Khaberni - A long-term study involving more than 11,000 children and adolescents showed that recreational cannabis use is linked to a slight slowdown in memory, attention, and thinking skills development.
This supports public health recommendations that advise adolescents to avoid using cannabis, due to its potential impact on the brain during developmental stages.
The study, which is the largest of its kind in the United States, was based on data from the Adolescent Brain Cognitive Development study, which followed more than 11,000 participants aged between 9 or 10 years to 16 or 17 years.
Over the follow-up period, participants underwent annual biological tests including blood, urine, breath, and saliva, alongside questionnaires about their use of cannabis and other substances. Most of the use was recreational, with a small percentage using cannabidiol (CBD) for medical purposes under medical supervision or parental consent.
Researchers assessed the cognitive development of participants through tests measuring memory, processing speed, attention, language, visual-spatial abilities, and behavioral control.
The results showed that adolescents who began using cannabis recorded a slowdown in the development of these skills compared to their peers. It was noted that they were performing similarly or better before starting use, but their progress rates slowed down thereafter.
Although the study does not prove a direct causal relationship, it took into account multiple factors such as family background, mental health, and the use of other substances, which reinforces the strength of the results.
Analyses showed that the effect was more pronounced among adolescents exposed to tetrahydrocannabinol (THC), the main psychoactive component of cannabis, while similar effects were not clearly observed in those who only used cannabidiol (CBD).
The lead researcher, Natasha Weed, states that "adolescence is a sensitive stage for brain development, and adolescents who begin using cannabis do not achieve the same cognitive development pace as their peers."
She adds that these differences may seem minor initially, but they could accumulate over time to affect learning, memory, and everyday performance.
Researchers also observed that even slight differences in cognitive abilities could reflect on academic achievement and standardized tests, potentially affecting higher education opportunities and extending to life skills such as driving.
Researchers emphasize the importance of family and adolescent awareness of the potential effects of cannabis during this sensitive life stage.
The study was published in the journal of Neuropsychopharmacology.
