Background: Schizophrenia is the most common psychotic disorder found in population. It is a severe form of psychotic disorders and tends to be chronic. Nearly 1% people suffer from schizophrenia. It has been proved that vitamin D plays crucial roles in neuroprotection and neurodevelopment, therefore low levels are commonly associated with schizophrenia. Methods: A total of 54 schizophrenic patients, Batak tribe, male, and female are diagnosed with semistructured MINI ICD-X. A Positive and Negative Syndrome Scale (PANSS) was used to evaluate disease activity and serum vitamin D level was measured using ELFA. Regression linear was used to analyze the relationship between serum vitamin D level and disease’s symptom. Results: There was a negative correlation between serum levels of vitamin D and the PANSS score in schizophrenic patients with r = -0.686 (p<0.001) for positive PANSS score, r = -0.773 (p<0.001) for negative PANSS score, r = -0.448 (p<0.001)  for general psychopathology, and r = -0.631 (p<0.001) for total PANSS score. Conclusion: There was a negative correlation between serum vitamin D levels and the total score of PANSS, the lower the serum levels of vitamin D, the higher the total score of the PANSS.Â
