact with sensitive periods to unfold over the course of maturation is integral to reducing their later impact on substance use. Arousal levels, gender/sex, inflammation, and the timing of stress exposure play a role in the vulnerability of these circuits. The current review focuses on how early postnatal stress impacts brain development during a sensitive period to increase externalizing and internalizing behaviors in adolescence that include social interactions (aggression; sexual activity), working memory impairment, and depression. How stress effects the developmental trajectories of brain circuits that are associated with addiction are discussed for both clinical and preclinical studies.

Acute and chronic methylphenidate administration in intact and VTA-specific and nonspecific lesioned rats

Methylphenidate (MPD) is a psychostimulant used for the treatment of ADHD and works by increasing the bioavailability of dopamine (DA) in the brain. As a major source of DA, the ventral tegmental area (VTA) served as the principal target in this study as we aimed to understand its role in modulating the acute and chronic MPD effect. Forty-eight male Sprague-Dawley rats were divided into control, sham, electrical lesion, and 6-OHDA lesion groups. Given the VTA's implication in the locomotive circuit, three locomotor indices-horizontal activity, number of stereotypy, and total distance-were used to measure the animals' behavioral response to the drug. Baseline recording was obtained on experimental day 1 (ED 1) followed by surgery on ED 2. After recovery, the behavioral recordings were resumed on ED 8. All groups received daily intraperitoneal injections of 2.5 mg/kg MPD for six days after which the animals received no treatment for 3 days. On ED 18, 2.5 mg/kg MPD was re-administered to assess for the chronic effect of the psychostimulant. Except for one index, there was an increase in locomotive activity in all experimental groups after surgery (in comparison to baseline activity), acute MPD exposure, induction with six daily doses, and after MPD re-challenge. Furthermore, the increase was greatest in the electrical VTA lesion group and lowest in the 6-OHDA VTA lesion group. In conclusion, the results of this study suggest that the VTA may not be the primary nucleus of MPD action, and the VTA plays an inhibitory role in the locomotive circuit.

Stimulant treatment profiles predicting co-occurring substance use disorders in individuals with attention-deficit/hyperactivity disorder

Adolescents with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of developing substance use disorders (SUDs) and nicotine dependence (ND). It remains unclear whether and how stimulant treatment may affect this risk. We aimed to investigate how stimulant use profiles influence the risk of SUDs and ND, using a novel data-driven community detection analysis to construct different stimulant use profiles. Comprehensive lifetime stimulant prescription data and data on SUDs and ND were available for 303 subjects with ADHD and 219 controls, with a mean age 16.3 years. Community detection was used to define subgroups based on multiple indicators of treatment history, start age, treatment duration, total dose, maximum dose, variability, stop age. In stimulant-treated participants, three subgroups with distinct medication trajectories were distinguished (late-and-moderately dosed, n = 91; early-and-moderately dosed, n = 51; early-and-intensely dosed, n = 103). Compared to stimulant-naïve participants (n = 58), the early-and-intense treatment group had a significantly lower risk of SUDs and ND (HR = 0.28, and HR = 0.29, respectively), while the early-and-moderate group had a significantly lower risk of ND only (HR = 0.30). The late-and-moderate group was at a significantly higher risk of ND compared to the other two treatment groups (HR = 2.66 for early-and-moderate, HR = 2.78 for early-and-intense). Our findings show that in stimulant-treated adolescents with ADHD, long-term outcomes are associated with treatment characteristics, something that is often ignored when treated individuals are compared to untreated individuals.

Pharmacotherapeutic strategies for the treatment of attention-deficit hyperactivity (ADHD) disorder with comorbid substance-use disorder (SUD)

INTRODUCTION

Substance use disorder (SUD) is very common amongst patients with attention deficit hyperactivity disorder (ADHD). The two disorders share partially overlapping features and SUD in ADHD is characterized by an early age of onset, high likelihood of poly-substance use, increased risk of suicide attempts, more hospitalizations, and scarce treatment adherence.

AREAS COVERED

This paper reviews randomized active comparator-controlled or placebo-controlled trials evaluating the use of pharmacotherapy in patients with ADHD and SUD. The authors include open label and observational studies.

