New evidence suggests a sense of meaning in life can mitigate symptoms of the degenerative disease, even when the illness's harmful plaque has already accumulated in the brain.
Few people would argue that having a sense of purpose in life is anything but a good thing. The Egyptian Book of the Dead even contains a prayer for it: "May I be given a god's duty; a burden that matters." In the modern world, exhorting young people to seek a sense of purpose in life is a mainstay of college commencement speeches, and a collective longing for a feeling of purpose and fulfillment drove evangelical minister Rick Warren's book The Purpose-Driven Life into the best-selling stratosphere.
Medical professionals have also found correlations between a person's sense of purpose and their physical health and survival. As far back as 1946, the Austrian psychiatrist Victor Frankl, who spent several years in concentration camps during WWII and lost his entire family in the Holocaust, found that the people who survived the concentration camps best were those who believed they had a reason, mission, or purpose that required their survival. Man's Search for Meaning, Frankl's classic book on the subject (which he wrote in nine days following his release from the camps) also notes that people who could find a reason or worthwhile purpose for their suffering were far less debilitated by it.
More recently, medical researchers have found that a strong sense of purpose and well-being correlates with better physical health, especially in older adults. But now there's another reason to rethink that stable but meaningless job versus a more meaningful job, life path, or vocation: it appears that a sense that your life has purpose, and that what you do matters, may actually protect your brain from the clinical effects of Alzheimer's disease.
In a paper coming out this week in the Archives of General Psychiatry, a group of researchers from the Rush University Medical Center in Chicago published the first results of a longitudinal study involving more than 1,400 senior citizens. The goal of the study is to evaluate how a strong sense of purpose in life changes the pathology of Alzheimer's disease, from a neurobiological perspective. A couple of previous studies (including one by Dr. Patricia A. Boyle, the lead researcher on this study) found a link between a sense of purpose in life and a lower risk of cognitive impairment. But in this study, Dr. Boyle's team wanted to find out how, neurobiologically, a strong sense of purpose provided that protective effect.
"What distinguishes this from symptomatic research is, you don't know why something is beneficial until you look at what's going on in someone's brain," Boyle explained. "We can say that physical activity, for example, [is] protective against dementia, because it lowers your risk of developing the clinical side of the disease. But until we know what's actually happening in someone's brain, we don't know how physical activity is working. So the element we added was the measured quantification of the actual changes of Alzheimer's disease. We're the first people to look at how purpose in life changes the effect of the Alzheimer's pathology by measuring in this way."
The study has been underway since 1997, and none of the study participants presented with signs of dementia when they entered the research group. The participants received baseline assessments in physical, social, psychological and cognitive health at the beginning and then received follow-up assessments every year. Along with those health- and lifestyle-oriented assessments, participants were also rated as to how strong their sense of purpose in life was, based on their range of answers to a 10-point questionnaire.
On the questionnaire, participants are asked to rate, on a five-point scale ranging from "totally agree" to "totally disagree," their reaction to statements like: "I feel good when I think of what I've done in the past and what I hope to do in the future." "I used to set goals for myself, but that now seems like a waste of time." "I live life one day at a time and don't really think about the future." Or, "I enjoy making plans for the future and working them to a reality."
When the study participants die, their brains are then autopsied to allow the researchers to correlate the physical condition of their brains with the results of each person's cognitive, physical, psychological and "purpose in life" assessments. So far, 246 individuals in the study have died and had their brains analyzed. And the results are surprising.
From a neurobiological perspective, two of the biggest markers of Alzheimer's disease are an accumulation of plaque and what neurologists call "tangles" in the pathways of the brain. The researchers did not find any physical difference in the level of plaque or tangles in the brains of people who rated highly on the purpose of life scale, versus those who did not. (A strong sense of purpose in life does not, in other words, prevent the accumulation of potentially harmful material in the brain.)
But when the Rush researchers looked at participants whose brains, upon autopsy, had identical levels of plaque and tangles, and then correlated that with how those people had rated in terms of both cognitive functioning and a strong purpose of life -- controlling for other factors ranging from overall physical health, exercise, education, and IQ to personality traits and inclinations for depression and other psychological issues -- the people who rated highly on the purpose of life scale had a 30 percent lower rate of cognitive decline, over the whole study period, than those with low scores on the purpose of life scale.
What that means, according to the researchers, is that a strong sense of purpose in life evidently strengthens or provides a higher level of what's known as "neural reserve" in the brain. "Reserve" is the quality that allows many physiological systems in the human body to sustain what the Rush researchers call "extensive organ damage" before showing clinical deficits. Neurobiologists specializing in aging have already determined that this concept also applies to the human brain, because most of us -- regardless of whether we develop clinical symptoms of "Alzheimer's disease" or not -- will accumulate harmful amounts of plaque and tangles in our brains as we age. Autopsies show that. What the Rush researchers' results indicate is that having a strong sense of purpose in life, especially beyond the age of 80, can give a person's brain the ability to sustain that damage and continue to function at a much higher level.
"[The results suggest] that purpose in life is either somehow making someone's brain quicker, brighter, or a faster processor, or it's somehow contributing to the development of other systems that can come on board to compensate when your systems that support memory, language and those things are being littered with bad stuff," Boyle said. The researchers were surprised, she added, at just how "robustly protective" a strong sense of purpose in life really was.
"It's very hard to identify factors that provide reserve, because reserve is a very complex thing," she explained. "There's lots of bad stuff happening in the brain as people get older, and it's hard to protect against it. So we were excited to find something so positive and so helpful, so beneficial. We looked at a whole host of things that would indicate how cognitively active someone was, how socially connected they were, whether they were exercising a lot ... all those things that have been shown to be protective against cognitive outcomes. And the findings for purpose in life was robust even when we adjusted for those things. This suggests that purpose in life really does promote cognitive health as people get older."
I asked Boyle if it was possible that people who rated high on the "purpose of life" scale might have stronger, more curious, and more flexible brains to start with ... making their strong sense of purpose more of a result than a cause of their brain's resiliency.
"I think it's some of both," she answered. "There probably is some association with purpose in life and your computing power, because by virtue of the fact that someone is goal directed, and focused and intentional, they're probably engaging in a whole repertoire of behaviors that do grow their brain and help it become stronger and more flexible. And I think it's certainly the case that people with purpose in life probably engage in a whole wide array of behaviors that are good for them. That said, we did control for those things and we still see this protective effect, which suggests that there may be a direct effect, as well."
Interestingly enough, other research (notably, work by Dr. Carol Ryff, published by the Institute on Aging) has found that the kind of protective effect that purposeful living offers does not accrue from mere happiness, or what researchers call "hedonistic well-being." It would appear that humans are hard-wired a bit like working dogs -- we may dream about a life of ease aboard luxury yachts, but we are at our best when we are gainfully engaged in meaningful work.
In a speech he gave in 1993, John W. Gardner, who was President Lyndon Johnson's Secretary of Health, Education and Welfare before founding Common Cause, the Experience Corps and, at the age of 76, taking a teaching position at Stanford University, said that he believed the key to a vital old age (he was 82 when he gave the speech) was to stay interested in life. "Everyone wants to be interesting," he said. "But the vitalizing thing is to be interested. Keep a sense of curiosity. Discover new things. Care. Risk failure. Reach out."
Twenty years later, the Rush University research team is essentially saying the same thing -- just with a bit more neurobiology to back it up. If we want to live well into old age, instead of just seeking happiness, pleasure, or a secure retirement of leisure, we should seek, instead, what the ancient Egyptians prayed to be given: "a god's duty; a burden that matters."