Objective: To examine the prevalence of selective mutism (SM) in a public school sample and compare the functioning and symptoms of children with SM to age- and gender-matched unaffected children.
Method: Kindergarten, first, and second grade teachers in a large district were asked to identify pupils who met DSM-IV criteria for SM and to complete ratings of speaking behavior, social anxiety, other internalizing and externalizing symptoms, and overall functioning for these and comparison youngsters. Teachers completed the same ratings on the SM children 6 months later.
Results: A participation rate of 94% (125 of 133 teachers) was obtained, and the prevalence of SM was .71% (16/2,256). Measures were completed for 12 (75%) of 16 identified children. Compared with peers, children with SM were more symptomatic on measures of frequency of speech, social anxiety, and other internalizing symptoms. As a group, children with SM had improved 6 months later but remained impaired and symptomatic when compared with the comparison group.
Conclusions: SM may not be as rare as previously thought. The functioning of children with SM is impaired, and although there is some improvement over time, notable impairment remains, suggesting that intervention is preferable to waiting for SM to remit spontaneously.