"After controlling for initial health conditions, we find that happiness extends life expectancy."
via @bakadesuyo
Happiness research is certainly interesting, but Will Wilkinson has questioned whether it's reliable and what it means for policy.
Wilkinson draws on the work of (among others) philosopher Dan Haybron:
Happiness itself seems to be multidimensional and plural in constitution, having complex biological underpinnings. First, neuroscientific studies have established that good and bad feelings do not exist on a single continuum—an increment of pleasure does not cancel out an equal increment of pain—and it is possible to feel happy and sad simultaneously.