Symptomatic Correlates of Vitamin D Deficiency in First-Episode Psychosis.

Previous studies indicate that low levels of vitamin D are associated with increased severity of psychiatric symptoms in chronic multiepisode psychosis (MEP). We aimed to compare vitamin D levels between first-episode psychosis (FEP) and MEP and to investigate the correlations between vitamin D levels and symptoms in FEP patients. The participants were adults aged 18-45 years who presented with affective and non-affective FEP to an early intervention team in Portugal. Depression was assessed using the Beck Depression Inventory, and positive and negative symptoms and general psychopathology were measured with the Positive and Negative Syndrome Scale. Blood samples were analyzed for 25-hydroxyvitamin D (25OHD). Thirty-three patients completed the study in the FEP group and 33 in the MEP group. FEP patients had low levels of 25OHD (18.16 ± 7.48 ng/mL), with no significant differences from MEP patients. Low 25OHD was significantly correlated with high severities of depressive (r=-0.484, p=0.004) and negative (r=-0.480, p=0.005) symptoms as well as general psychopathology (r=-0.569, p=0.001) in FEP patients. Multiple regression revealed an inverse association between general psychopathology and vitamin D level (p=0.027). More investigation of the association of vitamin D and schizophrenia is needed, namely, using a nonpatient control group and trying to clarify possible causality between vitamin D and psychiatric symptoms.