[Genetic research in childhood and adolescent psychiatry]. / Genetisch onderzoek in de kinder- en jeugdpsychiatrie.

BACKGROUND: Childhood mental health problems are partly influence by genetic factors with heritability estimates varying between 40% and 90%. AIM: We provide examples of genetic research focusing on explaining the continuity of symptoms and the association between parental traits and offspring psychopathology. METHOD: We summarize two recently publish review papers RESULTS: There are significant genetic correlations between childhood and adult mental disorders. Genetic factors also explain part of the associations between parental traits and offspring psychopathology, because parents and children share 50% of their genetic material. CONCLUSION: The role of genetic factors is not restricted to influencing the risk to develop a mental disorder. They also play a role in persistence of symptoms and the associations with the environment.

Sociodemographic and clinical characteristics in child and youth mental health; comparison of routine outcome measurements of an Australian and Dutch outpatient cohort.

AIMS: Although of great value to understand the treatment results for mental health problems obtained in clinical practice, studies using naturalistic data from children and adolescents seeking clinical care because of complex mental health problems are limited. Cross-national comparison of naturalistic outcomes in this population is seldomly done. Although careful consideration is needed, such comparisons are likely to contribute to an open dialogue about cross-national differences and may stimulate service improvement. The aim of this observational study is to investigate clinical characteristics and outcomes in naturalistic cohorts of specialized child and adolescent mental health outpatient care in two different countries. METHODS: Routinely collected data from 2013 to 2018 of 2715 outpatients in the Greater Area of Brisbane, Australia (CYMHS) and 1158 outpatients in Leiden, the Netherlands (LUMC-Curium) were analysed. Demographics, clinical characteristics and severity of problems at start and end of treatment were described, using Children's Global Assessment Scale (CGAS), Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA) and the parental Strength and Difficulties Questionnaire (SDQ-P). RESULTS: Routine outcome measures (CGAS, HoNOSCA, SDQ-P) showed moderate to severe mental health problems at start of treatment, which improved significantly over time in both cohorts. Effect sizes ranged between 0.73-0.90 (CYMHS) and 0.57-0.76 (LUMC-Curium). While internalizing problems (mood disorder, anxiety disorder and stress-related disorder) were more prevalent at CYMHS, externalizing developmental problems (ADHD, autism) prevailed at LUMC-Curium. Comorbidity (>1 diagnosis on ICD10/DSM-IV) was relatively similar: 45% at CYMHS and 39 % at LUMC-Curium. In both countries, improvement of functioning was lowest for conduct disorder and highest for somatoform/conversion disorders and obsessive-compulsive disorders (OCD). Overall, 20-40% showed clinically significant improvement (shift from clinical-range at start to a non-clinical-range at the end of treatment), but nearly half of patients still experienced significant symptoms at discharge. CONCLUSIONS: This large-scale outcome study showed both cohorts from Australia and the Netherlands improve during the course of treatment on clinician- and parent-reported measures. Although samples were situated within different contexts and differed in patient profiles, they showed similar trends in improvement per diagnostic group. While 20-40% showed clinically significant change, many patients experienced residual symptoms reflecting increased risk for negative outcome into adulthood. We emphasize cross-national comparison of naturalistic outcomes faces challenges, although it can similarly reveal trends in treatment outcome providing direction for future research: what factors determine discharge from specialized services; and how to improve current treatments in this severely affected population.

Unraveling the genetic architecture of major depressive disorder: merits and pitfalls of the approaches used in genome-wide association studies.

To identify genetic risk loci for major depressive disorder (MDD), two broad study design approaches have been applied: (1) to maximize sample size by combining data from different phenotype assessment modalities (e.g. clinical interview, self-report questionnaires) and (2) to reduce phenotypic heterogeneity through selecting more homogenous MDD subtypes. The value of these strategies has been debated. In this review, we summarize the most recent findings of large genomic studies that applied these approaches, and we highlight the merits and pitfalls of both approaches with particular attention to methodological and psychometric issues. We also discuss the results of analyses that investigated the heterogeneity of MDD. We conclude that both study designs are essential for further research. So far, increasing sample size has led to the identification of a relatively high number of genomic loci linked to depression. However, part of the identified variants may be related to a phenotype common to internalizing disorders and related traits. As such, samples containing detailed clinical information are needed to dissect depression heterogeneity and enable the potential identification of variants specific to a more restricted MDD phenotype. A balanced portfolio reconciling both study design approaches is the optimal approach to progress further in unraveling the genetic architecture of depression.

