IN A RECENT STUDY,1 it was reported that 11 of 32 chronically schizophrenic patients (34%) who had been receiving perphenazine over a "considerable period," had an elevated PBI level, ie, over 8.0 μg/100 cc. These patients did not exhibit any evidence of thyrotoxicosis. It was assumed that perphenazine alters the PBI by some unexplained mechanism.
The current study was pursued both to confirm these previous findings and to elicit further data in this area. Fifty hospitalized, chronically psychotic individuals (29 males and 21 females) who had been receiving perphenazine for at least 6 months were chosen at random. The only other criterion for inclusion in the study was the absence of administration of any other drug. In the group there were 46 schizophrenic patients, 2 chronically manic, and 2 with psychosis due to mental deficiency. They had received perphenazine for periods ranging from 8 to 50 months.