Patients in early phases of schizophrenia or mood disorders with psychotic symptoms have a wide array of metabolic abnormalities. We analysed the potential predictive value of uric acid (UA) levels and other metabolic parameters in first-episode psychosis patients to differentiate between non-affective and affective psychosis. Retrospective chart review of all patients referenced to a first-episode psychosis unit (n = 149), between 2012 and 2017, with available UA levels. Patients included (n= 37) were compared according to the follow-up diagnosis of schizophrenia or mood disorder. Mood disorder patients presented higher UA levels (p= .030) and lower fasting blood glucose levels (p= .020) compared with schizophrenia patients. The remaining variables did not show significant intergroup differences. Findings in this first-episode psychosis cohort support previous evidence suggesting higher UA levels as a predictor of affective psychosis and glucose dysfunction as predictive of schizophrenia. Further studies are needed to explore metabolic parameters as possible diagnostic predictors in first-episode psychosis.