Many people who are not mentally ill also have spiritual experiences. I have had several spiritual experiences that were distinctly different from psychosis.

My stance is that if a person is able to function, take care of themselves, not harm others, etc, while also being spiritual, then it is simply genuine spirituality (which different people experience differently) and is harmless, sometimes even helpful or fulfilling.

But with psychosis it's like everything gets scrambled up. I can't function, I'm confused, my self-care goes down the drain and so on. I might interpret things as spiritual in my confusion, but my inability to care for myself and function is the dead giveaway.