Antipsychotic properties of Des-enkephalin-gamma-endorphin in treatment of schizophrenic patients.

Animal experiments have shown that the gamma-endorphin fragment des-enkephalin-gamma-endorphin (DE gamma E; beta-lipotropin 66-77) is the shortest sequence with neuroleptic-like activity with potency comparable to des-tyrosine-gamma-endorphin. We postulated that DE gamma E may be an endogenous peptide implicated in psychopathologic disease, particularly schizophrenia. To investigate the purported antipsychotic action of DE gamma E, 23 patients with different types of relapsing schizophrenia were treated with DE gamma E dissolved in saline or placebo. Neuroleptic medication was continued during the experimental period. In the first single-blind trial, two patients were treated with 1 mg of DE gamma E and two with 10 mg of DE gamma E intramuscularly (IM) daily for ten days. In the second double-blind placebo-controlled trial 13 patients were treated with 3 mg of DE gamma E IM daily for ten days and six received placebo. Of the 17 patients treated with DE gamma E, two did not respond, 11 had a slight to moderate effect, and four responded markedly. No side effects were observed. The response to DE gamma E appeared to be negatively correlated with the dosage of neuroleptic medication and the duration of the last psychotic episode. These results support the hypothesis that disturbances in gamma-endorphin fragmentation might contribute to the pathogenesis of schizophrenic psychoses.