Short-lived effect of (Des-Tyr)-gamma-endorphin in schizophrenia.

Des-tyrosine-gamma-endorphin (DT gamma E) has been reported to alleviate symptoms of schizophrenia. Attempting to replicate those reports, we administered 1 mg of DT gamma E, i.m., for 8 consecutive days to nine patients meeting the DSM-III criteria for schizophrenia. Patients in this double-blind, crossover, and placebo-controlled study showed a statistically significant, but clinically modest improvement. The improvement was detectable during the first several days of the DT gamma E treatment; the symptoms then returned to baseline level in spite of continued doses of DT gamma E. Testing the metabolism of DT gamma E in the patients' plasma, we found a high rate of formation and of degradation, but the metabolic rates were not related to clinical symptoms.