Marijuana Doesn’t Alter the Brain
Great news from the world of science: “Daily Marijuana Use Is Not Associated with Brain Morphometric Measures in Adolescents or Adults”. This is the tile of a research carried out by Barbara J. Weiland, Rachel E. Thayer, Brendan E. Depue, AmithrupaSabbineni, Angela D. Bryan, and Kent E. Hutchison, from the Department of Psychology and Neuroscience of the University of Colorado, and the Department of Psychological and Brain Sciences of University of Louisville.
“Recent research has suggested that marijuana use is associated with volumetric and shape differences in subcortical structures, including the nucleus accumbens and amygdala, in a dose-dependent fashion,” point out the scientists, before they explain they decided to replicate the “results in well controlled studies is essential to clarify the effects of marijuana.”
In the paper they published, the group of researches also explains how they did it: “To that end, this retrospective study examined brain morphology in a sample of adult daily marijuana users (n = 29) versus nonusers (n = 29) and a sample of adolescent daily users (n = 50) versus nonusers (n = 50). Groups were matched on a critical confounding variable, alcohol use, to a far greater degree than in previously published studies. We acquired high-resolution MRI scans, and investigated group differences in gray matter using voxel-basedmorphometry, surface-based morphometry, and shape analysis in structures suggested to be associated with marijuana use, as follows: the nucleus accumbens, amygdala, hippocampus, and cerebellum.”
What kind of results did the scientists reported? Well, “No statistically significant differences were found between daily users and nonusers on volume or shape in the regions of interest. Effect sizes suggest that the failure to find differences was not due to a lack of statistical power, but rather was due to the lack of even a modest effect.” In other words, “the results indicate that, when carefully controlling for alcohol use, gender, age, and other variables, there is no association between marijuana use and standard volumetric or shape measurements of subcortical structures.”
More studies are needed, of course, to better understand how cannabis affects our body and mind, but it really looks like you can relax, go online and buy some nice weed and smoke it: you are not killing your brain, and if someone says you are, you can use the results of this study to point out that, actually, daily use of marijuana doesn’t affect your subcortical structures. On the other hand, alcohol does.
