Two analyses of existing research demonstrate that marijuana does not effectively treat anxiety, depression, post-traumatic stress disorder, and other mental health conditions despite widespread use. A study published in the Lancet Psychiatry analyzed 54 randomized controlled trials conducted between 1980 and 2025, representing the gold-standard of medical research. No evidence supported the effectiveness of any form of cannabis in treating anxiety, depression, or PTSD—the three leading reasons cannabis is prescribed. The cannabis medications in these trials were largely oral formulations including capsules, sprays, and oils; real-world use typically involves smoked cannabis, which has even less evidence of mental health benefit. Marijuana also failed to improve anorexia nervosa, bipolar disorder, obsessive-compulsive disorder, or psychotic disorders such as schizophrenia.
Despite the absence of evidence, almost every state in the United States approves medical marijuana for mental health conditions. Among 27% of people ages 16 to 65 in the United States and Canada who have used marijuana for medical purposes, about half report using it to manage mental health. Doctors continue prescribing medical marijuana for mental health treatment despite lack of proof of efficacy, a pattern complicated by cannabis industry connections to some studies, which represent potential conflicts of interest.
Potent marijuana poses significant risks, particularly for vulnerable populations. Use during pregnancy, adolescence, and young adulthood interferes with brain development. Heavy use by teens and young adults with mood disorders correlates with increased risk of self-harm, suicide attempts, and death. Individuals at high risk for bipolar or psychotic disorders face increased risk of developing these conditions through marijuana use. Daily users of high-potency cannabis may be six times more likely to develop psychotic disorder compared to non-users.
Modern cannabis potency has increased dramatically, with THC content rising from approximately 4% in the 1970s to an average of 18% to 20% today. Dispensaries now sell products with 35% THC, and concentrates reach 80%—approximately 20 times greater than 1960s and 1970s cannabis. This increase contributes to rising addiction: about 3 in 10 people who use marijuana develop cannabis use disorder. Proven treatments include selective serotonin reuptake inhibitors (SSRIs) combined with cognitive behavioral therapy (CBT), a goal-oriented approach addressing negative thoughts and behaviors to improve emotional regulation and mood.
This article is an AI-assisted summary. All facts and figures are drawn from the original report: https://ktvz.com/health/cnn-health/2026/03/16/using-marijuana-to-ease-anxiety-or-depression-science-shows-the-evidence-isnt-there/