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In Value in Health,2017

The past decades have seen a surge in stimulant prescriptions for the treatment of attention-deficit/hyperactivity disorder (ADHD). Stimulants acutely alleviate symptoms and cognitive deficits associated with ADHD by modulating striatal dopamine neurotransmission and induce therapeutic changes in brain activation patterns. Long-term functional changes after treatment are unknown, as long-term studies are scarce and have focused on brain structure. In this observational study (2009-2012), we investigated associations between lifetime stimulant treatment history and neural activity during reward processing.Participants fulfilling DSM-5 criteria for ADHD (N = 269) were classified according to stimulant treatment trajectory. Of those, 124 performed a monetary incentive delay task during magnetic resonance imaging, all in their nonmedicated state (nEARLY&INTENSE = 51; nLATE&MODERATE = 49; nEARLY&MODERATE = 9; nNAIVE = 15; mean age = 17.4 years; range, 10-26 years). Whole-brain analyses were performed with additional focus on the striatum, concentrating on the 2 largest treatment groups.Compared to the late-and-moderate treatment group, the early-and-intense treatment group showed more activation in the supplementary motor area and dorsal anterior cingulate cortex (SMA/dACC) during reward outcome (cluster size = 8,696 mm³; PCLUSTER < .001). SMA/dACC activation of the control group fell in between the 2 treatment groups. Treatment history was not associated with striatal activation during reward processing.Our findings are compatible with previous reports of acute increases of SMA/dACC activity in individuals with ADHD after stimulant administration. Higher SMA/dACC activity may indicate that patients with a history of intensive stimulant treatment, but currently off medication, recruit brain regions for cognitive control and/or decision-making upon being rewarded. No striatal or structural changes were found.
In The journal of clinical psychiatry.,2017

Objective
To assess the prospective risk of developing substance-related disorders after childhood mental health disorders (i.e., attention-deficit/hyperactivity disorder [ADHD], oppositional defiant disorder [ODD] or conduct disorder [CD], anxiety disorder, and depression) using meta-analysis.

Conclusion
Childhood ADHD, ODD, CD, and depression increase the risk of developing substance-related disorders. Anxiety disorders do not seem to increase the risk for future substance-related disorders, although the findings are highly heterogeneous. These findings emphasize the need for early detection and intervention to prevent debilitating substance-related disorders in later life.
In Journal of the American Academy of child and adolescent psychiatry,2017

Introduction:
Methylphenidate is the first-line pharmacological treatment of attention-deficit/hyperactivity disorder (ADHD). Although methylphenidate has a well-established evidence base for treating ADHD, its long-term benefits are unclear.
Areas covered:
Physical adverse effects, psychiatric adverse events and brain development.
Expert opinion:
Some physical adverse events have been described (e.g. sleep disturbances, growth reduction, loss of appetite), although most are of transient nature. Psychiatric adverse events seem more related to the diagnosis ADHD itself, and not stimulant treatment. Concluding, short-to-mid-term use (i.e., up to 2 years) stimulants are relatively safe, but much less is known about longer-term efficacy and safety of these drugs.
In Expert opinion on Drug Safety.,2017

Objective
Attention-deficit/hyperactivity disorder (ADHD) has been associated with dopaminergic imbalance and subtle volume decreases in the brain. Stimulants acutely enhance dopaminergic neurotransmission. Long-term effects of prolonged manipulation of the dopaminergic system on brain structure remain poorly understood; they could be beneficial or unfavorable and could be moderated by common genetic variants and/or age.
Method
In a large observational ADHD cohort study (N = 316), the effects of cumulative stimulant treatment, genotype (for DAT1 haplotype and DRD4 variants), and treatment-by-genotype interactions on striatal, frontal, and hippocampal volumes and their interactions with age were evaluated.
Results
No main effects of treatment were found. Associations between treatment and bilateral frontal and left hippocampal volume depended on DRD4 genotype and age. At a younger age and lower treatment levels, but not at a younger age and higher treatment levels, carriers of the DRD4 7R allele showed decreased frontal cortex volumes. At an older age, carriers and non-carriers showed smaller frontal volumes irrespective of treatment history. Left hippocampal volume was similar to that in controls at average treatment levels and increased with treatment only in carriers of the DRD4 risk allele and at a younger age. No interaction effects were found in the striatum.
Conclusion
Carriers of the DRD4 risk allele at a younger age might be sensitive to cortical remodeling after stimulant treatment. The cross-sectional nature of this study warrants cautious interpretation of age effects. The present findings, although of small effect size, might ultimately contribute to optimal care for individuals with ADHD.
In Journal of the American Academy of child and adolescent psychiatry,2016

