The criteria for diagnosing selective mutism disorder given by the reference manual, the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision include the failure to speak in some social situations even though the child may talk at other times. This criterion is not met if the child does not speak at all in any situation.
The child’s inability to talk must interfere with the achievement of such relevant goals as schoolwork, play with friends, or communication of needs. In addition, the lack of speech must persist for at least one month. The first month of school should not be included in this measurement because many children are shy and unwilling to talk freely until they feel comfortable with their new teacher, classmates, and surroundings.
Furthermore, the child’s lack of speech cannot be attributed to unfamiliarity with the language they must use in school or social settings. The diagnosis of selective mutism does not apply to children from immigrant families who may not feel comfortable conversing in a second language. Moreover, the child’s inability to talk cannot be attributed to stuttering or similar speech disorders, which may make the child uncomfortable because they are aware that their speech sounds different from the speech of their peers. The lack of speech also must not be attributable to schizophrenia, autism, or other mental health disorders.
The disorder of selective mutism is usually noticed first by parents or teachers of affected children. It is often hard for doctors to diagnose selective mutism because it is unlikely that the child in question will talk to them. Therefore it may be difficult for a general practitioner to assess the existence of any underlying language or developmental problems that may be either causing or exacerbating the disorder. Tests that evaluate mental development without verbal responses from the patient may be used successfully to evaluate children with selective mutism.
