At what age do you think it's appropriate for children to stop interacting with their imaginary friends? Is having imaginary friends as an adult a sign of mental illness, even if you know they are not real? I'm asking for advice because I frequently talk to my favorite imaginary companion when no one else is around. I think it's just because I don't like to be by myself, although I do spend a great deal of my time alone... Anyway, someone heard me one time and she was pretty weirded out. But after I explained it and everything she seemed more pitying than disturbed.