Effects of depressive and anxious symptoms on norepinephrine and platelet P-selectin responses to acute psychological stress among elderly caregivers.
BACKGROUND
Caring for a spouse with Alzheimer's disease is associated with increased psychological distress, impaired immunity, and heightened cardiovascular risk. Hyperreactivity of sympathetic and platelet activation responses to acute psychological stress, or the failure to recover quickly from stressful events, may constitute an important pathway linking stress and negative affect with cardiovascular disease (CVD).


OBJECTIVE
(1) To evaluate associations between negative affect (i.e., depressive and anxious symptoms) with increased norepinephrine and P-selectin responses to an acute psychological stress task. (2) To establish whether these associations are augmented among elderly spousal caregivers (CG) compared to non-caregivers (NC).


METHODS
Depressive (DEP) and anxious (ANX) symptoms from the Brief Symptom Inventory were assessed among 39 CG and 31 NC. Plasma norepinephrine levels (NE) and percent platelet P-selectin (PSEL) expression were assayed at three time-points: rest, immediately following a laboratory speech test (reactivity), and after 14 min of recovery.


RESULTS
Among CG, but not NC, increased symptoms of depression and anxiety were associated with delayed NE recovery (DEP: beta=.460, p=.008; ANX: beta=.361, p=.034), increased PSEL reactivity (DEP: beta=.703, p<.001; ANX: beta=.526, p=.002), and delayed PSEL recovery (DEP: beta=.372, p=.039; ANX: beta=.295, p=.092), while controlling for age, gender, aspirin use, antidepressant use, and preexisting CVD. Bivariate correlations showed delayed NE recovery was also associated with increased PSEL reactivity (r=.416) and delayed PSEL recovery (r=.372; all ps<.05) among CG but not NC.


CONCLUSIONS
Among chronically stressed caregivers, increased levels of depressive and anxious symptoms are associated with prolonged sympathetic activation and pronounced platelet activation. These changes may represent one pathway linking caregiving stress to cardiovascular risk.
Aschbacher
Kirstin
K
Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla CA 92093 0680, USA.
Mills
Paul J
PJ
von Känel
Roland
R
Hong
Suzi
S
Mausbach
Brent T
BT
Roepke
Susan K
SK
Dimsdale
Joel E
JE
Patterson
Thomas L
TL
Ziegler
Michael G
MG
Ancoli-Israel
Sonia
S
Grant
Igor
I
D000208:Acute Disease; D000368:Aged; D001007:Anxiety / Q000453:epidemiology / Q000503:physiopathology*; D050197:Atherosclerosis / Q000453:epidemiology; D001792:Blood Platelets / Q000378:metabolism; D017028:Caregivers / Q000523:psychology*; D003863:Depression / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D009638:Norepinephrine / Q000097:blood*; D019007:P-Selectin / Q000378:metabolism*; D012307:Risk Factors; D013315:Stress, Psychological / Q000453:epidemiology / Q000378:metabolism / Q000503:physiopathology*; D013564:Sympathetic Nervous System / Q000503:physiopathology
D019007:P-Selectin; D009638:Norepinephrine