[Genetic diagnostics: part of the psychiatric clinic]. / Genetisch onderzoek: onderdeel van psychiatrische kliniek.

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A Potential Role for the STXBP5-AS1 Gene in Adult ADHD Symptoms.

We aimed to detect Attention-deficit/hyperactivity (ADHD) risk-conferring genes in adults. In children, ADHD is characterized by age-inappropriate levels of inattention and/or hyperactivity-impulsivity and may persists into adulthood. Childhood and adulthood ADHD are heritable, and are thought to represent the clinical extreme of a continuous distribution of ADHD symptoms in the general population. We aimed to leverage the power of studies of quantitative ADHD symptoms in adults who were genotyped. Within the SAGA (Study of ADHD trait genetics in adults) consortium, we estimated the single nucleotide polymorphism (SNP)-based heritability of quantitative self-reported ADHD symptoms and carried out a genome-wide association meta-analysis in nine adult population-based and case-only cohorts of adults. A total of n = 14,689 individuals were included. In two of the SAGA cohorts we found a significant SNP-based heritability for self-rated ADHD symptom scores of respectively 15% (n = 3656) and 30% (n = 1841). The top hit of the genome-wide meta-analysis (SNP rs12661753; p-value = 3.02 × 10-7) was present in the long non-coding RNA gene STXBP5-AS1. This association was also observed in a meta-analysis of childhood ADHD symptom scores in eight population-based pediatric cohorts from the Early Genetics and Lifecourse Epidemiology (EAGLE) ADHD consortium (n = 14,776). Genome-wide meta-analysis of the SAGA and EAGLE data (n = 29,465) increased the strength of the association with the SNP rs12661753. In human HEK293 cells, expression of STXBP5-AS1 enhanced the expression of a reporter construct of STXBP5, a gene known to be involved in "SNAP" (Soluble NSF attachment protein) Receptor" (SNARE) complex formation. In mouse strains featuring different levels of impulsivity, transcript levels in the prefrontal cortex of the mouse ortholog Gm28905 strongly correlated negatively with motor impulsivity as measured in the five choice serial reaction time task (r2 = - 0.61; p = 0.004). Our results are consistent with an effect of the STXBP5-AS1 gene on ADHD symptom scores distribution and point to a possible biological mechanism, other than antisense RNA inhibition, involved in ADHD-related impulsivity levels.

Risk factors for parental psychopathology: a study in families with children or adolescents with psychopathology.

The parents of children with psychopathology are at increased risk for psychiatric symptoms. To investigate which parents are mostly at risk, we assessed in a clinical sample of families with children with psychopathology, whether parental symptom scores can be predicted by offspring psychiatric diagnoses and other child, parent and family characteristics. Parental depressive, anxiety, avoidant personality, attention-deficit/hyperactivity (ADHD), and antisocial personality symptoms were measured with the Adult Self Report in 1805 mothers and 1361 fathers of 1866 children with a psychiatric diagnosis as assessed in a child and adolescent psychiatric outpatient clinic. In a multivariate model, including all parental symptom scores as outcome variables, all offspring psychiatric diagnoses, offspring comorbidity and age, parental age, parental educational attainment, employment, and relationship status were simultaneously tested as predictors. Both 35.7% of mothers and 32.8% of fathers scored (sub)clinical for at least one symptom domain, mainly depressive symptoms, ADHD symptoms or, only in fathers, avoidant personality symptoms. Parental psychiatric symptoms were predicted by unemployment. Parental depressive and ADHD symptoms were further predicted by offspring depression and offspring ADHD, respectively, as well as by not living together with the other parent. Finally, parental avoidant personality symptoms were also predicted by offspring autism spectrum disorders. In families with children referred to child and adolescent psychiatric outpatient clinics, parental symptom scores are associated with adverse circumstances and with similar psychopathology in their offspring. This signifies, without implying causality, that some families are particularly vulnerable, with multiple family members affected and living in adverse circumstances.

Collaborative meta-analysis finds no evidence of a strong interaction between stress and 5-HTTLPR genotype contributing to the development of depression.

