title: Neuroticism combined with slower and more variable reaction time: synergistic risk factors for 7-year cognitive decline in females.
abstract: OBJECTIVE
  Among adults, slower and more variable reaction times are associated with worse cognitive function and increased mortality risk. Therefore, it is important to elucidate risk factors for reaction time change over the life course.  Method.  Data from the Health and Lifestyle Survey (HALS) were used to examine predictors of 7-year decline in reaction time (N = 4,260). Regression-derived factor scores were used to summarize general change across 4 reaction time variables: simple mean, 4-choice mean, simple variability, and 4-choice variability (53.52% of variance).
  
  
  RESULTS
  Age (B = .02, p < .001) and HALS1 baseline reaction time (B = -.10, p = .001) were significant risk factors for males (N = 1,899). In addition to these variables, in females (N = 2,361), neuroticism was significant and interacted synergistically with baseline reaction time (B = .06, p = .04). Adjustment for physiological variables explained the interaction with neuroticism, suggesting that candidate mechanisms had been identified.  Discussion.  A priority for future research is to replicate interactions between personality and reaction time in other samples and find specific mechanisms. Stratification of population data on cognitive health by personality and reaction time could improve strategies for identifying those at greater risk of cognitive decline.
authors.affiliation: Department of Epidemiology and Public Health, University College London, 1-19 Torrington Place, London WC1E 6BT, UK. g.hagger-johnson@ucl.ac.uk
authors.forename: Gareth E
authors.initials: GE
authors.lastname: Hagger-Johnson
authors.forename: Darren A
authors.initials: DA
authors.lastname: Shickle
authors.forename: Beverly A
authors.initials: BA
authors.lastname: Roberts
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Deary
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000523:psychology; D005120:Extraversion, Psychological; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D009497:Neurotic Disorders / Q000175:diagnosis / Q000523:psychology*; D011446:Prospective Studies; D011594:Psychometrics / Q000706:statistics & numerical data; D011930:Reaction Time; D012307:Risk Factors; D012737:Sex Factors; D013223:Statistics as Topic; D006113:United Kingdom