Logorrhea literally means excessive use of words - speech that runs on and on.
Sources disagree whether pressured speech is a form of logorrhea. Dorland's Medical Dictionary includes pressured speech in its definition of logorrhea; on the other hand, in Clinical Management of Bipolar Disorder, Dr. Paul Keck lists the two as separate symptoms. Dr. Keck refers to studies that found logorrhea was one of the most common symptoms of bipolar mania, occurring in 89% of cases.
Logorrhea may also be a symptom of catatonia, as rapid, often incoherent mumbling.