title: Anxiety and behavioural disturbance as markers of prodromal Alzheimer's disease in patients with mild cognitive impairment.
abstract: BACKGROUND
  Depression and anxiety have been reported to be independently predictive of conversion to Alzheimer's disease (AD) in patients with mild cognitive impairment (MCI). Anxiety symptoms have been less well studied and findings in this regard have been inconsistent. The objectives of this study are to determine which symptoms among a range of neuropsychiatric symptoms known to commonly occur in patients with MCI are predictive of later conversion to AD. We also wish to determine whether these symptoms track existing measures of declining cognitive and functional status or may be considered distinct and sensitive biomarkers of evolving Alzheimer's pathology.
  
  
  METHODS
  One hundred and sixty-one patients with MCI were identified from consecutive referrals to a memory clinic. Univariate, multivariate and cox regression analyses were conducted.
  
  
  RESULTS
  Seventy-six per cent of all patients had at least one neuropsychiatric symptom at baseline of which anxiety (52%), affective disturbance (37%) and aggression (32%) were the most common. Increasing symptom frequency was observed with increasing clinical severity. Anticipatory anxiety and activity disturbances were significantly associated with earlier conversion to AD although this association did not remain significant following adjustment for cognitive status at baseline.
  
  
  CONCLUSIONS
  Neuropsychiatric symptoms and anxiety symptoms in particular are common in patients with MCI. In this sample anxiety for upcoming events and purposeless activity frequently co-occurred and were significant clinical predictors of earlier conversion to AD. However, these findings were not independent of cognitive status at baseline and therefore may be markers of severity rather than independent predictors of disease progression.
authors.affiliation: Mercer's Institute for Research on Ageing, St. James's Hospital, Dublin, Ireland. gallagherdamien@hotmail.com
authors.forename: Damien
authors.initials: D
authors.lastname: Gallagher
authors.forename: Robert
authors.initials: R
authors.lastname: Coen
authors.forename: Dana
authors.initials: D
authors.lastname: Kilroy
authors.forename: Kate
authors.initials: K
authors.lastname: Belinski
authors.forename: Irene
authors.initials: I
authors.lastname: Bruce
authors.forename: Davis
authors.initials: D
authors.lastname: Coakley
authors.forename: Bernard
authors.initials: B
authors.lastname: Walsh
authors.forename: Conal
authors.initials: C
authors.lastname: Cunningham
authors.forename: Brian A
authors.initials: BA
authors.lastname: Lawlor
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000523:psychology*; D001007:Anxiety / Q000209:etiology*; D001526:Behavioral Symptoms / Q000209:etiology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D012720:Severity of Illness Index