Dopamine is a brain chemical that plays a big role in how humans experience rewards and pleasure, such as from food, sex and drugs. People differ in the amount of dopamine they produce and in the number of dopamine receptors in the brain. Someone with fewer dopamine receptors has less ability to regulate how much dopamine is released.
A new study carries this understanding further by showing that people who are natural risk-takers have less of a particular type of dopamine receptor. That may explain, in part, why such people seek thrills or behave impulsively. The research, published this week in the Journal of Neuroscience, looked at 34 people who filled out a questionnaire that measured risk-taking and impulsiveness as a personality trait. Those who scored higher on the novelty-seeking scale had decreased dopamine autoreceptors compared with people who scored lower. Researchers, from Vanderbilt University, used PET scans to measure dopamine uptake.
"Novelty-seeking personality traits are a major risk factor for the development of drug abuse and other unsafe behaviors," the lead author of the study, David Zald, said in a news release. "Our research suggests that in high novelty-seeking individuals, the brain is less able to regulate dopamine, and this may lead these individuals to be particularly responsive to novel and rewarding situations that normally induce dopamine release."
-- Shari Roan
Photo credit: Jacqueline Mia Foster / For the Times