Excerpts from my recent Scientific American article:
"Loneliness and social isolation are on the rise, leading many to call it an epidemic. In recent decades, the number of people with zero confidants has tripled, and [...] more than one third of Americans over the age of 45 report feeling lonely, with prevalence especially high among those under 25 and over 65 years old. [...]
"While this alarming trend has grown, so has understanding of its impact. By now, the evidence is abundant and decisive: social connection significantly affects health. [...] For instance, you may be less likely to catch a cold, have a stroke or heart disease, slip into early cognitive decline, and develop depression. You may even be more likely to overcome socio-economic disadvantages, recover quickly from illness, and live longer. [...]
"But the threat of loneliness is still largely absent from common health discourse, medical training and practice, and public awareness. [...] In the same way that mental health has risen up in prominence, yielding more and better research, treatment, and advocacy, so too should social health. [...] Elevating relationships in the public health realm through a variety of individual, community, and societal efforts holds the potential to significantly improve population health."