There you have it, folks — a study of around a million women found that being happy or unhappy doesn't affect how long you live, contradicting the results of countless past studies.
The current study, published Dec. 8 in The Lancet, claims that past links between happiness and longevity were simply the result of misinterpreted cause and effect. The idea is that sick people tend to be less happy than healthy people, said lead study author Dr. Bette Liu, a researcher at the University of New South Wales in Australia.
"Illness makes you unhappy, but unhappiness doesn't make you ill," Dr. Liu, who was at the University of Oxford while conducting this research, said in a press release. "We found no direct effect of unhappiness or stress on mortality, even in a 10-year study of a million women."
That study was the UK Million Women Study, which is exactly what it sounds like. About a million women were surveyed on their happiness, feelings of control, stress and health, among other items. Dr. Liu and team also recorded how many of these women died over a 10-year period (around 30,000).
And guess what? Happy women were just about as likely as unhappy women to die.
"Being healthy definitely plays a part in a person's happiness, but the opposite is not necessarily true," said Jeffrey M. Schussler, MD, an interventional cardiologist on the medical staff at Baylor Heart and Vascular Hospital and Baylor University Medical Center at Dallas, in an interview with dailyRx News. "While some previous studies have suggested a link between happiness and your health, the most recent large study from Liu et. al. does not find a direct link between how happy you are and better health."
Dr. Schussler added, "Unhappiness is just not the cause of your poor health."
Still, that doesn't mean you should just let your happiness fall by the wayside. Depression is still thought to be a major contributor to disease and suicide. Also, while this study's findings may be compelling, it's only one study in a sea of others with conflicting findings.
The UK Medical Research Council and Cancer Research UK funded this research. Dr. Liu and colleagues disclosed no conflicts of interest.