Canada: PTSD Study Targets Benefits, Risks Of Pot

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A Dalhousie University research team is looking for the story behind the risks and benefits of marijuana for people with post-traumatic stress disorder.

The team led by addictions expert Dr. Sherry Stewart wants to talk to veterans in the Halifax area who either self-administer marijuana or get the drug through medicinal prescriptions.

“They all tell us their own stories and we design their own little scripts and pictures that go along with it,” said Stewart, who runs the Mood, Anxiety, and Addiction Co-morbidity (MAAC) lab at Dal’s Department of Psychology and Neuroscience.

The script approach allows the researchers to document the specifics of what may spark an individual’s craving for a substance, a learned response called cue reactivity.

This process has been studied in alcohol addiction research but not marijuana, Stewart said in a recent interview.

Previous studies have found marijuana use is a double-edged sword for people with PTSD. Links have been found between high rates of stress and marijuana dependence, but on the other hand, medicinally prescribed pot is used to treat PTSD.

“This study is trying to determine, are there particular ways of using marijuana that are more risky or less risky or more helpful,” Stewart said. “So that might be part of the answer as to why these questions seem to be two polar opposites: One suggesting that people with PTSD shouldn’t use marijuana because it could be very addictive and others saying that it can be helpful.”

The consequences of PTSD for veterans has come into the spotlight after being linked to suicide rates and incidents of violence. About 15 to 17 per cent of veterans have PTSD compared to six to eight per cent in the civilian population.

The study also is timely given recreational cannabis will be decriminalized in Canada in July, Stewart said.

The veterans will be divided into four groups so the researchers can compare their cues, cravings and other results: Those with PTSD who self-administer marijuana, and those who have a medicinal prescription; those who don’t have PTSD who self-administer marijuana, and those who have a prescription.

Stewart surmises that people dealing with traumatic triggers with PTSD who use pot through prescriptions may be less vulnerable to addiction.

“Because when somebody is prescribed pot, typically they’re prescribed it in a more regularly scheduled way. They don’t take it (just when they have a traumatic memory),” she said. “But instead they take it at certain times of day so they shouldn’t have those same kinds of memory associations between … the trauma cue and taking the drug.”

The project is being funded by the Nova Scotia Health Authority. Stewart’s research team includes post-doctoral students Dr. Pablo Romero-Sanchiz and Dr. Mohammed Al-Hamdani.

They are hoping to get 30 people in each of the four categories, which Stewart admits could be difficult, so they may expand the study outside Halifax and/or to cannabis users who aren’t veterans. Those interested in participating can call the MAAC lab at 902-494-3793 or they can email

The study is strictly confidential and has ethics approval from Health Canada. The team will connect participants in need with the appropriate services they may require, Stewart said.