Youth Marijuana Consumption Not Linked to Adult Brain Structure

Since the legalization of marijuana, countless studies have been conducted to locate the true potential and risk that come with using cannabis. According to a new study published earlier this month in the journal Drug and Alcohol Dependence shakes up previous clinical trials that once spread concern about youth cannabis use and brain development.

The team of experts at Arizona State University studied the use of cannabis among 200 boys in Pittsburgh in the late 1980s, then correlated those in take rates to high-resolution MRI brain scans of the same men 20 years later, when they turned 30.

“We found no differences in adult brain structure” within the boys who reported heavy cannabis use during there teen and young adult years, those who reported occasional use and those who reported never using marijuana, wrote the team.

They added, “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.”

As of now, the science around adolescent marijuana use and the way the brain reacts during development appears to be very politically charged and barley unresolved. The new study conducted by ASU now sheds a unique perspective of reality when it comes to the ever-growing issue. However, many find it unlikely that this data will debunk the myth of concerns.

The research team was directed by Madeline Meier, director of ASU’s Substance use, Health and Behavior Lab. The team announced that their findings were somewhat small and very limited. They acknowledged the difficulties they faced with young men in Pittsburgh who had conduct problems as youth and relies on self-reported cannabis use. Another complex issue within the study was the MRI imaging scans only took place once per subject when they were in their 30s.

“Importantly, several [previous] case-controlled studies have found brain structure differences in adolescent or young adult cannabis users with cumulative levels of cannabis exposure,” Meier and colleagues addressed. “It was unclear from those studies if brain structure differences among [those subjects] persisted into later adulthood. Our study suggests they might not.” The brain structure difference may appear in an early onset cannabis user’s ’20s, however diffuse and clear up by their 30s.

In previous studies, experts have used other measures (gray matter shape and density, white matter integrity) to study structural brain abnormalities between youth cannabis users and non-users. Miere confirmed that her teams MRI data may not be the most accurate when it comes to measuring cannabis-correlated brain dysmorphia.

According to the context of the study, the authors, “found no association between prospectively-assessed adolescent cannabis use and subcortical brain volume and cortical brain volume and thickness in adulthood.”

“Reviews of these studies have revealed that, although a few studies have found evidence of an association between an earlier age-of-onset of cannabis use and adult brain structure, most studies have not,” the team concluded.