This is a bizarre post.

How exactly does someone who is having auditory or visual hallucinations exert self-discipline?

I'd certainly agree that some people know the voices they hear are hallucinations, and that some of those people live happily with those voices and don't need meds. Is that what you're trying to say?

Because it sounds like you're saying "pull yourself together", or "try harder" or similar.

Someone who has a severely broken leg needs to have a cast and needs to do the physiotherapy, and both of those need some self discipline. But after that discipline isn't going to make the bone knit faster.

Many people with "mental issues" can't just think themselves better.