• To study the effects of β-endorphin in chronic schizophrenia, nine male patients participated in a double-blind crossover comparison of a single intravenous 20-mg injection of β-endorphin and saline. Bolus injection of β-endorphin from an albumincoated syringe produced markedly higher plasma concentrations than did slow intravenous infusion from a non$albumincoated syringe. β-endorphin intravenously injected in nine patients produced a statistically significant increase in serum prolactin levels. In one patient, both 10 mg of morphine sulfate and 20 mg of β-endorphin produced similar increases in the alpha power of the EEG. In eight patients, β-endorphin administration was associated with a statistically significant but not clinically obvious improvement in schizophrenic symptoms.
Berger PA, Watson SJ, Akil H, Elliott GR, Rubin RT, Pfefferbaum A, Davis KL, Barchas JD, Li CH. β-Endorphin and Schizophrenia. Arch Gen Psychiatry. 1980;37(6):635–640. doi:10.1001/archpsyc.1980.01780190033003