Teen cannabis use linked to slower memory and thinking growth

A University of California San Diego study reveals that teenagers who begin using cannabis may experience slower growth in memory and cognitive abilities compared to their non-using peers. This conclusion was drawn from an analysis of over 11,000 participants in the Adolescent Brain Cognitive Development (ABCD) Study, a large-scale investigation into brain development among young people in the United States.

Dr. Natasha Wade, lead author of the study and assistant professor in the Department of Psychiatry at UC San Diego School of Medicine, highlighted that while the differences in cognitive performance may appear minor initially, they could accumulate and impact learning, memory, and daily functioning over time. The researchers followed the participants from ages 9 to 10 through adolescence, monitoring their cognitive performance as well as their cannabis and other substance use.

Cannabis exposure was measured through both self-reported data and biological tests, including hair, urine, and saliva samples. The study found that teenagers who used cannabis exhibited slower improvements in various cognitive areas, such as memory, attention, language, and processing speed. Notably, those with evidence of tetrahydrocannabinol (THC) exposure, the primary psychoactive compound in cannabis, showed greater declines in memory performance compared to those who did not use cannabis.

Although the researchers adjusted their analysis for various factors that could influence cognitive differences, they concluded that THC might be a key driver of the observed changes. The findings emphasize the importance of delaying cannabis use to support healthy brain development, particularly given the significant role the brain undergoes during adolescence.

The research team intends to continue tracking the participants as they transition into young adulthood, which may provide further insight into the long-term effects of cannabis use.