• Correlation between baseline blood folate, homocysteine or B12 levels and dietary intake or cigarette smoking [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]
  

• Correlations between red blood cell folate concentrations and clinical ratings of negative symptoms and by comparing folate concentrations in deficit syndrome versus non-deficit syndrome patients [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]
  
• Efficacy of folate supplementation for reducing negative symptoms as measured by the SANS [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]
  

Drug: Folate
Folic acid or placebo taken as 2, 1mg capsule daily for 12 weeks

This study is a three-month, placebo-controlled trial of folate 2mg/d in 50 schizophrenia patients who score at least a 3 (moderate or greater severity) on at least one of the SANS global assessment subscales, with the exception of the attention global assessment subscale. The specific aims of this study are:

• To examine factors potentially contributing to differences in blood folate, homocysteine or B12 levels between patients at baseline, including dietary intake and cigarette smoking.
• To test the hypothesis that low folate is associated with negative symptoms by examining correlations between red blood cell folate concentrations and clinical ratings of negative symptoms and by comparing folate concentrations in deficit syndrome versus non-deficit syndrome patients. We will also control for dietary intake cigarettes smoking, gender, and age.
• To examine the efficacy of folate supplementation for reducing negative symptoms