Longtime, chronic marijuana use causes significant abnormalities in brain function and structure – and perhaps lower IQ – according to a major new study conducted in part at the Mind Research Network on the campus of the University of New Mexico.
Chronic users tend to have a smaller volume of gray matter in a part of the brain associated with decision making and addiction and a marked increase in a function called brain connectivity, which researchers said may be an attempt by the brain to make up for the decreased gray matter volume.
The study – the first of its kind and the most significant to date – was published Tuesday in the Proceedings of the National Academy of Sciences. It was funded by the National Institute of Drug Abuse and comes at a time some policymakers in Albuquerque and elsewhere are pushing to legalize marijuana use.
Using three different MRI techniques to analyze the subjects, Dr. Vince Calhoun, a distinguished research professor of electrical and computer engineering at UNM, worked closely with colleagues from the Center for BrainHealth at the University of Texas at Dallas.