For various reasons we became interested in the possibility that nicotinic acid or nicotinamide might be of some benefit to the chronic schizophrenic. Many workers have noticed clinical similarities between the acute schizophrenias and the encephalopathies of nicotinic acid deficiency (4). Nicotinic acid is known to be of value in pellagra (2) and in the treatment of delirium tremens and allied states (1), and Osmond and Hoffer have had promising results with these substances in the treatment of schizophrenia in its acute phase (3). There seemed therefore to be sufficient reason for an investigation of their effects in the schizophrenic in the chronic phase, for, as far as we are aware, the therapeutic possibilities have not been explored. Since patients often respond strikingly to the giving of any tablet, regardless of its contents, we also gave similar tablets of an innocuous substance, here referred to as Placebo. For convenience the three preparations employed will be referred to in future as A (Nicotinic Acid), M (Nicotinamide) or P (Placebo).