Treatment Strategies for Cannabis Use in Schizophrenia

Abstract

Schizophrenia I Psychosis I Cannabis use disorder I Psychosocial treatment I Pharmacological treatment Opinion statement 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.

Clinical Barriers in Treating Patients with Schizophrenia Who Use Cannabis

“…Participants reportedly utilize a range of treatments tailored to each patient, including substance abuse therapy, abstinence, and even treatment with safer cannabis compounds. Such treatment variation reflects larger uncertainty and infancy of the field, with current literature undecided on a singular accepted "best treatment" (Hjorthøj, 2009;Schultz, 2015). Furthermore, participants generally agreed that clinicians are responsible for their understanding of how to treat this patient population, leaving room for clinicians to update themselves at varied frequencies.…”

“…In simple terms, cannabis is often falsely attributed as a formidable treatment for symptoms of schizophrenia, leading patients with schizophrenia to use it erroneously. While it may afford short-term relief of symptoms of schizophrenia, the long-term result often involves psychotic relapse (Schoeler et al, 2016), worsening of symptoms, rehospitalization (Hides et al, 2006), and other products of dependence (Schultz et al, 2015), further contributing to a cycle of abuse, poor treatment outcomes, and worsened schizophrenia (Hjorthøj, 2009).…”

Investigating repetitive transcranial magnetic stimulation on cannabis use and cognition in people with schizophrenia

“…For instance, retrospective studies 22 , 23 and two randomized controlled trials (RCTs) 24 , 25 using atypical antipsychotics, particularly clozapine, found beneficial effects on psychosis and cannabis use. RCTs evaluating behavioral therapies (e.g., contingency management (CM), cognitive behavioral therapy) for schizophrenia and CUD, are limited as typically patients with co-occurring mental illness are excluded in CUD trials, and most studies evaluated the efficacy on cannabis use rather than CUD, or early psychosis versus schizophrenia 26 , 27 . Notably, our group demonstrated that a 28-day cannabis abstinence paradigm with CM produced high rates of abstinence (~43%) in cannabis-dependent schizophrenia outpatients, comparable to cannabis-dependent non-psychiatric controls (~55%) 28 .…”