Attention-deficit/hyperactivity Disorder Symptomatology Research Articles

Molecular Characterisation of the Mechanism of Action of Stimulant Drugs Lisdexamfetamine and Methylphenidate on ADHD Neurobiology: A Review.

Attention-deficit/hyperactivity disorder (ADHD) is a common childhood-onset neurodevelopmental disorder characterised by persistent inattention, hyperactivity and impulsivity. Moreover, ADHD is commonly associated with other comorbid diseases (depression, anxiety, bipolar disorder, etc.). The ADHD symptomatology interferes with subject function and development. The treatment of ADHD requires a multidisciplinary approach based on a combination of non-pharmacological and pharmacological treatments with the aim of ameliorating the symptomatology; among first-line pharmacological treatments are stimulants [such as methylphenidate (MPH) and lisdexamfetamine dimesylate (LDX)]. In this review we explored recent ADHD- and stimulants-related literature, with the aim of compiling available descriptions of molecular pathways altered in ADHD, and molecular mechanisms of current first-line stimulants MPH and LDX. While conducting the narrative review, we applied structured search strategies covering PubMed/MEDLINE database and performed handsearching of reference lists on the results of those searches. The aetiology and pathophysiology of ADHD are incompletely understood; both genetic and environmental factors have been associated with the disorder and its grade of burden, and also the relationship between the molecular mechanisms of pharmacological treatments and their clinical implications. The lack of comprehensive understanding of the underlying molecular pathology makes both the diagnosis and treatment difficult. Few published studies evaluating molecular data on the mechanism of action (MoA) of MPH and LDX on ADHD are available and most of them are based on animal models. Further studies are necessary to improve the knowledge of ADHD pathophysiology and how the MoAs of MPH and LDX differentially modulate ADHD pathophysiology and control ADHD symptomatology.

Attention-Deficit/Hyperactivity Disorder and the Gut Microbiota–Gut–Brain Axis: Closing Research Gaps through Female Inclusion in Study Design

The gastrointestinal tract harbors a densely populated community of microbes that exhibits sexual dimorphism. Dysbiosis of this community has been associated with chronic human disease states ranging from metabolic diseases to neuropsychiatric disorders (NPDs). The gut microbiota–gut–brain axis (GMGBA) is a bi-directional pathway that facilitates the interaction of the gut microflora with host physiological functions. Recently, research surrounding the potential roles of the GMGBA in the development of NPDs (e.g., depression, anxiety, and autism spectrum disorders (ASDs)) has increased. However, the role of the GMGBA in attention-deficit/hyperactivity disorder (ADHD), an NPD that affects an estimated 8.4% of children (5.1% of female and 11.5% of male children) and 4% of adults (with a male–female odds ratio of 1.6) in the United States, remains understudied. Herein, we synthesize the current literature regarding the GMGBA, ADHD, and the potentially relevant intersections between the GMGBA and ADHD. Recommendations are presented for pathways of future research into the role(s) of the GMGBA in ADHD etiology and symptomatology. Particular focus is given to the potential for the variable of host sex to act as an outcome modifier of the relationship between the GMGBA and ADHD.

Seasonality and ADHD: Summer time is associated with less symptoms of inattention among children and adolescents with ADHD

BackgroundAlthough alertness and activity status are related to light intensity, the effects of seasonal light variability on patients with Attention Deficit Hyperactivity Disorder (ADHD) have been scarcely studied. Our objective was to investigate the effect of seasonality (summer time vs. winter time) on ADHD symptomatology and on the circadian pattern of motor activity in children and adolescents with ADHD and healthy controls. MethodsA total of 117 participants (56.4 % males; age [mean ± SD] 9.2 ± 2.8 years; 51 % patients with ADHD) were included in this cross-sectional study. For all participants we assessed ADHD symptomatology using the Conners Parents Rating Scale-Revised and the circadian pattern of motor activity using actigraphy. Data were collected when schools were in session. General linear models were used to test for differences in outcome variables based on seasonality and ADHD subtype. ResultsThe results revealed that seasonality had a significant effect among ADHD-I patients. Particularly, we observed that inattention symptoms were ~8.1 points lower (p = 0.002) in summer time, relative to winter time. In addition, we observed that among patients with ADHD-I, the intradaily variability was also significantly lower in summer (p = 0.024). ConclusionThe results from this preliminary study suggest that seasonal light variability could be a factor that modifies the behavior of children and adolescents with ADHD-I.

