If a person can be alone and be happy then there is no reason to label him or her as having a disease. However, obviously we are all here because this lack of social connection is causing significant distress. By hiding we are destroying ourselves emotionally. It may not seem so, and it may even be preferable to that of going outside and risking what we perceive to be a far worse fate. By staying inside you will torture yourself the same, except it will be a slow and painful emotional death as opposed to a quick one. And perhaps if you were to step outside, you would actually get better even if it is, initially, a painful experience.