[The niacin test in schizophrenia]

The niacin test (oral administration of 200 mg of nicotine acid) was done in 33 schizophrenics and 18 endogenous depressed drug-free patients in the presence of intense symptomatology. The erythema reaction was found in 25 schizophrenics (76%) and in all depressed patients. No significant differences in basal clinical features between schizophrenics with and without erythema reaction were found. The measurements of maximal increase of the left ear lap temperature after nicotine acid administration as well as time needed to note such increase did not show significant differences between schizophrenic patients with and without erythema reaction, and patients with endogenous depression. The results show a limited usefulness of the niacin test in schizophrenia. Nevertheless, the results suggest the possibility that among the small number of schizophrenics there is metabolic defect probably connected with the low activity of PGE1 prostaglandins.