Catatonia and epilepsy: An underappreciated relationship.

Catatonia is currently conceived in the major diagnostic manuals as a syndrome with a range of possible psychiatric and general medical underlying conditions. It features diverse clinical signs, spanning motor, verbal and behavioural domains and including stupor, catalepsy, mutism, echolalia, negativism and withdrawal. The existing literature suggests that seizure activity may underlie catatonia in approximately 2% of cases. There are three possible temporal relationships between catatonia and seizure activity: (1) ictal catatonia, in which catatonia is a presentation of non-convulsive status epilepticus; (2) postictal catatonia, in which catatonia follows a seizure, and (3) interictal catatonia, in which catatonia and seizures occur in the same individual without any clear temporal relationship between them. Electroencephalographic (EEG) abnormalities are common in catatonia, even in those cases with a presumed primary psychiatric origin, and often consist of generalised background slowing. Paradoxically, electroconvulsive therapy is an effective treatment for catatonia. There are several converging pieces of evidence suggesting that there may be underlying seizure activity in more cases of catatonia than has hitherto been recognised, though identification of these seizures may require intracranial EEG recording.