 Statistical Analysis: The association between weight gain and vitamin D deficiency will be analyzed using 2x2 contingency tables and tests for independence. The three most common tests for independence are the likelihood ratio test LRT, the Pearsons chi-square statistic, and Fishers exact test. Both Pearsons chi-square and Fishers exact test will be used to analyze the data. If the expected number of counts in any one cell is less than five 5, only Fishers exact test will be reported. The purpose of this pilot is to estimateconfirm a reasonable confidence interval for the true odds ratio and reference proportion to design a larger scale study. We believe we can reasonably recruit between 30 and 40 patients. Should we recruit a total of 40 patients, we believe we can achieve a minimum detectable odds ratio of 9 with desired power of 0.80 and significance level of 0.05 with reference proportion of 0.35. This initial analysis was based on a preliminary study where 35 of schizophrenic patients gained weight on atypical antipsychotic drugs. Since there is no follow up of these patients, but the collection of the blood and clinical data only at one time point, the question of potential drop-outs or the follow-ups does not arise. 