title: Depressive symptoms predict longitudinal change in executive control but not memory.
abstract: OBJECTIVE
  Depression in non-demented persons has been identified as a possible risk factor for incident Alzheimer's disease (AD).
  
  
  METHODS
  Latent Growth Curve models were developed of baseline depressive symptoms as a predictor of longitudinal changes in cognition. Depressive symptoms were assessed using the 15-item Geriatric Depression Scale (GDS). Memory was assessed by the California Verbal Learning Task (CVLT). Executive control function (ECF) was assessed by the Executive Interview (EXIT25) and Trail-Making Test Part B (Trails-B). Five hundred forty-seven non-institutionalized older retirees living in a single comprehensive care retirement community participated.
  
  
  RESULTS
  Depressive symptoms were significantly associated only with the 3-year rate of decline in psychomotor speed, as measured by Trails A, and ECF, as measured by the EXIT25. Both associations withstood adjustment for age, gender, education, and baseline level of care.
  
  
  CONCLUSIONS
  Depressive symptoms are associated with longitudinal decline in cognition. However, this association selectively involves executive control, not memory, and possibly only a subset of 'executive' functions. Although depressive symptoms may hasten conversion from mild cognitive impairment (MCI) to dementia, depression-related conversion is not likely to be mediated by evolution of the AD pathological process.
authors.affiliation: Department of Psychiatry, University of Texas Health Science Center, San Antonio, TX, USA. royall@uthscsa.edu
authors.forename: Donald R
authors.initials: DR
authors.lastname: Royall
authors.forename: Raymond
authors.initials: R
authors.lastname: Palmer
authors.forename: Laura K
authors.initials: LK
authors.lastname: Chiodo
authors.forename: Marsha J
authors.initials: MJ
authors.lastname: Polk
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology* / Q000523:psychology; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000503:physiopathology* / Q000523:psychology; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D012307:Risk Factors