Cannabis could help alleviate depression and suicidality among people with PTSD, new study suggests

published on November 5, 2019

Cannabis may be helping Canadians cope with the effects of post-traumatic stress disorder (PTSD), according to new research from the BC Centre on Substance Use (BCCSU).

In an analysis of data collected by Statistics Canada from more than 24,000 Canadians, researchers from the BCCSU and University of British Columbia (UBC) found that having PTSD was strongly associated with suffering a major depressive episode or suicidal ideation among people who did not use cannabis, but not among the cannabis-using population – suggesting that cannabis could have therapeutic benefits for those with PTSD.

This is the first study to document the relationships between PTSD, cannabis use, and severe mental health outcomes in a representative population sample. The findings were published today in the Journal of Psychopharmacology.

“We know that with limited effective treatment options for PTSD, many patients take to medicating with cannabis to alleviate their symptoms,” says lead author Stephanie Lake, a PhD candidate at UBC and research associate at the BCCSU. “However, until now, there has been no population-level data to suggest that cannabis might have a possible therapeutic role in the course of PTSD. These findings offer those patients seeking treatment options some promise.”

People exposed to trauma, including survivors of acute injury, conflict, violence, and disaster, suffer from depression, suicide, and substance use disorders at much higher rates compared to the general population. Canada is estimated to have one of the highest prevalence rates of PTSD worldwide, affecting an estimated 9.2% of the population.

“We’re only just beginning to understand what the therapeutic potential of cannabis for a variety of health conditions may be,” says senior author Dr. M-J Milloy, research scientist at BCCSU and the Canopy Growth professor of cannabis science at UBC. “These findings are promising, and merit further study in order to fully understand the benefits of cannabis for people living with PTSD.”

Among 24,089 eligible respondents, 420 reported a current clinical diagnosis of PTSD. In total, 106 people with PTSD, or 28.2 per cent, reported past-year cannabis use, compared to 11.2 per cent of those without PTSD. PTSD was significantly associated with recent major depressive episode and suicidal ideation among people who don’t use cannabis. Specifically, cannabis non-users with PTSD were about seven times more likely to have experienced a recent major depressive episode and 4.7 times more likely to have thoughts of suicide compared to cannabis non-users without PTSD, the researchers found.

Among cannabis-using respondents, PTSD was not associated with a recent depressive episode or suicide ideation. Over one-quarter of Canadians with PTSD reported past-year cannabis use, which is remarkably high compared to the prevalence of recent use in the general Canadian population (estimated at 11.4 per cent in the present study). Data was obtained from Statistics Canada’s 2012 Canadian Community Health Survey – Mental Health (CCHS-MH), which covers Canadians aged 15 from all 10 provinces.

Study co-author Zach Walsh, an associate professor with UBC-Okanagan and affiliate researcher with the BCCSU, is currently leading Canada’s first clinical trial to evaluate the therapeutic potential of medical cannabis as treatment for PTSD.

Read the full study here: