Amid growing concerns about drug misuse among teenagers, research suggests that smoking cannabis may damage the protective lining of the brain.

Canadian researchers found that individuals who had smoked cannabis before the age of 16 had a thinner cerebral cortex—the brain's outermost layer—compared to those who had not. The cerebral cortex is critical for cognition, memory, and reasoning, making these findings particularly alarming, experts say.

The scientists behind the study argue that tetrahydrocannabinol (THC), the psychoactive component in cannabis, could be causing the cerebral cortex to shrink.

This research emerges amid heightened scrutiny over the dangers of cannabis use, with nearly one in ten people in the UK reporting they have used the drug in the past year. Among those aged 16 to 24, this figure increases to 15 per cent.

Earlier this month, US medics reported a surge in serious side-effects related to chronic cannabis use, where the drug has been legalised in 24 states. One such effect is 'scromiting,' a distressing condition involving simultaneous screaming and vomiting.

Previous studies have linked adolescent cannabis use to a higher risk of developing severe psychotic disorders later in life. A 2007 study found that teens who had smoked cannabis at least five times were twice as likely to develop psychosis over the next decade compared to non-users.

The latest research, conducted at the Université de Montréal Faculty of Medicine, further explores cannabis's impact on the brain. Dr Tomas Paus, a psychologist and co-author of the study, warned that cannabis use might impair the brain's ability to learn, interact with others, and handle new experiences.

“In other words,” Dr Paus explained, “it makes the brain more vulnerable to everything that can happen in a young person’s life.”