"Shy" child? Don't overlook selective mutism

Children with selective mutism speak spontaneously in the company of parents, other family members, or a circle of trusted peers, but are consistently mute and noncommunicative, or communicate only nonverbally, with everyone else. The condition occurs in approximately 0.5 to 0.7 of every 1,000 young school-age children: There are likely to be several children with this condition diagnosed in every primary pediatric practice, therefore.

Yet selective mutism is seldom cited in pediatric literature.^1-4 It is discussed briefly in the 17th edition of Nelson's Textbook of Pediatrics. The fourth edition of Hoekelman's Primary Pediatric Care (2001) and the 2002 edition of Gellis and Kagan's Current Pediatric Therapy contain no citations of selective mutism in the index. The third edition of Developmental-Behavioral Pediatrics states that selective mutism is a rare condition with onset before 5 years of age. The brief text goes on to state, erroneously, that "symptoms usually resolve within a few months."

Early psychoanalytic theory held that selective mutism was almost always caused by severe psychological or physical trauma.^5-7 Although psychologically traumatic events occur occasionally in temporal relation to the onset of selective mutism, they are now not believed to cause the psychopathology.

Too often, children with selective mutism are misdiagnosed with shyness, autism spectrum disorder, oromotor dyspraxia, or oppositional-defiant disorder, and valuable time is lost during therapeutic misadventures. Early diagnosis and appropriate management can cure the cardinal symptom of selective mutism, although the child's social anxiety usually persists. When appropriate treatment is delayed until after 7 years of age, few children are "cured" during the early primary school years.

Prevalence and natural history Selective mutism is a social and communication anxiety disorder of childhood. Several studies of children with this disorder have determined that more than 90% have all the DSM-IV-TR criteria necessary for diagnosis of an extreme form of social anxiety disorder.^11-13 These criteria include, in addition to selective mutism, symptoms such as social avoidance, distress in social situations, behavioral inhibition, and fear of speaking to strangers.

Estimates of the prevalence of selective mutism in early primary grades range from 0.18/1,000 in a small Swedish study,¹⁴ to 0.5/1,000 in a German and Swiss study,¹⁵ to 0.7/1,000 in studies from Los Angeles and Israel.^16,17 Series of more than 100 children with selective mutism have been reported from Germany, Switzerland, and the United States.^15,18 In most studies, girls with selective mutism outnumbered boys, but this observation has not been fully substantiated.

A point prevalence series of 100 Swiss and German children with selective mutism, based on results of a questionnaire, found that the condition persisted in 54% of the total sample, decreased over time in 35%, and fluctuated over time in 8%.¹⁵ Analysis of interventions indicated that psychotherapy (42%) was the most common form of treatment.¹⁵ R. Lindsey Bergman, PhD, of the Anxiety Center at University of California at Los Angeles estimates that only 30% to 40% of children older than 12 years who are diagnosed and treated appropriately will speak to a wide circle of schoolmates during primary school.¹⁹