Your ‘cognitive life expectancy’ may not be as depressing as you think

People dread dementia, but new research finds it may not be as bad from a psychological standpoint as many of us would guess.

Anthony Bardo, a sociologist at the University of Kentucky, looked at the relationship between happiness and cognitive health in people 65 and older. He found that most people were happy during most of their senior years, whether or not their cognitive functioning was good.

"I was really surprised to see the vast majority of impaired years are happy ones," Bardo said.  The question of how brain health relates to happiness is important, he said, because people are living longer, with physical problems compressed into fewer years at the end of life.  That shifts the spotlight to brain functioning, which also tends to decline in later life, and  how that affects the quality of life in those extra years.

Bardo, who worked with Scott Lynch at Duke University on the project, started with the idea of "cognitive life expectancy," or how long people can expect to live with good brain health.  He then analyzed how cognitive impairment affected happiness. The research has been presented at a professional conference but has not yet been published.

The study analyzed responses from 15,000 people who participated in the Health and Retirement Study from 1998 to 2014.  There were measures of brain function, and people were asked whether they had been happy all or most of the time in the last week, or only some or none of the time.  Bardo said this measure of happiness is widely used in research, and the questions can be answered even by people with cognitive impairment.

In the study, people were either happy or not, or impaired or not.  Bardo did not attempt to compare degrees of happiness with severity of impairment. While we often picture people in the final throes of Alzheimer's disease when we imagine dementia, he said, most people have more minor cognitive impairment in their final years.  Those with severe dementia tend to die fairly quickly.

The results were surprisingly positive, although some of the numbers can be sobering if you're around retirement age. Things look considerably better for whites, especially white women, than for blacks and Hispanics. Whites live longer, and with fewer years of cognitive impairment.  Still, the period when people were both impaired and unhappy was about a year or less for all groups, Bardo's analysis showed.

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Overall, of the respondents who completed all study questions, more than 80 percent were happy into their 90s. When questions went unanswered, possibly because study participants could no longer answer them, that number dipped only to 75 percent if Bardo assumed non-answerers in their 80s were unhappy.

Bardo's analysis found that at age 65, a white woman can expect to live about 19 more years. Of those years, she will be cognitively sharp and happy for about 13 and sharp and unhappy for about a year and a half.  She'll be cognitively impaired for a little over five years.  Four of those will be happy.  Those numbers are based on averages for the group, not on how individuals actually progress, Bardo said.

Black and Hispanic women lived a year or two less than white women with more years of cognitive impairment.  They, too, were happy most of those years.

Men in all racial groups lived two to three fewer years than women.  They also had less time with cognitive impairment and most of it was happy.

Bardo has previously studied happiness throughout the lifespan and found that it tends to increase from the late teens to the early 60s, when it begins to level off. It starts to curve downward in the late 70s.

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Amy Yotopoulos, director of the Mind Division of the Stanford Center for Longevity, said the study resonated with her because of what she has witnessed in her father-in-law, who has dementia. "He is much happier now with the disease than he ever was without it," she said.

Shana Stites, a Penn Medicine psychologist who has studied how Alzheimer's disease affects quality of life, said people with dementia often say they are happy if cognitive impairment is not keeping them from doing things they want to do or causing friction in relationships.  People may have a "surge of anxiety" when they first experience symptoms, but they "sort of adapt to this new way of life and anxiety goes down."

In one study comparing quality of life in people with normal cognition, mild cognitive impairment, and early Alzheimer's disease, she said, it was those in the middle — the ones with mild cognitive impairment — who had the most trouble.

>>READ MORE: This is what Shana Stites learned about the psychological impact of a dementia diagnosis. 

Depression can be among the earliest symptoms of dementia, but becomes less common as the disease progresses, she said.

People with cognitive impairment are most likely to be happy when others accept them as they are and urge them to live in the moment or reminisce about happy times, said Stites, who is also a member of the medical and science committee of the Alzheimer's Association Delaware Valley Chapter.

Even if Bardo's study shows older people with cognitive impairment are happy, there's reason to wonder whether their caregivers are doing equally well.  It is stressful to care for someone who is losing independence and emotionally wrenching to watch a family member decline.  Families can help caregivers by working together so the burdens are shared. Caregivers also should seek out groups where they can talk about their experiences.  "Social engagement's really important," Stites said.