According to a new study in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, published by Elsevier, shifting from brain systems controlling reward-driven use to habit-driven use is what differentiates between addicted heavy cannabis users and those who are not addicted, even if they are long-time users.
Through the use of brain imaging, this study monitored neural activity as cannabis users were shown images associated with their cannabis use. Researchers refer to this as drug cues. Based on their findings, it appears that although all users reported being heavy, long-term users, only some were truly dependent on the drug.
It turned out that all users in the study had exaggerated responses in their ventral striatum, the region of the brain that recognizes and processes reward. With a strong connection to other emotion generators in the brain, this region is most active during the expectancy, and receipt of, monetary, social, and emotional rewards.
However, those users that proved to be dependent on the drug had a noticeably larger response in the dorsal striatum as well. The dorsal striatum is the region of the brain where habits are formed. The dorsal striatum is heavily involved in the planning, execution, and automatization of our motor behavior.
What this means is that heavy cannabis use is a result of changes in your brain's reward system, but this may not be an indicator of an addictive relationship with the drug. Addictive qualities are likely controlled by the brain system that promotes habit and habitual use. Those who were dependent on the drug saw changes in other regions of the brain as well.
With an increasing cannabis landscape, it is crucial to begin to understand what causes cannabis users to develop addictive qualities when it comes to this drug. In terms of treatment, these findings could be beneficial in assisting the many long-term, heavy users that are now addicted to this drug.