TORONTO -- Cannabis use could be helping Canadians alleviate some of the effects of post-traumatic stress disorder, according to new research from the BC Centre on Substance Use and University of British Columbia.

The study, published in the Journal of Psychopharmacology, found people with PTSD who were not using cannabis were “far more likely” to have suicidal thoughts and suffer from severe depression than self-proclaimed pot users, according to data taken from Statistics Canada’s 2012 Canadian Community Health Survey – Mental Health.

People who suffered trauma -- including survivors of acute injury, violence, conflict and disasters -- suffer at disproportionately higher rates of depression, suicide and substance abuse than the general population.

The research team found that among non-cannabis users, PTSD was “significantly associated” with a major recent depressive episode and suicidal thoughts.

More specifically, PTSD sufferers who didn’t use pot were seven times more likely to have a depressive episode and nearly five times more likely to have suicidal thoughts compared to non-cannabis users without PTSD.

“Among the cannabis-non-using population, there was a strong association between having PTSD and experiencing these indicators of severe mental distress,” lead author Stephanie Lake said during a phone interview with, adding that pot users didn’t see this same association.

Her research was the first to track the relationship between PTSD, cannabis use and “severe mental health outcomes” among the average Canadian population, according to a university press release.

Lake, a research assistant at the British Columbia Centre on Substance Use, said this was the first study examining how PTSD’s connection to suicidal thoughts or severe depression “could be interrupted by the use of cannabis.”

Her study also found one in four Canadians with PTSD said they used cannabis -- which is “remarkably high” compared to the prevalence of pot use among the general Canadian population (which is an estimated 11.4 per cent).


Lake stressed her study didn’t outright show a definitive, causal link between cannabis use and decreased PTSD symptoms.

The PhD candidate at UBC’s School of Population and Public Health said the study “didn’t tell us whether people are successfully using cannabis to treat PTSD … but it is a promising signal that there might be a therapeutic (benefit) to cannabis use.”

Of the 24,089 respondents to the 2012 Canadian Community Health Survey – Mental Health, 420 people had a clinical diagnosis of PTSD.

From those with PTSD, 106 of them -- 28 per cent -- said they used cannabis. This rate is nearly three times the rate of pot users without PTSD (11.2 per cent).

Lake’s overall findings could be extremely helpful to many Canadians, as the study mentions that 9.2 per cent of Canadians have PTSD -- one of the highest prevalence rates for the disorder in the world.


Lake explained that cannabinoid receptors in people’s bodies help regulate mood and sleep, and some research suggests that trauma from PTSD could compromise this endocannabinoid system.

“So when you introduce external cannabinoids (from pot products) to the body, it might help to get the system working as normal again,” she suggested.

Lake also noted that, according to the study, PTSD patients did have cannabis-use disorders at a higher rate than the general population.

In a press release, senior author Dr. M-J Milloy, BCCSU research scientist and Canopy Growth Professor of Cannabis Science at UBC, said that “we’re only just beginning to understand what the therapeutic potential of cannabis may be for a variety of health conditions.”

“These findings are promising, and merit further study in order to fully understand the benefits of cannabis for people living with PTSD,” he added.

Lake added that UCB researchers are currently conducting a clinical trial looking at the effectiveness of cannabis products in specifically treating PTSD.