Qualitative analysis of verbal fluency in school-age children with high-functioning autism spectrum disorders. Associations with age and IQ

This study analyzes performance on both a Semantic and a Letter verbal fluency (VF) task in school-age children with high-functioning autism spectrum disorder (HF-ASD) (n = 20) and without ASD (n = 20) and investigates the relationship between VF indicators and age, verbal and non-verbal IQ, ASD severity, and attention deficit hyperactivity disorder (ADHD) symptomatology. Furthermore, the Poor Lexical-Semantic Structure Model and the Slow-Retrieval Model are tested if they could account for semantic retrieval difficulties in children with HF-ASD. The HF-ASD group generated significantly fewer correct responses in both VF tasks in comparison to the control group. The type of task significantly affected performance and both groups showed higher word generativity on the Semantic task. The groups did not differ in clustering, switching, and errors. Age significantly correlated with the VF indicators in the ASD group, but in the control group, there was a significant negative correlation with the number of errors. Non-verbal and verbal IQ did not correlate with any VF indicators in both groups, while ASD severity and ADHD symptomatology correlated positively and significantly with error responses in the ASD group. The Slow-Retrieval Model explains VF difficulties in the HF-ASD group indicating that poorer word generativity can be attributed to slower retrieval of words from the semantic network.

Individual Differences in Germ Spreading Behaviors Among Children With Attention-Deficit/Hyperactivity Disorder: The Role of Executive Functioning.

ObjectiveInfectious diseases, such as coronavirus disease 2019 (COVID-19), are commonly transmitted by respiratory droplets and contact with contaminated surfaces. Individuals with attention-deficit/hyperactivity disorder (ADHD) are more likely to be infected with COVID-19 and experience more hospitalizations than individuals without ADHD. The current study investigated the role of ADHD symptomatology and executive functioning (EF) in germ spreading behavior frequency among young children with and without ADHD and parenting responses to these behaviors.MethodsParticipants included 53 children diagnosed with ADHD and 47 typically developing (TD) children between the ages of 4–5 years (76% male; Mage = 4.62; 86% Hispanic/Latinx). Parents and teachers reported on children’s ADHD symptomatology and children completed three EF tasks. Germ spreading behavior frequency (direct contact of hand to face and toy in mouth) and parenting responses (verbal and nonverbal behaviors) were observed during a 5-min parent–child play situation.ResultsNegative binomial regression analyses indicated that both ADHD diagnostic status and poor metacognition predicted both higher rates of toy to mouth (β = 1.94, p < .001; β = 0.03, p = .004) and face touching frequency (β = 0.60, p = .03; β = 0.03, p = .004), respectively. Additionally, poor attention and worse cognitive flexibility only predicted higher rates of toy to mouth frequency (β = 0.09, p < .001; β = −0.04, p = .001), respectively.ConclusionsYoung children with ADHD are at high risk for spreading germs via putting toys in their mouth and touching their face. Particularly, high levels of inattention and poor EF appear to be associated with higher rates of germ spreading behaviors.

Attention-Deficit/Hyperactivity Disorder (ADHD) and Time Perception in Adults: Do Adults with Different ADHD Symptomatology Severity Perceive Time Differently? Findings from the National Czech Study.

