A comparative study on the antipsychotic properties of desenkephalin-gamma-endorphin and ceruletide in schizophrenic patients.

The neuropeptides desenkephalin-gamma-endorphin (DE gamma E) and ceruletide were administered intramuscularly to patients with schizophrenic psychoses following a double-blind placebo-controlled design, including a total of 44 subjects. Neuroleptic medication was continued during the experimental period, which was started with one placebo injection for all patients. One week later subjects received a single intramuscular injection with 3 mg DE gamma E, 40 micrograms ceruletide or placebo. After an interval of 10 days, the patients received six similar injections over a period of 2 weeks. Treatment with either peptides resulted in a decrease of psychotic symptomatology as compared to placebo treatment. The beneficial effect of the peptides lasted at least 2 weeks after the experimental treatment period. Of the 14 patients treated with placebo only, three showed a slight response. Of the 30 patients treated with the neuropeptides, eight did not respond (DE gamma E: 3; ceruletide: 5), eight had a slight response (DE gamma E: 6; ceruletide: 2) and 14 responded moderately or markedly (DE gamma E: 6; ceruletide: 8). No obvious difference between the effects of the two neuropeptides was found, besides a somewhat earlier onset of the effect of ceruletide. Patients presenting relatively less negative psychotic symptoms were particularly susceptible to treatment with either peptide. Apart from slight and short-lasting gastrointestinal complaints after the first injections with ceruletide in some patients, no side effects were observed.