Abstract. Vitamin D is made endogenously in the skin from UVB radiation from sunlight. And its deficiency is common in patients with severe mental illness such as schizophrenia. There also seems to be relationship between the risk of schizophrenia and latitude, with an increased incidence rate of schizophrenia seen at a higher latitude Aims : To determine differences in serum levels of vitamin D based on residence in the highland and lowland male schizophrenic patient Methods: This study was an analytical study, in  RS Jiwa Prof. dr. M. Ildrem Medan, approach to see the comparison 60 samples (30 patients live in the Highland  and Lowland). Sample inspection for serum vitamin D using ELFA method. Results: The results showed median levels of vitamin D subjects living in high land Tanah Karo was 22,20 ng / mL with minimum-maximum  levels of 19,3-34,5 ng / mL and in the low land Pemko Medan vitamin D levels higher with  median  27,95ng / mL with  minimum-maximum level of vitamin D 20,4-42,6 ng / mL. Conclusions: Analysis using the Mann Whitney U test showed significant differences between the levels of vitamin D based on residence with a value of  p = 0.001.

Keywords: Schizophrenia, Serum vitamin D, latitude