Association of personality facets and cognition in the Lifelines population-based Study

Background: Personality traits have been associated with cognitive functioning and risk of cognitive decline. Fewer studies have investigated how personality facets are associated with cognition in large cohorts with a prospective design. 
Methods: The association between eight personality facets and cognition (speed measures reflecting psychomotor speed and visual attention; hit rate measures reflecting visual learning and working memory) was analyzed in middle-aged adults from the Lifelines cohort (N= 79911; age 43±10 years). 
Results: High hostility, vulnerability, low excitement seeking, and competence were associated with worse cognitive performance on all tasks. Impulsivity-related facets had weak and differential associations, with self-discipline negatively associated with accuracy and deliberation negatively associated with speed. These associations remained largely unchanged when accounting for lifestyle factors (smoking, alcohol consumption, physical activity). The associations with cognition were stronger in older people for impulsiveness, deliberation, hostility, and vulnerability, while stronger in younger people for excitement seeking and self-discipline. 
Conclusion: In a large population-based sample with a broad age range, the associations of personality facets with cognitive functioning had small effect sizes, were independent of lifestyle factors, and varied with age and among facets within the same personality domain. These findings highlight the importance of developmental stages and facet-level research in personality-cognition associations.   

Keywords: Cognitive Dysfunction; Behavior and Behavior Mechanisms; Cohort Studies; Personality Traits; Risk Factor; Dementia.