Although several qualitative reviews on pharmacological interventions for pathological gambling have been published, no quantitative review of this field has been conducted. METHODS: Studies of pharmacological interventions of pathological gambling were identified by computer searches in the PsychINFO and MEDLINE databases covering the period from 1966 to July 2006, as well as from relevant reference lists. The inclusion criteria were as follows: the target problem had to be pathological gambling, the interventions were pharmacological, the study was written in English, and the study reported outcomes particularly pertaining to gambling. A total of 130 potential studies were identified of which 16 met the inclusion criteria. A total of 597 subjects were included in the outcome analyses of these studies. The grand mean age was 43.3 years. The overall proportion of men was 62.8%. The included studies were coded for outcome measures of pathological gambling. For each condition, means and SDs for gambling-related outcome measures were compiled at 2 points in time: baseline and posttreatment. RESULTS: At posttreatment, the analysis showed that the pharmacological interventions were more effective than no treatment/placebo, yielding an overall effect size of 0.78 (95% confidence interval, 0.64-0.92). A multiple regression analysis showed that the magnitude of effect sizes at posttreatment was lower in studies using a placebo-control condition compared with studies using a predesign/postdesign without any control condition. Effect sizes were also negatively related to the proportion of male participants in the included studies. No differences in outcome between the 3 main classes of pharmacological interventions (antidepressants, opiate antagonists, mood stabilizers) were detected. CONCLUSION: Pharmacological interventions for pathological gambling may be an adequate treatment alternative in pathological gambling.