Study Finds Adolescent Cannabis Use To Have No Effect On Adult Brain Structure

Concerns regarding cannabis use on brain development in adolescents have dampened legalization hopes for quite some time now. Like many other substances with psychoactive properties, cannabis is thought to have negative effects on the brain structure of adults who frequently smoked in their youth. However, based on new research, this may not be the case.

Leading the research are investigators from Arizona State University and the University of Pittsburgh who assessed the impact of adolescent cannabis use on structural brain differences in adulthood. The director of ASU’s Substance Use, Health and Behavior Lab, Madeline Mier, led the investigation to test and analyze cannabis’ effects on structural alterations in the brains of boys aged 13-19.

First examined in the 1980s, researchers tracked the use of about 200 boys in Pittsburgh and compared those rates to MRI scans of the same subjects 20 years later. According to the soon-to-be-published data, which will appear in the Drug and Alcohol Dependance journal, the use of cannabis during youth showed no association with changes in brain structure in adults. 

“Adolescent cannabis use is not associated with structural brain differences in adulthood,” the study highlighted. “Even boys with the highest level of cannabis exposure in adolescence showed subcortical brain volumes and cortical brain volumes and thickness in adulthood that were similar to boys with almost no exposure to cannabis throughout adolescence,” Mier explained. 

While the data is interesting, due to the small sample size and questionable effectivity of MRI scans, it’s unlikely the results will change the majority of minds. NORML advisory board member, Mitch Earleywine, noted the most significant aspect of the study is that it proves cannabis’ influences to be far from permanent. “These data replicate previous work to reveal that even some of the most frequent users of cannabis do not show changes later in brain structure,” he stated in a blog.

“The measures are very sensitive and the researchers looked throughout the brain very thoroughly,” he added. “Let’s hope that these findings mitigate some of the alarmist cries that have too often persisted and dominated this narrative.”