BackgroundStudies show neurological differences between patients with attention-deficit/hyperactivity disorder (ADHD) and healthy controls. Furthermore, it is possible that poor timing is linked with impairments in neural circuitry. This study aimed to test the hypothesis that there is a difference in time perception between adults with severe ADHD symptomatology and adults with no ADHD symptomatology.Material/MethodsPreviously, we collected data from a more extensive set of participants (n=1518) concerning the prevalence of ADHD in adulthood. We recruited participants from 3 groups defined by increasing ADHD severity out of this participant pool. Each participant was presented with 2 experimental tasks (in counterbalanced order): duration estimation and duration discrimination.ResultsIn general, we did not find any specific differences in time perception related to the severity of ADHD. Regarding duration estimation, we found that the difference between the actual and estimated durations increased with the actual duration (F(1, 7028.00)=2685.38, P<0.001). Although the differences between groups were not significant, the group×duration interaction was (F[1, 7028.00]=10.86, P<0.001), with a very small effect size (ηp2<0.001, 95% CI [0.00, 0.01]).ConclusionsThe results suggest that although individuals may demonstrate increased ADHD symptomatology, they may not have objectively more significant difficulties in time perception tasks than their counterparts with mild symptomatology. Nonetheless, time perception should be further studied because, as qualitative research suggests, participants with more severe ADHD symptomatology subjectively perceive more significant differences in time management in real life.

Self-reported symptoms of developmental dyslexia predict impairments in everyday cognition in adults

BackgroundResearch into the impact of dyslexia on everyday cognition in adults with dyslexia is relatively limited and has tended to focus on university students. Aims and methodsThe present online study aimed to add to this small corpus by investigating the everyday effects of dyslexia on memory and attention in a larger community-based sample. One hundred and seventy-two adult volunteers completed five well-established self-report questionnaires, assessing dyslexia and Attention Deficit Hyperactivity Disorder symptomatology and everyday experiences with memory, attention, and mind-wandering. ResultsAfter controlling for ADHD symptomatology, hierarchical regression analyses revealed that higher levels of dyslexia-related symptomatology were associated with greater, more frequent everyday memory and attentional problems, but not with a greater propensity to mind-wandering. Increased levels of dyslexia symptomatology were positively associated with the frequency of both everyday attentional lapses (at least when performing a pair of tasks or easy tasks while inhibiting intervening stimuli) and everyday memory failures. No significant associations were found between dyslexia symptomatology and attentional lapses when performing difficult tasks in the presence of concurrent stimuli or between dyslexia symptomatology and the propensity to mind-wandering. Conclusions and implicationsDyslexia symptomatology was perceived as being associated with more everyday memory and attention problems in adulthood. Adjustments to educational and workplace settings and interventions to compensate for these difficulties are proposed.

Sexuality in Adults With ADHD: Results of an Online Survey.

Establishing a secure sexual identity is a major developmental goal of an individual's transition from childhood to adolescence and the years that follow. Attention deficit/hyperactivity disorder (ADHD) as a neurodevelopmental disorder defined by the core symptoms of inattention, hyperactivity, and impulsivity, but also with emotional dysregulation, oppositional behaviors, or disorganization appearing early in life, can affect several areas of an individual's personal and social development, including sexual health. Yet, the scientific knowledge about the relationship between ADHD and sexual functioning is still scarce. Using an anonymous online survey, we compared different sexual behaviors including risky sexual behaviors, hypersexual behaviors, and sexual dysfunctions between 206 individuals with (n = 139) and without (n = 76) ADHD. Individuals with ADHD reported significantly more hypersexual behaviors than non-ADHD individuals, whereas no differences were found concerning risky sexual behaviors or sexual dysfunctions. In women with ADHD, hypersexual behaviors, sexual risk-taking as well as sexual dysfunctions were closely related to symptoms of emotional dysregulation, impulsivity, and oppositional symptoms. In men with ADHD, the associations between ADHD symptomatology and the sexuality-related measures were less clear, however, signs of emotional dysregulation seemed to be relevant as well. Since individuals with ADHD seem to be at an increased risk of some peculiarities in sexual behavior, sexuality-related issues should be routinely addressed during clinical consultations to provide more holistic treatment in order to enhance individual well-being and quality of life.

