title: Novelty seeking and introversion do not predict the long-term risk of Parkinson disease.
abstract: OBJECTIVE
  It has been suggested that people who develop Parkinson disease (PD) may have a characteristic premorbid personality. We tested this hypothesis using a large historical cohort study with long follow-up.
  
  
  METHODS
  We conducted a historical cohort study in the region including the 120-mile radius centered in Rochester, MN. We recruited 7,216 subjects who completed the Minnesota Multiphasic Personality Inventory (MMPI) for research at the Mayo Clinic from 1962 through 1965 and we considered 5 MMPI scales to measure sensation seeking, hypomania, positive emotionality, social introversion, and constraint. A total of 6,822 subjects (94.5% of the baseline sample) were followed over 4 decades either actively (via interview and examination) or passively (via medical records).
  
  
  RESULTS
  During follow-up, 227 subjects developed parkinsonism (156 developed PD). The 3 MMPI scales that we selected to measure the extroverted personality construct (sensation seeking, hypomania, and positive emotionality) did not show the expected pattern of higher scores associated with reduced risk of PD. Similarly, the 2 MMPI scales that we selected to measure the introverted personality construct (social introversion and constraint) did not show the expected pattern of higher scores associated with increased risk of PD. However, higher scores for constraint were associated with an increased risk of all types of parkinsonism pooled together (hazard ratio 1.39; 95% CI 1.06-1.84; p = 0.02).
  
  
  CONCLUSIONS
  We suggest that personality traits related to introversion and extroversion do not predict the risk of PD.
authors.affiliation: Division of Epidemiology, Department of Health Sciences Research, College of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: G
authors.initials: G
authors.lastname: Arabia
authors.forename: B R
authors.initials: BR
authors.lastname: Grossardt
authors.forename: R C
authors.initials: RC
authors.lastname: Colligan
authors.forename: J H
authors.initials: JH
authors.lastname: Bower
authors.forename: D M
authors.initials: DM
authors.lastname: Maraganore
authors.forename: J E
authors.initials: JE
authors.lastname: Ahlskog
authors.forename: Y E
authors.initials: YE
authors.lastname: Geda
authors.forename: W A
authors.initials: WA
authors.lastname: Rocca
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005106:Exploratory Behavior; D005120:Extraversion, Psychological; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007439:Introversion, Psychological; D008950:MMPI; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000453:epidemiology* / Q000523:psychology*; D010551:Personality; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012307:Risk Factors; D055815:Young Adult