Before knowing anything about bipolar disorder, I called this sensation "racy brain." Thoughts and music would be zooming through my head so fast that sometimes I wanted to scream. If it was going on at bedtime, it could take me an hour or more of concentrating on word games to get myself to sleep.
Components of racing thoughts can include music, snatches of conversation from movies or television or books, one's own voice or other voices repeating a phrase or sentences again and again, or even rhythms of pressure without any "sound" in the thought.
The phenomenon called racing thoughts is distinct from "hearing voices," which is a symptom of schizophrenia, schizoaffective disorder, severe mania or other psychotic disorders. Racing thoughts can be a symptom of mania, hypomania or a mixed episode, but unlike some other symptoms of these moods, they can also occur with depression or an anxiety disorder. Sometimes racing thoughts are accompanied by a pounding heart or pounding pulses, including drumming in the ears.