Objective: There is information in the literature that vitamin B12 and folate play a role in the etiology of schizophrenia and
bipolar disorder. On the basis of this idea, in this study, we compared patients with schizophrenia and bipolar disorder in their
first episode of illness with healthy controls (HC) regarding their vitamin B12 and folate levels.
Method: In this study, vitamin B12 and folate blood levels of patients with first-episode psychosis (FEP) and first-episode mania
(FEM) were compared with those of HC. Sixty-seven volunteers aged 18–65 years without any additional psychiatric or organic
diseases were recruited from all three groups.
Results: According to the statistical analysis, vitamin B12 blood level was significantly lower in the FEP group than in HC
(p=0.002). According to the logistic regression analyses, it was determined that vitamin B12 blood levels significantly predicted
being in the FEP group (p=0.009), whereas neither vitamin B12 nor folate blood levels were associated with being in the FEM
group. The predictive effect of vitamin B12 deficiency for being in the FEP group was statistically significant (p=0.002), whereas
the diagnosis of vitamin B12 deficiency alone was not associated with being in the FEM group.
Conclusion: Low vitamin B12 serum levels can be seen in patients with FEP. In these patients, vitamin B12 replacement therapy
may increase the effect of antipsychotic therapy.