There are very few studies on the long-term outcome of children and adolescents with ADHD-combined type in Europe. The objective of the present study is to assess the 6-year outcome (including pharmacological treatment) of a large cohort of participants with ADHD-combined type (N = 347, mean age 11.4 years) in late adolescence and early adulthood. At study entry and follow-up (mean age 17.4 years), participants were comprehensively assessed on ADHD and comorbid disorders by structured psychiatric interviews and multi-informant questionnaires. Overall functioning was assessed by the Children’s Global Assessment Scale. The retention rate was 75.6 %. The majority of participants (86.5 %) persisted in a DSM-5 ADHD diagnosis, 8.4 % had a subthreshold diagnosis, and 5.1 % remitted from the disorder at follow-up. Comorbidities decreased strongly; oppositional defiant disorder: 58 > 31 %, conduct disorder: 19 > 7 %. At follow-up, mood- and anxiety disorders were virtually non-existent following strict criteria (1–3 %). Percentage of children having had pharmacological treatment at any time increased from 79 to 91 %. On the Children’s Global Assessment Scale, 48.5 % of participants were still functionally impaired at follow-up. Parental ADHD, higher ADHD symptom severity at baseline and higher parent-reported impairment at baseline positively predicted current ADHD symptom severity (R2 = 20.9 %). Younger baseline age, higher ADHD symptom severity at baseline and higher parent-reported impairment at baseline were positively associated with poorer overall functioning (R2 = 17.8 %). Pharmacological treatment had no (beneficial) impact on either ADHD symptom severity or overall functioning. Results confirm that ADHD is largely persistent into late adolescence with severity and family history for the disorder as important risk factors.
In ECAP, 2016

Individuals with attention deficit/hyperactivity disorder (ADHD) are at increased risk of developing substance use disorders (SUDs) and nicotine dependence. The co-occurrence of ADHD and SUDs/nicotine dependence may in part be mediated by shared genetic liability. Several neurobiological pathways have been implicated in both ADHD and SUDs, including dopamine and serotonin pathways. We hypothesized that variations in dopamine and serotonin neurotransmission genes were involved in the genetic liability to develop SUDs/nicotine dependence in ADHD. The current study included participants with ADHD (n = 280) who were originally part of the Dutch International Multicenter ADHD Genetics study. Participants were aged 5–15 years and attending outpatient clinics at enrollment in the study. Diagnoses of ADHD, SUDs, nicotine dependence, age of first nicotine and substance use, and alcohol use severity were based on semi-structured interviews and questionnaires. Genetic risk scores were created for both serotonergic and dopaminergic risk genes previously shown to be associated with ADHD and SUDs and/or nicotine dependence. The serotonin genetic risk score significantly predicted alcohol use severity. No significant serotonin × dopamine risk score or effect of stimulant medication was found. The current study adds to the literature by providing insight into genetic underpinnings of the co-morbidity of ADHD and SUDs. While the focus of the literature so far has been mostly on dopamine, our study suggests that serotonin may also play a role in the relationship between these disorders.
In Addiction Biology,2016

Background
Attention-Deficit/Hyperactivity Disorder (ADHD) is a risk factor for substance use disorders (SUDs) and nicotine dependence (ND). Neurocognitive deficits may predict the increased risk of developing SUDs and nicotine dependence.
Methods
This study comprised three groups derived from the Dutch part of the International Multicenter ADHD Genetics (IMAGE) study: ADHD probands (n = 294), unaffected siblings (n = 161), and controls (n = 214). At baseline (age = 12.2), a range of neurocognitive functions was assessed including executive functions (inhibition, working memory, timing), measures of motor functioning (motor timing and tracking) and IQ. After a mean follow-up of 4.2 years, SUDs and ND were assessed.
Results
None of the neurocognitive functions predicted later SUDs or ND in ADHD probands, even after controlling for medication use and conduct disorder. Slower response inhibition predicted later nicotine dependence in unaffected siblings (OR = 2.06, 95% CI = 1.22–3.48), and lower IQ predicted increased risk for SUDs in controls (OR = 1.96, 95% CI = 1.12–3.44).
Conclusions
Cold executive functions, motor functioning, and IQ did not predict the elevated risk of SUDs and ND in ADHD. Future studies should target ‘hot’ executive functions such as reward processing as risk factors for SUDs or ND.
In JCPP, 2015

