In an effort to broaden the options for pharmacotherapy of alcoholism, this study will examine the effects of sertraline, a selective serotonin reuptake inhibitor (SSRI), for the treatment of alcohol dependence. The study is based on evidence that, although SSRI therapy is not appropriate for all alcoholics, there exists a substantial subgroup of alcoholics for whom SSRIs appear to exert a clinically important effect. Sertraline is among the most widely prescribed psychotropic medications in the world. Consequently, this study will examine the safety and efficacy of sertraline, the mechanism and duration of those effects and the best method for subtyping alcoholics to identify individuals for whom the medication is most likely to produce a clinically important reduction in drinking behavior.