Catatonia is a complex neuropsychiatric behavioral syndrome that is characterized by abnormal movements, immobility, abnormal behaviors, and withdrawal. The onset of catatonia can be acute or subtle and symptoms can wax, wane, or change during episodes. It has historically been related to schizophrenia (catatonic schizophrenia), catatonia is most often seen in mood disorders. It is now known that catatonic symptoms are nonspecific and may be observed in other mental, neurological, and medical conditions. Catatonia is not a stand-alone diagnosis (although some experts disagree), and the term is used to describe a feature of the underlying disorder.

There are several subtypes of catatonia: akinetic catatonia, excited catatonia, malignant catatonia, delirious mania, and self-injurious behaviors in autism.

Recognizing and treating catatonia is very important as failure to do so can lead to poor outcomes and can be potentially fatal. Treatment with benzodiazepines or ECT can lead to remission of catatonia. There is growing evidence of the effectiveness of the NMDA receptor antagonists amantadine and memantine for benzodiazepine-resistant catatonia. Antipsychotics are sometimes employed, but they can worsen symptoms and have serious adverse effects.