Atypical Antipsychotic Drugs in Dual Diagnosis Patients: A Review

Abstract

Introduction: Dual Diagnosis (DD), defined as the co-occurrence of a Substance Use Disorder (SUD) and a Severe Mental Illness (SMI), is associated with several negative outcomes. Typical antipsychotics (TAP) are not of great value for patients with DD as they are associated with poorer responses and can worsen SUD. Atypical antipsychotics (AAP) offer several advantages compared to TAP. In DD, they have been found to be effective in treating both, psychiatric symptoms and substance use. The aim of this article is to review the use of AAP for treating DD patients. Methods: A search of MEDLINE, EMBASE and Pubmed was performed in order to identify publications that examined the use of AAP in the treatment of DD. Results: The largest number of studies focuse on clozapine, with consistently positive data. Data regarding aripiprazole are also consistent but less substantial. Olanzapine, risperidone and quetiapine have given inconclusive and inconsistent results. Finally, there is little use of amisulpride, ziprasidone, paliperidone and asenapine or it is has not been documented. Discussion: Today, there is a consensus on using AAT instead of TAP for treating patients with DD. Patients with DD show a poorer response to treatment with TAP, and TAP may even worsen the addictive behaviour. AAP are as effective as TAP in treating psychiatric symptoms, but they are more effective in reducing substance use in DD patients. Because with the exception of CLO none of the AAP have shown to be superior to the others, when choosing between the different AAP agents clinicians should take into account other variables such as medical comorbidity, possible pharmacological interactions of concomitant treatments and profile of side effects. Even though a growing body of evidence suggests the beneficial effects of AAP in DD patients, further randomized, blinded, controlled trials, with larger sample sizes and longer followups are needed.