The Development of an Internet-Based Treatment for Problem Gamblers and Concerned Significant Others: A Pilot Randomized Controlled Trial.

Problem gambling creates significant harm for the gambler and for concerned significant others (CSOs). While several studies have investigated the effects of individual cognitive behavioral therapy (CBT) for problem gambling, less is known about the effects of involving CSOs in treatment. Behavioral couples therapy (BCT) has shown promising results when working with substance use disorders by involving both the user and a CSO. This pilot study investigated BCT for problem gambling, as well as the feasibility of performing a larger scale randomized controlled trial. 36 participants, 18 gamblers and 18 CSOs, were randomized to either BCT or individual CBT for the gambler. Both interventions were Internet-delivered self-help interventions with therapist support. Both groups of gamblers improved on all outcome measures, but there were no differences between the groups. The CSOs in the BCT group lowered their scores on anxiety and depression more than the CSOs of those randomized to the individual CBT group did. The implications of the results and the feasibility of the trial are discussed.

Childhood attention-deficit/hyperactivity disorder symptoms and the development of adolescent alcohol problems: A prospective, population-based study of Swedish twins.

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 monozygotic (MZ) and dizygotic (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 co-occurrence may result from a general predisposition to externalizing behaviors in youth. © 2015 Wiley Periodicals, Inc.

The association between childhood autistic traits and adolescent psychotic experiences is explained by general neuropsychiatric problems.

Studies suggest associations between childhood autistic traits and adolescent psychotic experiences. However, recent research suggests that a general neuropsychiatric problems factor predicts adverse outcomes better than specific diagnostic entities. To examine if the alleged association between autistic traits and psychotic experiences could rather be explained by a general neuropsychiatric problems factor comprising symptoms of ADHD, tic disorder, developmental coordination disorder, and learning disorder, we conducted a prospective cohort study based on the Child and Adolescent Twin Study in Sweden. In addition, we examined the genetic and environmental influences on the associations. A total of 9,282 twins with data on childhood autistic traits and other neuropsychiatric problems, and follow-up data on psychotic experiences at ages 15 and/or 18 years were included. First, psychotic experiences were regressed on autistic traits and second, the general neuropsychiatric problems factor was added to the model. Auditory hallucinations were analyzed separately from the other psychotic experiences. Finally, twin analyses were employed to disentangle genetic from environmental influences in the observed associations. Replicating prior research, significant associations were found between autistic traits in childhood and auditory hallucinations at ages 15 and 18. However, after controlling for the general neuropsychiatric problems factor, the associations between autistic traits and auditory hallucinations disappeared, whereas the association between the general neuropsychiatric problems factor and auditory hallucinations persisted after controlling for autistic traits. Twin analyses revealed that the association between the general neuropsychiatric problems factor and auditory hallucinations was driven by shared genetic influences. © 2015 Wiley Periodicals, Inc.

Selective Serotonin Reuptake Inhibitors and Violent Crime: A Cohort Study.

BACKGROUND: Although selective serotonin reuptake inhibitors (SSRIs) are widely prescribed, associations with violence are uncertain. METHODS AND FINDINGS: From Swedish national registers we extracted information on 856,493 individuals who were prescribed SSRIs, and subsequent violent crimes during 2006 through 2009. We used stratified Cox regression analyses to compare the rate of violent crime while individuals were prescribed these medications with the rate in the same individuals while not receiving medication. Adjustments were made for other psychotropic medications. Information on all medications was extracted from the Swedish Prescribed Drug Register, with complete national data on all dispensed medications. Information on violent crime convictions was extracted from the Swedish national crime register. Using within-individual models, there was an overall association between SSRIs and violent crime convictions (hazard ratio [HR] = 1.19, 95% CI 1.08-1.32, p < 0.001, absolute risk = 1.0%). With age stratification, there was a significant association between SSRIs and violent crime convictions for individuals aged 15 to 24 y (HR = 1.43, 95% CI 1.19-1.73, p < 0.001, absolute risk = 3.0%). However, there were no significant associations in those aged 25-34 y (HR = 1.20, 95% CI 0.95-1.52, p = 0.125, absolute risk = 1.6%), in those aged 35-44 y (HR = 1.06, 95% CI 0.83-1.35, p = 0.666, absolute risk = 1.2%), or in those aged 45 y or older (HR = 1.07, 95% CI 0.84-1.35, p = 0.594, absolute risk = 0.3%). Associations in those aged 15 to 24 y were also found for violent crime arrests with preliminary investigations (HR = 1.28, 95% CI 1.16-1.41, p < 0.001), non-violent crime convictions (HR = 1.22, 95% CI 1.10-1.34, p < 0.001), non-violent crime arrests (HR = 1.13, 95% CI 1.07-1.20, p < 0.001), non-fatal injuries from accidents (HR = 1.29, 95% CI 1.22-1.36, p < 0.001), and emergency inpatient or outpatient treatment for alcohol intoxication or misuse (HR = 1.98, 95% CI 1.76-2.21, p < 0.001). With age and sex stratification, there was a significant association between SSRIs and violent crime convictions for males aged 15 to 24 y (HR = 1.40, 95% CI 1.13-1.73, p = 0.002) and females aged 15 to 24 y (HR = 1.75, 95% CI 1.08-2.84, p = 0.023). However, there were no significant associations in those aged 25 y or older. One important limitation is that we were unable to fully account for time-varying factors. CONCLUSIONS: The association between SSRIs and violent crime convictions and violent crime arrests varied by age group. The increased risk we found in young people needs validation in other studies.

