Risk of psychosis following mild traumatic brain injury: a systematic review and meta-analysis.

Background: Mild traumatic brain injury (mTBI), commonly known as concussion, has historically been regarded as a transient and benign condition. However, recent studies suggest it may increase the risk of long-term psychiatric outcomes, including psychosis. This study aimed to systematically review and meta-analyze the association between mTBI and subsequent risk of psychosis.

Methods: A comprehensive search of PubMed, PsycINFO, and Google Scholar was conducted through June 2025. Studies were eligible if they included individuals with a history of mTBI, a non-TBI control group, and reported psychosis-related outcomes with estimable risk measures. Random-effects meta-analysis was performed using the metafor package in R. Risk of bias and publication bias were assessed, and meta-regression was conducted to explore moderators such as adjustment status and effect size type.

Results: Seven studies comprising pediatric and adult populations were included. The pooled risk ratio (RR) for psychosis following mTBI was 1.57 (95% CI: 1.28-1.91, p < 0.001), indicating a statistically significant association. The 95% prediction interval (1.03-2.38) suggests generalizability across future studies. No significant publication bias was detected (Egger's test p = 0.10). Meta-regression found no difference between adjusted and unadjusted estimates (p = 0.802). Sensitivity analyses confirmed the robustness of the findings.

Conclusions: mTBI is associated with a moderate but statistically significant increase in the risk of psychosis. Given the prevalence of mTBI in the general population, these findings highlight the need for long-term psychiatric monitoring and preventive strategies, particularly in youth and high-risk individuals.