Catatonia: the tension insanity.

A historical review of Kahlbaum's Catatonia is presented. He attributed the condition to organic cerebral disease. It is now best considered as a neuropsychiatric syndrome due to a wide variety of organic disease processes, manifest in catelepsy in a setting of an abnormal mental state, most commonly an affective disorder. Chronic catatonic states were common sequelae of encephalitis lethargica; this disease has now disappeared in epidemic form with a resulting fall in the incidence of catatonia in psychiatric hospitals. Acute catatonia, due to medical and particularly pharmacogenic causes, continues to occur in current psychiatric practice.