Predictors of adolescents' consent to use health records for research and results from data collection in a Swedish twin cohort.

INTRODUCTION: Non-random 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 sex, 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 analyzed 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 siblings' 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 collection. Whether this will induce participation bias in future studies depends on the research questions' relationship to the identified predictors.

Physical domestic violence exposure is highly associated with suicidal attempts in both women and men. Results from the national public health survey in Sweden.

BACKGROUND: Studies on a national level concerning domestic violence (DV) among both men and women are few. DV and its relation to other social and health outcomes within the framework of the Swedish Public Health Survey have remained unexplored. AIM: To compare women and men regarding their social situation and health status in relation to self-reported exposure to physical DV as measured in the Swedish National Public Health Survey. METHODS: This study used cross-sectional data from the Swedish Public Health Survey, years 2004-09 with a total sample of 50 350 respondents, of which 205 women and 93 men reported DV exposure. Logistic regression analyses stratified by sex with physical DV exposure as the outcome measure were conducted, and the multivariate models were fitted using the likelihood ratio test. RESULTS: Being foreign-born [women odds ratio (OR) = 1.52, men OR = 1.92] and lack of social support (women OR = 2.81, men OR = 1.92) were associated with DV exposure among both sexes. Higher psychological distress (women OR = 2.81, men OR = 1.92) and hazardous drinking (women OR = 1.61, men OR = 2.33) were also associated with DV exposure. Among women, financial problems were associated with DV exposure (OR = 1.83), whereas among men, sum of medicines used and higher odds of DV were associated (OR = 1.17). Further, suicidal attempts were associated with DV exposure among both women (OR = 5.59) and men (OR = 8.34). CONCLUSIONS: In this national survey, prevalence rates of violence exposure were lower than in other studies, but despite this, both women and men exposed to physical DV reported increased odds of having attempted suicide.

Reliability of Autism-Tics, AD/HD, and other Comorbidities (A-TAC) inventory in a test-retest design.

The Autism-Tics, AD/HD, and other Comorbidities (A-TAC) inventory is used in epidemiological research to assess neurodevelopmental problems and coexisting conditions. Although the A-TAC has been applied in various populations, data on retest reliability are limited. The objective of the present study was to present additional reliability data. The A-TAC was administered by lay assessors and was completed on two occasions by parents of 400 individual twins, with an average interval of 70 days between test sessions. Intra- and inter-rater reliability were analysed with intraclass correlations and Cohen's kappa. A-TAC showed excellent test-retest intraclass correlations for both autism spectrum disorder and attention deficit hyperactivity disorder (each at .84). Most modules in the A-TAC had intra- and inter-rater reliability intraclass correlation coefficients of > or = .60. Cohen's kappa indi- cated acceptable reliability. The current study provides statistical evidence that the A-TAC yields good test-retest reliability in a population-based cohort of children.

Predictive properties of the A-TAC inventory when screening for childhood-onset neurodevelopmental problems in a population-based sample.

