A small study of marijuana users yielded some potentially troubling results, with researchers claiming that marijuana consumption might have a profound impact on the parts of the brain that process decision-making, emotional assessment, addiction and the processing of rewards.

This means — at least based on this particular study’s findings — that weed holds the potential to alter the volume, shape and density of essential structures in the brain.

“Just casual use appears to create changes in the brain in areas you don’t want to change,” said study co-author Dr. Hans Breiter, a psychiatrist mathematician at Northwestern University.

Study Finds Marijuana May Be Damaging to Users Brains

AP Photo/Matilde Campodonico, File

Researchers examined the brains of 20 recreational pot smokers as well as the brains of 20 non-users, using MRI images to compare similarities and differences, NBC News reported.

These individuals, who were all college students in the Boston area, shared comparable educational levels, personalities, level of alcohol use and anxiety — and they were all between the ages of 18 and 25.

The results, which will be published in the Journal of Neuroscience Wednesday, point to key differences in two areas of the brain — the nucleus accumbens, which deals with addiction and the processing of rewards, and the amygdalas, which is responsible for emotional processing.

The density of grey matter in these areas increased among marijuana users, indicating abnormal neuron growth. Additionally, the brain regions took on abnormal shapes.

It appears the changes were directly related to how much marijuana was consumed.

It’s essential to note that a definitive cause-effect link has not been proven, though the study did find an association between brain anatomy and weed consumption, HealthDay reported.

The outlet added, “These changes show that pot users’ brains adapt to even low-level marijuana exposure, potentially making a person more vulnerable to drug addiction or changing their thought processes and emotions in unknown ways, the researchers said.”

Considering that the human brain continues to develop into a person’s 20s and 30s, Breiter expressed concern over the findings.

“When we saw that there was a consistent abnormality and that it was directly related to the amount of cannabis one took in, it gave us some significant pause,” he said. “Seeing these differences raises a cautionary flag that we need to do more research.”

In this Dec. 5, 2013, photo marijuana matures in ideal conditions at the Medicine Man dispensary and grow operation in northeast Denver. As Colorado prepares to be the first in the nation to allow recreational pot sales, opening Jan. 1, hopeful retailers are investing their fortunes into the legal recreational pot world, all for a chance to build even bigger ones in a fledgling industry that faces an uncertain future. (AP Photo/Ed Andrieski) AP Photo/Ed Andrieski

AP Photo/Ed Andrieski

The study’s findings are important, as there is little information on the true benefits and negatives of lighter recreational marijuana usage, according to USA Today.

While the results will lead some to claim that marijuana should not be legalized, others, like Paul Armentano, deputy director of NORML, a pro-pot group, believe otherwise.

“A pragmatic regulatory framework that allows for the legal, licensed commercial production and retail adult sale of marijuana but restricts its use among young people — coupled with a legal environment that fosters open, honest dialogue between parents and children about cannabis’ potential harms — best reduces the risks associated with the plant’s consumption or abuse,” he told HealthDay.

It is important to note that the study was funded by the National Institutes of Health, the Office of National Drug Control Policy and the Northwestern Medicine’s Warren Wright Adolescent Center.

Funding coming from government agencies which are generally opposed to marijuana consumption might lead to some skepticism surrounding the study’s results.

(H/T: NBC News)