Therapeutic effects of vitamin D as adjunctive therapy to fluoxetine in patients with major depressive disorder

Abstract

To compare the therapeutic effects of vitamin D3 plus fluoxetine and fluoxetine alone in patients with major depressive disorder. In the present double-blind, randomized, placebo-controlled trial, 42 patients with a diagnosis of major depressive disorder based on DSM-IV criteria were randomly assigned into two groups to receive daily either 1500 IU vitamin D3 plus 20 mg fluoxetine or fluoxetine alone for 8 weeks. Depression severity was assessed at 2-week intervals using the 24-item Hamilton Depression Rating Scale (HDRS) as a primary outcome measure and the 21-item Beck Depression Inventory (BDI) as a secondary outcome measure. Serum 25(OH) vitamin D was measured at baseline and after intervention. Forty patients completed the trial. A two-way repeated-measures analysis of variance showed that depression severity based on HDRS and BDI decreased significantly after intervention, with a significant difference between the two groups. The vitamin D + fluoxetine combination was significantly better than fluoxetine alone from the fourth week of treatment. In the present 8-week trial, the vitamin D + fluoxetine combination was superior to fluoxetine alone in controlling depressive symptoms.