BACKGROUND: Identifying children with childhood-onset neurodevelopmental problems (NDPs, defined here as autism spectrum disorders [ASDs], attention-deficit/hyperactivity disorder [AD/HD], tic disorders [TDs], learning disorders [LDs] and development coordination disorder), using easily administered screening instruments, is a prerequisite for epidemiological research. Such instruments are also clinically useful to prioritize children for comprehensive assessments, to screen risk groups, and to follow controls.Autism-Tics, ADHD, and other Co-morbidities inventory (A-TAC) was developed to meet these requirements; here the A-TAC's prospective and psychometric properties are examined, when used in a population-based, epidemiological setting. METHODS: Since 2004, parents of all Swedish twins have been asked to take part in an ongoing, nation-wide twin study (The Child and Adolescent Twin Study in Sweden). The study includes the A-TAC, carried out as a telephone interview with parents of twins aged 9 or 12. In the present study, screen-positive twins from three birth year cohorts (1993-1995) were invited to a comprehensive clinical follow-up (blinded for previous screening results) together with their co-twins and randomly selected, healthy controls at age 15 (Total N = 452). RESULTS: Sensitivity and specificity of A-TAC scores for predicting later clinical diagnoses were good to excellent overall, with values of the area under the receiver operating characteristics curves ranging from 0.77 (AD/HD) to 0.91 (ASDs). Among children who were screen-positive for an ASD, 48% received a clinical diagnosis of ASDs. For AD/HD, the corresponding figure was also 48%, for LDs 16%, and for TDs 60%. Between 4% and 35% of screen-positive children did not receive any diagnosis at the clinical follow-up three years later. Among screen-negative controls, prevalence of ASDs, AD/HD, LDs, and TDs was 0%, 7%, 4%, and 2%, respectively. CONCLUSIONS: The A-TAC appeared to be a valid instrument to assess NDPs in this population-based, longitudinal study. It has good-to-excellent psychometric properties, with an excellent ability to distinguish NDPs (mainly ASDs) from non-NDPs at least three years after the screening evaluations, although specific diagnoses did not correspond closely to actual clinical diagnoses.

The Swedish Twin Registry: establishment of a biobank and other recent developments.

The Swedish Twin Registry (STR) today contains more than 194,000 twins and more than 75,000 pairs have zygosity determined by an intra-pair similarity algorithm, DNA, or by being of opposite sex. Of these, approximately 20,000, 25,000, and 30,000 pairs are monozygotic, same-sex dizygotic, and opposite-sex dizygotic pairs, respectively. Since its establishment in the late 1950s, the STR has been an important epidemiological resource for the study of genetic and environmental influences on a multitude of traits, behaviors, and diseases. Following large investments in the collection of biological specimens in the past 10 years we have now established a Swedish twin biobank with DNA from 45,000 twins and blood serum from 15,000 twins, which effectively has also transformed the registry into a powerful resource for molecular studies. We here describe the main projects within which the new collections of both biological samples as well as phenotypic measures have been collected. Coverage by year of birth, zygosity determination, ethnic heterogeneity, and influences of in vitro fertilization are also described.

Intimate partner violence and help-seeking--a cross-sectional study of women in Sweden.

BACKGROUND: Intimate partner violence (IPV) is a global public health concern with possible detrimental consequences for its victims. Studies have found prevalence rates of 15 to 71% for IPV. There is evidence that IPV exposed women perceive barriers to help-seeking and many remain undetected by care givers and authorities. This cross-sectional study aimed to examine IPV exposed women in relation to help-seeking versus non help-seeking from the social services or women's shelters with regard to social and psychological characteristics as well as relationship with the perpetrator and type of violence exposure. METHODS: Two groups of Swedish IPV exposed women were included: non help-seekers (n = 128) were recruited through ads in newspapers, while help-seekers (n = 347) were recruited from four social service sites and twenty women's shelters around Sweden. Participants were assessed with questionnaires regarding age, education, occupation and relation to the perpetrator as well as validated instruments measuring psychological distress, psychosocial functioning alcohol use and violence. Analyses were made using Chi2 and multivariate logistic regression. RESULTS: Help-seekers had significantly more often children together with the perpetrator than non help-seekers (64% and 29% respectively) and a high association was found in the fully adjusted model (Adj. OR = 5.46 95% CI 2.99-9.97). Many women in both groups reported a poor social situation and high levels of psychological distress, although more psychological distress was associated with elevated odds for help-seeking (Adj. OR = 2.83 95% CI 1.84-4.34). No differences were found between the groups regarding violence exposure and most women in both groups had experienced severe violence from an intimate partner (95% to 98%). CONCLUSIONS: Results indicate a high problem load among women who had not contacted the social services or women's shelters due to IPV, and that non help-seekers had similar experiences of severe IPV as help-seekers. This stresses a need to identify IPV exposed women outside specialized settings within the social services and women's shelters. Asking about partner violence in various health and social care settings could be a feasible strategy to identify battered women and provide them with alternatives for help that ultimately could lead to a life without violence.

