Mood disorders such as a bipolar disorder and depression are the most common etiologies to progress to catatonia. Other psychiatric associations include schizophrenia and other primary psychotic disorders. It also is related to autism spectrum disorders.Catatonia is also seen in many medical disorders, including infections (such as encephalitis), autoimmune disorders, meningitis, focal neurological lesions (including strokes), alcohol withdrawal, abrupt or overly rapid benzodiazepine withdrawal, cerebrovascular disease, neoplasms, head injury, and some metabolic conditions (homocystinuria, diabetic ketoacidosis, hepatic encephalopathy, and hypercalcaemia). Pathogenesis
The pathophysiology that leads to catatonia is still poorly understood and a definite mechanism remains unknown. Neurologic studies have implicated several pathways; however, it remains unclear whether these findings are the cause or the consequence of the disorder.Abnormalities in GABA, glutamate signaling, serotonin, and dopamine transmission are believed to be implicated in catatonia.Furthermore, it has also been hypothesized that pathways that connect the basal ganglia with the cortex and thalamus is involved in the development of catatonia. Diagnosis
There is not yet a definitive consensus regarding diagnostic criteria of catatonia. In the American Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and the World Health Organizations eleventh edition of the International Classification of Disease (ICD-11) the classification is more homogeneous than in earlier editions. Prominent researchers in the field have other suggesions for diagnostic criteria.DSM-5 classification
The DSM-5 does not classify catatonia as an independent disorder, but rather it classifies it as catatonia associated with another mental disorder, due to another medical condition, or as unspecified catatonia.
Malignant Catatonia: Malignant catatonia is a life-threatening condition that may progress rapidly within a few days. It is characterized by fever, abnormalities in blood pressure, heart rate, respiratory rate, diaphoresis (sweating), and delirium. Certain lab findings are common with this presentation; however, they are nonspecific, which means that they are also present in other conditions and do not diagnose catatonia. These lab findings include: leukocytosis, elevated creatine kinase, low serum iron. The signs and symptoms of malignant catatonia overlap significantly with neuroleptic malignant syndrome (NMS) and so a careful history, review of medications, and physical exam are critical to properly differentiate these conditions. For example, if the patient has waxy flexibility and holds a position against gravity when passively moved into that position, then it is likely catatonia. If the patient has a "lead-pipe rigidity" then NMS should be the prime suspect.Other forms:

Periodic catatonia is an inconsistently defined entity. In the Wernicke-Kleist-Leonhard school, it is a distinct form of "non-system schizophrenia" characterized by recurrent acute phases with hyperkinetic and akinetic features and often psychotic symptoms, and the build-up of a residual state in between these acute phases, which is characterized by low-level catatonic features and aboulia of varying severity. The condition has a strong hereditary component. According to modern classifications, this may be diagnosed as a form of bipolar disorder, schizoaffective disorder or schizophrenia.