Negative naloxone effects in schizophrenic patients.

On the basis of the hypothesis that the opiate-like neuropeptides, such as beta-endorphin, may be involved in the etiology of schizophrenic symptoms, naloxone 1,2 mg and placebo were administered intravenously to 8 schizophrenic patients, using a double-blind, crossover design. Naloxone was not found to be different from placebo in effecting schizophrenic symptoms, including hallucinations and delusions.