People from recreational marijuana states should watch their regular dosage of weed and take a better care of their brain health. A group of researchers from The University of Texas at Dallas discovered that a long-term cannabis use is linked to alterations in the brain's reward system. The study was funded by the National Institute on Drug Abuse (NIDA) and published in the Human Brain Mapping journal.
The researchers discovered that heavy cannabis users have a different reaction to marijuana-related cues. In particular, marijuana users show a higher activity in the reward-associated areas of the brain when presented with marijuana-related cues. The non-users, on the other hand, have more brain activity in the same areas when presented with a natural reward.
In order to explore the specificity of neural sensitivity to marijuana-related cues in weed users, the researchers used fMRI. All the participants were spread into two groups: 53 daily, long-term marijuana users and 68 non-users. Both groups were presented with two types of visual cues. The first type—cannabis-related cues such as a pipe, a bong, a blunt, etc. The second type of used cues was representing a natural reward, and for that, the researchers used an image of a self-selected fruit, like a banana or an orange.
Those images were meant to evaluate marijuana users' brain response to different hedonic stimuli. After looking at each of these cues, the study participants rated their need to use cannabis. According to the results of the experiment, marijuana users show an enhanced response in the reward-associated brain areas when presented with weed-related cues compared to fruits.
Along with fMRI data, the researchers asked the marijuana-using participants of the study about their daily problems associated with cannabis use. According to Dr. Francesca Filbey, the leading author of the study, the researchers found a correlation between the level of brain reward system's disruption and the number of problems the person has because of using weed. And if a person continues to use cannabis even despite having these problems, it may be considered an indicator of weed dependence.