Double-blind naltrexone and placebo comparison study in the treatment of pathological gambling

Background: The authors' goal was to assess the efficacy and tolerability of naltrexone in the treatment of pathologic gambling disorder. Methods: Eighty-three subjects who met criteria for DSM-IV pathologic gambling disorder were enrolled in a 1-week single-blind placebo lead-in followed by an 11-week double-blind naltrexone or placebo trial. Naltrexone was started at 25 mg/day and titrated upward until maximum symptom improvement or 250 mg/day was achieved. Gambling symptom change was assessed with the patient-rated Clinical Global Impression (PG-CGI-PT), clinician-rated CGI (PG-CGI-MD), and the Gambling Symptom Rating Scale (G-SAS). Side effects were monitored weekly and liver function tests biweekly. Results: Data from 45 patients were analyzed. Using random regression analysis, significant improvement was noted in all three gambling symptom measures: patient-rated Clinical Global Impression, p < .001; clinician-rated CGI, p < .001; Gambling Symptom Rating Scale, p < .019. At study end, 75% of subjects taking naltrexone were much or very much improved on both the PE-CEI PT and the PG-CGI-MD, compared with only 24% of those on placebo. Elevated liver enzymes occurred in four subjects who were taking analgesics concurrently. Nausea was common during the first week of treatment. Conclusions: Results suggest that naltrexone is effective in reducing the symptoms of pathologic gambling. Until further studies corroborate the present findings, our report should be interpreted cautiously.