Researchers from the University of Montreal have found that cannabis consumption among teenagers can cause long-term damage to their developing brains. The new study, which was published in the American Journal of Psychiatry, suggests that teenage cannabis use has a worse impact on memory, behavior, and thinking skills than teenage drinking.
The researchers are therefore urging teens to delay their use of marijuana for as long as they are able.
The Canadian study tracked and tested around 3,800 adolescents as young as 13 years old over a period of four years. Once a year, these teenagers, who were from 31 different schools in the country, provided details of their drinking and drug habits.
The researchers also tested the teens’ brain skills every year in school with the use of computer-based cognitive tests.
Taking drugs, including pot, and drinking alcohol at a young age is already known to lead to problems with a young user’s learning, decision-making, and attention, as well as their academic performance at school.
The study found that these problems increased as cannabis consumption also increased. What’s more, the effects were lasting, unlike the effects brought by alcohol.
Although the levels of marijuana use in the study were low compared with alcohol use, 28 percent of teens still admitted to using pot. This compared with 75 percent who admitted that they drank alcohol at least occasionally.
According to lead author Professor Patricia K. Conrod, she had expected alcohol to have more negative impact on the teenage subjects’ brains. However, it turned out that cannabis affected the brain worse than alcohol.
The researchers found that there were greater increases in errors in the cognitive tests conducted on those who use cannabis, both while they were taking the drug and after they had stopped taking it. The effects were detected in their reasoning, working memory, and ability to control their behavior.