New research from Northwestern University links casual marijuana smoking with brain abnormalities in young adults.

The study, published in the Journal of Neuroscience, observed the brains of 20 casual smokers with a variety of smoking habits in comparison with 20 non-smokers. The smokers were selected based on their outward appearance as having exhibited no effects from their marijuana use, as in doing well in their studies and behaving as otherwise normal citizens.

The study used Magnetic Resonance Imaging – or MRI’s – to produce visuals of the brains of the participants, with particular focus applied to the observance of the Nucleus Accumbens and the Nucleus Amygdala, two portions of the brain closely tied to emotion regulation and motivation, according to Yahoo News.

The study focused on the volume, shape and density of the aforementioned brain regions, with results showing significant changes in all three areas of emphasis in the brains of the smokers compared with the non-smokers, with changes in volume correlating with the frequency of intake, according to Fox News.

The group most likely to be affected by these biochemical changes is the young adult group between the ages of 18 and 25, given that their brains are still developing. In addition, the theory exists that these changes may be linked to the behaviors of amotivation or apathy seen in habitual smokers later in life.

This study has produced a lot of controversy with its opposition, typically supporters of marijuana legalization, pointing out the small sample size and the cognitive functions of the smokers analyzed in the study. Many claim that because the smokers exhibit no adverse behaviors as a result of their use of the drug, the abnormalities detected mean little to nothing.

“Just because there’s an abnormality doesn’t necessarily mean that it’s a bad abnormality,” said freshman marine biology major Christopher Eaves, when asked about his opinion of the study.

Others are not shocked by the matter, but would still like to see further investigations conducted.

“I would say I’m not surprised (by the study) but I would like to know how severe the brain abnormalities are,” said Olivia Wooton, a freshman graphic design major.

Of course, more studies must be conducted in the future to determine the extent of this damage and to determine what the long-term consequences of these abnormalities may be. In addition, studies may be conducted to determine whether or not the damage can be corrected with abstinence from the substance over time.

The fact that the abnormalities exist, however, is cause for alarm, especially when taking into account studies previously conducted that show heavy marijuana use is linked to brain abnormalities consistent with those suffering from schizophrenia.

Scientists involved in the formulation and execution of this study also acknowledge the issues with conducting a study with such a small sample size, though they believe that the study should still be cause for alarm and reason for further investigation into the matter, according to Fox. In short, this study was an experiment to pave the way for future, more targeted studies.

While further research must be conducted in the future to determine the extent to which these abnormalities may affect casual marijuana smokers over the course of their lives, this study should raise awareness of the matter and should make it clear to advocates of marijuana use that the use of the substance is not without consequence. It does change the basic structure and chemistry of the brain, which is not something one should take lightly, and it still remains an illegal substance on both a state and federal level.