Cannabis linked to depression, suicidal behaviour in teens: McGill Study
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Parents should not be complacent about the risks of teenagers using cannabis, experts are warning. UK and Canada researchers said they had found “robust” evidence showing using the drug in adolescence increased the risk of developing depression in adulthood by 37%.
They said the findings should act as a warning to families who saw cannabis use as part of the growing-up process. The team added that the developing brain was particularly susceptible.
The researchers – from University of Oxford and Montreal’s McGill University – said cannabis use in the young was an “important public health issue”, particularly given that cannabis available today tends to be much stronger than it was previously.
Key Findings:
Question Is adolescent cannabis consumption associated with risk of depression, anxiety, and suicidality in young adulthood?
Findings In this systematic review and meta-analysis of 11 studies and 23 317 individuals, adolescent cannabis consumption was associated with increased risk of developing depression and suicidal behavior later in life, even in the absence of a premorbid condition. There was no association with anxiety.
Meaning Preadolescents and adolescents should avoid using cannabis as use is associated with a significant increased risk of developing depression or suicidality in young adulthood; these findings should inform public health policy and governments to apply preventive strategies to reduce the use of cannabis among youth.
Report author Prof Andrea Cipriani conceded some parents had a relaxed attitude to the drug, but added the evidence was clear.
“This is important information for parents and teenagers. The risk is modest, but it can have a devastating impact.”
This is the first time the actual risk has been quantified in this way. The team looked at 11 previous studies, covering more than 23,000 young people, the journal JAMA Psychiatry reported.
Young people who had already shown signs of depression or had a family history of the condition were excluded. It found cannabis use before 18 increased the chance of an individual developing depression in young adulthood – defined as before the age of 35 – by 37%. In terms of numbers that means around one in 14 cases of depression in that age group – around 60,000 in the UK – could be attributed to drug use in the teenage years
Although the researchers were unable to prove cannabis use was definitively causing depression, they could only say it looked to be a strong link.
This is because of the figures they found, but also what is known about the impact cannabis has on the developing brain. Evidence has suggested that the drug affects the parts of brain that govern rational and emotional thinking as well as serotonin levels that influence mood. To prove the link, trials would have to be conducted on young people – something that will never be done because it is unethical.
