Medical News Today 9 June 2016
Long-term marijuana use disrupts the brain’s normal reward processes, which may lead to dependence on the drug, according to a new study.
Researchers found that individuals who were long-term marijuana users had increased activity in certain areas of the brain associated with reward when presented with marijuana-associated cues, compared with when they were presented with fruit-associated cues.
Study co-author Dr. Francesca Filbey, of the School of Behavioral and Brain Sciences at the University of Texas at Dallas, and colleagues publish their findings in the journal Human Brain Mapping.
Though marijuana is the most commonly used illicit drug in America, with around 22.2 million users in the past month, an increasing number of states are legalizing its use for recreational or medical purposes.
However, despite this increase in marijuana legalization, Dr. Filbey and colleagues note that there is limited information on how the drug might lead to problematic use.
While only a small number of studies have investigated how marijuana use impacts the neural circuits of the brain to trigger cravings for the drug, some of these studies have suggested that the mesocorticolimbic reward system is involved.
This system incorporates several brain regions that release dopamine – a neurotransmitter that regulates the reward and pleasure centers – in response to certain cues.
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