(3-4) DSM-IV and DSM-IV-TR required at least 2 criteria from 5 areas, including motoric immobility, excessive motor activity, extreme negativism or mutism, peculiarities of voluntary movement, and echolalia or echopraxia . Instead of grouping symptoms into clusters, DSM-5 requires 3 criteria of 12 individual symptoms.

The team of researchers explored the possibility that the cognitive processes underlying a broad range of empathetic responses -- including emotional contagion, contagious yawning, and pathologies like echopraxia (compulsive repetition of others' movements) and echolalia (compulsive repetition of others' speech) -- could evolve in the absence of kin selection or any other mechanism directly favouring cooperation or coordination.

Peculiarity of voluntary movements such as posturing, stereotyped movements, mannerisms or grimacing were detected in 20 (47.61%) patients and echolalia or echopraxia in 15 (38.10%) patients.

A DSM-5 [7] diagnosis of catatonia requires the presence of three or more of the following symptoms: stupor, catalepsy, waxy flexibility, mutism, negativism, posturing, mannerism, stereotypy, agitation, grimacing, echolalia, and echopraxia . The patient exhibited (see Supplementary Table S2) stupor, mutism, negativism, posturing, stereotypy, and agitation.

Mutism, negativism, echolalia, echopraxia , and waxy flexibility are the most important clinical findings in catatonia.

"Contagious yawning, in which yawning is triggered involuntarily when we observe another person yawn, is a common form of echophenomena - the automatic imitation of another's words (echolalia) or actions ( echopraxia )," the study said.

These behaviours varied over the days and she developed posturing, echopraxia , echolalia, and ambivalence subsequently.