Parkinson's disease, personality, and dopamine.

Clinicians have long observed an anecdotal association of Parkinson's disease with stoic, industrious, and inflexible personality traits, both premorbidly and after the onset of motor symptoms. In this study, using the Tridimensional Personality Questionnaire, we found significantly less novelty-seeking behavior (behavior thought to be dopamine-dependent) in Parkinson's disease patients than in matched controls, but no differences between groups in behaviors thought to be dependent on serotonin and norepinephrine. We discuss the literature and propose a mechanism that may explain the relationship between brain dopaminergic systems and personality in Parkinson's disease.