The hypothesis that the S allele of the 5-HTTLPR serotonin transporter promoter region is associated with increased risk of depression, but only in individuals exposed to stressful situations, has generated much interest, research and controversy since first proposed in 2003. Multiple meta-analyses combining results from heterogeneous analyses have not settled the issue. To determine the magnitude of the interaction and the conditions under which it might be observed, we performed new analyses on 31 data sets containing 38 802 European ancestry subjects genotyped for 5-HTTLPR and assessed for depression and childhood maltreatment or other stressful life events, and meta-analysed the results. Analyses targeted two stressors (narrow, broad) and two depression outcomes (current, lifetime). All groups that published on this topic prior to the initiation of our study and met the assessment and sample size criteria were invited to participate. Additional groups, identified by consortium members or self-identified in response to our protocol (published prior to the start of analysis) with qualifying unpublished data, were also invited to participate. A uniform data analysis script implementing the protocol was executed by each of the consortium members. Our findings do not support the interaction hypothesis. We found no subgroups or variable definitions for which an interaction between stress and 5-HTTLPR genotype was statistically significant. In contrast, our findings for the main effects of life stressors (strong risk factor) and 5-HTTLPR genotype (no impact on risk) are strikingly consistent across our contributing studies, the original study reporting the interaction and subsequent meta-analyses. Our conclusion is that if an interaction exists in which the S allele of 5-HTTLPR increases risk of depression only in stressed individuals, then it is not broadly generalisable, but must be of modest effect size and only observable in limited situations.

Validity of LIDAS (LIfetime Depression Assessment Self-report): a self-report online assessment of lifetime major depressive disorder.

BACKGROUND: There is a paucity of valid, brief instruments for the assessment of lifetime major depressive disorder (MDD) that can be used in, for example, large-scale genomics, imaging or biomarker studies on depression. We developed the LIfetime Depression Assessment Self-report (LIDAS), which assesses lifetime MDD diagnosis according to DSM criteria, and is largely based on the widely used Composite International Diagnostic Interview (CIDI). Here, we tested the feasibility and determined the sensitivity and specificity for measuring lifetime MDD with this new questionnaire, with a regular CIDI as reference. METHOD: Sensitivity and specificity analyses of the online lifetime MDD questionnaire were performed in adults with (n = 177) and without (n = 87) lifetime MDD according to regular index CIDIs, selected from the Netherlands Study of Depression and Anxiety (NESDA) and Netherlands Twin Register (NTR). Feasibility was tested in an additional non-selective, population-based sample of NTR participants (n = 245). RESULTS: Of the 753 invited persons, 509 (68%) completed the LIDAS, of which 419 (82%) did this online. User-friendliness of the instrument was rated high. Median completion time was 6.2 min. Sensitivity and specificity for lifetime MDD were 85% [95% confidence interval (CI) 80-91%] and 80% (95% CI 72-89%), respectively. This LIDAS instrument gave a lifetime MDD prevalence of 20.8% in the population-based sample. CONCLUSIONS: Measuring lifetime MDD with an online instrument was feasible. Sensitivity and specificity were adequate. The instrument gave a prevalence of lifetime MDD in line with reported population prevalences. LIDAS is a promising tool for rapid determination of lifetime MDD status in large samples, such as needed for genomics studies.

Spousal resemblance in psychopathology: A comparison of parents of children with and without psychopathology.

BACKGROUND: Spouses resemble each other for psychopathology, but data regarding spousal resemblance in externalizing psychopathology, and data regarding spousal resemblance across different syndromes (e.g. anxiety in wives and attention deficit/hyperactivity disorder [ADHD] in husbands) are limited. Moreover, knowledge is lacking regarding spousal resemblance in parents of children with psychiatric disorders. We investigated and compared spousal resemblance within and across internalizing and externalizing symptom domains in parents of children with and without psychopathology. METHODS: Symptoms of depression, anxiety, avoidant personality, ADHD, and antisocial personality were assessed with the Adult Self Report in 728 mothers and 544 fathers of 778 children seen in child and adolescent psychiatric outpatient clinics and in 2075 mothers and 1623 fathers of 2784 children from a population-based sample. Differences in symptom scores and spousal correlations between the samples were tested. RESULTS: Parents in the clinical sample had higher symptom scores than in the population-based sample. In both samples, correlations within and across internalizing and externalizing domains of psychopathology were significant. Importantly, correlations were significantly higher in the clinical sample (P=0.03). Correlations, within and across symptoms, ranged from 0.14 to 0.30 in the clinical sample and from 0.05 to 0.23 in the population-based sample. CONCLUSIONS: This large study shows that spousal resemblance is not only present within but also across symptom domains. Especially in the clinical sample, ADHD symptoms in fathers and antisocial personality symptoms in mothers were correlated with a range of psychiatric symptoms in their spouses. Clinicians need to be alert of these multiple affected families.

