Research involving over 11,000 youths reveals that cannabis use during adolescence may impair memory and thinking skills growth, underscoring the vulnerability of teenage brain development.
Teenagers who begin using cannabis may not build memory and thinking skills as quickly as their non-using peers, according to researchers at the University of California, San Diego. Their study, published in Neuropsychopharmacology and based on data from more than 11,000 participants in the long-running Adolescent Brain Cognitive Development study, suggests that adolescence is a sensitive period in which cannabis use may be linked to slower cognitive growth.
The research followed 11,036 children from ages 9 and 10 into their mid-teens, tracking changes in memory, attention, language and processing speed alongside reports of cannabis and other substance use. To strengthen the exposure data, the team also relied on hair, urine and saliva testing, which could detect use that had happened recently or months earlier. Teens who used cannabis tended to show weaker gains over time, even when some had started out performing as well as, or slightly better than, their peers.
Natasha Wade, the study’s lead author and an assistant professor at UC San Diego School of Medicine, said the pattern suggested that cannabis users were not improving at the same pace as other adolescents. The team also found that evidence of tetrahydrocannabinol, or THC, the main intoxicating compound in cannabis, was associated with greater memory decline over time in a smaller subgroup. No similar pattern was seen with cannabidiol, or CBD, although the researchers said that group was small and some products marketed as CBD can still contain THC.
The findings do not prove cannabis caused the slower development, and the authors said other influences, including family background, mental health and use of other substances, could also play a role. Even so, the results fit with broader public health advice that adolescence is a particularly vulnerable stage for brain development. The Centers for Disease Control and Prevention says the brain continues maturing until about age 25 and that cannabis can affect memory, learning, attention and decision-making. Earlier research has also linked teenage cannabis use with poorer later cognitive performance and has raised concerns that THC can disrupt memory systems.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
