Cannabinoids Show Benefits for Patients with Mental Illnesses

In 1990, Congress officially established the first full week of October as Mental Illness Awareness Week (MIAW). In honor of MIAW, KannAInsight highlights some newer research that examined whether cannabis/cannabinoid products might be a safe and effective treatment options for patients with mental illnesses.

According to the National Alliance on Mental Health, approximately 1 in 5 adults in the U.S. experiences mental illness in a given year, with three-quarters of all chronic mental illnesses beginning by the age of 24. Estimates suggest that only half of the people with mental illnesses receive treatment, and many of those individuals are non-responsive or experience serious side effects from treatment. 

Indeed, some patients are seeking alternative treatment options. New research suggests that anxiety and depression/mood disorders are some of the most commonly reported reasons that patients seek medical cannabis. 

In a recent trial, schizophrenia patients received cannabidiol (CBD) or placebo in addition to their regularly prescribed antipsychotic medication for six weeks. 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. 

Likewise, in a similar study, three-week treatment with CBD was useful in relieving symptoms and distress in patients with a clinical high-risk of psychosis. As compared to placebo, CBD was associated with a significantly greater reduction in anxiety and distress associated with psychotic symptoms, as well as a trend toward greater reduction in the severity of psychotic symptoms. It is believed that CBD may (at least partially) normalize alterations in brain function in patients at a high risk for psychosis. 

Because cannabinoids have a different mechanism of action than conventional antidepressant, anxiolytic, and antipsychotic medications, cannabis/cannabinoid products may represent a new class of treatment for patients with mental illnesses, particularly for treatment-resistant individuals. However, the potential clinical utility of cannabinoids in these patients requires further controlled studies to determine the long-term safety and efficacy. 


Bhattacharyya S, Wilson R, Allen P, Bossong M, Appiah-Kusi E, McGuire P. 17.3 Effect of cannabidiol on symptoms, distress and neurophysiological abnormalities in clinical high-risk for psychosis patients: A placebo-controlled study. Schizophrenia Bulletin. 2018 Apr. 44(Suppl 1): S28 [Presented at Sixth Biennial SIRS Conference]

Bhattacharyya S, Wilson R, Appiah-Kusi E. Effect of cannabidiol on medial temporal, midbrain, and striatal dysfunction in people at clinical high risk of psychosis. JAMA Psychiatry. 2018 Nov 1; 75(11): 1107-1117.

Kosiba JD, Maisto SA, Ditre JW. Patient-reported use of medical cannabis for pain, anxiety, and depression symptoms: Systematic review and meta-analysis. Social Science & Medicine. 2019 July; 233: 181-192. 

McGuire P, 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. 

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