Naltrexone in chronic schizophrenia. Results of a clinical trial

A 4-week clinical trial, including a 1-week placebo washout period, assessed the antipsychotic activity of naltrexone in 'newly admitted', actively hallucinating, chronic schizophrenics. Chronic naltrexone administration was found to benefit 2 patients and to be of no value in 3 patients. Responsive patients differed from non-responders by the presence of hallucinations despite adequate neuroleptic maintenance therapy and an appropriate response to pathological hallucinatory experience. On the basis of these findings, the possibility of a naltrexone-responsive schizophrenic subgroup was considered.