EXPERT OPINION

Stimulant and non-stimulant treatments should be used to aid ADHD symptomatology in patients with SUD. SUD seems to be less responsive, suggesting a relative independence of the two conditions. For this reason, the association of ADHD-specific drugs and SUD-treatments should be recommended in a large proportion of patients suffering from both disorders. The rate and the quality of ADHD response to specific pharmacological treatments is highly variable, depending on the dose and the duration of the treatment, the age of the patient, and the severity and the chronicity of addiction. Further research is necessary to explore the divergences in treatment response of different ADHD subtypes in different subtypes of SUD.

Undiagnosed attention deficit/hyperactivity disorder (ADHD) among unionized drivers in Ghana: Public health and policy implications

Road traffic accidents (RTA) are among the leading causes of mortality in sub-Saharan Africa. Many males that drop out of school in Ghana, a population at risk for attention-deficit hyperactivity disorder (ADHD), find employment by joining driver's unions. Moreover, the vehicles of Ghanaian unionized drivers are over-represented in fatal road accidents. Untreated ADHD has been linked with higher rates of RTAs. The objectives of this cross-sectional analysis is to determine the following among unionized drivers in Ghana: 1) the prevalence of ADHD, and 2) the association between self-reported ADHD risk and driving behavior. Data comes from participants' responses (200 unionized drivers and 171 community controls) to a 6-item ADHD Self - Report Scale (ASRS), the Driving Behavior Survey (DBS), and a culturally adapted version of the Jerome Driving Questionnaire (JDQ-GH). The self-reported prevalence of ADHD was 17.6% for the unionized drivers and 7.8% for the control group (χ²=7.7, df=1, p=0.006). Also, ADHD drivers endorsed that they were more likely to pay bribes to police and having worse driving behaviors across among both unionized drivers and controls. Study findings suggest that increased awareness of ADHD and possible screening of drivers for ADHD with subsequent evaluation and treatment may result in prevention of vehicle accidents.

Amphetamine, but not methylphenidate, increases ethanol intake in adolescent male, but not in female, rats

INTRODUCTION

There has been an increasing interest in analyzing the interactions between stimulants and ethanol during childhood and adolescence. Stimulants are used to treat attention-deficit hyperactivity disorder (ADHD) in these developmental stages, during which ethanol initiation and escalation often occur.

METHODS

This study assessed the effects of repeated d-amphetamine (AMPH) or methylphenidate (MPH) treatment during adolescence [male and female Wistar rats, between postnatal day (PD) 28 to PD34, approximately] on the initiation of ethanol intake during a later section of adolescence (PD35 to PD40).

RESULTS

Amphetamine and MPH exerted reliable acute motor stimulant effects, but there was no indication of sensitized motor or anxiety responses. MPH did not affect dopamine (DA) levels, whereas AMPH significantly reduced insular levels of DA in both sexes and norepinephrine levels in females only. Repeated treatment with AMPH, but not with MPH, enhanced ethanol intake during late adolescence in male, but not in female, rats.

CONCLUSION

A short treatment with AMPH during adolescence significantly altered DA levels in the insula, both in male and females, and significantly enhanced ethanol intake in males. The present results suggest that, in adolescent males, a very brief history of AMPH exposure can facilitate the initiation of ethanol intake.

A Prospective 30-Year Follow-Up of ADHD Associated With Perinatal Risks

OBJECTIVE

Longitudinal follow-up of ADHD suggests a poorer outcome in those affected. Studies extending to 30 years however are rare. We investigated the adult outcome of ADHD associated with perinatal risks (PRs), treated non-pharmacologically.

METHOD

A study group of 122 participants (86 men, 36 women) with PR-associated ADHD was followed-up from birth and compared with a control group also prospectively studied.

RESULTS

The study group showed more cognitive, motor perception, and learning impairments as well as psychiatric problems at ages 5, 9, and 16. At age 30, the study group reported less education, more involuntary job dismissals and more alcohol abuse. Self-reported ADHD symptoms were still prevalent in adulthood.

CONCLUSION

ADHD symptoms persist and impair the long-term educational, occupational, and psychiatric outcome. ADHD in participants with PR appears to follow a course seen in studies of unselected ADHD.