Gender differences in re-offending among psychiatrically examined Swedish offenders.

BACKGROUND: The gender gap for violent offending is narrowing in the general population. Substance abuse and mental health problems are known risk factors for criminality. While substance abuse treatment has been associated with reduced risk of re-offending, women seem less likely to engage than men. People misusing substances tend to be high users of emergency room (ER) services. Such use may be an indicator both of treatment failure for substance misuse and offending. Little is known about gender differences in this respect. AIMS: This study aims to test for gender differences in re-offending, use of substance abuse treatment, and hospital ER visits among offenders referred for forensic psychiatric assessment in Sweden. METHOD: The study used a longitudinal retrospective design. Data on all 31 women from a 2-year (2000-2001) cohort of serious offenders referred for forensic psychiatric assessment in Stockholm county, and 31 men from the same cohort, were extracted from forensic service and national records. Selection of the men was by initial random sampling followed by matching on age and substance misuse. The two resulting samples were compared on health service use and re-offending data between release and the census date (30 April 2004). RESULTS: There were no gender differences for violent re-offending or for engagement in planned substance abuse treatment, in spite of longer time at risk for the men. Re-offending was reduced for women but not men who did not present in the ER with physical health problems. CONCLUSIONS: Our study is limited by sample size, although it included all women referred to the specialist forensic psychiatric service over 2 years, but it does indicate that differences between men and women in this situation are likely, and worthy of further study. The only way of achieving adequate sample sizes is likely to be through multi-centre collaboration.

Autism and Convictions for Violent Crimes: Population-Based Cohort Study in Sweden.

OBJECTIVE: Recent systematic reviews have highlighted that the relationship between autism and violent offending is still unclear, but some cases have received extensive media scrutiny. We investigated whether autism is associated with convictions for violent crimes, and studied the associated risk and protective factors. METHOD: We analyzed data from the Stockholm Youth Cohort, a total population-based record-linkage cohort in Stockholm County comprising 295,734 individuals followed up between 15 and 27 years of age. Of these, 5,739 individuals had a recorded autism diagnosis. The main outcome measure was a conviction for violent crimes identified using the Swedish National Crime Register. RESULTS: Individuals with autism, particularly those without intellectual disability, initially appeared to have a higher risk of violent offending (adjusted relative risk = 1.39, 95% CI = 1.23-1.58). However, these associations markedly attenuated after co-occurring attention-deficit/hyperactivity disorder (ADHD) or conduct disorder were taken into account (adjusted relative risk = 0.85, 95% CI = 0.75-0.97). Among individuals with autism, male sex and psychiatric conditions were the strongest predictors of violent criminality, along with parental criminal and psychiatric history and socioeconomic characteristics. There was some evidence that a delayed diagnosis of autism was associated with a greater risk of violent crime. Better school performance and intellectual disability appeared to be protective. CONCLUSION: An initially observed association between autism and violent crimes at a population level was explained by comorbidity with ADHD and conduct disorder. Better understanding and management of comorbid psychopathology in autism may potentially help preventive action against offending behaviors in people with autism.

Development and Validation of a Brief Version of the Difficulties in Emotion Regulation Scale: The DERS-16.

The Difficulties in Emotion Regulation Scale (DERS) is a widely-used, theoretically-driven, and psychometrically-sound self-report measure of emotion regulation difficulties. However, at 36-items, the DERS may be challenging to administer in some situations or settings (e.g., in the course of patient care or large-scale epidemiological studies). Consequently, there is a need a briefer version of the DERS. The goal of the present studies was to develop and evaluate a 16-item version of the DERS - the DERS-16. The reliability and validity of the DERS-16 were examined in a clinical sample (N = 96) and two large community samples (Ns = 102 and 482). The validity of the DERS-16 was evaluated comparing the relative strength of the association of the two versions of the DERS with measures of emotion regulation and related constructs, psychopathology, and clinically-relevant behaviors theorized to stem from emotion regulation deficits. Results demonstrate that the DERS-16 has retained excellent internal consistency, good test-retest reliability, and good convergent and discriminant validity. Further, the DERS-16 showed minimal differences in its convergent and discriminant validity with relevant measures when compared to the original DERS. In conclusion, the DERS-16 offers a valid and brief method for the assessment of overall emotion regulation difficulties.

