title: Clock-drawing potentially mediates the effect of depression on mortality: replication in three cohorts.
abstract: OBJECTIVE
  Previously studies have associated visuospatial tasks, particularly 'clock-drawing', with mortality. We sought to determine whether clock-drawing also mediates the association between depressive symptoms and mortality.
  
  
  METHODS
  Non-institutionalized Hispanic and non-Hispanic White elderly volunteers.
  
  
  METHODS
  Survival curves were generated as a function of baseline depressive symptom ratings. Significant models were adjusted for CLOX performance. CLOX is divided into CLOX1, a measure of executive control, and CLOX2, a measure of visuospatial skills.
  
  
  METHODS
  Retrospective analysis of three longitudinal cohorts.
  
  
  RESULTS
  CLOX2 and depressive symptoms were both associated with mortality in unadjusted models. CLOX2 predicted survival independently of CLOX1 in all three cohorts. CLOX2 also attenuated, and/or mediated the association between depressive symptoms and mortality. These results withstood adjustment for age and education in all three cohorts.
  
  
  CONCLUSIONS
  Regardless of the sample examined, or the measure of depressive symptoms applied, the association between depressive symptoms and mortality appears to be at least partially mediated by visuospatial skills. This finding supports our hypothesis that right hemisphere structural brain disease, particularly that involving the insula, may mediate depression's effects on mortality.
authors.affiliation: Department of Psychiatry, The South Texas Veterans' Health System Audie L Murphy Division GRECC and the University of Texas Health Science Center, San Antonio, TX, USA. royall@uthscsa.edu <royall@uthscsa.edu>
authors.forename: Donald R
authors.initials: DR
authors.lastname: Royall
authors.forename: Raymond F
authors.initials: RF
authors.lastname: Palmer
authors.forename: Laura K
authors.initials: LK
authors.lastname: Chiodo
authors.forename: Marsha J
authors.initials: MJ
authors.lastname: Polk
authors.forename: Kyriakos S
authors.initials: KS
authors.lastname: Markides
authors.forename: Helen
authors.initials: H
authors.lastname: Hazuda
mesh_terms: D000368:Aged; D003704:Dementia / Q000401:mortality / Q000503:physiopathology; D003866:Depressive Disorder / Q000401:mortality* / Q000503:physiopathology; D004812:Epidemiologic Methods; D005260:Female; D015577:Geriatric Assessment / Q000379:methods; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000592:standards*; D011594:Psychometrics; D011597:Psychomotor Performance / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results