New Study: Alcohol is More Damaging to the Brain Than Marijuana

A highway safety official in Colorado, where marijuana is legal, said that “a lot of people don't think D.U.I. laws apply.” (File image via Reuters)
A highway safety official in Colorado, where marijuana is legal, said that “a lot of people don't think D.U.I. laws apply.” (File image via Reuters)

While research continues digging into the truth, a new study from the University of Colorado Boulder showed that alcohol is more damaging to the brain than marijuana.

Medical News Today reported on Monday that the study conducted a review of existing imaging data that looked at the effects of alcohol and marijuana on the brain.

What the scientists found is that alcohol made long-term changes to the structure of white matter and gray matter in the brain. In comparison, the use of marijuana did not seem to have significant long-term effects on brain structure.

Gray matter is a key component of the central nervous system, containing numerous cell bodies. However, white matter is the deeper brain tissue that contains myelinated nerve fibers, which are branches protruding from nerve cells that transmit electrical impulses to other cells and tissues. White matter affects learning and brain functions.

Any decrease in the size of white or gray matter or a loss in their integrity can lead to impairments in brain functioning.

The data gleaned were broth from adolescents and adults, ranging from as young as 14 till 55 years in age. There were 853 adults – from 18 to 55, who were tested, and 439 teenagers – from 14 to 18. All the people tested varied in both their consumption of alcohol and marijuana.

"With alcohol, we've known it's bad for the brain for decades," notes Hutchison. "But for cannabis, we know so little." (File image via Reuters)
“With alcohol, we’ve known it’s bad for the brain for decades,” notes Hutchison. “But for cannabis, we know so little.” (File image via Reuters)

Mixed Results?

Meanwhile, studies researching marijuana’s effects teenagers remain contradictory and inconclusive. For example, Medical News Today reported last year a study associating cannabis use to a greater risk of psychosis in adolescents.

Co-author Kent Hutchison of this study, at the Department of Psychology and Neuroscience, shed some light on this issue of mixed results.

“When you look at these studies going back years,” he said, “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 […].”

“The point is that there’s no consistency across all of these studies in terms of the actual brain structures.”

A woman holds up a cannabis plant during a demonstration in support of the legalization of marijuana in Buenos Aires, December 4, 2014. (File image via Reuters)
A woman holds up a cannabis plant during a demonstration in support of the legalization of marijuana in Buenos Aires, December 4, 2014. (File image via Reuters)

Final Say?

To put a final say on this contradiction, the researchers of the Colorado Boulder study conducted a new analysis of existing brain imaging data.

They looked at how marijuana use affects white matter and gray matter in the brain, and how its effects compared with alcohol.

“With alcohol, we’ve known it’s bad for the brain for decades,” notes Hutchison. “But for cannabis, we know so little.”

What they found is that chronic alcohol use, especially for adults, was associated with a reduction in gray matter volume, as well as a reduction in the integrity of white matter.

But the use of marijuana showed no impact on the structure of gray or white matter in both teenagers and adults.

However, the research team said there need to be more studies to be done to fully understand the benefits of marijuana use to make produce clear and solid conclusions.

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