Objective: Vitamin D deficiency is one of the implicated factors in ethio-pathogenesis of schizophrenia. Low serum vitamin D levels have been reported in many schizophrenia studies. However, the question is still not answered: Is there an association between disease activity and serum vitamin D level? This is the first study evaluating the relationship between serum vitamin D levels and disease activity, by comparing vitamin D levels in two schizophrenia groups abruptly different in terms of disease activity (in remission and in acute episode, according to Andreasen remission criteria).
Methods: 41 schizophrenic patients in remission, 40 schizophrenic patients in acute episode and 40 age and sex matched controls with no major psychopathology were recruited in this study. Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression – Severity scale (CGI-S) were used to evaluate disease activity. Blood samples were taken from all patients and controls. 25-OH vitamin D3, calcium, phosphorus, parathyroid hormone values were measured.
Results: Schizophrenic patients in acute episode had significantly lower vitamin D levels compared to schizophrenic patients in remission and to healthy controls (in terms of median values respectively, 7.18, 15.03, 15.02, p<0,001). We observed negative and moderate correlations between vitamin D levels and CGI scores (r: -0.624, p<0.001), vitamin D levels and PANNS scores (r: -0.508, p< 0.001).
Conclusion: The inverse association between vitamin D levels and disease activity brings the following Result: Low serum vitamin D levels may cause exacerbation of psychotic symptoms in patients with schizophrenia. Additionally, this result exposes another question: Can vitamin D supplementation prevent acute episodes in schizophrenic patients? Based on this idea, future studies may enlighten the possible effects of vitamin D supplementation in patients with schizophrenia.