The way my illness works, with visual hallucinations, is that at first I think they're real. Real cockroaches running around my room, real homeless people laying in puddles of their own urine, real cars heading straight for me, real cops pulling their guns out of holsters as they prepare to blow me away. Then after a few seconds they go away. I don't think this sort of hallucination lasts more than about ten seconds. But there comes a point, a few seconds into it, where I just know they're fake.

I've had delusions last more than a decade, but audio hallucinations that go on for days, but visual hallucination only last for seconds.