Vitamin B12 and homocysteine in patients with major depressive disorder

Background: Alterations in the level of neurotransmitters are evident in patients with major depressive disorder (MDD). Vitamin B12 mediates the synthesis of neurotransmitters, and hence, vitamin B12 deficiency could be associated with depression. Aims and Objectives: To assess the levels of serum vitamin B12, homocysteine (Hcy), and haematological profiles in patients of MDD. Materials and Methods: Fifty-nine patients with MDD were recruited based on ICD-10 criteria. Severity of depression was assessed by HAM-D scale. Vitamin B12, Hcy levels, and haematological profiles were analysed. Results: Vitamin B12 was deficient or depleted in all patients with MDD. The median level of vitamin B12 in serum was 164.2 pg./ml and significantly lower in patients with severe MDD. The mean value of Hcy was 18.34 μmol/L, which was high compared to the normal reference range. The red cell distribution width (RDW-CV) varied significantly between the three groups of MDD patients. Patients consuming non-vegetarian food had a significantly higher median value of serum vitamin B12. Conclusion: Vitamin B12 deficiency is found in patients with MDD and varies inversely with severity of MDD. Hcy is found to be higher in patients with MDD. The manifestation of depressive symptoms precedes the more commonly known haematological manifestations of vitamin B12 deficiency in this study.