Abstract
BACKGROUND: Psychotic disorders such as schizophrenia (SCZ) have been frequently linked with oxidative stress, with uric acid (UA) levels being of particular interest, although evidence remains inconclusive. A possible reduction of UA levels in early phases of SCZ, namely first-episode psychosis (FEP), has been hypothesized. In this systematic review, we aimed to analyze and summarize current evidence regarding UA levels in patients with early psychosis. METHODS: We conducted a systematic review of case-control studies comparing serum or plasma UA levels in individuals experiencing FEP with those in healthy controls (HC). RESULTS: Eight studies met the inclusion criteria, with a total sample of 950 individuals that included 520 FEP patients and 430 HC. A tendency for lower UA levels in FEP was described, albeit without definitive evidence, and decreased UA levels were restricted to certain ethnic populations. CONCLUSIONS: Our findings do not fully support the hypothesis of an oxidative stress response in early psychosis translatable with reduced UA levels in patients with FEP. Further research is warranted to elucidate the nature and magnitude of the relationship between oxidative stress, UA levels, and early psychosis.