Patients with dementia are more likely to die sooner if their family caregivers are in poor mental health, regardless of other patient health risks, according to new research.
Brett Ford, assistant psychology professor at U of T Scarborough, co-authored the study, which was conducted at the University of California, Berkeley and published in the Proceedings of the National Academy of Sciences. Ford says their findings may have important implications.
“These findings suggest that by improving the lives of caregivers, we can also improve the lives of patients,” she says.
The study is one of the first to focus on how caregiver health influences a patient’s mortality across several types of neurodegenerative diseases, while also accounting for other mortality risk factors.
After being diagnosed, patients with dementia and other neurodegenerative disease typically live less than five years. Patients are more likely to die earlier based on key risk factors, including sex, age, mental health and subtype and severity of disease. The study accounted for these risk factors and still found that caregiver mental health was a significant factor in mortality.
The researchers found that patients of caregivers with high levels of mental health problems, such as higher levels of anxiety and depressive symptoms, were about 1.5 times more likely to die sooner than those with better mental health.
“I think our results underscore how important it is to provide support to these caregivers, whose numbers are growing but who may not be receiving much support,” Ford says. “It may be useful to view the caregiver and patient as an interconnected system, where both can influence each others’ lives in powerful ways.”
The study tracked 176 patients and their caregivers from 2007 to 2016. Patients had one of six types of neurodegenerative disease. Of the caregivers, 85 per cent were spouses, eight per cent were adult children, and seven per cent were siblings.
Caregivers and patients were first examined at the UCSF Memory and Aging center by Dr. Bruce Miller and his team, then at Dr. Robert Levenson’s Berkeley Psychophysiology Laboratory. Ford and co-authors Sandy Lwi and James Casey compared caregivers’ initial self-reports of mental and physical health to the patients’ annual follow-up exams that tracked their status. Of the 176 patients, 76 died during the nine-year study.
The researchers note that there are many reasons why poor caregiver mental health could influence patient health. Caregivers with poor mental health may be more likely to neglect their patients. Caregivers in poor mental health may also have weakened bonds with patients which, in relationship partners, can predict poor immune system function. Stress, which is associated with poor health and mortality, can also spread from caregiver to patient through emotion contagion and behavior mimicry.
Ford says rates of dementia are rising at “an alarming rate.” Additional research cited by the study has found that caregivers experience depression at four times the rate of non-caregivers, and that there are over 35 million adults globally with dementia or other neurodegenerative diseases.
“Given the growing number of people that will be affected by dementia in the coming years, it’s important to keep studying how we can improve the lives of not only patients, but also their caregivers,” Ford says.