Teenagers who use marijuana are 37 percent more likely than their peers to develop depression later in life, according to a new study carried out jointly by Canadian and British researchers.
As BBC News reports, researchers from the University of Oxford and Montreal’s McGill University reviewed 11 previous studies of teenagers in the two countries who admitted to using cannabis — 23,000 cases — and drew their conclusions based on their review.
Excluding teens who had already been diagnosed with depression, or those who had a family history of depression, the study found that 37 percent of the teenagers who used pot would be diagnosed with depression by age 35. In raw numbers, that means that — in the United Kingdom at least — one out of every 14 cases of depression in adults could, in theory, be attributed to pot use as a teen.
Further, the study found a slight but statistically insignificant correlation between pot use as a teen and anxiety and suicide attempts as an adult. Specifically, those who used cannabis as teens were considered three times more likely to attempt suicide as adults. Researchers caution that the data is incomplete on that point, and that more research is needed.
Researcher Andrea Cipriani, the report’s lead author, said that the findings should be a wake-up call to British and Canadian parents who think pot use is no big deal, and just a part of the adolescent experience.
“This is important information for parents and teenagers. The risk is modest, but it can have a devastating impact.”
@JustinTrudeau @CDNMinHealth #marijuana This is the reason Canada's physicians wanted a 25 year age minimum for recreational marijuana use. Please reconsider: Teens who use cannabis at a higher risk of developing depression, suicidal behaviour: https://t.co/kxIsaqSp8X
— Dr Chris Leighton (@ccleighton) February 13, 2019
The impact of marijuana use on adolescents is not fully understood in the pediatric community, largely because of cannabis’ status as a Schedule I drug in the United States. That means that it is considered to have “no medical benefit,” and there has been little federally-funded research on the topic.
Still, the consensus among pediatricians and health officials has been that cannabis is definitely not good for the developing adolescent brain, although the specific risks remain elusive.
As Scientific American noted in 2017, however, what little studies that have been done on the adolescent brain while on pot are not encouraging. The drug is believed to have long-term effects in the areas of memory when teens use it. Similarly, in adults, THC — the psychoactive component in marijuana — affects appetite, sleep, emotion, memory, and movement. In teens, those areas of the brain are already going through huge and drastic changes, and the addition of cannabis to the mix is believed to be disruptive and perhaps even permanently damaging.
However, unless and until marijuana is rescheduled — or until the federal government authorizes more money for research — the effects of cannabis on the adolescent brain are not yet fully understood.