Major depressive disorder: association with vitamin C levels and role of vitamin C supplementation in pharmacotherapy

Background: Oxidative stress has a well-documented role in pathophysiology of depression. Decrease in levels of vitamin C, an antioxidant, has also been reported in major depressive patients. This study was conducted to assess the association of vitamin C deficiency with major depressive disorder and any change in clinical response to antidepressant therapy with vitamin C co-administration vis-a-vis baseline vitamin C level status. Methods: This study was a prospective, interventional, parallel, randomized and open label study. Sixty patients diagnosed as a case of major depressive disorder in accordance to ICD-10 criteria were enrolled after taking a written informed consent. Two clinical scales namely Hamilton depression rating scale (HDRS) and clinical global impressionillness severity (CGI-S) scale were used for assessment and monitoring. Results: Vitamin C deficient subjects had relatively severe disease as assessed by HDRS and CGI-S scales. A highly significant (p<0.001) reduction was observed in HDRS and CGI-S scores in vitamin C deficient and insufficient groups with supplementation. A statistically insignificant (p>0.05) reduction was seen in HDRS and CGI-I scores in vitamin C sufficient group while also showing a comparatively milder disease. Conclusions: Vitamin C deficiency was found to have a direct relation with severity of illness, as those patients who had insufficient and sufficient vitamin C levels at recruitment were found to exhibit milder symptoms compared to those who were vitamin C deficient. With treatment, greater improvement was observed in those patients who were deficient at the outset.