Approximately half of the patients who suffer from schizophrenia are also substance abusers at some time during their illness. The motivational drive toward abusive consumption is compounded in individuals with schizophrenia who turn toward substances with reinforcing properties to alleviate aspects of psychosis. This review examines the prevalence, etiology, and clinical effects of substance abuse (e.g., alcohol, nicotine, cocaine) among individuals with schizophrenia. Clearly, substance abuse persists despite and in spite of treatment with typical antipsychotics. The efficacy of newer generation antipsychotics in the reduction of substance abuse among the schizophrenic population has yet to be established, but clozapine has been shown to reduce alcohol, smoking, and cocaine use. Hence, clozapine is a therapeutic option for dually diagnosed patients because of its superior efficacy relative to conventional neuroleptics and its capacity to control substance abuse.