BY: AYA TSINTZIRAS
A new study has good and bad news for regular pot smokers: it appears that marijuana affects the brain, making one region smaller yet also increasing its connectivity.
Researchers at the University of Texas recently published a study that, for the first time, suggested how regular marijuana use affects the brain. One hundred and ten participated in the study, with 48 marijuana users and 62 non-users (the “control” group). The authors were quick to point out that previous studies have had problems such as being too focused on one narrow age group, so this study used people of several ages. Participants had no brain disorders, brain injury or incidences of psychosis, and smoked pot regularly (at least four times a week for the past six months). MRIs were then done across the entire brain of each participant.
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The results? Pot use affects the region of the brain called the orbitofrontal cortex, located in the frontal lobe, which regulates behaviours such as adjusting socially and controls responsibility, drive and mood. The OFC had “lower gray matter density” – in other words, it was smaller in pot users than non-users. The surprising news is that this OFC region had more connectivity between it and other areas of the brain. Some believe this is the body’s way of making up for its smaller size.
It turns out that the age at which you start smoking pot matters: that connectivity was increased if users started smoking at a young age.
The brain has receptors that respond to THC, the cannabis plant’s main ingredient. The OFC is part of the brain’s “reward network” and its gray matter is affected the most by THC.
The researchers also discovered that the participants who used marijuana had lower IQs than the non-users, echoing a previously published study from this past June. The New England Journal of Medicine concluded that smoking pot at a young age results in a lower IQ. The teenage years are a crucial time for the development of the brain, so many have been concerned about how smoking pot as a teen affects that development.
A “Marijuana Problem Survey” was also given to the participants, with 19 questions about how pot use has affected their social lives, work lives and mental health in the past 90 days — for example, whether they lost a job, missed work, or fought with romantic partners or family members.
The study authors have said that the findings don’t completely prove that pot was the reason for these changes in the brain, as there could be environmental or biological reasons. More research will have to be done.
