Review Finds Cannabis Ineffective for Common Mental Health Conditions

A comprehensive review conducted by researchers from universities in Australia and the UK has found minimal evidence supporting the efficacy of cannabis-based therapies in treating common mental health disorders. The study, published in The Lancet Psychiatry, analyzed 54 randomized controlled trials involving 2,477 participants and concluded that cannabinoids are rarely justified for routine use in treating mental health and substance use disorders.

The researchers noted that while some evidence suggests medicinal cannabis may reduce dependence on cannabis, alleviate symptoms of Tourette syndrome, and improve sleep in insomniacs, there were no significant effects on outcomes associated with anxiety, anorexia nervosa, psychotic disorders, post-traumatic stress disorder, and opioid use disorders. They emphasized the scarcity of evidence and advised against the routine use of cannabinoids for these conditions.

Sir Robin Murray, a professor of psychiatric research at King's College London, commented on the findings, stating that the therapeutic benefits of cannabis are extremely limited, and side effects are common. He expressed concern that many people are misled into using cannabis to treat their problems, bolstered by claims from the cannabis industry and the proliferation of cannabis clinics.

In contrast, Mike Morgan-Giles, chief executive of the Cannabis Industry Council, argued that real-world evidence shows medical cannabis reduces symptoms for patients with anxiety and post-traumatic stress. He criticized the study for not adequately reflecting how clinical prescribing is undertaken in the UK.

The Advisory Council on the Misuse of Drugs is currently reviewing the impact of the 2018 legalization of cannabis-based products in the UK, including any unintended consequences. Prof Owen Bowden-Jones, registrar of the Royal College of Psychiatrists, emphasized the importance of providing patients with accurate and transparent information about these products to enable informed decisions about their care and treatment.