Selective mutism

Definition:

A rare condition occurring in childhood where a child who is fluent with language consistently fails to speak in situations where language is expected. This typically occurs is school or social situations.

Causes, incidence, and risk factors:

The cause of selective mutism is due to a psychologically determined refusal to speak. Some children have histories of speech problems or delay of onset of speech. Problems within the family or at school appear to acerbate this disorder. Young children have a higher incidence of this disorder.