Evidence of the relationship between attention deficit/hyperactivity disorder (ADHD) and emotional abuse in a sample of preschool children

ABSTRACT This study has aimed to evaluate the relationship between preschool attention deficit/hyperactivity disorder (ADHD) and emotional abuse. Fifty-six children with ADHD aged 5 and 6 years and their mothers, and sixty-five children without a diagnosis of ADHD and their mothers have been included in this study. ADHD symptomatology and emotional abuse potential of mothers have been assessed by the Conners’ Parent Rating Scale-Revised-Short Form (CPRS-RS) and the Scale for Emotional Abuse Potential of Parents with Children Aged 3 to 6 (SEAPP-C3-6) respectively. Mothers of children with ADHD had significantly higher causal sub-dimension scores of SEAPP-C3-6 than that of the mothers of the controls. The higher emotional abuse potential scores of mothers have been significantly associated with higher Conners scores, male gender, disruptive behavior disorders comorbidity, low income and parental education level and parental psychopathology. This study has revealed that preschool ADHD is an important risk factor for emotional abuse. Clinicians shall be aware of the emotional abuse potential among children with ADHD.

Attention-Deficit/Hyperactivity Disorder-Related Self-Reported Symptoms Are Associated With Elevated Concussion Symptomatology.

The aim of the present investigation was to provide insight into how postconcussion symptomatology may be altered in individuals exhibiting attention-deficit/hyperactivity disorder (ADHD)-related behaviors and examine factors that may be responsible for driving such relationships. A total of 99 individuals were assessed during the subacute phase of concussion recovery. Inattentive symptomatology, but not diagnosis of ADHD, was related to greater concussion-symptom severity and overall symptoms endorsed. Cluster and factor analyses highlighted that the relationship between ADHD symptomatology and concussion symptomatology was not a function of overlapping constructs being assessed (i.e.,concussion-related symptomatology was not a proxy of ADHD-related symptomatology). These relationships were not mediated by parental observations of impairments in behaviors associated with executive functioning (i.e.,executive dysfunction was not driving the greater concussion-related symptomatology associated with ADHD-related symptomatology). These findings highlight the importance of moving beyond categorical frameworks of ADHD to, instead, consider the continuum of underlying behaviors.

Acute effects of physical exercise on cognitive and psychological functioning in college students with attention-deficit/hyperactivity disorder

We sought to elucidate the acute effects of high-intensity interval training (HIIT) among college students with and without attention-deficit/hyperactivity disorder (ADHD). Participants were age- and sex-matched across ADHD (n = 18) and non-ADHD groups (n = 18) and both groups completed baseline (non-HIIT) and experimental sessions (HIIT). We examined within- and between-subject effects on a continuous performance task (CPT) and self-reported ADHD and internalizing symptomatology. We found that the degree of improvement on ADHD and depressive symptomatology, as well as processing speed and response variability following HIIT was significantly greater for the ADHD group than the comparison group. Further investigations such as randomized controlled trials focusing on the chronic effects of sustained HIIT interventions are needed to substantiate the potential feasibility and efficacy of HIIT as an intervention. HIIT may be a useful adjunct to psychosocial and/or pharmacological treatments for college students with ADHD because it: (a) yields immediate, acute improvements in executive functioning, ADHD, and mood; (b) promotes improved physical and mental health; (c) poses a relatively low risk of deleterious effects in apparently healthy college students. Even with the need for additional research, current data suggest a single, brief, high-intensity bout of aerobic exercise can yield immediate significant short-term improvements. These improvements may enhance functioning and improve outcomes for college students with ADHD.