Attention-deficit/hyperactivity disorder (ADHD) is a persistent neuropsychiatric disorder which is associated with impairments on a variety of cognitive measures and abnormalities in structural and functional brain measures. Genetic factors are thought to play an important role in the etiology of ADHD. The NeuroIMAGE study is a follow-up of the Dutch part of the International Multicenter ADHD Genetics (IMAGE) project. It is a multi-site prospective cohort study designed to investigate the course of ADHD, its genetic and environmental determinants, its cognitive and neurobiological underpinnings, and its consequences in adolescence and adulthood. From the original 365 ADHD families and 148 control (CON) IMAGE families, consisting of 506 participants with an ADHD diagnosis, 350 unaffected siblings, and 283 healthy controls, 79 % participated in the NeuroIMAGE follow-up study. Combined with newly recruited participants the NeuroIMAGE study comprehends an assessment of 1,069 children (751 from ADHD families; 318 from CON families) and 848 parents (582 from ADHD families; 266 from CON families). For most families, data for more than one child (82 %) and both parents (82 %) were available. Collected data include a diagnostic interview, behavioural questionnaires, cognitive measures, structural and functional neuroimaging, and genome-wide genetic information. The NeuroIMAGE dataset allows examining the course of ADHD over adolescence into young adulthood, identifying phenotypic, cognitive, and neural mechanisms associated with the persistence versus remission of ADHD, and studying their genetic and environmental underpinnings. The inclusion of siblings of ADHD probands and controls allows modelling of shared familial influences on the ADHD phenotype.
In ECAP, 2015

Brain white matter (WM) tracts, playing a vital role in the communication between brain regions, undergo important maturational changes during adolescence and young adulthood, a critical period for the development of nicotine dependence. Attention-deficit/hyperactivity disorder (ADHD) is associated with increased smoking and widespread WM abnormalities, suggesting that the developing ADHD brain might be especially vulnerable to effects of smoking. This study aims to investigate the effect of smoking on (WM) microstructure in adolescents and young adults with and without ADHD. Diffusion tensor imaging was performed in an extensively phenotyped sample of nonsmokers (n = 95, 50.5% ADHD), irregular smokers (n = 41, 58.5% ADHD), and regular smokers (n = 50, 82.5% ADHD), aged 14–24 years. A whole-brain voxelwise approach investigated associations of smoking, ADHD and their interaction, with WM microstructure as measured by fractional anisotropy (FA) and mean diffusivity (MD). Widespread alterations in FA and MD were found for regular smokers compared to irregular and nonsmokers, mainly located in the corpus callosum and WM tracts surrounding the basal ganglia. Several regions overlapped with regions of altered FA for ADHD versus controls, albeit in different directions. Irregular and nonsmokers did not differ, and ADHD and smoking did not interact. Results implicate that smoking and ADHD have independent effects on WM microstructure, and possibly do not share underlying mechanisms. Two mechanisms may play a role in the current results. First, smoking may cause alterations in WM microstructure in the maturing brain. Second, pre-existing WM microstructure differences possibly reflect a risk factor for development of a smoking addiction.
In Human Brain Mapping,2015

Aim
To examine the relationship between a childhood diagnosis of attention deficit hyperactivity disorder (ADHD) with or without oppositional defiant disorder (ODD)/conduct disorder (CD) and the development of later alcohol/drug use disorder [psychoactive substance use disorder (PSUD)] and nicotine dependence in a large European sample of ADHD probands, their siblings and healthy control subjects.
Conclusions
A childhood diagnosis of attention deficit hyperactivity disorder is a risk factor for psychoactive substance use disorder and nicotine dependence in adolescence and comorbid conduct disorder, but not oppositional defiant disorder, further increases the risk of developing psychoactive substance use disorder and nicotine dependence.
In Addiction,2013

Background
Attention-deficit hyperactivity disorder (ADHD) is linked to increased risk for substance use disorders and nicotine dependence.
Aims
To examine the effects of stimulant treatment on subsequent risk for substance use disorder and nicotine dependence in a prospective longitudinal ADHD case-control study.
Method
At baseline we assessed ADHD, conduct disorder and oppositional defiant disorder. Substance use disorders, nicotine dependence and stimulant treatment were assessed retrospectively after a mean follow-up of 4.4 years, at a mean age of 16.4 years.
Results
Stimulant treatment of ADHD was linked to a reduced risk for substance use disorders compared with no stimulant treatment, even after controlling for conduct disorder and oppositional defiant disorder (hazard ratio (HR) = 1.91, 95% CI 1.10-3.36), but not to nicotine dependence (HR = 1.12, 95% CI 0.45-2.96). Within the stimulant-treated group, a protective effect of age at first stimulant use on substance use disorder development was found, which diminished with age, and seemed to reverse around the age of 18.
Conclusions
Stimulant treatment appears to lower the risk of developing substance use disorders and does not have an impact on the development of nicotine dependence in adolescents with ADHD.
In British Journal of Psychiatry.,2013