If you suffer from a mental illness and can't cure yourself of it then it's very likely that you can be helped. Mental illness nearly always stems from possession. A person starts to behave strangely or even dangerously because ghosts are manifesting themselves through him or her. Many of them know that the body isn't theirs so they lose all restraints and moderation. They simply do as they damned well please. They are often amused by the reactions of those around “the mentally ill” person. What's more, ghosts don't behave in a moderate manner. If they manifest an emotion then they do it in an extreme way, they become that emotion, and then the person become it, too, which is often a loss of control over themselves.