"Novelty-seeking personality traits are a major risk factor for the development of drug abuse and other unsafe behaviors," Zald and his colleagues wrote.
"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," Zald said.
Previous research in rodents showed that some respond differently to novel environments. Those who explore novel environments more are also more likely to self-administer cocaine when given the chance. Dopamine neurons fire at a higher rate in these novelty-responsive rodents, and the animals also have weak autoreceptor control of their dopamine neurons. Zald and colleagues speculated that the same relationships would be seen in humans.
The researchers used positron emission topography to view the levels of dopamine receptors in 34 healthy humans who had taken a questionnaire that measured the novelty-seeking personality trait. The questionnaire measured things such as an individual's preference for and response to novelty, decision-making speed, a person's readiness to freely spend money, and the extent to which a person is spontaneous and unconstrained by rules and regulations. The higher the score, the more likely the person was to be a novelty seeker.
The researchers found that those that scored higher on the novelty-seeking scale had decreased dopamine autoreceptor availability compared to the subjects that scored lower.
|Contact: Melanie Moran|