Varenicline and risk of psychiatric conditions, suicidal behaviour, criminal offending, and transport accidents and offences: population based cohort study.

OBJECTIVE: To examine associations between varenicline and the incidence of a range of adverse outcomes. DESIGN: Population based cohort study using within person analyses to control for confounding by indication. SETTING: Whole population of Sweden. PARTICIPANTS: 7,917,436 people aged 15 and over, of whom 69,757 were treated with varenicline between 2006 and 2009. MAIN OUTCOME MEASURES: Incidence of new psychiatric conditions, suicidal behaviour, suspected and convicted criminal offending, transport accidents, and suspected and convicted traffic offences. RESULTS: In the whole population, 337,393 new psychiatric conditions were diagnosed during follow-up. In addition, 507,823 suspected and 338,608 convicted crimes, 40,595 suicidal events, 124,445 transport accidents, and 99,895 suspected and 57,068 convicted traffic crimes were recorded. Within person analyses showed that varenicline was not associated with significant hazards of suicidal behaviour, criminal offending, transport accidents, traffic offences, or psychoses. However, varenicline was associated with a small increase in the risk of anxiety conditions (hazard ratio 1.23, 95% confidence interval 1.01 to 1.51) and mood conditions (1.31, 1.06 to 1.63), which was only seen in people with pre-existing psychiatric disorders. CONCLUSIONS: Concerns that varenicline is associated with an increased risk of many adverse outcomes, including suicidality and accidents, are not supported in this observational study. The small increase in risk of two psychiatric conditions in people with pre-existing psychiatric disorders needs to be confirmed using other research designs.

Childhood Symptoms of ADHD Overrule Comorbidity in Relation to Psychosocial Outcome at Age 15: A Longitudinal Study.

OBJECTIVE: Neurodevelopmental problems (NDPs) may influence the transition from childhood to adolescence. Our aim was to study long-term psychosocial outcomes of NDPs, focusing on ADHD. METHOD: Data was collected through a telephone interview with parents of twins at ages 9 or 12 years. NDP screen-positive children were clinically assessed at age 15; N = 450. Psychosocial outcome concerning peers, school, internalizing problems, antisocial behavior, alcohol misuse, drug misuse, and impaired daily functioning was examined. RESULTS: Even after controlling for other NDP comorbidity, screen-positivity for ADHD doubled or tripled the odds of later psychosocial problems. When controlling for parental education level, the significant effect of ADHD remained only for antisocial behavior and impaired daily functioning. CONCLUSIONS: Signs of NDPs as well as other psychiatric diagnoses at ages 9 or 12 years are associated with a more problematic adolescence. However, despite the presence of comorbidity, early ADHD symptoms stand out as the most important risk factor for later antisocial development and impaired daily functioning.

Mental Health Services and Public Safety: Substance Abuse Outpatient Visits Were Associated with Reduced Crime Rates in a Swedish Cohort.

Substance abuse is related to offending and substance abuse treatment has been associated with reductions in criminal behavior. This cohort study aimed to explore the relationship between participation in substance abuse interventions and general criminal recidivism among offenders with a combination of mental health problems and substance use problems. In total, 150 Swedish offenders with self-reported mental health and substance use problems were followed for approximately three years with regard to participation in substance abuse interventions and criminal recidivism. Participants with at least three planned visits to specialized outpatient substance abuse clinics had a substantially reduced risk of reoffending as compared to those with fewer than three such visits (HR = 0.47, 95% CI 0.29-0.77). For those with at least three planned visits, general criminal recidivism was reduced by 75% during periods of participation in outpatient visits, as compared to periods of non-participation (HR = 0.25, 95% CI 0.11-0.60). For offenders with mental health problems and substance use problems, outpatient substance abuse interventions could be regarded as important from a clinical risk management perspective, and be encouraged.

