I have experienced psychosis in the past. I believe that if I don't carefully manage medication and certain other general aspects of my life I could experience psychosis again. It hasn't taken the form of hallucinations, but rather delusional beliefs that certain specific people are out to get me, are following me, and are determined to harm me or are engaged in a conspiracy against me. A psychiatrist has said this is the product of mental illness which can become so extreme as to produce psychotic episodes, which I generally agree with.