Depressive symptoms predict norepinephrine response to a psychological stressor task in Alzheimer's caregivers.
OBJECTIVE
Increased depressive symptoms have been associated with increased basal plasma norepinephrine (NE), and may be associated with exaggerated NE response to stress. This exaggerated response may play a role in health consequences associated with caring for a loved-one with Alzheimer's disease. The current study examined the relations between the level of depressive symptoms in spousal caregivers and the physiological response to a psychological stress task.


METHODS
Fifty-five spousal caregivers (mean age 73 +/- 8 years) completed the depression subscale of the Brief Symptom Inventory (BSI). Plasma NE levels were assessed before and immediately after a speech stressor conducted at the caregiver's home. Hierarchical linear regression was used to determine whether caregiver depressive symptoms significantly improved prediction of change in NE levels beyond other factors theoretically and empirically related to NE.


RESULTS
Level of depressive symptoms significantly predicted post-stressor change in NE levels (p < .01), even when controlling for age, caregiver distress, presence of caregiver hypertension, and care recipient level of cognitive function. Higher levels of depressive symptoms were associated with a greater plasma NE response to the psychological stress task.


CONCLUSIONS
Depressive symptoms may act to exaggerate NE response to the stress of caregiving, potentially leading to an allostatic load that might predispose caregivers to negative health consequences, including cardiovascular morbidity.
Mausbach
Brent T
BT
Department of Psychiatry, University of California at San Diego,La Jolla, CA 92093-0680, USA. bmausbach@ucsd.edu
Dimsdale
Joel E
JE
Ziegler
Michael G
MG
Mills
Paul J
PJ
Ancoli-Israel
Sonia
S
Patterson
Thomas L
TL
Grant
Igor
I
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease; D017028:Caregivers / Q000523:psychology*; D003863:Depression / Q000097:blood / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood*; D013060:Speech; D013315:Stress, Psychological / Q000097:blood / Q000503:physiopathology*
D009638:Norepinephrine