The relationship between vitamin B12 and vitamin D levels and subjective cognitive complaints in patients with first episode major depressive disorder

Abstract

Objective: Cognitive dysfunction is an important component of major depressive disorder (MDD). The aim of this study is to investigate the relationship between vitamin B12 and D and subjective cognitive complaints in patients with first-episode MDD. Method: In this cross-sectional study, patients (n=120) diagnosed with first-episode MDD filled out self-report questionnaires that evaluate subjective neurocognitive symptoms (Perceived Deficits Questionnaire-Depression [PDQ-D] and British Columbia Cognitive Complaints Inventory [BC-CCI]). Disease severity was evaluated using the Hamilton Depression Rating Scale (HDRS). Serum 25-OH vitamin D and vitamin B12 levels were measured using a chemiluminescence microparticle immunoassay technology. Results: The PDQ-D and BC-CCI scores were significantly higher in patients with combined vitamin B12 and D deficiency than patients with normal vitamin levels. We found a negative correlation between vitamin B12 level and HDRS, BC-CCI and PDQ-D scores. In addition, there was a positive correlation between HDRS scores and PDQ-D and BC-CCI scores. Linear regression analysis revealed that HDRS score and vitamin B12 level have influence on PDQ-D and BC-CCI scores. Conclusion: In this study, it was found that subjective cognitive impairment was significantly higher in MDD patients with both of vitamin B12 and vitamin D deficiency. Vitamin B12 levels were also associated with depressive symptom severity and subjective cognitive impairment. Depression severity and vitamin B12 level were found to be significant predictors of subjective cognitive impairment. Our findings highlight the importance of depression severity and vitamin B12 and D levels during routine clinical evaluation of MDD.