First 150 years of catatonia: Looking back at its complicated history and forward to the road ahead.

Karl Ludwig Kahlbaum (1828-1899) was the first to conceptualize and describe the main clinical features of a novel psychiatric illness, which he termed catatonia in his groundbreaking monograph published 150 years ago. Although Kahlbaum postulated catatonia as a separate disease entity characterized by psychomotor symptoms and a cyclical course, a close examination of his 26 cases reveals that most of them presented with motor symptom complexes or syndromes associated with various psychiatric and medical conditions. In his classification system, Kraepelin categorized catatonic motor symptoms that occur in combination with psychotic symptoms and typically have a poor prognosis within his dementia praecox (schizophrenia) disease entity. Because of the substantial influence of Kraepelin's classification, catatonia was predominantly perceived as a component of schizophrenia for most of the 20th century. However, with the advent of the psychopharmacotherapy era starting from the early 1950s, interest in catatonia in both clinical practice and research subsided until the early 2000s. The past two decades have witnessed a resurgence of interest in catatonia. The Diagnostic and Statistical Manual of Mental Disorders Fifth Edition, marked a paradigmatic shift by acknowledging that catatonia can occur secondary to various psychiatric and medical conditions. The introduction of an independent diagnostic category termed "Catatonia Not Otherwise Specified" significantly stimulated research in this field. The authors briefly review the history and findings of recent catatonia research and highlight promising directions for future exploration.