Hallucinations occur frequently in people with psychiatric conditions, including schizophrenia and bipolar disorder, however, you don’t necessarily need to have a mental illness to experience hallucinations. Auditory : Hearing voices or sounds that no one else can (most common type of hallucination). Hallucinations can involve any of your senses, though usually just one at a time. Three types of hallucinations appear most commonly with bipolar disorder: It’s also possible to hallucinate tastes or smells, but older research suggests these hallucinations usually happen alongside delusions.