Treatment Strategies for Cannabis Use in Schizophrenia

Abstract

Cannabis is used by more than 25 % of schizophrenia patients and is associated with symptom exacerbation and poorer clinical outcome. To date, evidence is scarce for treating cannabis use disorders among schizophrenia patients. Psychosocial interventions such as cognitive behavioral therapy, motivational interviewing, or contingency management have been evaluated as potential treatments for cannabis use disorders (CUD) among schizophrenia patients and in the general population. However, results are somewhat inconsistent, and efficacy appears to wane after treatment concludes. Pharmacotherapy has also been examined as a potential treatment for CUD but has not yet demonstrated consistent efficacy in the general population. The administration of second-generation antipsychotic medications is the pharmacological standard of care for schizophrenia as well as the treatment of choice for comorbid cannabis use among schizophrenia patients. Recent preliminary trials of pharmacotherapy agents in the general population must be further tested to confirm their potential efficacy at treating CUD. Based on the current evidence, we recommend a multi-faceted approach to treatment for CUD in the schizophrenia population, employing pharmacological and psychosocial modalities. We recommend using a second-generation antipsychotic medication; to date risperidone, olanzapine, and clozapine show the most promise for this population. We also recommend engaging patients in a combination of motivation-based treatment (motivational interviewing or motivation enhancement therapy) and cognitive behavioral treatment directed at cannabis use. When family systems allow, multidimensional family therapy should also be considered, particularly for adolescent patients. The available evidence suggests that CUDs will require ongoing treatment in order to maintain long-term efficacy.