New research from two major studies reveals that marijuana, whether smoked or taken as CBD or THC products, does not effectively treat anxiety, depression, post-traumatic stress disorder (PTSD), or other common mental health conditions. This finding challenges a widespread belief among the roughly 27% of Americans and Canadians who use marijuana for medical purposes, with about half using it specifically to manage mental health symptoms. What Do the Latest Studies Actually Show About Cannabis and Mental Health? Researchers at the University of Sydney analyzed 54 randomized controlled trials published between 1980 and 2025, the gold-standard type of research that provides the strongest evidence. "We found no evidence any form of cannabis is effective in treating anxiety, depression or post-traumatic stress disorder, which are three of the leading reasons for which cannabis is prescribed," said Jack Wilson, a postdoctoral research fellow at the University of Sydney's Matilda Centre for Research in Mental Health and Substance Use. A separate analysis published in JAMA by researchers at Yale, including Dr. Deepak Cyril D'Souza, reached the same conclusion. "These two papers clearly show there isn't any evidence to recommend the use of cannabis or cannabis derivatives to treat mental health," D'Souza explained. The troubling part: despite this lack of evidence, doctors continue prescribing medical marijuana for mental health conditions in nearly every U.S. state. The studies examined both oral formulations like capsules, sprays, and oils, as well as the effects of smoked cannabis. Cannabis products containing cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC), the compound that produces the "high," showed no meaningful benefit for mental health conditions. Does Marijuana Help With Other Mental Health Conditions Beyond Anxiety and Depression? The research found that marijuana also failed to improve symptoms of several other serious mental health conditions. According to the studies, cannabis did not help with anorexia nervosa, bipolar disorder, obsessive-compulsive disorder (OCD), or psychotic disorders such as schizophrenia. This is particularly concerning because people with these conditions sometimes turn to marijuana hoping for relief, only to find their symptoms may actually worsen. Why Is Today's Marijuana More Dangerous Than in the Past? One critical factor making marijuana use riskier is the dramatic increase in potency. The THC content in marijuana has skyrocketed from approximately 4% in the 1970s to an average of 18% to 20% today. Some products sold in dispensaries contain 35% THC, and marijuana concentrates can reach 80% THC, roughly 20 times stronger than cannabis from the 1960s and 1970s. This increased potency is contributing to a rise in cannabis use disorder, the medical term for marijuana addiction. In the United States, about 3 in 10 people who use marijuana develop cannabis use disorder, according to the Centers for Disease Control and Prevention. People with this condition experience cravings, irritability, restlessness, and mood and sleep difficulties when they try to quit. The risks are especially serious for vulnerable populations. Heavy use of marijuana by teenagers and young adults with mood disorders like depression and bipolar disorder is linked to an increased risk of self-harm, suicide attempts, and death. For individuals at high risk of developing bipolar or psychotic disorders, such as those with family histories, marijuana use raises the risk of actually developing these conditions. "If you are a daily user of high potency cannabis, for example, you may be six times more likely to develop a psychotic disorder such as schizophrenia or bipolar disorder than somebody who's never used cannabis," D'Souza noted. Additionally, using marijuana during pregnancy, adolescence, and young adulthood can interfere with brain development, and using it after a mental health condition has started can worsen cognition and increase the chance of relapse. Steps to Take If You're Struggling With Anxiety or Depression - Seek Evidence-Based Therapy: Cognitive behavioral therapy (CBT) is the leading psychotherapy for anxiety and depression. It is goal-oriented and focuses on changing negative thoughts and behaviors to improve emotional regulation and mood. Research shows CBT can reduce anxiety symptoms by 50 to 60% within 12 to 16 sessions. - Consider Medication Management: Selective serotonin reuptake inhibitors (SSRIs) are a common and effective pharmaceutical approach for depression and anxiety. These medications work best when combined with therapy like CBT. - Find a Qualified Therapist: The Association for Behavioral and Cognitive Therapies has a searchable directory of CBT-trained therapists by zip code. The American Psychological Association also lists CBT-trained therapists under "treatment methods" in its "Find a Psychologist" tool. If you are experiencing thoughts of self-harm or suicide, contact the National Suicide Prevention Lifeline at 988 or text "HELLO" to 741741 to reach the Crisis Text Line. What Should People Know About Trauma-Based Approaches to Mental Health? For those dealing with trauma or PTSD, emerging research shows that body-based therapies may be more effective than talk therapy alone. Psychiatrist Bessel van der Kolk's groundbreaking research demonstrates that trauma is stored in the body's nervous system, not just the mind, requiring evidence-based somatic therapies like EMDR (Eye Movement Desensitization and Reprocessing), trauma-sensitive yoga, and other body-based approaches to achieve lasting healing. During a traumatic event, the brain's prefrontal cortex, which handles rational thinking and planning, essentially goes offline. At the same time, the amygdala, the brain's alarm system, kicks into overdrive and floods the body with stress hormones. The problem is that after trauma, the amygdala often stays hyperactive, continuing to scan for threats long after the danger has passed. This explains why people with PTSD can be triggered by reminders of their trauma years later. Additionally, Broca's area, the brain region responsible for speech, shows significantly reduced activity during trauma. This explains why trauma is often described as "speechless terror." The experience gets encoded in the body and emotional brain without the verbal framework that would allow someone to tell a coherent story about what happened. This is why traditional talk therapy alone may not fully address trauma; the body needs new experiences of safety, movement, and connection to update its deeply ingrained survival programming. The bottom line: while marijuana remains popular for self-treating mental health symptoms, the scientific evidence simply doesn't support its use. Proven treatments like CBT, SSRIs, and trauma-informed therapies offer real relief and lasting improvement. If you're struggling with anxiety, depression, or trauma, speaking with a mental health professional about evidence-based options is the most effective path forward.
