FOLATE, VITAMIN-B-12, AND HOMOCYSTEINE IN MAJOR DEPRESSIVE DISORDER

Objective: The authors examined the relationships between levels of th ree metabolites (folate, vitamin B-12, and homocysteine) and both depr essive subtype and response to fluoxetine treatment in depressed patie nts. Method: Fluoxetine, 20 mg/day for 8 weeks, was given to 213 outpa tients with major depressive disorder. At baseline, depressive subtype s were assessed and a blood sample was collected from each patient. Se rum metabolite levels were assayed. Response to treatment was determin ed by percentage change in score on the 17-item Hamilton Depression Ra ting Scale. Results: Subjects with low folate levels were move likely to have melancholic depression and were significantly less likely to r espond to fluoxetine. Homocysteine and B-12 levels were not associated with depressive subtype or treatment response. Conclusions: Overall, the results are consistent with findings linking low folate levels to poorer response to antidepressant treatment. Folate levels might be co nsidered in the evaluation of depressed patients who do not respond to antidepressant treatment.