Antipsychotic drug treatment of schizophrenic patients with substance abuse disorders

In recent years, there has been a growing interest in developing adequate treatments for patients with a diagnosis of schizophrenia and a comorbid substance use disorder (SUD). In the present paper we aim to critically review published reports on the use of conventional and second-generation antipsychotics in the treatment of patients with schizophrenia and comorbid SUD, to provide clinicians with a clearer view of the pharmacological treatment of this highly prevalent dual diagnosis based upon the evidence arising from the scientific literature.

A search of the relevant literature from Medline, PsycLIT and EMBASE databases, included in the Science Citation Index, and available up to November 2006 was conducted using the terms: 'schizophrenia', 'substance use disorder' and 'antipsychotics'.

While research on the use of conventional antipsychotics has remained limited, the majority of studies suggest the effectiveness of second-generation antipsychotics, particularly clozapine, for patients with schizophrenia and a comorbid substance use disorder.

In the absence of randomized controlled trials that could provide more reliable information, clinical decisions may need to rely on indirect data provided by the increasing number of case reports, open trials and retrospective studies showing a decrease in cigarette smoking, alcohol, cocaine or cannabis use and an improvement of overall psychiatric symptoms.