title: Personality and medication non-adherence among older adults enrolled in a six-year trial.
abstract: OBJECTIVE
  Personality factors parsimoniously capture the variation in dispositional characteristics that affect behaviours, but their value in predicting medication non-adherence is unclear. We investigated the relationship between five-factor model personality factors (Conscientiousness, Neuroticism, Agreeableness, Extraversion, and Openness) and medication non-adherence among older participants during a six-year randomized placebo-controlled trial (RCT).
  
  
  METHODS
  Observational cohort data from 771 subjects aged ≥ 72 years enrolled in the Ginkgo Evaluation of Memory study, a RCT of Ginkgo biloba for prevention of dementia.
  
  
  METHODS
  Random effects logistic regression analyses examined effects of NEO Five-Factor Inventory scores on medication non-adherence, determined via pill counts every 6 months (median follow-up 6.1 years) and defined as taking <80% of prescribed pills. Analyses adjusted for covariates linked with non-adherence in prior studies.
  
  
  RESULTS
  Each 5 year increment in participant age was associated with a 6.7% greater probability of non-adherence (95% confidence interval, CI [2.4, 11.0]). Neuroticism was the only personality factor associated with non-adherence: a 1 SD increase was associated with a 3.8% increase in the probability of non-adherence (95% CI [0.4, 7.2]). Lower cognitive function was also associated with non-adherence: a 1 SD decrease in mental status exam score was associated with a 3.0% increase in the probability of non-adherence (95% CI [0.2, 5.9]).
  
  
  CONCLUSIONS
  Neuroticism was associated with medication non-adherence over 6 years of follow-up in a large sample of older RCT participants. Personality measurement in clinical and research settings might help to identify and guide interventions for older adults at risk for medication non-adherence.
authors.affiliation: Center for Healthcare Policy and Research, Department of Family and Community Medicine, University of California Davis School of Medicine, Sacramento, California, USA. aflerant@ucdavis.edu
authors.forename: Anthony
authors.initials: A
authors.lastname: Jerant
authors.forename: Benjamin
authors.initials: B
authors.lastname: Chapman
authors.forename: Paul
authors.initials: P
authors.lastname: Duberstein
authors.forename: John
authors.initials: J
authors.lastname: Robbins
authors.forename: Peter
authors.initials: P
authors.lastname: Franks
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology; D015331:Cohort Studies; D003704:Dementia / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D015577:Geriatric Assessment / Q000379:methods / Q000706:statistics & numerical data; D020441:Ginkgo biloba; D006801:Humans; D008297:Male; D055118:Medication Adherence / Q000523:psychology*; D008568:Memory; D009497:Neurotic Disorders / Q000453:epidemiology / Q000523:psychology; D010551:Personality; D010555:Personality Inventory; D008517:Phytotherapy / Q000379:methods; D014481:United States / Q000453:epidemiology; D016903:Drug Monitoring