Attention deficit hyperactivity disorder as a neglected psychiatric disease in prison: Call for identification and treatment

Mis-diagnosis of attention deficit hyperactivity disorder (ADHD) is an important public health concern because the disease is treatable, yet can have a disastrous effect on the life of those affected. ADHD is associated with delinquency, criminality, and recidivism; and thus, people living in detention are especially at risk of having ADHD. This study investigated prevalence rates of ADHD diagnosis and treatment in prison. Data were collected in a Swiss prison (n=158). Medical files were screened for ADHD clinical diagnosis and treatment, and participants completed five items assessing ADHD symptomatology (ASRS-5). We computed prevalence rates with 95% confidence intervals (CI). Overall, 1.9% [95% CI: 1.1%–5.8%] of the participants had a clinical diagnosis of ADHD in medical files. Nobody received ADHD treatment. For the self-reported questionnaire, 12.9% [95% CI: 8.5%–19.2%] of the participants met the cut-off and were screened as potentially having ADHD. This study suggested that ADHD was under-diagnosed and under-treated in prison, with a lower prevalence rate according to the medical files of the participants in comparison with self-reports and with the worldwide meta-analytic prevalence rate of 26.2%. ADHD should receive more attention in order to promote health equity between incarcerated and general populations, to reduce health (care) disparities, and to enhance rehabilitation following incarceration.

Sex differences in microstructural alterations in the corpus callosum tracts in drug-naïve children with ADHD.

Widespread alterations in the corpus callosum (CC) microstructure and organization have been found in children with attention-deficit/hyperactivity disorder (ADHD); however, few studies have investigated the diffusion characteristics and volume of transcallosal fiber tracts defined by specific cortical projections in ADHD, which is important for identifying distinct functional interhemispheric connection abnormalities. In the current study, an automated fiber-tract quantification (AFQ) approach based on diffusion tensor imaging identified seven CC tracts according to their cortical projections and estimated diffusion parameters and volume among 76 drug-naïve ADHD patients (53 boys and 23 girls) and 37 typically developing children (TDC) (20 boys and 17 girls) matched for age, IQ, and handedness. We found significantly lower fractional anisotropy (FA) in the occipital and superior parietal tracts and higher mean diffusivity (MD) in the posterior, superior parietal and anterior frontal tracts in children with ADHD compared with TDC. In addition, lower FA and higher radial diffusivity (RD) in the occipital callosal tract were significantly associated with higher hyperactivity and impulsivity performance in ADHD. In addition, sex-by-diagnosis interactions were observed in the occipital, posterior and superior parietal tracts. Girls with ADHD showed decreased FA and volume in the occipital tract, which were significantly associated with increased impulsivity performance and poor response control, and increased MD in the posterior and superior parietal callosal tracts, which were significantly associated with increased inattention performance, whereas boys with ADHD merely showed decreased volume in the frontal tract. Our results elucidated that sex-specific alterations in the CC tracts potentially underlie ADHD symptomatology and further suggested a differential contribution of abnormalities in different CC tracts to impulsivity and inattention among girls with ADHD.

Family Context and ADHD Symptoms in Middle Childhood: an Explanatory Model

Recent research suggests that Attention Deficit Hyperactivity Disorder (ADHD) may be influenced by interactions between the individual and their social context. This study examined the predictive value of family context variables and attentional control levels on child ADHD symptoms. A new explanatory model of the relationship amongst these variables was also tested. A sample of 754 families with children aged 7 to 11 was assessed through the Conners Parent Rating Scale, the Haezi-Etxadi Family Assessment Scale, and the Attention Network Test. Path analysis models showed a predictive association between children ADHD symptoms and Social Support Network, Parental Stress, Parental Self-efficacy, Attentional Control and being male. Furthermore, a stronger Social Support Network was associated with greater Parental Self-efficacy, a variable that predicted Parental Stress levels and children ADHD symptoms. In conclusion, a new multi-influence model of variables linked to ADHD symptomatology during mid-childhood is provided, which may be useful to support the design of family interventions.

Inhibitory Control in Children with Tourette Syndrome Is Impaired in Everyday Life but Intact during a Stop Signal Task.

