Smoking cannabis could damage the lining of smokers’ brains, research suggests amid fears over drug use among teenagers

Teenagers who smoke cannabis may be damaging the lining of their brain, research shows.

Canadian researchers found that those who had smoked cannabis before the age of 16 had a thinner cerebral cortex (the outermost layer of the brain) than those who had not.

Experts say the findings are worrying because the cerebral cortex is a crucial part of the brain, responsible for cognition, memory and reasoning.

The scientists behind the research maintain that THC (or tetrahydrocannabinol, the psychoactive substance in cannabis) could be reducing this section of the brain.

The findings come amid increased scrutiny over the dangers of smoking cannabis. Almost one in ten people in the UK say they have used the drug in the last year. Among young people aged 16 to 24, this figure increases to 15 percent.

Earlier this month, doctors in the US, where cannabis use has been legalized in 24 states, said they had seen an increase in debilitating side effects related to chronic use of the drug.

This includes a growing number of cases of “scromiting,” a phenomenon in which sufferers scream and vomit.

Previous studies have also linked cannabis use in adolescents with an increased risk of developing serious psychotic disorders later in life.

A 2007 study found that adolescents who had smoked marijuana at least five times were twice as likely to develop psychosis within ten years as those who had never tried the drug.

The latest research on the effect of cannabis on the brain was conducted by scientists at the Faculty of Medicine at the University of Montreal.

Dr. Tomas Paus, a psychologist and co-author of the study, said it was possible that cannabis use “made it more difficult for the brain to learn new things, interact with people and cope with new situations.”

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