Study: Heavy Marijuana Use May Shrink Part of Brain Controlling Muscle, Senses
A recently released study has shown that there is a connection between marijuana usage and the volume of gray matter a person may have.
Published Monday in the Proceedings of the National Academy of Sciences, the study was overseen by researchers from the Center for BrainHealth at the University of Texas, The Mind Research Network of Albuquerque, New Mexico, the University of New Mexico, and Advance MRI, LLC of Frisco, Texas.
"…we measured gray matter (GM) volume via structural MRI across the whole brain by using voxel-based morphology, synchrony among abnormal GM regions during resting state via functional connectivity MRI, and white matter integrity (i.e., structural connectivity) between the abnormal GM regions via diffusion tensor imaging in 48 marijuana users and 62 age- and sex-matched nonusing controls," read the abstract.
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"The results showed that compared with controls, marijuana users had significantly less bilateral orbitofrontal gyri volume, higher functional connectivity in the orbitofrontal cortex (OFC) network, and higher structural connectivity in tracts that innervate the OFC (forceps minor) as measured by fractional anisotropy (FA)."
"We have seen a steady increase in the incidence of marijuana use since 2007," said Dr. Francesca Filbey, lead researcher for the study, according to the Center for Brain Health.
"However, research on its long-term effects remains scarce despite the changes in legislation surrounding marijuana and the continuing conversation surrounding this relevant public health topic."
Ben Cort, director of the Center for Dependency, Addiction & Rehabilitation at the University of Colorado Hospital, told The Christian Post that the study showed once again that pot is "not a benign substance."
"We are seeing again and again and again through peer-reviewed longitudinal studies exactly what we've all known," said Cort.
Cort directed CP to another scholarly review published in June by Dr. Nora D. Volkow, National Institute on Drug Abuse, which showed the harms of teenage marijuana usage.
"It is important to alert the public that using marijuana in the teen years brings health, social, and academic risk," stated Volkow regarding the review, published in New England Journal of Medicine.
"Physicians in particular can play a role in conveying to families that early marijuana use can interfere with crucial social and developmental milestones and can impair cognitive development."
The study comes as various states in the country consider or pass legislation meant to allow for the legal use of recreational marijuana.
Last week, voters in the District of Columbia overwhelmingly approved a referendum initiative that allowed for the possession, though not the commercial sale, of marijuana.
Mike Elliott, executive director of the Marijuana Industry Group, said in a statement provided to CP that this is just one of multiple studies that have drawn different conclusions.
"While some studies have shown that marijuana use may negatively affect the teen brain, other studies have shown no effect, and that alcohol is far more damaging to the teen brain than marijuana," said Elliot.
Elliot also stated that while his organization is supportive of legalization, "the industry will continue to work to prevent teen marijuana use."
"Since licensing, regulating, and taxing marijuana businesses, Colorado has seen nearly a 5 percent decrease in teen marijuana use, based on studies conducted by the Center for Disease Control," said Elliot.
"Unlike the drug cartels that prey upon children, the marijuana industry is dedicated to preventing teen marijuana use."
While the Center for BrainHealth study's findings imply a link between marijuana usage and smaller brain matter, some experts have expressed caution regarding correlation and causation.
Dr. Asaf Keller, a professor of anatomy and neurobiology at the University of Maryland School of Medicine, told The Huffington Post on Tuesday that "it is impossible to determine whether individual differences in brain anatomy are related to genetic or environmental factors other than marijuana use."
"In sum, there is not indication that the anatomical differences in the brains of marijuana users are caused by marijuana use," said Keller.
