Effects of B Vitamins on Symptoms and Cognitive Functions in Schizophrenia: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Objective: Schizophrenia which is a chronic disabling burdensome psychotic disorder has been treated with different antipsychotic medications. Some studies have reported a possible correlation between deficiency in minerals, nutrients and vitamins — mainly group B vitamins — and the development of schizophrenia. In the present study, we aimed to examine the effect of the B vitamin group as an adjuvant treatment to antipsychotics in individuals with chronic schizophrenia. Method: In a randomized, double-blind clinical trial study, involving two groups of 25 patients with chronic schizophrenia, we compared the effects of a 12-week adjuvant treatment with a combination of B vitamins — B1 (15mg), B2 (15mg), B6 (10mg), B12 (10µg) and nicotinamide (50 mg) — with a placebo. The impact on negative, positive and cognitive symptoms of schizophrenia was assessed for both groups before the intervention (T0) and at 4, 8 and 12 weeks after the intervention (T1, T2, and T3, respectively). Results: Following the treatment, negative symptoms scores decreased in the treatment group at 12 weeks following the beginning of the treatment (F (4, 45) = 464.7, P < 0.0001). Although a trend toward improvement in positive symptoms and cognitive scores was seen, these changes were not significant. Conclusion: Our results suggest that selecting the group B vitamins as an adjuvant treatment to the antipsychotics may have beneficial effects on improving negative symptoms of patients with chronic schizophrenia.