Summary: No – data from the most comprehensive study ever conducted on cannabis for mental health shows that cannabis does not improve treatment for mental health disorders, with exceptions for a small number of symptoms in a limited number of disorders.
Key Points:
- Cannabis and several of its derivatives have received approval for use to support and treat people with diagnoses such as depression and anxiety.
- The decriminalization movement has led to a change in attitudes toward cannabis in the U.S.: many people are now open to trying cannabis to improve treatment for mental health disorders.
- Informal support for cannabis for mental health treatment is common, and easy to find on social media and niche news outlets.
- Anecdotal and informal reports of positive outcomes notwithstanding, peer-reviewed evidence from random controlled trials shows that – except for narrow uses in limited contexts – cannabis does not improve mental health symptoms, when compared with placebo.
Changing Attitudes About Cannabis Don’t Change the Evidence for Cannabis in Mental Health Treatment
We’ve all watched it happen ourselves. Over the past five decades, the cannabis legalization movement gained significant momentum. In the 1970s, a total of 14 states legalized/decriminalized cannabis. In the 1990s, 21 state legislature approved medical cannabis. Then, between 2012 and the present, over 20 states passed laws allowing sale of cannabis for recreational use.
Those legal changes reflect changing attitudes around the country. A recent nationwide survey shows what people think about cannabis and the law:
- Always no: 1 in 10 people think cannabis should never be legal.
- Sometimes yes: 3 in 10 people think cannabis should only be legal for medical purposes only.
- Always yes: 6 out of 10 people think cannabis should be legal for both medical and nonmedical use.
As we can see, far more people think cannabis should be legal – with some restrictions – than think cannabis should be illegal. And many people use cannabis for various purposes. They use it to relax. They give it to their pets. Their parents might use cannabis oils for joint pain, or for insomnia. Many people say it help ease social anxiety, and believe it helps with anxiety in general.
However, public and persona opinion is not peer-reviewed mental health data assessed and applied in a clinical context and cannot verify – with math – whether cannabis can improve treatment for mental health disorders. That’s what scientific studies can do, and those studies don’t align with popular opinion.
New research from the well-established and respected journal the Lancet offers the kind of data we need to confirm or refute the benefit of cannabis for mental health treatment. We’ll take a look at the data in that study – “The Efficacy and Safety of Cannabinoids for The Treatment of Mental Disorders and Substance Use Disorders: A Systematic Review and Meta-Analysis” – throughout the rest of this article.
Cannabis and Mental Health Treatment
The authors of the study recognize the trends we point out in the survey above, and address the recent approval of some cannabis derivative for mental health treatment:
“Mental disorders and substance use disorders (SUDs) are among the leading reasons for which the medical use of cannabinoids has been approved, but their efficacy and safety in treating these conditions is yet to be established.”
To address the disconnect between public opinion, regulatory approval, and evidence, the researchers describe the goal of their study:
“We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) testing the efficacy and safety of cannabinoids as the primary treatment for mental disorders or SUDs.”
The researchers amassed a data set of close to 2,500 adults, average age, mid-30s, roughly 2/3rd male and 1/3rd female, and assessed the effect of cannabis on the treatment of eleven (11) mental or behavioral disorder, including:
- Major depressive disorder (MDD)
- Generalized anxiety disorder (GAD)
- Bipolar disorder (BD-I&II)
- Obsessive-compulsive disorder (OCD)
- Psychosis and psychotic disorders such as schizophrenia
- Attention-deficit hyperactivity disorder (ADHD)
- Eating and feeding disorders
- Post-traumatic stress disorder (PTSD)
- Opioid addiction
- Cannabis addiction
- Tobacco addiction
We’ll review their results below.
Cannabis and Treatment for Mental Health Disorders: Does it Work?
We’ll cut right to the chase:
Data shows cannabis, overall, is not an effective treatment for mental health disorders. In most cases, cannabis does not improve mental health treatment in any significant way.
Evidence from over fifty studies shows no significant for cannabis or its derivatives on ten of the eleven disorders examined:
- Anxiety (GAD)
- Social anxiety disorder (SAD)
- Post-traumatic stress disorder (PTSD)
- Obsessive-compulsive disorder (OCD)
- Attention-deficit hyperactivity disorder (ADHD)
- Bipolar disorder (BD-I&II)
- Psychotic disorders, i.e. schizophrenia
- Anorexia nervosa
- Opioid use disorder (OUD)
- Tobacco use disorder
Cannabis and derivatives did help in four instances: one was a primary outcome for the researchers, while three were related to secondary outcomes. Results for the primary outcome, impact on cannabis use disorder, showed that cannabis oil helped:
-
- Reduce intensity of cannabis withdrawal
- Reduce cannabis use
For the first of the secondary outcomes that showed improvement with cannabis – impact on people with Tourette’s syndrome – treatment with cannabis showed:
-
- Decreased in severity of Tourette’s-associated tics.
