A comprehensive study was done to determine the efficacy of niacin as a supplement in the treatment of schizophrenic patients over a two-year period. Newly admitted schizophrenic men were assigned at random to either high-dosage niacin (3,000 mg/day) or low-dosage niacin (6 mg/day) as a control medication. The only significant untoward result was the occurrence of a pigmented hyperkeratosis in about one third of the patients receiving the high-dosage regimen.
Analyses of rating scale, social adjustment, and self-report data for patients in treatment at least 18 months failed to indicate any advantage for the high dosage of nicotinic acid group. Rate of attrition, duration of hospitalization, and need for tranquilizing medication failed also to reveal an advantage for this group.
Wittenborn JR, Weber ES, Brown M. Niacin in the Long-Term Treatment of Schizophrenia. Arch Gen Psychiatry. 1973;28(3):308-315. doi:10.1001/archpsyc.1973.01750330010002