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Objective: The Quantified Behavioral Test (QbTest) is a computerized diagnostic test for ADHD, used in clinical psychiatric care, but its validity may be questioned. We analyzed the QbTest's diagnostic validity and its relation to cognitive ability and psychosocial factors in an adolescent population with a high occurrence of neurodevelopmental disorders. Method: In total, 340 participants aged 15 years, completed the QbTest, along with questionnaires, clinical and intelligence quotient (IQ) assessments. Results: The clinical assessment resulted in 89 (26%) participants with ADHD. Area under curve (AUC) scores indicated a random to poor validity of the QbTest (AUC range = 0.48-0.64). QbTest scores of inattention and impulsivity correlated with IQ. Conclusion: The QbTest was insufficient as a diagnostic test for ADHD, and was not able to differentiate ADHD from other neurodevelopmental conditions. Clinicians should be aware of the dubious discriminating power of the QbTest.

Det svenska rättssystemet som tillåter att vi dömer psykiskt sjuka för brott och att personer som saknar vårdbehov kan hållas frihetsberövade inom rättspsykiatrin under mycket lång tid med oklart vårdinnehåll, är unikt och har fått rättmätig kritik under lång tid. Ändå händer ingenting.

BACKGROUND: We examined whether childhood conduct problems predicted a wide range of adverse outcomes in emerging adulthood and whether the association with internalizing problems remained after adjusting for general comorbidity and externalizing problems. METHODS: Participants were 18,649 twins from the Child and Adolescent Twin Study in Sweden. At age 9/12, parents rated their children on eight conduct problems. Adverse outcomes were retrieved from national registers in emerging adulthood (median follow-up time = 9.2 years), including diagnoses of six psychiatric disorders, prescriptions of antidepressants, suicide attempts, criminality, high school ineligibility, and social welfare recipiency. We estimated risk for the separate outcomes and examined if conduct problems predicted an internalizing factor above and beyond a general comorbidity and an externalizing factor. We used twin analyses to estimate genetic and environmental contributions to these associations. RESULTS: On the average, each additional conduct symptom in childhood was associated with a 32% increased risk of the adverse outcomes in emerging adulthood (mean hazard ratio = 1.32; range = 1.16, 1.56). A latent childhood conduct problems factor predicted the internalizing factor in emerging adulthood (beta(boys) = .24, standard error, SE = 0.03; beta(girls) = .17, SE = 0.03), above and beyond its association with the externalizing (beta(boys) = 0.21, SE = 0.04; beta(girls) = 0.17, SE = 0.05) and general factors (beta(boys) = 0.45, SE = 0.03; beta(girls) = 0.34, SE = 0.04). These associations were differentially influenced by genetic and environmental factors. CONCLUSIONS: It is important to monitor boys and girls with conduct problems not only for future externalizing problems, but also for future internalizing problems. Prevention of specific outcomes, however, might require interventions at different levels.

Introduction: Nonrandom selection into a study population due to differences between consenters and non-consenters may introduce participation bias. Past investigations of factors predicting consent to collection of medical health records for research imply that age, sex, health status and education are of importance for participation, but disagree on the direction of effects. Very little is known about influences on consent from adolescents. Methods: Two cohorts of Swedish 15-year-old twins (total n=4,611) previously invited to the Child and Adolescent Twin Study in Sweden (CATSS) responded to a questionnaire with information on gender, individual’s health, height, weight and parental factors. The questionnaire included a question for consent to collection of medical health records. Predictors for consent were analysed using logistic regression. Additionally, regional differences in the collection of health records of consenters were evaluated. Results: Males were significantly less likely to consent compared to females (OR 0.74, 95% CI 0.64-0.85). The twin sibling’s decision to consent was strongly associated with consent (OR 10.9, 95% CI 8.76-13.5), and individuals whose parents had responded to the original CATSS study were more likely to consent to record collection at age 15 (OR 2.2, 95% CI 1.81-2.75). Results of the subsequent collection of consenters’ medical health records varied between geographical regions of Sweden. Conclusion: We identified several predictors for adolescents’ consent to collection of their medical health records. Further selection was introduced through the subsequent record Page 3 of 32 collection. Whether this will induce participation bias in future studies depends on the research questions’ relationship to the identified predictors.

