The Effect of Physical Limitations on Depressive Symptoms Over the Life Course: Is Optimism a Protective Buffer?

We examined the extent to which optimism buffers the effects of physical limitations on depressive symptoms across 4 mid- and later-life age groups (ages 40-49, 50-64, 65-74, 75 and older at baseline). Analyses are motivated by stress theories, which propose that the protective effects of coping resources are evidenced only at high levels of stress. We further explore whether these purportedly protective effects diminish with age, as health-related stressor(s) intensify and become irreversible.

We use data from 2 waves (2004-2006 and 2013-2014) of the Health and Retirement Study (HRS, n = 4,515) and Midlife in the United States (MIDUS, n = 2,138). We estimate ordinary least squares regression models with 3-way interaction terms to examine prospectively the benefits of optimism as a coping resource for persons with physical limitations across 4 age groups. Physical limitations are assessed with a composite measure encompassing mobility and activity of daily living limitations.

In HRS and MIDUS, persons with 3+ limitations reported significantly more depressive symptoms than persons with 0-2 limitations, yet these disparities diminished at higher levels of optimism. Buffering effects of optimism vary by age. For midlife and young-old persons with 3+ limitations, optimism is strongly and inversely related to depressive symptoms at follow-up. Comparable protective effects are not evident among the oldest sample members.

Stress and coping models should consider more fully factors that limit older adults' capacity to deploy purportedly protective personal resources. Investments in structural or institutional supports may be more effective than interventions to enhance positive thinking.