Treatment of selective mutism: a 5-year follow-up study

Selective mutism (SM) has been defined as an anxiety disorder in the diagnostic and statistical manual of mental disorders (DSM-5). Cognitive behavioral therapy (CBT) is the recommended approach for SM, but prospective long-term outcome studies are lacking. Reports from the children themselves, and the use of more global quality of life measures, are also missing in the literature. We have developed a school-based CBT intervention previously found to increase speech in a pilot efficacy study and a randomized controlled treatment study. Continued progress was found in our 1-year follow-up studies, where older age and more severe SM had a significant negative effect upon outcome. In the present study, we provide 5-year outcome data for 30 of these 32 children with SM who completed the same CBT for mean 21 weeks (sd 5, range 8-24) at mean age 6 years (10 boys). Mean age at the 5-year follow-up was 11 years (range 8-14). Outcome measures were diagnostic status, the teacher- and parent-rated selective mutism questionnaires, and child rated quality of life and speaking behavior. At the 5-year follow-up, 21 children were in full remission, five were in partial remission and four fulfilled diagnostic criteria for SM. Seven children (23%) fulfilled criteria for social phobia, and separation anxiety disorder, specific phobia and/or enuresis nocturna were found in a total of five children (17%). Older age and severity at baseline and familial SM were significant negative predictors of outcome. Treatment gains were maintained on the teacher- and parent questionnaires. The children rated their overall quality of life as good. Although most of them talked outside of home, 50% still experienced it as somewhat challenging. These results point to the long-term effectiveness of CBT for SM, but also highlight the need to develop more effective interventions for the subset of children with persistent symptoms.Clinical trials registration NCT01002196.