A number of studies have demonstrated that depression symptoms and disability increase the risk of each other, but new research comparing caregivers and noncaregivers digs deeper into this relationship and provides some surprising results. While the observed reciprocal relationship between depression symptoms and disability was observed in noncaregivers, the findings for caregivers surprisingly did not show any reciprocal or longitudinal relationships between disability and depression symptoms, suggesting some unrecognized benefits from caring for a family member or friend. (For other positive benefits associated with caregiving, click here.)
This study included 345 caregivers and 611 noncaregivers, who were part of the Caregiver Study of Osteoporotic Fractures. These were all women, withan average age of 81. The participants were interviewed three times over a six-year period, and at each interview were asked about symptoms of depression and limitations in activities of daily living (ADLs) andinstrumental activities of daily living(IADLs). Age, BMI, medical conditions, race, and marital status were also collected.
In terms of the relationship between depression and disability, previous studies spanning periods of seven to 10 years have suggested that depression symptoms influence the likelihood to disability at a later point in time and vice versa. However, this relationship appears to take time to develop, and is not consistently seen in studies that span only one to three years.
As for the impact of caregiving observed in prior research, studies consistently show caregivers to have more symptoms of depression than noncaregivers. However, other studies have shown caregivers to have better cognitive and physical functioning;this may be because healthier, more active individuals are more likely to become caregivers, or there may be mental and/or physical health benefits to caregiving duties.
At baseline, the study’s caregiver participants were significantly more likely to be married, to be college educated, and to have fewer ADL and IADL limitations than noncaregivers. At baseline, caregivers and noncaregivers did not differ on depression scores, BMI, number of medical conditions, or race.Among noncaregivers, participants who were non-white, less educated, unmarried, and had more medical conditions were more likely to have more depression symptoms. Among caregivers a similar pattern was assumed, but for them there was no association with race, and married caregivers had higher depression symptoms than unmarried caregivers. As for disability, older age, higher BMI, lower education, and a greater number of medical conditions were associated with greater disability. Caregivers showed the same pattern, except for showing no association with education.
Turning to the main focus of the study, the researchers found that for noncaregivers, higher baseline depression symptoms predicted greater disability at follow-up interviews, and greater disability at baseline predicted a higher number of symptoms of depression at follow-up. Quite surprisingly, for caregivers there were no significant associations between symptoms of depression and disability at baseline compared to follow-ups.In an attempt to examine whether physical health differences were responsible for the differences observed, the researchers statistically examined whether differences between BMI and number of medical conditions between the two groups played a role, but taking these into account did not change the differences in the relationship between depression and disability seen between the two groups.
Although this study was not able to address this directly, the authors suggested a few possible reasons for this difference. One was the a potential greater amount of social interaction and social support among caregivers compared to noncaregivers, which would be in line with studies showing greater social engagement associated with fewer depression symptoms, and social support having a stronger impact on depression symptoms than disability. The physical or emotional tasks of caregiving may have also helped caregivers prevent or delay declines in their own health. The authors also suggested that caregiving may have given caretakers a sense of purpose,which can keep a self-reinforcing cycle of depression and physical decline from becoming established.
At present, this study provides more evidence for the underappreciated positive aspects associated with caregiving. Future research will need to examine more closely the reasons for the differences observed here, but at a minimum these group differences suggest that previously observed relationships between depression symptoms and disability need not be inevitable. More closely examining the caregivers who do not show an association between depression symptoms and disability may provide important insights into how all older adults can potentially avoid the reinforcing relationship between depression symptoms and disability from becoming established.
Bacon KL, Heeren T, Keysor JJ, et al. Longitudinal and reciprocal relationships between depression and disability in older women caregivers and noncaregivers. The Gerontologist. (2015).gnu157 DOI:10.1093/geront/gnu157