How bad is loneliness for your health? "According to a paper published last year in the Public Library of Science, Medicine, the effect on mortality of loneliness is comparable with that of smoking and drinking. It examined, and combined the results of, 148 previous studies that followed some 300,000 individuals for an average period of 7.5 years each, and controlled for factors such as age and pre-existing illness. It concluded that, over such a period, a gregarious person has a 50% better chance of surviving than a lonely one."