I thought this article was interesting:
Loneliness More Damaging Than Addiction
Loneliness is as bad for the health as smoking, says a recent research.While common definitions of loneliness describe it as a state of solitude or being alone, loneliness is actually a state of mind which causes people to feel empty, alone and unwanted. People who find themselves in this situation are lonely and often crave human contact, but their state of mind makes it more difficult to form connections with other people.
The research also found that those with a poor social network are at increased risk of high blood pressure, which makes the genes, the body needs to fight off serious viral infection less active. Loneliness may also cause cancer or heart disease.
Psychologists explain that feeling alone and unloved can also make it difficult to sleep and even increase the risk of dementia.
Loneliness causes stress, and stress appears to be bad for memory (apparently shrinks the hippocampus)…