EVIDENCE GROWS THAT HEAVY MARIJUANA USE MAY HARM THE BRAIN
New research published by scientists at the Center for BrainHealth at The University of Texas at Dallas in the Proceedings of The National Academy of Sciences (PNAS) and funded by the National Institute on Drug Abuse (NIDA), USA shows that heavy marijuana use (at least four times per week over he past six months) is linked to adverse changes in the function and structure of brain areas associated with reward, decision making and motivation.
Researchers for the first time comprehensively describe existing abnormalities in brain function and structure of long-term marijuana users with multiple magnetic resonance imaging (MRI) techniques.
Findings show chronic marijuana users have smaller brain volume in the orbitofrontal cortex, a part of the brain commonly associated with addiction but also increased brain connectivity. Heavy marijuana use can also enhance some brain circuits possibly to compensate for reduced function in specific brain regions.
This effect was more pronounced in those who started using marijuana at a young age indicating that developing brains are particularly vulnerable to marijuana’s effects.
Although further long-term studies are needed to determine whether marijuana caused these effects, these scientific findings add to the growing literature showing that heavy marijuana use may harm the brain particularly since “We have seen a steady increase in the incidence of marijuana use since 2007,” said Dr. Francesca Filbey, Associate Professor in the School of Behavioral and Brain Sciences at the University of Texas at Dallas and Director of the Cognitive Neuroscience research in Addictive Disorders at the Center for BrainHealth.
Article Source
1. Filbey FM et al. Long-term effects of marijuana use on the brain. PNAS 2015; 111(47): 16913-16918.
2. National Institute on Drug Abuse and press release by authors http://www.brainhealth.utdallas.edu/blog_page/study-shows-marijuanas-long-term-effects-on-the-brain