[Psychopathology in families: an integral approach via the family outpatient clinic]. / Psychiatrische stoornissen binnen gezinnen: een integrale benadering via de familiepoli.

BACKGROUND: Psychiatric disorders run in families. To bridge the gap between child and youth psychiatry and adult psychiatry, GGZ inGeest has started screening parents of new registered children for psychopathology - and if indicated - offers parents treatment in the same department as their children. AIM: To examine the feasibility and usefulness of this procedure, to investigate how many parents agree to screening, further diagnostics and treatment, and to find out how many parents have in fact suffered from recent psychiatric problems. METHOD: Prior to the children's first appointment, the parents were asked to complete a questionnaire, the Adult Self Report (ASR), about their own problems. If these scores were (sub)clinical, parents were invited to participate in a telephonic interview. This consisted of the Composite International Diagnostic Interview (CIDI) and Conners' Adult ADHD Rating Scales (CAARS). If the results indicate psychopathology, further psychiatric assessment and, if necessary, treatment is offered. RESULTS: The first response was 55.7% and, if indicated, most of the parents agreed on further diagnostics. On the ASR 2 out of 5 mothers (42.1%) and 1 out of 5 fathers (21.8%) reported problems that could point to a psychiatric disorder. According to the ASR, within this high-risk group 37% of the mothers met the criteria for an axis I diagnosis (less than one month earlier) compared to 70.6% of the fathers. A mood disorder was the primary diagnosis for women, whereas men most often suffered from an anxiety disorder. In total, 19.1% of the parents screened were suffering from recent psychopathology and 75% of this group agreed to receive mental health care (treatment at the family outpatient clinic or referred to another clinic). CONCLUSION: Implementation of the family outpatient clinic scheme is feasible. However, further efforts are needed in order to reach a larger group of parents, particularly fathers. The family outpatient clinic is useful because parents who suffer from psychopathology do not always receive mental health care. However, a randomised control trial is needed to determine whether parallel treatment of parents and children can improve the treatment outcome for children.

Meta-analysis of genome-wide association studies of anxiety disorders.

Anxiety disorders (ADs), namely generalized AD, panic disorder and phobias, are common, etiologically complex conditions with a partially genetic basis. Despite differing on diagnostic definitions based on clinical presentation, ADs likely represent various expressions of an underlying common diathesis of abnormal regulation of basic threat-response systems. We conducted genome-wide association analyses in nine samples of European ancestry from seven large, independent studies. To identify genetic variants contributing to genetic susceptibility shared across interview-generated DSM-based ADs, we applied two phenotypic approaches: (1) comparisons between categorical AD cases and supernormal controls, and (2) quantitative phenotypic factor scores (FS) derived from a multivariate analysis combining information across the clinical phenotypes. We used logistic and linear regression, respectively, to analyze the association between these phenotypes and genome-wide single nucleotide polymorphisms. Meta-analysis for each phenotype combined results across the nine samples for over 18 000 unrelated individuals. Each meta-analysis identified a different genome-wide significant region, with the following markers showing the strongest association: for case-control contrasts, rs1709393 located in an uncharacterized non-coding RNA locus on chromosomal band 3q12.3 (P=1.65 × 10(-8)); for FS, rs1067327 within CAMKMT encoding the calmodulin-lysine N-methyltransferase on chromosomal band 2p21 (P=2.86 × 10(-9)). Independent replication and further exploration of these findings are needed to more fully understand the role of these variants in risk and expression of ADs.

Stability in symptoms of anxiety and depression as a function of genotype and environment: a longitudinal twin study from ages 3 to 63 years.

