Marijuana in small jar

"Instead of helping, the limited evidence points to a increased risk for depression."

Whether you call it weed, pot, cannabis, ganja, chronic, dope, buddha, or bud, recreational use of marijuana is now legal across Canada and a number of US states.

Though recreational use in the UK, Australia, and almost all other nations remains illegal, a lot of guys – especially young men – use marijuana (smoke, oil, pills, or edibles – still illegal in Canada for several more months) to get high, lift their mood, or help relax.

The two main components of marijuana are THC (this is what has the psychoactive effects) and CBD (no psychoactive effects, often sold as CBD oil). These components both interact with a system in our brains that plays a role in regulating our mood, leading some to wonder if marijuana could be used to treat a mood disorder like depression.[1]

It’s an interesting question, but because of its past and/or current status as a controlled substance, we don’t have a lot of quality research available. What research there is doesn’t always specify the levels or amounts of THC and CBD, varies in form or environment taken, doesn’t track long term effects, or have only been animal based research. [2][3][5]

Nevertheless, there are a few studies and reports (see below) that we can draw on. Here’s what the current evidence points to:

Short term or infrequent use of marijuana:

  • Minimal evidence for relieving stress and anxiety.[4]
  • Limited and mixed evidence for positive and negative effects on depression.[3][4]
  • Can cause anxiety or paranoia, depending on amount of THC and CBD.  [3][4]

Sometimes levels of THC and CBD are labelled on different strains, but there isn’t a lot of oversight yet.

For long term, frequent use of marijuana:

  • Substantial evidence for increased risk for development of schizophrenia or other psychoses.[4]
  • Moderate evidence for increased suicidal thoughts.[4]
  • Emerging evidence for increased risk for depression.[2][4][5]
  • No evidence for decreased symptoms of depression.

The bottom line:

Available research indicates that use of marijuana is more likely to be associated with increased mental health problems rather than providing relief of mental health problems.[4][5]

If you are an infrequent user:

  • You don’t have to worry much, but do inform your doctor if you are using. Now that it’s legal in Canada, there’s no reason to be dishonest and it’s important for your doc to know about any substances that can affect your mood.

If you are a frequent user:

  • Inform your doctor if you are using.
  • It is a good idea to limit and reduce your use of marijuana to decrease any long term mental health risks.
  • Use of marijuana is more likely going to get in the way of getting better than it is to help with your depression.[5]

If you are thinking about using for anxiety or depression:

  • Don’t self-medicate! Speak with a doctor about treatment options. 
  • Though it may provide some temporary relief, marijuana won’t help you get to bottom of issues like talk therapy can.

In the coming months and years, we’re likely to hear many claims about what marijuana can do. Some of its benefits are well researched with substantial supporting evidence (like for adults with chemotherapy-induced nausea, chronic physical pain, and short-term use for multiple sclerosis), but many other claims (like for anxiety and depression) are not supported by science.[4]

So if you see marijuana being promoted as a ‘natural’ alternative for many medications, be cautious and sceptical – instead of helping, the limited evidence actually points to a increased risk for depression.


  1. Mechoulam, R., & Parker, L. (2013). The endocannabinoid system and the brain. Annual Review of Psychology, 64, 21-47.
  2. Cuttler, C., Spradlin, A., & McLaughlin R. (2018). A naturalistic examination of the perceived effects of cannabis on negative effect. Journal of Affective Disorders, 235, 198-205.
  3. Walsh, Z., Gonzalez, R., Crosby, K., Thiessen, M., Carroll, C., & Bonn-Miller, M. (2017). Medical cannabis and mental health: A guided systematic review. Clinical Psychology Review, 51, 15-29.
  4. National Academies of Sciences, Engineering, and Medicine. (2017). The health effects of cannabis and cannabinoids: The current state of evidence and recommendations for research. Washington, DC: The National Academies Press.
  5. Lev-Ran, S., Roerecke, M., Le Foll, B., George, T., McKenzie, K., & Rehm, J. (2014). The association between cannabis use and depression: a systematic review and meta-analysis of longitudinal studies. Psychological Medicine, 44(4), 797-810.