Meta-Analysis Finds Limited Evidence for Medical Cannabis in Mental Health Treatment

A recent meta-analysis published in The Lancet Psychiatry on 16 March 2026 suggests that current evidence does not support the routine use of medical cannabis for treating mental health disorders. The study reviewed 54 randomized controlled trials conducted between 1980 and 2025, encompassing data from 2,477 participants. The analysis found that a combination of cannabidiol and delta-9-tetrahydrocannabinol showed promise in reducing cannabis withdrawal symptoms and usage among individuals with cannabis use disorder, as well as in alleviating tic severity in patients with tic or Tourette syndrome. However, no significant effects were observed for anxiety, anorexia nervosa, psychotic disorders, post-traumatic stress disorder, or opioid use disorder. The authors noted insufficient data to assess the efficacy of medical cannabis in treating ADHD, bipolar disorder, and obsessive-compulsive disorder, and found no evidence supporting its use for depression. They emphasized the need for larger, more representative randomized controlled trials and concluded that, given the scarcity of evidence, the routine use of cannabinoids for treating mental disorders and substance use disorders is currently rarely justified. Mike Barnes, founder of the Medical Cannabis Clinicians Society and Cannabis Industry Council, criticized the study, stating that cannabis cannot be subjected to traditional placebo-controlled, double-blind studies due to its complex composition and personalized dosing requirements. He argued that real-world evidence, such as the approximately 100,000 cannabis-prescribed patients in the UK, many of whom use it for mental health issues like anxiety, should be considered. The Care Quality Commission's annual report, 'The safer management of controlled drugs: annual update 2025,' noted a 130% increase in the dispensing of cannabis-based products for medicinal use between 1 April 2023 and 31 March 2024, totaling 346,600 items. The report indicated that nearly all of these prescriptions were issued in the independent sector but did not specify the reasons for the prescriptions.