Authored by Ladson Hinton, UC Davis professor of psychiatry, the study examined the influence of one spouse’s depression on his or her own cognitive functioning as well as on the cognitive functioning of his or her spouse.

“A number of studies have noted depression as a possible risk factor for cognitive decline, but no prior study on older couples has investigated the impact of depression on the other spouse’s mental functioning,” said Hinton. “We hypothesized that depression in the individual or spouse might affect cognitive function in the other spouse over time.”

The results provided some evidence that elevated depression in older adults may have an adverse impact on the cognitive functioning of the people in their social environment.

To conduct the study, Hinton and his research team selected 279 married couples (558 people) from participants already enrolled in a much larger study — the Sacramento Area Latino Study on Aging (SALSA), a longitudinal, community-based study of 1,789 Latinos aged 60 and older living in the greater Sacramento area. The lead investigator for SALSA, Mary Haan, former director of the UC Davis Center for Aging and now a professor of epidemiology at the University of Michigan School of Public Health, is a co-author of the current study. Because caregivers of individuals with dementia frequently suffer from depression, the study excluded participants with dementia and those who were institutionalized.

To develop the data, the research team interviewed the participants in their homes and in their language of choice, either Spanish or English. The researchers met with participants every 12 to 18 months to assess cognitive functioning, depression and a number of other variables. Most couples were involved in the study for an average of three years, with some participating for up to eight years.

Hinton’s team notes that living with a spouse who is depressed may be stressful. That stress, in turn, may negatively impact their partner’s cognitive functioning. One possible explanation is that a person who is depressed may be more socially withdrawn and less socially interactive with their spouse.

The study also found differences in cognitive abilities related to gender. The wives’ cognition was related to baseline depression levels in their husbands but not the reverse. The researchers suggest that women could be more interpersonally attuned to emotional changes in their spouse, or that older Latinas are more affected by their spouse’s depression because of traditional gender values that emphasize sacrifice and responsibility for the well-being of the family.

“Future studies might examine how cognitive function in older couples is affected by additional characteristics, such as the quality of the marriage. These findings need to be replicated in other populations, because there’s no reason to think the results are unique to the Latino community,” Hinton said.

Funding for the study was provided by the National Institute of Aging.