BACKGROUND: The influence of genetic factors on major depressive disorder is lower than on other psychiatric disorders. Heritability estimates mainly derive from cross-sectional studies, and knowledge on the longitudinal aetiology of symptoms of anxiety and depression (SxAnxDep) across the lifespan is limited. We aimed to assess phenotypic, genetic and environmental stability in SxAnxDep between ages 3 and 63 years. METHOD: We used a cohort-sequential design combining data from 49 524 twins followed from birth to age ⩾20 years, and from adolescence into adulthood. SxAnxDep were assessed repeatedly with a maximum of eight assessments over a 25-year period. Data were ordered in 30 age groups and analysed with longitudinal genetic models. RESULTS: Over age, there was a significant increase during adolescence in mean scores with sex differences (women>men) emerging. Heritability was high in childhood and decreased to 30-40% during adulthood. This decrease in heritability was due to an increase in environmental variance. Phenotypic stability was moderate in children (correlations across ages ~0.5) and high in adolescents (r = 0.6), young adults (r = 0.7), and adults (r = 0.8). Longitudinal stability was mostly attributable to genetic factors. During childhood and adolescence there was also significant genetic innovation, which was absent in adults. Environmental effects contributed to short-term stability. CONCLUSIONS: The substantial stability in SxAnxDep is mainly due to genetic effects. The importance of environmental effects increases with age and explains the relatively low heritability of depression in adults. The environmental effects are transient, but the contribution to stability increases with age.

[Genetics and psychiatric disorders: heritability and the search for genes]. / Genetica en psychische stoornissen op de kinderleeftijd: erfelijkheid en de zoektocht naar genen.

BACKGROUND: Much of the research is focused on the role that genetic factors play in the development of psychiatric disorders during childhood and adolescence. AIM: To present an overview of the heritability of these disorders and to describe the current state of the search for specific genetic variants. METHOD: The results of (mainly) Dutch studies in this area are summarised. RESULTS: It is estimated that about 60-70% of externalising symptoms and about 40-50% of internalising symptoms are heritable. No genes have yet been identified which influence psychiatric disorders in children. It is clear, however, that even in children, psychiatric symptoms are polygenic, i.e. influenced by many genetic variants, each having a small effect. CONCLUSION: Research on the role of genetic factors is advancing rapidly even in child psychiatry. When sample sizes are enlarged, it should be possible to identify genetic variants.

Further confirmation of the association between anxiety and CTNND2: replication in humans.

The rat genome sequencing and mapping consortium found evidence for an association between the catenin-δ2 gene (CTNND2) and anxious behaviour. We replicated these results in humans by carrying out a genetic association test in patients with panic disorder, social phobia, generalized anxiety disorder and/or agoraphobia (N = 1714) and controls (N = 4125). We further explored the association between CTNND2 and other psychiatric disorders based on publicly available genome-wide association results. A gene-based test showed that single nucleotide polymorphisms (SNPs) in CTNND2 have a significantly increased signal (P < 1e(-5) ) and decreased P-values. Single nucleotide polymorphism rs1012176 showed the strongest association with any anxiety disorder (odds ratio: 0.8128, SE = 0.063, P = 0.00099), but this effect was not significant after correction for multiple testing. In available genome-wide association results from the Psychiatric Genomics Consortium we found that SNPs in CTNND2 collectively showed an increased signal for schizophrenia (P < 1e(-5) ) and major depressive disorder (P < 1e(-5) ), but not for bipolar disorder. These signals remained significant after correction for potential confounders. The association between CTNND2 and anxiety was not strong enough to be picked up in the current generation of human genome-wide analyses, indicating the usefulness of and need for animal genetic studies to identify candidate genes for further study in human samples.

Genome-wide association study of major depressive disorder: new results, meta-analysis, and lessons learned.

Major depressive disorder (MDD) is a common complex disorder with a partly genetic etiology. We conducted a genome-wide association study of the MDD2000+ sample (2431 cases, 3673 screened controls and >1 M imputed single-nucleotide polymorphisms (SNPs)). No SNPs achieved genome-wide significance either in the MDD2000+ study, or in meta-analysis with two other studies totaling 5763 cases and 6901 controls. These results imply that common variants of intermediate or large effect do not have main effects in the genetic architecture of MDD. Suggestive but notable results were (a) gene-based tests suggesting roles for adenylate cyclase 3 (ADCY3, 2p23.3) and galanin (GAL, 11q13.3); published functional evidence relates both of these to MDD and serotonergic signaling; (b) support for the bipolar disorder risk variant SNP rs1006737 in CACNA1C (P=0.020, odds ratio=1.10); and (c) lack of support for rs2251219, a SNP identified in a meta-analysis of affective disorder studies (P=0.51). We estimate that sample sizes 1.8- to 2.4-fold greater are needed for association studies of MDD compared with those for schizophrenia to detect variants that explain the same proportion of total variance in liability. Larger study cohorts characterized for genetic and environmental risk factors accumulated prospectively are likely to be needed to dissect more fully the etiology of MDD.

