With the legalization of marijuana on the rise in some countries, a growing number of studies explore the potential benefits and harms of this drug. However, new research brings to the table that when it comes to brain health , alcohol is far more harmful than marijuana.
Scientists at the University of Colorado at Boulder (USA) conducted a review of existing imaging data that analyzed the effects of alcohol and marijuana, or cannabis, on the brain. The results have been published in the journal Addiction.
Marijuana vs. alcohol: what’s worse?
For this latest study, research leader Rachel Thayer and her colleagues tried to learn more about how marijuana use affects the brain because, so far, research results have been mixed.
“When you look at these studies dating back years, we will see that one study will report that marijuana use is related to a reduction in hippocampal volume. Then the next study comes out, and it says marijuana use is related to changes in the cerebellum … The point is that there is not consistency in all these studies in terms of the real brain structures “, clarifies Kent Hutchison, co-author of the work.
In order to bridge the gap in this inconsistency, the scientists conducted a new analysis on existing brain imaging data. They looked at how marijuana use affects white matter and gray matter in the brain, and how its effects compare to another “drug” we’ve become so used to: alcohol.
Gray matter is the tissue on the surface of the brain that consists mainly of nerve cell bodies. The white matter is the deepest brain tissue that contains myelinated nerve fibers, which are protruding branches of nerve cells that transmit electrical impulses to other cells and tissues. Any reduction in the size of the white or gray matter or a loss in its integrity can cause alterations in the functioning of the brain.
The study included brain images from 853 adults who were between the ages of 18 and 55 and 439 adolescents between the ages of 14 and 18. All participants varied in their use of alcohol and marijuana.
The researchers found that alcohol consumption, especially in adults who had been drinking for many years, was associated with a reduction in the volume of gray matter, as well as a reduction in the integrity of the white matter.
However, marijuana use did not appear to have any impact on the structure of gray or white matter in adolescents or adults.
Marijuana had no significant impact on the brain
Based on these findings, the researchers believe that drinking alcohol is likely to be much more damaging to brain health than using marijuana.
“Although marijuana can also have some negative consequences, it is definitely not close to the negative consequences of alcohol,” says Kent Hutchison, co-author of the paper.
However, regarding the possible benefits of marijuana use, scientists clarify that more research is still needed to reach concrete conclusions.
Reference: Structural neuroimaging correlates of alcohol and cannabis use in adolescents and adults. Rachel E. Thayer et al. Addiction. DOI: 10.1111 / add.13923
