Refusal or inability to speak. Mutism may occur as a symptom of profound congenital deafness, severe manic–depressive illness, catatonic schizophrenia, or a rare form of conversion disorder. The term may also apply to a religious vow of silence.
Elective mutism is a rare childhood disorder (usually starting before age 5), in which the child can speak properly but refuses to do so most of the time.
Akinetic mutism describes a state of passivity caused by some brain tumours or by hydrocephalus. People with akinetic mutism are incontinent, require feeding, and respond at most with a whispered “yes” or “no”.... mutism
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