Depression is a common mental disorder that endangers physical and mental health. In our study, we aimed to explore whether B vitamins are associated with depression and cognitive dysfunction.

We enrolled a total of 220 patients with depression and selected 100 controls at the same time. We determined depression and cognitive impairment by assessments. We recorded the basic parameters of the participants and collected blood samples. In addition, we measured serum levels of B vitamins and brain-derived neurotrophic factor (BDNF).

We found significant differences in the duration of depression, education, and Hamilton Depression Rating Scale scores between the D-NCI and D-CI groups. We also identified the independent risk factors for patients with depression and cognitive dysfunction. Compared with the healthy controls, serum folate, vitamin B6, and vitamin B12 positively correlated with cognitive dysfunction. The patients with depression and cognitive dysfunction had the lowest levels of B vitamins compared with the other two groups. Our results also showed that the levels of serum folate, vitamin B6, and vitamin B12 in the patients with depression had a positive correlation with each other.

Our results indicate that vitamin B is associated with depression and cognitive dysfunction and is positively associated with cognitive dysfunction.