Clock-drawing potentially mediates the effect of depression on mortality: replication in three cohorts.
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.
Royall
Donald R
DR
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>
Palmer
Raymond F
RF
Chiodo
Laura K
LK
Polk
Marsha J
MJ
Markides
Kyriakos S
KS
Hazuda
Helen
H
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