The Trump administration recently moved to reclassify some cannabis products as less dangerous. But research points to a growing concern around how cannabis affects the developing teenage brain in ways that may have dangerous, long-term ramifications.
More regulation to lower barriers to researching cannabis for potential medicinal use could come soon—including further investigating how marijuana products might affect teens. What scientists know so far about the effects of cannabis on the teenage brain includes work by Dr. Albaugh reported in June 2021 in JAMA Psychiatry suggesting that when teens use cannabis, it is associated with increased thinning of the cerebral cortex, the outermost layer of the brain, compared with those who don’t use it or use it less.
As we age, our brain undergoes natural cortical thinning, which results in a reduction in gray matter, says Albaugh, lead author of the study. The brain changes seen in young people who used cannabis resembled those normally associated with aging. “The more [cannabis] use that these youths were reporting, the faster thinning was occurring in certain prefrontal areas,” Albaugh says. This may be driven by synaptic pruning, or the brain’s elimination of unused neural connections, which is thought to accelerate cortical thinning, he says.
Other studies have shown that if a teenager is already prone to depression and anxiety, and marijuana becomes a temporary solution to the problem, it can cause dependency at a time when that young person should be developing healthy coping mechanisms. Teens end up creating a cycle in which they’re using marijuana to treat mental health issues—and this only exacerbates the problems they’re trying to address.