A large, long-term study finds that teenagers who start using cannabis tend to show slower improvement in cognitive abilities compared to their non-using peers, particularly in memory. These findings underscore concerns about how cannabis, especially THC, may impact the developing adolescent brain.
- Memory, attention, and processing speed growth slows after cannabis use starts.
- THC exposure linked to greatest memory declines among teen users.
- Study tracked cognitive development in 11,000+ youths over several years.
What happened
Researchers at the University of California San Diego analyzed data from the Adolescent Brain Cognitive Development (ABCD) Study, the largest effort tracking brain changes in young people. More than 11,000 children were followed from ages 9 to 10 through ages 16 and 17. The study combined self-reports with biological tests to confirm cannabis use.
They found that while cognitive skills like memory, attention, language, and processing speed normally improve during adolescence, teens who used cannabis showed slower gains over time. Initially, some cannabis users performed as well or better than their peers, but this advantage faded as their cognitive development plateaued.
Why it feels good
Understanding these effects can empower families and teens to make informed choices about cannabis use during this critical brain development period. The study highlights THC, the main psychoactive ingredient in cannabis, as most likely responsible for the observed declines in memory performance.
Since the adolescent brain rapidly matures, even subtle decreases in cognitive growth can influence academic performance and daily functioning. These findings provide valuable insight into how cannabis use might affect essential thinking skills, helping to clarify potential risks.
What to enjoy or watch next
The research team plans to continue following participants as they graduate into young adulthood to better determine long-term effects and how age and frequency of cannabis use shape brain outcomes. This ongoing work could help tailor guidance on delaying cannabis use for healthier brain development.
Families and educators can stay informed on emerging findings to support youth in making decisions that protect their cognitive health. Meanwhile, awareness of the complex cannabis products and varying impacts of compounds like THC and CBD will remain important as usage patterns evolve.