• Ten depressed and eight schizophrenic patients received synthetic human β-endorphin infusions in a double-blind, placebo-controlled, crossover design. Physicians' and nurses' ratings and patients' self-ratings were used to measure behavioral change. Depressed patients improved significantly two to four hours after β-endorphin treatment when compared with placebo treatment. There was no significant change in the schizophrenic patients as a group, although six of eight worsened after β-endorphin treatment. No significant behavioral effects were observed during the infusions themselves or on postinfusion days.
Gerner RH, Catlin DH, Gorelick DA, Hui KK, Li CH. β-EndorphinIntravenous Infusion Causes Behavioral Change in Psychiatric Inpatients. Arch Gen Psychiatry. 1980;37(6):642-647. doi:10.1001/archpsyc.1980.01780190040005