Catatonia and autism spectrum disorder: A common comorbid syndrome or a core feature?

Table 4 Symptoms of catatonia based on the Diagnostic and Statistical Manual of Mental Disorders-5-TR

Catatonia symptoms	Definitions
Mutism	No or very little verbal response (excluding known aphasia)
Posturing	Spontaneous and active maintenance of a posture against gravity
Stupor	No psychomotor activity; not actively relating to the environment. An extreme manifestation of the previous phenomena
Agitation	Emotionally restless, not as a result of external stimuli
Waxy flexibility	Slight, even resistance to positioning by the examiner
Catalepsy	Passive induction of a posture held against gravity
Echolalia	Mimicking another’s speech
Echopraxia	Mimicking another’s movements
Negativism	Opposition or no response to instruction or external stimuli. Negativism can be a complex behavior
Stereotypies	Repetitive, abnormally frequent, non-goal-directed movements
Mannerisms	Odd, circumstantial caricature of normal actions
Grimacing	Displaying contorted facial expressions