What Do Four Decades of Research Tell Us About the Association Between Childhood Adversity and Psychosis: An Updated and Extended Multi-Level Meta-Analysis

Estimating the current association between childhood adversity and the risk of psychosis is crucial for prevention and intervention. We provided an updated synthesis of evidence from the past four decades, expanded the available data by investigating a broad array of adversity subtypes, and explored sex differences and the age of psychosis onset as relevant factors. We searched PubMed, EMBASE, PsycINFO, Web of Science, WANFANG, and CNKI, for case-control, cross-sectional and cohort studies on the association between adversity and psychotic symptoms/illness. Multi-level meta-analysis, prediction intervals calculation, and sensitivity analyses were conducted. The main analysis included 183 study samples (N=349,265), with 119 case-control studies (15,186 cases; 14,879 controls), 51 cross-sectional studies (N=299,659), and 13 cohort studies (N=19,541). Significant associations between adversity and psychosis were observed across all study designs, yielding an overall odds ratio of 2.80 (95% CI=2.18, 3.60). Secondary analyses revealed that exposure to each adversity subtype increased the odds of psychosis, with the highest odds ratio (3.54 [95% CI=3.04, 4.13]) for emotional abuse, and the lowest odds ratio of (1.58 [95% CI=1.48, 1.68]) for parental antipathy. No statistically significant sex differences were observed, although the odds ratio for sexual abuse was higher for women. Onset of psychosis was earlier in adversity-exposed individuals (mean difference=-0.79 years, 95% CI=-1.47 to -0.12). This is the largest meta-analysis to date on the association between childhood adversity and psychosis. The results have broad clinical implications, as they highlight the need for selective prevention of exposure to early adversities and the implementation of trauma-informed therapies in the treatment of psychosis.