Cannabis & # 39; more harmful than alcohol & # 39; for the adolescent brain

A Canadian study suggests that teenagers who use cannabis cause lasting damage to their developing brain.

It appears that the impact on thinking skills, memory and behavior was worse than that of alcohol consumption among adolescents.

Researchers at the Université de Montréal urged teens to postpone their cannabis use for as long as they could.

The study followed and tested 3,800 adolescents over a four-year period, starting about 13 years old.

Drinking alcohol and taking drugs, such as cannabis, from an early age is known to cause problems with cognitive abilities such as learning, attention and decision-making, as well as school performance at school.

This study found that these problems increased as cannabis use increased – and the effects were lasting, unlike those of alcohol.

• What are the health risks of cannabis use?

Adolescents from 31 different Canadian schools gave details of their drug and alcohol use patterns once a year.

Their brain skills were also tested each year at school with the help of computer-based cognitive tests.

Develop brains

Although cannabis use levels in the study were low relative to alcohol consumption, 28% of adolescents admitted to some form of consumption.

This compared to 75% of teens who reported drinking alcohol at least occasionally.

Professor Patricia J Conrod, senior author of the study, from the Department of Psychiatry of Montreal, said she expected alcohol to have more impact on the brain of teenagers.

But instead, research has found a greater increase in errors in cognitive testing among adolescent cannabis users – while they were taking the drug and after stopping it.

These effects have been observed in working memory, reasoning and their ability to control their behavior.

"Their brains are still developing, but cannabis interferes with that," said Professor Conrod, to teenagers.

"They should delay their cannabis use as long as they can."

She also said the results underscore the importance of substance abuse prevention programs.

Cannabis is considered the most widely used illicit drug in the United Kingdom.

It can be addictive and its use increases the risk of developing psychotic diseases, especially in adolescents.

Quitting cannabis can lead to withdrawal symptoms, such as sleep problems and mood swings, according to experts.

The study is published in the American Journal of Psychiatry.