I wouldn't say I have imaginary friends, but I do often make up scenarios about people that I know to comfort myself. For example, one of the mental health counselors at the hospital was very caring and helpful to me. When I am going to bed at night I imagine him doing bed checks and that helps me calm and go to sleep.

I have other scenarios that aren't at all healthy and they usually come during depression or mixed episodes.

I wonder if when you are feeling manic, you don't need your imaginary friends because you are feeling good and don't need comforting.