Study of over 11,000 teenagers/ Cannabis use linked to slow brain development

2026-04-22 22:43:00, Kuriozitete CNA

A large, long-term study conducted in the United States, involving more than 11,000 adolescents, has found a significant link between cannabis use and slower cognitive development. According to researchers, young people who use cannabis tend to improve more slowly in areas such as memory, attention and thinking compared to their peers.

The study was based on data from a large research project that followed the brain development of young people from the ages of 9–10 to 16–17. Each year, participants underwent various biological tests, including hair, urine, breath, and saliva analyses, and completed questionnaires on substance use.

According to the results, adolescents who used cannabis often performed equally or even better at the start of the study. However, after starting to use cannabis, the pace of their cognitive development slowed significantly, falling behind those who did not use the substance.

The researchers analyzed a wide range of mental abilities, including immediate and delayed memory, information processing speed, impulse control, visual-spatial skills, language, and working memory. In almost all of these areas, cannabis users showed slower improvement.

An important element of the study was the difference between the components of cannabis. It was observed that adolescents exposed to THC (tetrahydrocannabinol), the main psychoactive component of cannabis, had more pronounced problems, especially in memory. Meanwhile, a small group that used only products with CBD (cannabidiol), mainly for medical reasons, did not show the same level of negative impact.

However, the authors emphasize that the study shows an association and not necessarily direct causation. They took into account other factors that can affect brain development, such as family situation, mental health, and other substance use, to ensure the most accurate results.

Experts warn that although the observed changes are relatively small, they could have important consequences in real life, especially in a competitive environment like school. These changes could affect test scores, educational advancement and even practical skills like driving.

At a time when cannabis is becoming increasingly available and the perception of risk is declining, researchers emphasize the importance of awareness. They recommend that adolescents avoid or delay cannabis use, as the brain at this stage is still developing and more sensitive to external influences.

According to them, although the social and personal pressures that push young people towards substance use do not easily disappear, understanding the long-term risks can help them make more informed decisions about their health and future./ CNA