Association study in eating disorders: TPH2 associates with anorexia nervosa and self-induced vomiting.

Twin studies suggest that genetic factors play a substantial role in anorexia nervosa (AN) and self-induced vomiting (SV), a key symptom that is shared among different types of eating disorders (EDs). We investigated the association of 25 single nucleotide polymorphisms (SNPs), capturing 71-91% of the common variance in candidate genes, stathmin (STMN1), serotonin receptor 1D (HTR1D), tryptophan hydroxylase 2 (TPH2) and brain-derived neurotrophic factor (BDNF), with AN and EDs characterized by regular SV. The first allele frequencies of all the SNPs were compared between a Dutch case group (182 AN, 149 EDs characterized by SV) and 607 controls. Associations rendering P-values < 0.05 from this initial study were then tested for replication in a meta-analysis with two additional independent ED case-control samples, together providing 887 AN cases, 306 cases with an ED characterized by SV and 1914 controls. A significant effect for the minor C-allele of tryptophan hydroxylase 2 rs1473473 was observed for both AN [odds ratio (OR) = 1.30, 95% CI 1.08-1.57, P < 0.003] and EDs characterized by SV (OR = 1.52, 95% CI 1.28-2.04, P < 0.006). In the combined case group, a dominant effect was observed for rs1473473 (OR = 1.38, 95% CI 1.16-1.64, P < 0.0003). The meta-analysis revealed that the tryptophan hydroxylase 2 polymorphism rs1473473 was associated with a higher risk for AN, EDs characterized by SV and for the combined group.

Genetic risk profiles for depression and anxiety in adult and elderly cohorts.

The first generation of genome-wide association studies (GWA studies) for psychiatric disorders has led to new insights regarding the genetic architecture of these disorders. We now start to realize that a larger number of genes, each with a small contribution, are likely to explain the heritability of psychiatric diseases. The contribution of a large number of genes to complex traits can be analyzed with genome-wide profiling. In a discovery sample, a genetic risk profile for depression was defined based on a GWA study of 1738 adult cases and 1802 controls. The genetic risk scores were tested in two population-based samples of elderly participants. The genetic risk profiles were evaluated for depression and anxiety in the Rotterdam Study cohort and the Erasmus Rucphen Family (ERF) study. The genetic risk scores were significantly associated with different measures of depression and explained up to ∼0.7% of the variance in depression in Rotterdam Study and up to ∼1% in ERF study. The genetic score for depression was also significantly associated with anxiety explaining up to 2.1% in Rotterdam study. These findings suggest the presence of many genetic loci of small effect that influence both depression and anxiety. Remarkably, the predictive value of these profiles was as large in the sample of elderly participants as in the middle-aged samples.

Life events and borderline personality features: the influence of gene-environment interaction and gene-environment correlation.

BACKGROUND: Traumatic life events are generally more common in patients with borderline personality disorder (BPD) than in non-patients or patients with other personality disorders. This study investigates whether exposure to life events moderates the genetic architecture of BPD features. As the presence of genotype-environment correlation (rGE) can lead to spurious findings of genotype-environment interaction (G × E), we also test whether BPD features increase the likelihood of exposure to life events. METHOD: The extent to which an individual is at risk to develop BPD was assessed with the Personality Assessment Inventory - Borderline features scale (PAI-BOR). Life events under study were a divorce/break-up, traffic accident, violent assault, sexual assault, robbery and job loss. Data were available for 5083 twins and 1285 non-twin siblings. Gene-environment interaction and correlation were assessed by using structural equation modelling (SEM) and the co-twin control design. RESULTS: There was evidence for both gene-environment interaction and correlation. Additive genetic influences on BPD features interacted with the exposure to sexual assault, with genetic variance being lower in exposed individuals. In individuals who had experienced a divorce/break-up, violent assault, sexual assault or job loss, environmental variance for BPD features was higher, leading to a lower heritability of BPD features in exposed individuals. Gene-environment correlation was present for some life events. The genes that influence BPD features thus also increased the likelihood of being exposed to certain life events. CONCLUSIONS: To our knowledge, this study is the first to test the joint effect of genetic and environmental influences and the exposure to life events on BPD features in the general population. Our results indicate the importance of both genetic vulnerability and life events.