Association between stressful life events and psychotic experiences in adolescence: evidence for gene-environment correlations.
Shakoor S., Zavos HM., Haworth CM., McGuire P., Cardno AG., Freeman D., Ronald A.
BACKGROUND: Stressful life events (SLEs) are associated with psychotic experiences. SLEs might act as an environmental risk factor, but may also share a genetic propensity with psychotic experiences. AIMS: To estimate the extent to which genetic and environmental factors influence the relationship between SLEs and psychotic experiences. METHOD: Self- and parent reports from a community-based twin sample (4830 16-year-old pairs) were analysed using structural equation model fitting. RESULTS: SLEs correlated with positive psychotic experiences (r = 0.12-0.14, all P<0.001). Modest heritability was shown for psychotic experiences (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. CONCLUSIONS: Further to dependent SLEs being an environmental risk factor, individuals may have an underlying genetic propensity increasing their risk of dependent SLEs and positive psychotic experiences.