For the next secondary outcome – impact on insomnia – treatment with cannabis was associated with:
-
- Longer duration of sleep, self-report
- Longer duration of sleep, clinician report.
Finally, for the final secondary outcome – effect on symptoms of autism spectrum disorder (ASD) – treatment with cannabis showed:
-
- Decrease in ASD related behaviors, clinician report.
Let’s summarize what we know from the study up to this point:
- Cannabis does not improve treatment for anxiety, post-traumatic stress disorder, obsessive-compulsive disorder, attention-deficit hyperactivity disorder, bipolar disorder, eating disorders, and schizophrenia.
- Cannabis has a moderate, positive effect on treatment for insomnia, Tourette’s syndrome, and aspect of autism spectrum disorders.
We’ve reviewed the results of the meta-analysis to show what cannabis helped and what cannabis did not have any effect on at all. The researchers also reported negative outcomes and any increased risk of adverse events associated with cannabis for mental health treatment. They found that for people in treatment for cocaine use disorder, cravings for cocaine increased.
That’s a negative outcome.
In their analysis of adverse events associated with cannabis treatment, they found that treatment with THC alone didn’t increase risk of adverse events, but treatment with cannabidiol alone and cannabidiol combined with THC increased risk of minor adverse events.
We’ll elaborate on these results below.
Outcome: Data Shows Cannabis Does Not Improve Treatment for Mental Health Disorders, With Very Few Exceptions
Data shows cannabis as a therapeutic medication had no effect on the majority of disorders assessed. That means there’s no reliable evidence base for the use of cannabis to treat anxiety, depression, PTSD, ADHD, OCD, psychosis and psychotic disorders, eating disorders, opioid use disorder, or tobacco use.
Here’s how the lead author of the study, Dr. Jack Wilson, views the results of this research:
“Though our paper didn’t specifically look at this, the routine use of medicinal cannabis could be doing more harm than good by worsening mental health outcomes, for example a greater risk of psychotic symptoms and developing cannabis use disorder, and delaying the use of more effective treatments.”
When discussing the positive outcomes for insomnia and autism, He adds:
“…the overall quality of evidence for these other conditions, such as autism and insomnia, was low. In the absence of robust medical or counseling support, the use of medicinal cannabis in these cases are rarely justified.”
We’ll offer our summary thoughts on cannabis and mental health treatment now.
Follow the Data, Question Every Headline with a Sensational Claim
This data we share above is particularly important when we consider the legalization movement and data from a nationwide survey on drug use conducted in 2025 which shows the following:
- 20 million people reported cannabis use disorder
- 44 million people reported past-month cannabis use
- 64 million reported past-month cannabis use
- 136 million people reported ever using cannabis
The same survey showed that over half a million – 615,000 – adolescents between ages 12 and 17 used cannabis for the first time, and 1.7 million adults 18+ used cannabis for the first time. That’s at least two million people who met criteria for initiation of use of cannabis.
What we hope for these millions of people is that they don’t rely on cannabis to treat any existing mental health issue they might have. We hope the teens pay attention to headlines like this one:
Teen Cannabis Use Linked to Psychosis and Bipolar Disorders in Study
And this one:
Huge Study Finds No Evidence Cannabis Helps Anxiety, Depression, Or PTSD
Those articles are based on data from random controlled trials, which are the gold standard in research. We also hope people with mental health disorders dive deeper when they see articles and studies that promote the benefits of cannabis for mental health, because they often contain disclaimers at the end of their data, like the one below from this study:
“Although causality cannot be definitively established due to the observational nature of the study, these results lay the groundwork for future randomized controlled trials. Such trials will be necessary to validate these promising findings, and to identify the patient populations most likely to benefit from this treatment.”
We’d also be remiss if we didn’t offer words of caution to veterans with PTSD who may consider using cannabis to manage their symptoms. The Veterans Administration National Center for PTSD – a department which is one hundred percent behind any treatment that helps veterans, including allocating millions of dollars toward research on psychedelics for PTSD – takes this position on cannabis for PTSD treatment:
“Cannabis use for medical conditions is an issue of growing interest and concern. Research to date does not support cannabis as an effective PTSD treatment, and some studies suggest cannabis can be harmful, particularly when used for long periods of time.”
When seeking treatment for mental health, we encourage everyone to speak with their primary care provider, then a specialized mental health provider, before using any medication or substance to manage mental health symptoms.
