The recent wave of recreational marijuana legalization in several U.S. states has caused a new industry to take roots, however, a recent study shows that, as with tobacco, cannabis use comes with a dear price. A team of researchers from the University of Texas at Dallas has analyzed the effects that long-term cannabis use has. They concluded that regular marijuana smokers had a smaller volume of their orbitofrontal cortex as opposed to subjects who did not smoke cannabis. This key brain region is involved in addiction as well as superior cognitive processes, such as decision-making.
Additionally, scientists observed that long-term marijuana smokers also presented greater connectivity in the same region as opposed to people not using pot. This connectivity, however, seemed to disappear over time in the case of users.
The sooner individuals began using the substance, scientists said, the more pronounced the brain abnormalities were. What researchers still haven’t determined is whether such brain abnormalities cause mental or emotional deficits.
This region represents a key portion of the brain’s reward system, researchers say, adding that motivation, decision-making and adaptive learning all originate in this region. Francesca Filbey, study leader and director of the university’s Center for Brain
“As such, our finding that chronic marijuana users had smaller brain volume in the orbital frontal cortex, might manifest behaviorally making it difficult for them to change learned behavior.”
Dr. Filbey said.
The research team used MRI scanners to compare the brains of 48 adults who had been long-time marijuana smokers (three times a day, for 10 years) to those of 62 non-smokers.
There are, however, limitations to this study. The findings, are indeed provocative but not conclusive enough to prove that marijuana use represents the cause of the mentioned changed in the brain.
“As this is a retrospective study—and not a prospective one—it is impossible to determine whether individual differences in brain anatomy are related to genetic or environmental factors other than marijuana use,”
Dr. Asaf Keller, professor of anatomy and neurobiology at the University of Maryland School of Medicine said.
He explains that a prospective study would also be required to observe how the substance alters the brains of users.