Idiopathic catatonia: validity of the concept.

Although catatonic features can be seen in various psychiatric and organic disorders, some patients with catatonia cannot be fitted into existing classification systems. In the current study various sociodemographic and clinical variables were compared between patients who presented with catatonia only (idiopathic catatonia), or with catatonia as a symptom of an identifiable underlying functional disorder. Patients seen over one year (1988) were classified into idiopathic catatonia (n = 30) and according to diagnosis (n = 35; schizophrenia n = 19, depression n = 16). There was an excess of females in the idiopathic group and the illness was of a shorter duration. There were no other differences between the groups. All subjects showed good response to ECTs and required almost the same mean number of ECTs. No clusters were observed using the average method. The current study suggests that catatonic symptoms can occur in the absence of any other identifiable psychiatric syndrome, although they cannot be otherwise differentiated from other psychiatric syndromes in which catatonia can present.