Emily Esfahani Smith in The Atlantic:
For at least the last decade, the happiness craze has been building. In the last three months alone, over 1,000 books on happiness were released on Amazon, including Happy Money, Happy-People-Pills For All, and, for those just starting out, Happiness for Beginners.
One of the consistent claims of books like these is that happiness is associated with all sorts of good life outcomes, including — most promisingly — good health. Many studies have noted the connection between a happy mind and a healthy body — the happier you are, the better health outcomes we seem to have. In a meta-analysis (overview) of 150 studies on this topic, researchers put it like this: “Inductions of well-being lead to healthy functioning, and inductions of ill-being lead to compromised health.”
But a new study, just published in the Proceedings of the National Academy of Sciences (PNAS) challenges the rosy picture. Happiness may not be as good for the body as researchers thought. It might even be bad.