How many children in the us are affected by selective mutism? how many teens in the us are affected by it? if you don't know the answer, don't answer.

Selective mutism is a rare and multidimensional childhood disorder that typically affects children entering school age. It is characterized by the persistent failure to speak in select social settings despite possessing the ability to speak and speak comfortably in more familiar settings. Many theories attempt to explain the etiology of selective mutism.
Comorbidities and treatment. Selective mutism can present a variety of comorbidities including enuresis, encopresis, obsessive-compulsive disorder, depression, premorbid speech and language abnormalities, developmental delay, and Asperger's disorders. The specific manifestations and severity of these comorbidities vary based on the individual. Given the multidimensional manifestations of selective mutism, treatment options are similarly diverse. They include individual behavioral therapy, family therapy, and psychotherapy with antidepressants and anti-anxiety medications.
Future directions. While studies have helped to elucidate the phenomenology of selective mutism, limitations and gaps in knowledge still persist. In particular, the literature on selective mutism consists primarily of small sample populations and case reports. Future research aims to develop an increasingly integrated, multidimensional framework for evaluating and treating children with selective mutism