Study Shows Marijuana’s Long-term Effects on the Brain

Researchers from the Center for BrainHealth at the University of Texas at Dallas published a paper in the journal Proceedings of the National Academy of Sciences revealing the long-term effects of marijuana use through comprehensive MRI techniques. The study compared the brain structures and cognition of 48 adult marijuana users, consuming the drug an average of three times a day against a control group of 68 non-users. Marijuana users were found to have smaller brain volume in the orbitofrontal cortex, a section of the brain involved in decision-making which has been linked to addiction in previous studies. However, marijuana users also displayed elevated levels of connectivity despite the loss of gray matter, particularly in individuals who had very recently began using the drug. This was speculated as the brain naturally adapting to the physical damage caused by drug usage, as long-term users appeared fully functional despite reduced orbitofrontal structures. “The results suggest increases in connectivity, both structural and functional that may be compensating for gray matter losses. Eventually, however, the structural connectivity or ‘wiring’ of the brain starts degrading with prolonged marijuana use,” explained the lead researcher. Further research is needed to confirm that these physical changes in the brain are directly linked to marijuana use, as well as if ceasing usage of the drug would allow the brain to regain the reduced gray matter. To learn more about this study, click here.