But according to a new study, published in Lancet, which investigated the link between mood and mortality, happiness has no real effect on death rates. The study was part of the Million Women Study programme in the UK, which also investigated the causes of breast and ovarian cancers in women. One million women between the ages of 50 and 69 were studied, where participants filled out a questionnaire about their happiness three years after joining the study. For the next 10 years of follow- up, the researchers kept track of how many died and how. The researchers excluded participants who had diseases like cancer as they thought poor health could cause gloom. The point was to see if unhappiness alone made people more likely to die.
The researchers found that the death rate among those who claimed they were unhappy was no higher than those who said they were usually happy. According to the researchers, poor health and adverse lifestyle choices could shorten lives, but after allowing for those things in their study, ‘The study shows no robust evidence that happiness itself reduces cardiac, cancer or overall mortality.’
They point out that previously established connections between unhappiness and short lives were actually ‘reverse causality’, in which unhappiness was a byproduct of the illnesses that led to the death. ‘It has been suggested that related subjective measures of wellbeing, including being in control, not being unduly stressed, or having positive or negative attitudes to life, could independently affect mortality,’ write the researchers in the journal. ‘However, just as for happiness, these associations were wholly accounted for by personal characteristics and ill health at baseline—after adjusting for these factors… we conclude that happiness and unhappiness have no material direct effect upon mortality.’