Objective: Attention-deficit/hyperactivity disorder (ADHD) is more common in males than females, yet little is known about why this is the case. We aimed to test for the existence of a ‘female protective effect’ against ADHD traits in two European twin samples. Specifically, we aimed to test whether cotwins of females displaying extreme ADHD traits would display more ADHD traits than co-twins of males displaying extreme ADHD traits. Method: Parents of approximately 7,000 pairs of non-identical twins in Sweden, and around 4,000 pairs of twins in England and Wales, completed dimensional assessments of ADHD traits. Probands were selected on the basis of scoring within the highest 10% of the distribution in each sample. Dimensional scores of co-twins of probands, as well as the categorical recurrence rate, were investigated by proband sex. Results: Co-twins of female probands displayed higher mean ADHD trait scores (mean=0.62-0.79) than co-twins of male probands (mean=0.38-0.55) in both samples. This trend was significant in the Swedish sample (p<.01) and when the two samples were merged into a single, larger sample (p<.001). When the samples were merged, there was also a significant association between proband sex and co-twin’s categorical status, with more co-twins of female probands also being probands than co-twins of male probands. Conclusions: These findings support a female protective effect against ADHD behaviors in the general population, indicating that females require exposure to a greater degree of etiological factors than males to develop ADHD.

Children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of problematic alcohol and other substance use in adolescence. This study used data from an ongoing, prospective, population-based twin study of Swedish children and adolescents to evaluate the extent to which the association between ADHD symptoms and alcohol problems reflects a unique source of genetic or environmental risk related to ADHD versus a broader predisposition to youth externalizing behavior. We used all available data from same-sex MZ and DZ twins on ADHD symptoms in childhood (age 9/12; N = 15,549) and alcohol problems in late adolescence (age 18; N = 2,564). Consistent with prior longitudinal studies, the phenotypic association between hyperactive/impulsive ADHD symptoms and alcohol problems was small in magnitude, whereas the association for inattentive symptoms was even weaker. Additive genetic influences explained 99.8% of the association between hyperactive/impulsive symptoms and alcohol problems. Furthermore, we found that the genetic risk specifically associated with hyperactive/impulsive symptoms was attenuated when estimated in the context of externalizing behavior liability during childhood, of which ADHD symptoms were specific expressions. In sensitivity analyses exploring hyperactivity in mid-adolescence, we found a similar pattern of genetic associations. These results are consistent with previous findings of genetically driven overlap in the etiology of ADHD and problematic alcohol use. At least some of this cooccurrence may result from a general predisposition to externalizing behaviors in youth.

Background Restrictive eating problems are rare in children but overrepresented in those with neurodevelopmental problems. Comorbidities decrease wellbeing in affected individuals but research in the area is relatively scarce. This study describes phenotypes, regarding psychiatric and gastrointestinal comorbidities, in children with restrictive eating problems. Methods A parental telephone interview was conducted in 9- or 12-year old twins (n = 19,130) in the Child and Adolescent Twin Study in Sweden. Cases of restrictive eating problems and comorbid problems were established using the Autism, Tics-AD/HD and other Comorbidities inventory, parental reports of comorbidity as well as data from a national patient register. In restrictive eating problem cases, presence of psychiatric and gastrointestinal comorbidity was mapped individually in probands and their co-twin. Two-tailed Mann–Whitney U tests were used to test differences in the mean number of coexisting disorders between boys and girls. Odds ratios were used to compare prevalence figures between individuals with or without restrictive eating problems, and Fisher exact test was used to establish significance. Results Prevalence of restrictive eating problems was 0.6% (concordant in 15% monozygotic and 3% of dizygotic twins). The presence of restrictive eating problems drastically increased odds of all psychiatric problems, especially autism spectrum disorder in both sexes (odds ratio = 11.9 in boys, odds ratio = 10.1 in girls), obsessive-compulsive disorder in boys (odds ratio = 11.6) and oppositional defiant disorder in girls (odds ratio = 9.22). Comorbid gastrointestinal problems, such as lactose intolerance (odds ratio = 4.43) and constipation (odds ratio = 2.91), were the most frequent in girls. Boy co-twins to a proband with restrictive eating problems generally had more psychiatric problems than girl co-twins and more girl co-twins had neither somatic nor any psychiatric problems at all. Conclusions In chi, Funders: ALF, Skåne; Dr. Sten Theander’s foundation for research in Anorexia Nervosa.