Cumulative exposure to childhood adversity and risk of adult psychosis: a dose–response meta-analysis

Background. Past meta-analyses have confirmed robust associations between childhood traumatic experiences and the risk of psychosis. However, the dose–response relationship between cumulative adversity exposure and psychosis risk observed in some, but not all, previous studies in this area has not been specifically scrutinized or substantiated via recommended meta-analytic methods. This meta-analysis aimed to synthesize the available evidence on dose–response effects between childhood trauma and psychosis outcomes.

Methods. PsycINFO, PubMed, EMBASE, Web of Science, CNKI, and WANFANG were searched from inception to July 2024 to identify observational studies reporting odds ratios for psychosis outcomes across multiple levels of childhood trauma exposure. Dose–response effects were extracted from eligible studies and synthesized via robust error meta-regression analyses.

Results. Twenty-one studies comprising 59,975 participants were included in the meta-analysis. A significant nonlinear relationship was observed between the number of childhood adversities and the risk of future psychosis experiences (p for nonlinearity = .021). The pooled odds ratio for psychosis increased from 1.76 (95% confidence interval [CI]: 1.39–2.22) for 1 exposure to 6.46 (95% CI: 4.37–9.53) for 5+ exposures compared to no traumatic experience.

Conclusions. This meta-analysis provides robust evidence for a dose–response relationship between cumulative childhood adversity and psychosis risk, with nonlinear patterns suggestive of an accelerating, more pronounced, risk at higher levels of trauma exposure. These findings underscore the importance of considering childhood traumatic experiences as a putative and potentially causative risk factor for psychotic experiences, as well as early prevention and intervention efforts targeting childhood adversity to reduce the risk of psychosis.