Abstract

Background Elevated homocysteine is observed in schizophrenia and associated with illness severity. The aim of this study was to determine whether vitamins B 12 , B 6 , and folic acid lower homocysteine and improve symptomatology and neurocognition in first-episode psychosis. Whether baseline homocysteine, genetic variation, sex, and diagnosis interact with B-vitamin treatment on outcomes was also examined.

Methods A randomized, double-blind, placebo-controlled trial was used. A total of 120 patients with first-episode psychosis were randomized to an adjunctive B-vitamin supplement (containing folic acid [5 mg], B 12 [0.4 mg], and B 6 [50 mg]) or placebo, taken once daily for 12 weeks. Coprimary outcomes were change in total symptomatology (Positive and Negative Syndrome Scale) and composite neurocognition. Secondary outcomes included additional measures of symptoms, neurocognition, functioning, tolerability, and safety.

Results B-vitamin supplementation reduced homocysteine levels (p = .003, effect size = −0.65). B-vitamin supplementation had no significant effects on Positive and Negative Syndrome Scale total (p = .749) or composite neurocognition (p = .785). There were no significant group differences in secondary symptom domains. A significant group difference in the attention/vigilance domain (p = .024, effect size = 0.49) showed that the B-vitamin group remained stable and the placebo group declined in performance. In addition, 14% of the sample had elevated baseline homocysteine levels, which was associated with greater improvements in one measure of attention/vigilance following B-vitamin supplementation. Being female and having affective psychosis was associated with improved neurocognition in select domains following B-vitamin supplementation. Genetic variation did not influence B-vitamin treatment response.