The effects can be horrifying. This is a woman by the name of Blanche Monnier. When she was young, Blanche wanted to marry a lawyer, which her family disapproved of. Her mother decided to prevent it from happening by locking the young woman in their Paris apartment. Blanche remained locked for 25 years. Her only contact was were the evil mother and brother. Blanche couldn’t communicate properly and suffered from severe mental health issues. She died about 10 years after being released from the prison, while her mother’s punishment consisted of 15 days under arrest. This is an extreme case, but it shows us something. Human beings are pack animals, we aren’t meant to be alone or confined for too long, even if we do manage to survive physically. In nature, a single human being is nothing, we can be killed easily by most other animals. That’s why we have this social instinct. Loneliness is painful to us. It triggers our real pain response, just like any physically damaging trauma would. A lot of our psychology is based around socializing. After all, we don’t invent our own languages or modes of behavior, we adopt what’s already there and maybe give small modifications to it. The solitary person doesn’t have that luxury. Loneliness can become a vicious circle, where people are ostracized from society, lose the ability to re-integrate back into it, as that requires social skills they can’t attain, and thus suffer from the pain responses associated with being alone in the world. It’s not an issue of introversion and extroversion. I sense that a lot of people in the comments would say “I enjoy being alone”. It’s true that some people need less social contact than others, just like some people need fewer calories to function and less sleep to be mentally sharp. But a complete lack? No, nobody can do that, and it’s possible that lack of social interaction is something we’re suffering from worldwide, similar to zinc or vitamin D deficiency. Source
