Their findings linked alcohol consumption with long-term changes to the structure of white matter and gray matter in the brain.
The use of marijuana, however, seemed to have no significant long-term effects on brain structure.
Study leader Rachel Thayer, of the Department of Psychology and Neuroscience at the University of Colorado Boulder, and colleagues
recently reported their results in the journal Addiction.
It is estimated that around 22.2 million people in the United States have used marijuana in the past month, making it "the most commonly
used illicit drug" in the country.
Across the U.S., however, it is increasingly becoming legalized for both medicinal and recreational purposes. As a result of this changing
legislation, researchers have been trying to find out more about how
marijuana may benefit health, as well as the damage that it could cause.
Last year, for example, Medical News Today reported on a study linking marijuana use to a greater risk of psychosis in teenagers, while
another study claimed that the drug is "worse than cigarettes" for
cardiovascular health.
On the other side of the coin, researchers have found that cannabinoids — which are the active compounds in marijuana — could help
to prevent migraine, and a more recent study linked marijuana use to an
increased sex drive.For this latest study, Thayer and colleagues sought
to learn more about how marijuana use affects the brain.
Study co-author Kent Hutchison, also of the Department of Psychology and Neuroscience, notes that to date, studies that have investigated
this association have produced mixed results.
"When you look at these studies going back years," he explains, "you see that one study will report that marijuana use is related to a
reduction in the volume of the hippocampus. The next study then comes
around, and they say that marijuana use is related to changes in the
cerebellum <...>."
