In Brief

Patients on dialysis for terminal kidney failure are just as happy as healthy people and are better at accurately estimating their overall happiness, according to a study in the February Journal of Experimental Psychology: General (Vol. 134, No. 1, pages 3-9). This is the case despite the fact that dialysis patients, and their healthy counterparts, believe poor health takes a significant toll on people's sense of well-being, the study finds.

"It's hard to imagine how kidney failure wouldn't have a big impact on a person's mood," says lead researcher Jason Riis, PhD, of Princeton University. "But we forget that people often adapt to their health conditions, and illness ends up having a much smaller effect on mood than the day-to-day ups and downs of work and personal life that everyone experiences."

Yet even though renal disease patients exhibit resilience, they are unaware that they are as happy as healthy people, the study indicates.

To reach these findings, Riis and his colleagues asked 49 end-stage renal patients receiving hemodialysis and 49 healthy control participants to estimate the percentage of time in a typical week that they would feel happy, depressed, unhappy, frustrated, angry or worried.

The researchers then gave the participants personal digital assistants (PDAs) for seven days. The PDAs prompted people to answer questions about their emotions every two hours. It also randomly asked other questions, such as the extent to which participants felt pain or fatigue.

After seven days, the participants estimated their typical moods throughout the past week. In the study's exit interview, the researchers asked the healthy participants to imagine that they were dialysis patients and to then estimate how much time they would spend in various moods. In turn, dialysis patients imagined the percentage of time they would spend in each mood if they had never developed kidney disease.

Healthy participants greatly underestimated the renal patients' happiness. On average, they also slightly underestimated their own average mood. Conversely, renal patients significantly overestimated healthy people's happiness.

"In imagining a life that had always been free of illness, [the patients] are instead imagining the initial mood increase that would follow the transition from their current state to good health," says Peter Ubel, MD, the study's senior researcher and the director of the Program for Improving Health-Care Decisions at the University of Michigan.

The researchers hope to expand the use of moment-to-moment well-being measures to assess people with a range of health conditions, including mental illness.

Future implications of the research may involve finding ways for people to more accurately predict the long-term emotional consequences of their illnesses, and in some contexts, to help them make better health-care decisions. In addition, the researchers say their research will inform economists' work assessing the cost-effectiveness of health-care interventions.