Offenders with mental health problems and problematic substance use: affective psychopathic personality traits as potential barriers to participation in substance abuse interventions.

Substance abuse is related to re-offending, and treatment of substance abuse may reduce criminal recidivism. Offender characteristics including problem severity, violence risk and psychopathic personality traits may be positively or negatively associated with participation in substance abuse treatment. We explored the relationships between such characteristics and participation in substance abuse interventions among Swedish offenders with mental health problems and problematic substance use. Our analyses revealed that problem severity regarding drugs, employment, and family/social situations predicted intervention participation, and that affective psychopathic personality traits were negatively associated with such participation. Thus, affective psychopathic personality traits could be considered as potential barriers to participation in substance abuse interventions. Among offenders with mental health problems and problematic substance use, such personality traits should be taken into account in order to optimize treatment participation and treatment outcome. Approaches used in cognitive-behavioral therapy (CBT) and dialectical behavioral therapy (DBT) could be applicable for these patients.

Childhood behavior problems and adolescent sexual risk behavior: familial confounding in the child and adolescent twin study in Sweden (CATSS).

OBJECTIVE: Previous studies have found associations between childhood behavior problems and adolescent sexual risk behavior. Using a quasi-experimental approach, we examined the extent to which this association may be due to between-family differences (i.e., unmeasured familial confounds) not adequately explored in prior research. METHODS: We used data from a longitudinal, population-based cohort of young twins in Sweden (first assessment: age 9 or 12 years; second assessment: age 15; n = 2,388). We explored the nature of the association between symptom scores for attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD) at age 9 or 12 and the likelihood of having had sexual intercourse and number of sexual partners by age 15. Two-level mixed-effects models were used to estimate the effect of symptom score on each outcome after controlling for potential unmeasured familial confounds. RESULTS: Higher ADHD, ODD, and CD scores were associated with significantly increased likelihood of sexual intercourse by age 15. Higher ADHD and ODD scores were also associated with increased number of sexual partners. After controlling for unmeasured familial confounds, however, behavior problems were no longer significantly associated with either outcome. CONCLUSION: The association between childhood behavior problems and sexual risk behaviors may be due to characteristics shared within families. Hence, prevention strategies aimed at reducing these behaviors might need to address broader risk factors that contribute to both behavior problems and a greater likelihood of sexual risk behavior.

Prevalence, comorbidity and heritability of hoarding symptoms in adolescence: a population based twin study in 15-year olds.

BACKGROUND: Hoarding Disorder (HD) is often assumed to be an 'old age' problem, but many individuals diagnosed with HD retrospectively report first experiencing symptoms in childhood or adolescence. We examined the prevalence, comorbidity and etiology of hoarding symptoms in adolescence. METHODS: To determine the presence of clinically significant hoarding symptoms, a population-based sample of 15-year old twins (N = 3,974) completed the Hoarding Rating Scale-Self Report. Co-occurring Obsessive Compulsive Disorder (OCD), Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) were estimated from parental report. Model-fitting analyses divided hoarding symptom scores into additive genetic, shared, and non-shared environmental effects. RESULTS: The prevalence of clinically significant hoarding symptoms was 2% (95% CI 1.6-2.5%), with a significantly higher prevalence in girls than boys. Exclusion of the clutter criterion (as adolescents do not have control over their environment) increased the prevalence rate to 3.7% (95% CI 3.1-4.3%). Excessive acquisition was reported by 30-40% among those with clinically significant hoarding symptoms. The prevalence of co-occurring OCD (2.9%), ASD (2.9%) and ADHD (10.0%) was comparable in hoarding and non-hoarding teenagers. Model-fitting analyses suggested that, in boys, additive genetic (32%; 95% CI 13-44%) and non-shared environmental effects accounted for most of the variance. In contrast, among girls, shared and non-shared environmental effects explained most of the variance, while additive genetic factors played a negligible role. CONCLUSIONS: Hoarding symptoms are relatively prevalent in adolescents, particularly in girls, and cause distress and/or impairment. Hoarding was rarely associated with other common neurodevelopmental disorders, supporting its DSM-5 status as an independent diagnosis. The relative importance of genetic and shared environmental factors for hoarding differed across sexes. The findings are suggestive of dynamic developmental genetic and environmental effects operating from adolescence onto adulthood.