Association between stressful life events and psychotic experiences in adolescence : evidence for gene-environment correlations

Background: Stressful life events (SLEs) are associated with psychotic experiences (PEs). SLEs might act as an environmental risk factor, but may also share a genetic propensity with PEs. Aims: Estimate the extent to which genetic and environmental factors influence the relationship between SLEs and PEs. Method: Self and parent-reports from a communitybased twin sample (4,830 16-year-old pairs) were analysed using structural equation modelfitting. Results: SLEs correlated with positive PEs (r = .12-.14, all p<. 001). Modest heritability was shown for PEs (25-57%) and dependent SLEs (32%). Genetic influences explained the majority of the modest covariation between dependent SLEs and paranoia and cognitive disorganisation (bivariate heritabilities = 74-86%). The relationship between SLEs and hallucinations and grandiosity was explained by both genetic and common environmental effects. Conclusion: Further to dependent SLEs being an environmental risk factor, individuals may have an underlying genetic propensity increasing their risk of dependent SLEs and positive PEs