For the first time, scientists have discovered a link between heavy marijuana use and reduced
dopamine production. Just so you know, dopamine is the hormone/neurotransmitter that is released during any kind of satisfaction - it's the same hormone that is released in your brain when you eat chocolate. In a recent study, lower dopamine release was found in the
striatum - a region of the brain that is involved in working memory, impulsive behavior, and attention, in addition to subregions involved in associative and sensorimotor learning, and in the
globus pallidus. Previous studies have shown that addiction to other drugs of abuse, such as
cocaine and
heroin, have similar effects on dopamine release, but such evidence for cannabis was missing until now.
Source: E van de Giessen, J J Weinstein, C M Cassidy, M Haney, Z Dong, R Ghazzaoui, N Ojeil, L S Kegeles, X Xu, N P Vadhan, N D Volkow, M Slifstein, A Abi-Dargham. Deficits in striatal dopamine release in cannabis dependence. Molecular Psychiatry, 2016; DOI: 10.1038/mp.2016.21