Here’s another reason to be happy – or not, depending on your disposition: Happiness may not be as strongly linked to longevity as previous research had indicated. A huge new study in The Lancet finds that among 700,000 women in Britain, those who were happy vs. unhappy had about the same risk of mortality over the years. Though being unhappy – or depressed, lonely, or stressed – may make you less apt to take care of your health in any number of ways, as the study reports, it may not itself make you less any healthy. And this is somewhat different from what other research had found in the past.
The researchers, led by the University of Oxford’s Professor Sir Richard Peto, looked at data from the UK Million Women Study, which tracked women’s health outcomes over the long term. At the beginning of the study, the women were on average 59 years old and none had any serious health issues like heart disease, cancer, stroke, or chronic obstructive lung disease. They were given questionnaires about their mental health and well-being near the beginning of the study: 39% of the women reported being happy most of the time, 44% said they were usually happy, and 17% said they were unhappy.
Although unhappiness was linked to self-reported poor health, it was not linked to mortality over the long term. After the team adjusted for potentially confounding variables like smoking, body mass index, and being treated for health problems like asthma, diabetes, and arthritis, there were no connections between unhappiness, stress, and lack of control and mortality. Unhappy and happy people both had about the same risk of death overall, including that from heart disease and cancer.
The authors suggest that we’ve been thinking about the relationship between health and happiness backwards. It’s not that unhappiness causes poor health directly – if anything, it’s the other way round. “Many still believe that stress or unhappiness can directly cause disease,” said Peto, “but they are simply confusing cause and effect.”
In other words, poor health may be the thing that comes first, and this can make a person unhappy, stressed, or feel out of control. ”Illness makes you unhappy, but unhappiness itself doesn’t make you ill,” said study author Bette Liu. “We found no direct effect of unhappiness or stress on mortality, even in a ten-year study of a million women.”
Certainly studies in the past have found connections between unhappiness – particularly depression – and health problems. But the subject is notoriously difficult to study, since you can’t do randomized clinical trials: You can’t assign people to being happy or unhappy and then watch their health outcomes. One has to use a natural setup, which is intrinsically more difficult to draw conclusions about. What the current study does have is a huge number of participants, which gives it more power, despite its illustrating only correlation, not causation.
Another issue in the current study is that men weren’t included, and it’s not clear how they might change things, if at all. Since there are known connections between depression, stress, and heart disease, it may be that including men may shift things slightly.
Finally, it’s worth pointing out that depression and anxiety were the central factors that, when taken out of the equation, weakened a connection between unhappiness and mortality. This suggests that depression and anxiety may actually be involved, but they don’t totally explain the connection.
More work will need to be done here, but the study does throw a little doubt on all the research and popular articles that suggest that the unhappy among us will die sooner. Unhappiness may well be linked to poor health in other ways – for instance, depression may lead a person not to eat poorly and be sedentary, loneliness may trigger a inflammatory response that leads to poor health, and so on and so on – but unhappiness may itself not kill you directly. This isn’t license to be unhappy, of course, but it may deepen the discussion just a little. And if nothing else, knowing that your unhappiness won’t be your downfall may make you just a little happier going forward.