A randomized double-blind fluvoxamine/placebo crossover trial in pathologic gambling

The study assessed the efficacy and tolerability of the selective serotonin reuptake inhibitor (SSRI) fluvoxamine in the treatment of pathologic gambling (PG).

A 16-week randomized double-blind crossover design insured that each subject received 8 weeks of fluvoxamine and 8 weeks of a placebo. Fifteen patients entered and 10 subjects, all male, completed the study.

Fluvoxamine resulted in a significantly greater percent improvement in overall gambling severity on the PG Clinical Global Impression (PG-CGI) scale. There was a significant drug effect on gambling urge and behavior as measured by the PG modification of the Yale-Brown Obsessive Compulsive Scale and PG-CGI scale improvement scores; however, there was a significant interaction of drug effect with the order of administration of drug and placebo. Post hoc analysis, treating each phase as a separate trial, demonstrated a significant difference between fluvoxamine and the placebo in the second phase of the trial but not in the first. Fluvoxamine side effects were of only mild intensity and consistent with SSRI treatment and were not associated with early withdrawal from the study.

These findings suggest that fluvoxamine is well tolerated and may be effective in the treatment of PG in an acute trial, and that an early placebo effect in PG treatment appears to diminish over time. To confirm this finding and to determine whether improvement persists over an extended period of time, a longer duration parallel-design trial with long-term maintenance follow-up should be conducted in a larger and more diverse PG population.