Canadian study links teenage pot use to increased risk of suicidal behaviour

Scientists at McGill University found a higher rate of diagnosed depression in young cannabis users

A new study suggests teens who regularly smoke weed are at greater risk of developing depression and suicidal behaviour in young adulthood.

Scientists at McGill University analyzed 11 international longitudinal studies involving people aged 18 to 32 who smoked weekly or daily when they were 18 or younger.

They found a higher rate of diagnosed depression, suicide ideation and suicide attempts compared to those who didn’t use cannabis in their teens.

Lead author Gabriella Gobbi says the increased individual risk is modest, but the popularity of pot means a large number of young people could be at risk of developing mental-health issues.

Researchers estimate seven per cent of Canadians between the ages of 18 and 30 are diagnosed with depression that could be linked to prior cannabis use, or roughly 25,000 young people. Researchers found even stronger links to suicidal ideation and suicide attempt, but weaker links to anxiety.

The study consisted of a systematic review and meta-analysis of studies comprising 23,317 individuals. It was done in collaboration with Oxford University and Rutgers University-Camden and published Wednesday in the journal JAMA Psychiatry.

Gobbi says the findings highlight the need for better education on the risks of marijuana.

“We have to do more prevention, to decrease the amount of young people and adolescents that smoke cannabis,” the McGill psychiatry professor says from Montreal, urging education for teens and parents.

Most provincial laws restrict usage to those 19 and older, but about 27 per cent of Canadians aged 15 to 24 — more than any other age group — used cannabis in the last three months of 2018, according to Statistics Canada.

“Since we had legalization, young people continue to smoke as before,” says Gobbi. “So legalization is not the only response. We need to do more prevention.”

Gobbi says the studies included were adjusted for any subjects that may have displayed signs of depression or suicidal tendencies before using pot.

She says adolescents are particularly vulnerable because their brain does not fully develop until age 25.

The findings also dispel misconceptions that weekly pot use is harmless, she adds, noting that scientists found it impossible to differentiate degree of risk between weekly use and daily use.

She explains that the psychoactive property in cannabis — tetrahydrocannabinol, or THC — remains in the body “for a long, long time.”

“THC is a lipid so it stays in the brain and in the body for one week or even more — in some individuals until one month. So smoking a joint is not like drinking two or three beers on a Saturday night,” says Gobbi, also a researcher in the Brain Repair and Integrative Neuroscience program at the Research Institute of the McGill University Health Centre.

Gobbi says there are many more questions to explore, noting the research did not consider alternate modes of consuming cannabis such as vaping or edibles.

She also notes the subjects were teens during the 1980s, 1990s, and 2000s, when the amount of THC content was generally relatively low.

“Now we have joints that have 10, 20, 30 per cent, even more content of THC so we don’t know the impact of the cannabis that we have today on mental health. This is something that of course we have to study more.”

The research was funded by the Canadian Institutes of Health Research and the Quebec Network on Suicide, Mood Disorders and Related Disorders.

If you or anyone you know needs support for depression or suicide-related mental health problems, call the Canadian Assistance in Suicide Prevention 24/7 hotline at 1-888-353-2273.

Cassandra Szklarski, The Canadian Press

Like us on Facebook and follow us on Twitter.

Just Posted

South Slocan woman killed in Friday crash

Police continue to investigate cause of fatal crash

What’s Up: Things to see and do on Family Day

There’s plenty of fun to be had across the West Kootenay this coming long weekend!

Province announces $23 million for upgrades at Kootenay Boundary Regional Hospital

West Kootenay-Boundary Regional Hospital District Board has yet to review the provincial proposal

Call a foul on cancer with the Pink Whistle Campaign

Local basketball referees are raising money for cancer research

UPDATE: Two-car accident closes Highway 3A at Thrums

Road expected to open for single-lane alternating traffic at 2 p.m.

‘Our entire municipality is heartbroken’: Seven children die in Halifax house fire

A man and woman remained in hospital Tuesday afternoon, the man with life-threatening injuries

B.C. man survives heart attack thanks to Facebook

A Princeton man suffered a heart attack while at an isolated property with no cell service

B.C. man sues Maxime Bernier’s People’s Party over trademark

Satinder Dhillon filed application for trademark same day Maxime Bernier announced the new party

New trial ordered over banning whales, dolphins at Vancouver aquarium

Park board’s appeal reverses previous decision that found it had no right to implement a ban

Make sure measles shots up to date, Public Health Agency says

Measles causes high fever, coughing, sneezing and a widespread painful rash

Minister says plans to fight poverty, climate change, focus of B.C. budget

The NDP said in its throne speech last week that affordability will be the hallmark of its initiatives

Bomb threats, gunfire, kidnapping: Drug war rocks Kamloops

Kamloops RCMP battles a series of violent events

B.C. hotel trashes Channing Tatum in favour of Ryan Reynolds

Tatum’s picture left in recycling bin, replaced with photo of Ryan Reynolds

B.C. firefighters rescue bear cub stuck up a tree

Family Day was eventful for cub, firefighters

Most Read