Enhanced behavioral response to repeated d-amphetamine and personality traits in humans

Background: This study examined whether the magnitude of the behavioral response to repeated d-amphetamine administration previously demonstrated in a double-blind study in humans was associated with certain personality characteristics. Methods: Eleven normal volunteers completed the Tridimensional Personality Questionnaire (TPQ) prior to being administered three doses of d-amphetamine (0.25 mg/kg) alternating with three doses of placebo over 6 consecutive days. Behavioral measures included eye-blink rates as well as ratings of elevated mood, increased motor activity/energy, and increased speech. These variables were assessed once prior to dosing, then hourly for 5 hours. Results: A greater magnitude of change in elevated mood over the three amphetamine doses significantly correlated with ratings of the Novelty Seeking on the TPQ. Conclusions: These results suggest that similar to findings in animal models, there are certain intrinsic behavioral characteristics that are associated with amphetamine sensitivity in humans.