I've been reading about the differences in delusionary states between the manic phase of bipolar and sz. Patients with bp tend to have many delusions that crop up but last for a short time (hours-days) while people with sz have delusions that last for longer.

From what I've learned from this forum over the years (having participated in both the sz and bp forums) bipolar patients tend to experience hallucinations that are brief as well (sometimes fading as soon as they are perceived or a voice that just says a few words) while schizophrenic patients experience more constant hallucinations of voices conversing, commenting on what they are doing, etc.