Cannabidiol as an Add-on Treatment for Schizophrenia

This week, KannAInsight features a study on beneficial effects of CBD for patients with schizophrenia.

Schizophrenia is a chronic and severe mental disorder that affects how a person thinks, feels, and behaves. At any one time, as many as 51 million people worldwide suffer from schizophrenia. However, it is estimated that between 20% and 60% of patients are treatment resistant. Therefore, the potential benefit of CBD for patients with schizophrenia is of critical importance. 

In a recent trial, patients received CBD (1000 mg/day) or placebo in addition to their regularly prescribed antipsychotic medication for six weeks. Patients were assessed before and after treatment on positive and negative psychotic symptoms, cognitive performance, level of functioning, and the treating psychiatrist’s overall clinical impression. 

Adjunctive CBD therapy was associated with significant effects on positive psychotic symptoms and on the treating clinicians’ impressions of improvement and illness severity. There were also trends in improvements in cognitive performance and the level of overall functioning. Only one-third of the patients in each group reported adverse events, and the majority of these were mild and resolved naturally. 

Because CBD has a different mechanism of action compared to conventional antipsychotic medication, it may represent a new class of treatment for schizophrenia, particularly for treatment-resistant individuals. However, the potential clinical utility of CBD requires further controlled studies to determine the long-term safety and efficacy. 

Citation: McGuire , Robson P, Cubala WJ, Vasile D, Morrison PD, Barron R, Taylor A, Wright S. Cannabidiol (CBD) as an adjunctive therapy in schizophrenia: A multicenter randomized controlled trial. Am J Psychiatry. 2018 Mar 1; 175(3): 225-231. 

Want to receive the latest science and insights on cannabis use in your inbox? Subscribe for free!