I agree with costello that it's a risk/benefit thing.

I have bipolar with possible psychotic features. I see and hear things randomly. I get paranoia. At one point I had a very long lasting delusion, (Lasted at least 5 years,) but it was before treatment or diagnosis for me. But, I would say I see things maybe once every 1-2 months, hear things maybe once every 3-6 months. Paranoia is more common, but I am learning reality checking skills for it. I'm only on lithium and not an anti-psychotic at this time, and I feel I don't really need that right now.