Selective Mutism is a relatively rare and complex childhood disorder. It is characterised by a child’s inability to speak in one or more types of social settings, even though the child has ability to speak and understand language.
Selective Mutism (SM), formerly called elective mutism, is best understood as a childhood anxiety disorder characterized by a child or adolescent’s inability to speak in one or more social settings (e.g., at school, in public places, with adults) despite being able to speak comfortably in other settings (e.g., at home with family).
Affected individuals understand language use and, although they have the physical and cognitive ability to speak, they demonstrate a persistent inability to speak in particular settings over a particular period of time due to anxiety. This differs from the developmentally appropriate behavior of a child with limited speaking and social interaction behaviors during the first month of school or daycare when he or she is adjusting to a new social environment with peers and teachers. SM also differs from shyness, which is a socially adaptable personality trait.
To meet diagnostic criteria, the child or adolescent with SM shows significant impairment in daily functioning, typically in educational or occupational settings, and by refraining from social participation at school and other settings due to a pronounced fear of speaking. Most affected children and adolescents function normally in other ways and learn age appropriate skills; however, some may have other comorbid anxiety disorders, developmental delays such as impaired social skills, and communication disorders in addition to SM.
Selective Mutism is found in about 1% of patients in mental health settings, but it occurs in only about 0.01% of the general United States population. Some researchers maintain, however that SM occurs more frequently than the data suggest. Cline and Baldwin (2004) adopt an “estimate of 6 – 8% cases of SM per 1000 children throughout childhood. Selective Mutism is often associated, but not always, with anxiety; clinicians and researchers familiar with the disorder consider it may be an extreme form of social anxiety / social phobia.