title: Patterns and persistence of behavioural and psychological symptoms in those with cognitive impairment: the importance of apathy.
abstract: OBJECTIVE
  To study the stability and emergence of a range of behavioural and psychological symptoms (BPS), their association with mortality and the effect of covariates on these transitions in a population-based study of cognitively impaired older people with a long follow-up period and large sample size, with a particular focus on apathy.
  
  
  METHODS
  Data were from a population-based, longitudinal cohort study of ageing. Interviews were conducted at 0, 2, 6, 8 and 10 years with 3626 participants aged 65+. The persistence of 11 BPS and their association with mortality in those with cognitive impairment (MMSE 25 or below) was investigated using multi-state models, allowing us to take into account estimations of the probability of transitions that occurred in the time between interviews.
  
  
  RESULTS
  Most BPS were persistent. Apathy was one of the most stable symptoms; in those with apathy, the probability of still having apathy after 1 year is 62%. Apathy, sleep problems, depression, irritability and wandering were most likely to develop. BPS are associated with mortality; in those with apathy, mortality is 3.1 times more likely than in those without apathy. Low cognitive function and dementia were associated with emergence of new symptoms.
  
  
  CONCLUSIONS
  This population-based, multi-centre study with a follow-up period of 10 years showed that BPS are associated with mortality and most symptoms are persistent. Apathy was characterised by a high prevalence, a high persistence and a strong association with mortality, and has a negative impact on disability, management of other disease and caregiver burden.
authors.affiliation: Institute of Public Health, University of Cambridge, UK.
authors.forename: Rianne M
authors.initials: RM
authors.lastname: van der Linde
authors.affiliation: Institute of Public Health, University of Cambridge, UK.|Institute of Health and Society, Newcastle University, UK.
authors.forename: Fiona E
authors.initials: FE
authors.lastname: Matthews
authors.affiliation: Institute of Mental Health, University of Nottingham, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Dening
authors.affiliation: Institute of Public Health, University of Cambridge, UK.
authors.forename: Carol
authors.initials: C
authors.lastname: Brayne
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D057565:Apathy; D017028:Caregivers; D003071:Cognition; D003072:Cognition Disorders / Q000453:epidemiology; D060825:Cognitive Dysfunction; D003704:Dementia / Q000523:psychology; D003863:Depression / Q000523:psychology; D003866:Depressive Disorder; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence
keywords: apathy; behavioural and psychological symptoms; cognitive impairment; cohort study