Personality traits in young patients with Parkinson's disease

Objectives - It has been hypothesized that the dopaminergic deficit of older patients with Parkinson's disease (PD) is associated with a reduction in the dopamine-dependent personality trait "novelty seeking". It is unknown whether this may also be found in younger patients with PD whose dopaminergic deficit is considered to be purely motor. Material and methods - We interviewed 122 patients below 51 years of age and 122 age- and sex-matched healthy controls with regard to clinical and sociodemographic data. Both groups had to fill out the Tridimensional Personality Questionnaire (TPQ) of Cloninger. Neuropsychological testing of formal intelligence and depression was also applied. Results - "Novelty seeking" was not different between both groups. Patients were more often depressed than controls, explaining their difference in "harm avoidance" on the TPQ. "Persistence". a subscale of the third TPQ dimension 'reward dependence". was significantly higher in patients. Neither sex, nor age, nor educational status were correlated with one of the three personality traits. Conclusions - The higher rate of depression explains our finding of more "harm avoidance" among young PD patients. According to a literature review the choice and performance of controls is crucial whether personality traits in PD patients may be assessed as abnormal.