People who use marijuana heavily experience a blunted response to dopamine, according to researchers at Brookhaven National Laboratory, New York University Langone Medical Center and the National Institute on Alcohol Abuse and Alcoholism. When marijuana abusers took methylphenidate, a drug that stimulates dopamine production, they did not experience the cardiovascular, behavioral and brain changes usually associated with an increase in dopamine levels. The research appears in the Proceedings of the National Academy of Sciences.
Scientists don’t know much about how excessive use of marijuana affects the brain. Marijuana doesn’t seem to affect the brain in the same way that other drugs of abuse do. Other drugs stimulate the release of dopamine, a neurotransmitter associated with feelings of pleasure, in a region of the forebrain known as the striatum. While some earlier studies have shown that marijuana does this as well, other studies have shown that marijuana does not have this effect. People who abuse alcohol, nicotine, cocaine, methamphetamine and heroin experience a decreased ability to produce dopamine. However, scientists have never found a link between marijuana use and reduced dopamine production.
Read more at: MedicalXpress