Cerebrospinal fluid [Met5]enkephalin level in schizophrenics during treatment with naloxone

The effect of naloxone on CSF [Met5]enkephalin level and on the suppression of psychotic symptoms associated with schizophrenia was studied. Seven patients were treated with naloxone at a dose of 0.4 mg/day for seven days and six were treated with saline for the same period. Of the seven patients receiving naloxone, three showed signs of improvement. In the saline group, only one case of obvious improvement was observed. The mean CSF [Met5]enkephalin level before and after treatment in both the naloxone and saline group did not change significantly. However, there was a highly significant correlation (r = -0.73, P less than 0.01) between the increase of [Met5]enkephalin level and the decrease in psychotic symptoms.