Long-term cannabis use could be elevating stress and anxiety levels in young adults, according to a new study by Toronto’s Centre for Addiction and Mental Health.
The study’s lead author, Dr. Romina Mizrahi, said the perception is so widespread that cannabis helps users cope with anxiety and stress that her team expected to see that in its results.
Instead, “this is exactly the opposite of what we were hypothesizing,” said Mizrahi, the senior scientist at CAMH’s Campbell Family Mental Health Research Institute.
The study was published in the psychiatric journal JAMA Wednesday, and was funded by the National Institute of Mental Health in the U.S.
Rather than finding that a brain protein linked to stress and anxiety decreased in people who had used cannabis regularly over a year, researchers found inflammation of that protein went up in study participants.
The protein is significant because it’s one of the indicators of depression, stress and anxiety. When tested, the study participants had increased levels of the protein, Mizrahi said.
The CAMH team tested 24 people in their 20s who used cannabis at least four times a week and had been doing so for a year.
Participants told the researchers “they like to feel high but they also feel that it helps them with their experiences,” though none of them were clinically depressed or diagnosed with anxiety disorders, Mizrahi said.
The study measured the 18-kDa translocator protein, referred to as TSPO, through imaging and blood tests to assess what happened when someone used cannabis.
Cannabis use creates ‘vicious cycle,’ psychiatrist believes
Dr. Clive Chamberlain, staff psychiatrist at CAMH and Toronto’s Hospital for Sick Children, has a caseload of 50 patients aged 14 to 24. Many of them are daily cannabis users who are “self medicating,” he said.
“They’ve discovered at least in the moment when they’re smoking marijuana, it relieves them of some anxiety or low mood,” he said.
He believed it’s creating a “vicious cycle,” because they don’t notice that it “lowers their threshold for anxiety so they gradually become more and more anxious.”
At this time of year, annually, he said he treats students who have to leave university studies because of heightened anxiety and he often finds they’re also daily cannabis users.
His evidence is exclusively observational, working as a psychiatrist for the last 50 years.