The things you run into on the web. I cannot remember what I searched last week that brought me to this title, and the excellent webcast lecture by social neuroscientist, John Cacioppo. "Connected Minds: Loneliness, Social Brains, and the Need for Community" is the title of his lecture, though dynamic relationship between health and loneliness was what caught my eye as a header.
Using a truly telescopic approach - going from micro to macro and back - Cacioppo explains how human brains evolved to feel loneliness when we perceive isolation, just as we evolved hunger pangs when our stomachs are empty. The key term was "perceived siolation" because, as we all know, you can be lonely in a crowd, maybe even lonelier than when you're actually physically alone. Perceived isolation causes the body (cued by the mind) to become hypervigilant. And no wonder. If you are either totally alone, or you feel you may as well be (because those around you don't bother with you, understand you, or show you sufficient caring), you had better watch your own back! Hypervigilance has many repercussions, among which is sleep disruption.
The loneliness-in-a-crowd feeling - of not belonging in the tribe in which you happen to find yourself - used to be something associated with travellers (think country boy arriving in the city), and free-thinking edge-dwellers ("no one understands me"). Some of these people manage to pour their angst into art or inventions or long-term projects that require solitude, and end up helping the world (not necessarily the human part of it). While others, feeling unjustly rejected by the pack, become lone wolves, loose cannons, social outcasts - dangers to others and themselves. I don't need to remind anyone how some of those stories play out.
We are social animals and need to feel connected in order to feel safe in our skins.