Tourette Syndrome (TS) has previously been associated with deficits in inhibitory control (IC). However, studies on IC in individuals with TS have produced conflicting results. In the present study, we investigated IC, comparing the Stop Signal Reaction Time (SSRT) measure with parent and teacher ratings of daily life IC in 169 children aged 8–12 (60 with TS, 60 typically developing controls, 27 with attention-deficit/hyperactivity disorder (ADHD), and 22 with TS + ADHD). We further investigated associations of IC with TS and ADHD symptom severity. Children with TS showed intact SSRT performance, but impairments in daily life IC, as reported by parents and teachers. For the latter, we observed a staircase distribution of groups, with the healthy controls presenting with the best IC, followed by TS, TS + ADHD, and finally ADHD. Dimensional analyses indicated a strong association between ADHD severity and both measures of IC. Our results indicate that children with TS are not impaired in a laboratory-based measure of IC, although some difficulties were evident from measures of everyday behaviour, which may in part be due to parents and teachers interpreting tics as disinhibited behaviour. Comorbid ADHD or the severity of subthreshold ADHD symptomatology appeared to account for IC deficits.

The effects of ADHD symptomatology and academic enabling behaviours on undergraduate academic achievement

AbstractUniversity students demonstrating higher levels of Attention‐Deficit Hyperactivity Disorder (ADHD) symptom severity largely experience lower academic achievement. Educational research has found that a group of behaviours (i.e., study skills, interpersonal skills, engagement, and motivation) known as academic enablers (AE) facilitate positive outcomes within a classroom‐based learning environment. The current study recruited 617 undergraduate students to explore whether ADHD symptomatology and AE emerge as significant predictors of academic achievement at the university level, and whether demonstration of AE contribute to predicting achievement above and beyond that of ADHD effects. Results from simple linear regression analysis indicated that higher ADHD symptom severity predicted poorer academic achievement. Greater application of AE—excluding interpersonal skills—predicted greater academic achievement among university students. Exploratory results from hierarchical linear regression analysis suggested that demonstration of engagement, motivation, and especially study skills contribute towards predicting greater academic achievement while controlling for negative effects from ADHD symptom presentation. These findings imply that undergraduate academic outcomes can potentially be improved for students struggling with more severe ADHD symptom presentation if more emphasis is placed by universities to promote academic enabling behaviours within the educational framework and environment.

Co-occurring medical and behavioural conditions in children with Down syndrome with or without ADHD symptom presentation.

Co-occurring attention deficit hyperactivity disorder (ADHD) is a challenge to characterise in the presence of other medical conditions commonly present in children with Down syndrome (DS). The current study examined differences among children with DS with or without ADHD symptomatology in terms of demographics, developmental level, co-occurring medical conditions, and parent and teacher ratings of behaviour and executive functioning. Parents and teachers of 108 school-age children with DS provided ratings of ADHD symptoms, behaviour problems and executive functioning skills. Children with DS and ADHD symptom presentation, as identified by a scoring algorithm, were compared with those without ADHD symptom presentation on demographic characteristics, developmental level, co-occurring medical conditions and parent-report and teacher-report measures of behaviours and executive functioning. Sleep disorders, disruptive behaviour disorder, allergies and seizures were more common in children with DS and ADHD symptom presentation than in children without ADHD symptom presentation. After controlling for ADHD medication use, children with DS and ADHD symptom presentation had poorer performance than those without ADHD symptom presentation on parent behaviour ratings, teacher behaviour ratings and parent but not teacher ratings of executive functioning. No significant group differences in demographic characteristics or developmental level were identified. Higher rates of co-occurring medical conditions present in children with DS and ADHD symptom presentation support the need for thorough differential diagnoses. The different pattern of group differences between parent-report and teacher-report has implications for diagnostic practices across settings as well as for treatment.

Acute and Long-Term Effects of an Internet-Based, Self-Help Comprehensive Behavioral Intervention for Children and Teens with Tic Disorders with Comorbid Attention Deficit Hyperactivity Disorder, or Obsessive Compulsive Disorder: A Reanalysis of Data from a Randomized Controlled Trial.

Attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD) and tic disorders (TD) commonly co-occur. In addition, specific inattention difficulties and poor impulse control are related to TD in the absence of comorbid ADHD. In this study we reanalyzed data from a recently completed study comparing internet-delivered, self-help comprehensive behavioral intervention for tics (ICBIT) with a waiting-list control group. The current study describes the effects of an (ICBIT) in children and adolescents with TD with and without comorbid diagnoses of ADHD or OCD at post intervention and over three- and six-month follow-up periods. Thirty-eight 7 to 18-year-olds completed the ICBIT. Of these, 16 were diagnosed with comorbid ADHD and 11 were diagnosed with OCD. A significant improvement in tic measures was found in all groups. Both the TD + ADHD and the TD − ADHD groups were similar in the magnitude of tic reduction from baseline to post-treatment, and at the three and six-month follow-up assessments. However, the TD + OCD group benefitted less from intervention than the TD—OCD group. There were meaningful reductions in parental reports of inattention, as well as hyperactive and impulsive symptoms at post intervention and over the 6-month follow-up period. Thus, ICBIT can be effectively delivered in the presence of comorbid ADHD or OCD symptomatology and may reduce symptoms of inattention and impulsivity. Larger studies of ICBIT in children and teens with TD and comorbid ADHD and OCD are needed to optimize responses to ICBIT.

The predictive and incremental validity of ADHD beyond the VRAG-R in a high-risk sample of young offenders

The VRAG-R is a well-established actuarial risk-assessment instrument, which was originally developed for assessing violent recidivism risk in adult male offenders. Whether or not the VRAG-R can also predict violent recidivism in young offenders is unclear so far. In the emergence of juvenile offending, attention-deficit/hyperactivity disorder (ADHD) seems to be of major importance suggesting that it could be relevant for risk assessment as well. Thus, we examined the predictive accuracy of the VRAG-R in a high-risk sample of N = 106 (M = 18.3 years, SD = 1.8) young offenders and assessed the incremental predictive validity of ADHD symptomatology beyond the VRAG-R. Within a mean follow-up time of M = 13 years (SD = 1.2), n = 65 (62.5%) young offenders recidivated with a violent offense. We found large effect sizes for the prediction of violent and general recidivism and re-incarcerations using the VRAG-R sum scores. Current ADHD symptomatology added incremental predictive validity beyond the VRAG-R sum scores concerning the prediction of general recidivism but not of violent recidivism. The results supported the use of the VRAG-R for predicting violent recidivism in young offenders. Because ADHD symptomatology improves the predictive performance of the VRAG-R regarding general recidivism, we argue that addressing ADHD symptoms more intensively in the juvenile justice system is of particular importance concerning a successful long-term risk management in adolescents and young adults.

A polygenic approach to the association between smoking and schizophrenia.

Smoking prevalence in schizophrenia is considerably larger than in general population, playing an important role in early mortality. We compared the polygenic contribution to smoking in schizophrenic patients and controls to assess if genetic factors may explain the different prevalence. Polygenic risk scores (PRSs) for smoking initiation and four genetically correlated traits were calculated in 1108 schizophrenic patients (64.4% smokers) and 1584 controls (31.1% smokers). PRSs for smoking initiation, educational attainment, body mass index and age at first birth were associated with smoking in patients and controls, explaining a similar percentage of variance in both groups. Attention-deficit hyperactivity disorder (ADHD) PRS was associated with smoking only in schizophrenia. This association remained significant after adjustment by psychiatric cross-disorder PRS. A PRS combining all the traits was more explanative than smoking initiation PRS alone, indicating that genetic susceptibility to the other traits plays an additional role in smoking behaviour. Smoking initiation PRS was also associated with schizophrenia in the whole sample, but the significance was lost after adjustment for smoking status. This same pattern was observed in the analysis of specific SNPs at the CHRNA5-CHRNA3-CHRNB4 cluster associated with both traits. Overall, the results indicate that the same genetic factors are involved in smoking susceptibility in schizophrenia and in general population and are compatible with smoking acting, directly or indirectly, as a risk factor for schizophrenia that contributes to the high prevalence of smoking in these patients. The contrasting results for ADHD PRS may be related to higher ADHD symptomatology in schizophrenic patients.