Does happiness itself directly affect mortality? The prospective UK Million Women Study

Abstract - The Lancet

 Summary - Background
Poor health can cause unhappiness and poor health increases mortality. Previous reports of reduced mortality associated with happiness could be due to the increased mortality of people who are unhappy because of their poor health. Also, unhappiness might be associated with lifestyle factors that can affect mortality. We aimed to establish whether, after allowing for the poor health and lifestyle of people who are unhappy, any robust evidence remains that happiness or related subjective measures of wellbeing directly reduce mortality.....

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......A complicated question of health and happiness

The study authors reached their conclusions by essentially excluding people who were unhappy and in poor health. They explain that unhappy people who suffer from illness, smoke or who are inactive, for instance, feel unhappy because of their health.

But excluding those people is a mistake, argues Timothy Lau, clinical lead of the geriatric program at the Royal Ottawa Mental Health Centre. The people who rated themselves as unhappy during the study who suffered poor health could have been unhappy long before those physical ailments began, he explained. In other words, people who are unhappy for a long time may develop health problems. This study didn’t properly address that issue, he said......