Australasian Science: Australia's authority on science since 1938

Unhappiness Has No Effect on Mortality

A study of a million women in the UK has concluded that the widespread belief that unhappiness and stress directly cause ill health comes from studies that confused cause and effect.

Life-threatening poor health can cause unhappiness, and for this reason unhappiness is associated with increased mortality. In addition, smokers tend to be unhappier than non-smokers. However, after taking into account previous ill health, smoking and other lifestyle and socio-economic factors, the study found that unhappiness itself was no longer associated with increased mortality.

Lead author Dr Bette Liu, now at the University of NSW, said: “Illness makes you unhappy, but unhappiness itself doesn’t make you ill. We found no direct effect of unhappiness or stress on mortality, even in a 10-year study of a million women.”

The investigation, published in The Lancet (www.tinyurl.com/opuf7ez), was conducted within the UK Million Women Study. Three years after joining this study, women were sent a questionnaire asking them to self-rate their health, happiness, stress, feelings of control, and whether they felt relaxed. Five out of six of the women said they were generally happy, but one in six said they were generally unhappy.

As in other studies, unhappiness was associated with deprivation, smoking, lack of exercise, and not living with a partner. The strongest associations, however, were that the women who were already in poor health tended to say that they were unhappy, stressed, not in control, and not relaxed.

The main analyses included 700,000 women of average age 59 years, and over the next 10 years these women were followed by electronic record for mortality, during which time 30,000 of the women died.

After allowing for any differences already present in health and lifestyle, the overall death rate among those who were unhappy was the same as the death rate among those who were generally happy. The study is so large that it rules out unhappiness being a direct cause of any material increase in overall mortality in women.

This was true for overall mortality, for cancer mortality and for heart disease mortality, and it was true for stress as well as for unhappiness.