A large review in The Lancet concludes there is no convincing evidence that medicinal cannabis improves symptoms of anxiety, depression or post-traumatic stress disorder. Researchers say the balance of data from randomized trials does not support routine prescribing for these mental health conditions.
The analysis arrives as medical cannabis use has expanded rapidly in North America and elsewhere, including among people seeking relief from mood and trauma-related symptoms. The authors note that patient demand has often moved faster than the clinical evidence base.
What the review examined
The study pooled results from 54 randomized controlled trials conducted between 1980 and 2025, making it one of the broadest assessments of cannabinoids across mental health indications to date. It focused on both effectiveness and safety outcomes, comparing cannabis-based medicines with placebo or other controls.
According to the authors, the evidence did not show meaningful improvements for anxiety, depression or PTSD when results were combined. They also cautioned that frequent use could be associated with harms, including psychotic symptoms and cannabis use disorder, and may delay more effective care.
Potential benefits, but limited certainty
The review found tentative signals that some cannabinoid preparations could help in a small number of other conditions, such as insomnia, tics or Tourette’s syndrome, autism-related symptoms, and cannabis use disorder. However, the authors stressed that the overall quality of evidence for these indications was low.
They also pointed to areas where cannabis-based treatment is supported by stronger evidence, including specific epilepsy syndromes treated with cannabidiol, spasticity in multiple sclerosis, and certain types of pain. Even in these areas, they emphasized the need to match products and dosing to conditions studied in rigorous trials.
Safety questions and regulation debate
The authors said the findings should inform clinicians weighing prescriptions for mental health, particularly given varying product potency and formulations across markets. They argued that inconsistent regulation and marketing claims can leave patients with unclear expectations about benefits and risks.
In substance use disorders, results differed by condition, with some evidence suggesting oral cannabinoid medicines may reduce cannabis smoking when combined with psychological therapy. But for cocaine-use disorder, the review reported increased cravings, indicating cannabis medicines should not be used for that purpose.
Researchers called for clearer prescribing guidance and more high-quality trials that measure standardized mental health outcomes over longer follow-up periods. Until then, they said established, evidence-based treatments for anxiety, depression and PTSD should remain first-line care.
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