Biopsychological markers of distress in informal caregivers

Thirty caregiving wives participated in a study of caregiving distress and negative mood (depressive symptoms) by making diary entries on stressful caregiving situations and collecting saliva samples 4 times a day. At the end of the 7-day study period, caregivers' salivary cortisol production was compared with their diary entries and correlated with pencil and paper self-report scores of caregiver distress and depressive symptoms.

Despite the inability to control a number of factors thought to confound cortisol production (exercise, smoking, alcohol ingestion, and prescription medications), there was a statistically significant difference between No Caregiving and Caregiving cortisol, F(1,739) = 7.67, P = 0.006, with cortisol production higher when caregiving events occurred. However, efforts to code specific types of caregiving situations (e.g., 1 = indirect care; 4 = AD problem behavior care) did not further differentiate cortisol production. Although caregivers' self-reports for the same 7-day period indicated they were depressed, pencil-and-paper measures of distress and negative affect were not significantly correlated with cortisol production.

The finding that this caregiving group was significantly stressed by caregiving, as evidenced by increased cortisol production during caregiving episodes, verifies the importance of further exploration of specific caregiving situations as contributory factors in caregiver health and well-being. In that saliva is a relatively economical and comparatively noninvasive biological data source for community-based stress studies, methodological limitations of the study are identified and 5 recommendations are made for future biological marker studies of caregiver distress in community-based settings.