Selective mutism is a condition in which what is often anxiety or excessive shyness causes a person to refuse to speak in certain situations, even though having the capability to.

In the DSM-IV selective mutism is described as a rare psychological disorder in children. Children with the disorder are fully capable of speech and understanding language, but fail to speak in certain social situations when it is expected of them. They function normally in other areas of behaviour and learning, though appear severely withdrawn and might be unwilling to participate in group activities. As an example, a child may be completely silent at school but speak freely at home. Sometimes the behaviour is triggered by the presence of strangers.

The disorder is not regarded as a communication disorder, in that most children communicate through facial expressions, gestures, etc. In some cases, selective mutism is a symptom of a pervasive developmental disorder or a psychotic disorder.

In diagnosis, it can be easily confused with autistic spectrum disorder, especially if the child acts particularily withdrawn around his or her psychologist. Unfortunatelly, this can lead to incorrect treatment.

Contrary to popular belief, people suffering from selective mutism do not necessarily naturally improve with age, and consequentlly, agressive treatment at an early age is suggestive. The effectiveness of current treatment methods, generally involving therapy and gentile and supportive introductions to social situations. There is some evidence indicating that antidepressants such as Prozac may be effective in treating children with selective mutism.