Investigating event-related potential (ERP) deviations in clinical high-risk populations for psychosis: a systematic...

Individuals at clinical high risk for psychosis exhibit cognitive and neurophysiological abnormalities that may predict transition to schizophrenia. Event-related potentials (ERPs), including mismatch negativity (MMN), P300, and N100, have been proposed as candidate biomarkers. This systematic review and meta-analysis aimed to synthesize evidence on ERP alterations in CHR populations compared with healthy controls (HCs) and to evaluate their predictive value for transition.

Following PRISMA guidelines, PubMed and Medline were systematically searched from January 1996 to March 2025. Studies reporting ERP data in CHR and HC participants, and longitudinal studies distinguishing converters (CHR-T) from non-converters (CHR-NT), were included. Data extraction and quality assessment followed Cochrane standards, and pooled effect sizes were estimated using random- or fixed-effects models.

Thirty-six studies were included. Compared with HCs, CHR individuals demonstrated significantly reduced P300 amplitude (MD (95%CI) = -2.35 (-3.31, -1.39), p < 0.05) and attenuated duration- and frequency-deviant MMN (MD (95%) = 0.31 (0.20, 0.43), p < 0.01), whereas N100 showed no significant group differences. In longitudinal analyses, only duration-deviant MMN differentiated CHR converters from non-converters (p < 0.05). Sensitivity analyses confirmed robustness of the findings.

ERP abnormalities, particularly reduced duration-deviant MMN, represent promising biomarkers for early detection of psychosis risk and may aid in risk stratification and intervention planning. These results highlight the potential utility of ERPs as clinically accessible, low-cost neurophysiological tools for predicting transition in CHR populations.