There is a persistent belief among many that unhappiness and stress can lead to ill health and even increase your risk of death. But a new extensive study of women in the U.K. has found that happiness appears to have no direct impact on mortality, and that earlier studies suggesting this link had simply confused cause and effect. Despite this reversal of the well-established myth, the researchers think that because the notion is so deep-seated, their results might not actually change much of the public’s mentality.
The research was conducted using the UK Million Women Study, a national study in collaboration with the National Health Service and Cancer Research UK of more than one million women over the age of 50. The new paper, published in The Lancet, looked at how the participants’ illness related to their happiness over a period of 10 years. “Illness makes you unhappy, but unhappiness itself doesn't make you ill,” explains Dr. Bette Liu, lead author of the study.
This is in contradiction to what previous studies have found. The dogged myth that unhappiness causes ill health likely has roots in the idea that stress can induce heart problems. To investigate this, the researchers sent questionnaires to women who were part of the UK Million Women Study. Every three to five years, they were asked to self-rate their health, happiness, stress, feeling of control, and if they felt relaxed or not. The vast majority of participants said that they felt happy in general, but around one in six said that they were generally unhappy.
Over the next decade, these women were followed using electronic records of mortality, during which time around 30,000 of them died. Taking into account other health risks, such as smoking and obesity, the researchers found that the death rate of those who recorded themselves as unhappy was no different to those who said they were. Because of the size of the study, it means that any observed increase in mortality among those who were unhappy cannot be seen as a direct cause.
“Many still believe that stress or unhappiness can directly cause disease, but they are simply confusing cause and effect,” says Professor Sir Richard Peto, co-author of the paper, in a statement. “Of course people who are ill tend to be unhappier than those who are well, but the UK Million Women Study shows that happiness and unhappiness do not themselves have any direct effect on death rates.”
The researchers, however, are not confident that their findings will cause a shift in the public’s perception of this issue. They think that the myth that unhappiness and stress can lead to bad health is simply far too deeply ingrained, and that once their study is forgotten about, people will simply revert to old notions.