Folic acid enhances lithium prophylaxis

Abstract

A double-blind trial was carried out to investigate the effect on affective morbidity of a daily supplement of 200 micrograms folic acid or a matched placebo in a group of 75 patients on lithium therapy. During the trial the patients with the highest plasma folate concentrations showed a significant reduction in their affective morbidity. Patients who had their plasma folate increased to 13 ng/ml or above had a 40% reduction in their affective morbidity. It is suggested that a daily supplement of 300-400 micrograms folic acid would be useful in long-term lithium prophylaxis.