Jason Koebler highlights a study linking marijuana use to brain abnormalities in young people:
High-resolution MRI scans of the brains of adults between the ages of 18-25 who reported smoking weed at least once a week were structurally different than a control group: They showed greater grey matter density in the left amygdala, an area of the brain associated with addiction and showed alterations in the hypothalamus and subcallosal cortex. The study also notes that marijuana use “may be associated with a disruption of neural organization.” The more weed a person reported smoking, the more altered their brain appeared, according to the Northwestern University and Harvard Medical School study, which was published in the Journal of Neuroscience.
The finding already has the study’s authors calling for states to reconsider legalizing the drug. Hans Breiter, the lead author, said he’s “developed a severe worry about whether we should be allowing anybody under age 30 to use pot unless they have a terminal illness and need it for pain.”
Saundra Young gets the response of another researcher:
“This data certainly confirms what others have reported with regard to changes in brain structure,” [Dr. Staci Gruber, director of the Cognitive and Clinical Neuroimaging Core at McLean Hospital in Boston] said. “When we consider the findings of the [Jodi] Gilman … study with our own and other investigations of marijuana use, it’s clear that further investigation is warranted, specifically for individuals in emerging adulthood, as exposure during a period of developmental vulnerability may result in neurophysiologic changes which may have long-term implications.”
Gruber says we need to take a closer look at all pot users whether they smoke once or twice a week or four or time times a week.
And she had this advice for adolescents: “Don’t do it early–prior to age 16. That’s what our data suggests, that regular use of marijuana prior to age 16 is associated with greater difficulty of tasks requiring judgment, planning and inhibitory function as well as changes in brain function and white matter microstructure relative to those who start later.”
Meanwhile, Mitch Earleywine criticizes the methodology of a different study purporting to show neuropsychological deficits from pot use:
First, we have to keep other drug use in mind. Unfortunately, the marijuana group in this study got drunk more than 4 times as much in the last six months as the controls. Given what we know about binge drinking and neuropsychological functioning, it’s going to be hard to attribute any differences between these groups to the plant. It’s just as likely that any deficits stem from pounding beers. Studying cannabis users who aren’t so involved with alcohol would help address neuropsychological functioning much better.