April 2009 Describes findings from an animal study showing that cocaine lowers availability of dopamine receptors in the basal ganglia, an area of the brain that includes portions of the reward system.
October 2010 Describes research results reporting that people who favor novelty have lower-than-average availability of a receptor that inhibits dopamine's release from neurons, which likely stimulates the activity of reward circuits.
October 2009 Reports on an animal study suggesting that the manic stage of bipolar disorder promotes signs of drug abuse vulnerability by enhancing sensitivity to rewards, both natural and drug-related.
April 2014 Exposing rats to THC increases the likelihood that the animals will later self-administer nicotine. THC-exposed rats are also willing to work harder to obtain nicotine. When extrapolated to people, the findings suggest that THC’s pharmacological impact on the brain may make a person who uses marijuana more vulnerable to developing nicotine addiction, an underappreciated health consequence of marijuana use.