Depressive symptoms, depletion or developmental change? Multidimensionality in the Geriatric Depression Scale according to contemporary interpretations of the disengagement theory of aging

Abstract

Lewinsohn et al. (1991) have noted that some symptoms of depression, such as lack of social interest and greater self-involvement, mirror normal attributes of older adults according to Disengagement Theory (Cumming & Henry, 1961), the early developmental theory of aging which stated that there is a mutual social and affective withdrawal between the older adult and his social environment. Socio-Emotional Selectivity Theory (Carstensen, 1992) and gerotranscendence (Tornstam, 1997) both also describe the narrowing of the older person's social world and decreasing investment in activities and social relationships. The Geriatric Depression Scale (GDS; Brink et al., 1982), a 30-item self-report scale, was developed specifically to screen older individuals for depressive symptoms. Six GDS items, comprising a "Withdrawal/Apathy/[Lack of] Vigor" (WAV) dimension appear to be descriptive of disengagement and may lead to over-identification depression in older adults. The GDS, demographic and health measures, and an index of changes in activity and interest level developed for this study were mailed to 990 members of a large Health Maintenance Organization 65 years of age or older. Respondents returned 327 completed surveys and 163 "Decline" postcards after one mailing. Key findings include that GDS WAV contributed disproportionately to identification of depression. Endorsement rates for the items in WAV were among the scale's highest, whereas those of the 14-item Dysphoria factor were among the lowest, suggesting that WAV items are less likely to be "pathological." WAV's correlation with age was significant; Dysphoria's was not. In a multiple regression on the 28-item disengagement score WAV was the strongest predictor after controlling for age, health and Dysphoria. Approximately one third of the full sample and 60% of those aged 75 and over were identified as having at least moderate disengagement without depression. Disengagement is akin to "depletion of normal aging" and relates to changes in physical health and functioning. Since the six WAV items appear congruent with disengagement or Socio-Emotional Selectivity, particularly in later old age, interpretation of the GDS in clinical or research settings may be improved by considering subscale scores, weighting the items, or figuring in age and health status of the respondent.