Happiness and unhappiness have no direct effect on mortality

Unhappiness was associated with smoking, lack of exercise and not living with a partner.

The researchers discovered that while poor health makes people unhappy, and poor health can shorten lives – unhappiness itself is not life-shortening.

The research, published in medical journal The Lancettoday, was part of Oxford University’s The Million Women Study and found participants who had self-rated as happy had the same death rate as those who had identified as unhappy. At least 700,000 women participated in the study between 1996 and 2001. Compared to happy people (or those who answered usually or most of the time in the questionnaires), those who believed they were unhappy (whose answers to the questionnaire might have been sometimes or rarely/never) were nearly 30% likely to die if their age was considered.

The researchers focused on a group of 719,671 women who answered all the questions regarding happiness, including 31,531 who died during the subsequent decade.

Therefore, the investigators concluded that unhappiness itself was not associated with increased mortality among the unhappy contingent of women.

He said that previous reports of reduced mortality being associated with happiness had not allowed properly for the strong effect of ill health on unhappiness and on stress.

Researchers initially found a significant link between those who said they were unhappy and those who passed away.

The study is so large that it rules out unhappiness being a direct cause of any material increase in overall mortality in women.

But the research team in the United Kingdom and Australia said those studies failed to deal with reverse causality – namely, that people who are ill are not very happy.

Dr Philipe de Souto Barreto and Professor Yves Rolland from the Institute of Ageing at the University Hospital of Toulouse, France said the study provided “valuable and robust information” about happiness. It found that poor health contributes to unhappiness and shorter life spans, but unhappiness itself is not life-shortening.

After adjusting for any differences already present in health and lifestyle, the researchers say the overall death rate among those who were unhappy was the same as the death rate among those who were generally happy. Surveying men could alter the results because there is a chance they could define happiness in a different way than women do.

They argue that emotions such as unhappiness or stress can cause people to take on unhealthy habits – such as smoking or drinking too much alcohol – rather than directly affecting lifespan.

Peto said particularly important data came from 500,000 women who reported on their baseline surveys that they were in good health, with no history of heart disease, cancer, stroke or emphysema.

“The fact that people who smoked were generally unhappy ties in with the statistic two thirds of smokers want to stop. It’s the poor health of those individuals who are unhappy that actually explains why they might have higher death rates”. However 17% said they were unhappy.