Heavy Marijuana Use May Reduce Your Brain’s Dopamine Release

Psychology Today 15 April 2016
Family First Comment: In a statement regarding the most recent study on heavy cannabis use and dopamine release, Jeffrey Lieberman MD, Chair of Psychiatry at CUMC and past president of the American PsychiatricAssociation, concluded, “these findings add to the growing body of research demonstrating the potentially adverse effects of cannabis, particularly in youth, at the same time that government policies and laws are increasing access and use.”   Yep!

The March 2016 study, “Deficits in Striatal Dopamine Release in Cannabis Dependence (link is external),” was published in Molecular Psychiatry. For this study, an international team of researchers used positron emission tomography (PET) brain scans to track a radiolabelled molecule that binds to dopamine receptors in the brain. The scientists specifically measured dopamine release in the striatum and its subregions.

The brain scans identified that severe marijuana dependence (now referred to as cannabis use disorder) is associated with a reduced release of dopamine within the striatum. The striatum is a brain region involved in working memory, impulsive behavior, and attention.

The researchers believe that lower dopamine release within the striatum may be linked to the greater emotional withdrawal and inattention observed in marijuana-dependent study participants. Previous studies have found that addiction to other drugs, such as cocaine and heroin, have similar effects on dopamine release. However, this is the first study to provide evidence that heavy cannabis use may reduce dopamine release.

In the brain, dopamine functions as a neurotransmitter which helps control the brain’s pleasure and reward centers. Dopaminergic pathways are neural pathways that transmit dopamine from one region of the brain to another. Dopamine drives reward-motivated behavior and helps us regulate movement and emotional responses.

Dopamine not only enables someone to identify rewards, it gives him or her the oomph to seize the day and achieve goals. People with low levels of dopamine are statistically more prone to drug abuse, addiction, and amotivational syndrome (link is external).

In the most recent study, the cannabis users had significantly lower dopamine release in the striatum, including subregions involved in associative and sensorimotor learning. The researchers also explored the relationship between dopamine release in key areas of the striatum and cognitive performance on learning and working memory tasks. Lower dopamine release was associated with subpar performance on both tasks.

In a statement regarding the most recent study on heavy cannabis use and dopamine release, Jeffrey Lieberman (link is external), MD, Chair of Psychiatry at CUMC and past president of the American Psychiatric Association, concluded, “these findings add to the growing body of research demonstrating the potentially adverse effects of cannabis, particularly in youth, at the same time that government policies and laws are increasing access and use.”
READ MORE: https://www.psychologytoday.com/blog/the-athletes-way/201604/heavy-marijuana-use-may-reduce-your-brains-dopamine-release

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