Most patients experience both depressive and manic episodes, although 10 to 20 percent experience only manic episodes. Patients with bipolar I disorder have a poorer prognosis than do patients with major depressive disorder. I disorder patients may have a second manic episode within two years of the first episode. Patients may be emotionally labile when manic, switching from laughter to irritability to depression in minutes or hours. Patients are not easily interrupted while they are speaking when manic, and they are often intrusive nuisance to those around them.
Patients do have bizarre and mood-incongruent delusions and hallucinations when manic.