Selective mutism is generally associated with children but it may extend through adolescence and into adulthood. The Selective Mutism Information and Research Association describe selective mutism as:
"an anxiety disorder in which affected people speak fluently in some situations but remain silent in others. It was once considered rare but is now known to affect more than 6 in 1000 children which is about the same number of children who are affected by classic autism."
According to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV), the following criteria must be met for a diagnosis of selective mutism:
1. Consistent failure to speak in specific social situations (in which there is an expectation for speaking, e.g., at school) despite speaking other situations.
2. The disturbance interferes with educational or occupational achievement or with social communication.
3. The duration of the disturbance is at least 1 month (not limited to the first month of school).
4. The failure to speak is not due to a lack of knowledge of, or comfort with, the spoken language required in the social situation.
5. The disturbance is not better accounted for by a Communication Disorder (e.g., stuttering) and does not occur exclusively during the course of a Pervasive Developmental Disorder, Schizophrenia, or other Psychotic disorder.
Selective mutism is usually transient and lasts, at most, for a few months. In some cases mutism extends beyond this and may last for years (persistent selective mutism). Although considered a rare condition (perhaps 1 per cent of children) it may be the case that it is under-recognized and under-reported.
There are various theories as to the causes. These range from over protective or possible domineering parents, to unresolved psychological trauma, to a response to a traumatic event. Children moving to a new area, or children who are not native speakers, may experience greater anxiety about their accent, the risk of being bullied or humiliated, or fitting in and making friends. The consistent theme appears to be anxiety and for this reason treatment options tend to center around behavior therapy, sometimes in combination with medication for anxiety. Treatment may include the family and sometimes an involvement by the school.
Without treatment selective mutism is very likely to worsen. Some children require help for extreme shyness and anxiety well into their adolescence.
Black, B., Uhde, T.W. (1995) Psychiatric Characteristics of Children with Selective Mutism: A Pilot Study. Child & Adolescent Psychiatry. 34. 7.
"Selective Mutism." Medline Plus. 02/06/2008. Web. 8 Jan 2010. <http://www.nlm.nih.gov/medlineplus/ency/article/001546.htm>.