In this study, researchers review seven types of evidence that shows high subjective well-being (SWB)--including life satisfaction, absence of negative emotions, optimism, and positive emotions--cause better health and longevity. Examples of each type of evidence are described, and issues such as causality, effect size, methodological rigor, whether too much happiness can be detrimental to health, and whether there is a threshold effect for SWB are discussed.
