Before beginning a discussion of causes of Selective Mutism in children it is important to define what Selective Mutism is. It is defined as a complex childhood anxiety disorder in which a child, who has the ability to both speak and understand language, fails to speak and communicate effectively in certain environments or social settings. However, to be clear, this is not the same as a child with mutism who never speaks, because they are unable to. Rather these children select not to speak.
Selective Mutism usually occurs in children under the age of 5 and presents most often in social settings or in school. Since the child’s ability to speak and understand spoken language isn’t impaired, children with Selective Mutism are able to speak and communicate in settings where they are relaxed, comfortable and secure. For this reason, speaking may occur in environments that are more familiar, such as at home with their family.
The cause of Selective Mutism is not known, however most experts believe that children with the condition inherit this through a familial tendency to be inhibited and anxious. As a result, some affected children have a family history of anxiety disorders, extreme shyness, or Selective Mutism, and most children with this condition have some form of extreme social phobia or social anxiety.
It is not uncommon for parents to think that the child is refusing to speak, however the child is really unable to speak in certain settings. For a child to be diagnosed as having Selective Mutism, this pattern of mutism must be observed for at least 1 month. This does not include the first month of school, since shyness is common during this period. It is important that other causes for the child not speaking be taken into consideration.