Effectiveness of a behavioral treatment protocol for selective mutism in children Design of a randomized controlled trial

Selective mutism (SM) is a relatively rare anxiety disorder, characterized by a child's consistent failure to speak in various specific social situations (e.g., at school), while being able to speak in other situations (e.g., at home). Prevalence rates vary from 0.2% to 1.9%. SM is usually identified between the ages of 3-5 years. It is often underdiagnosed and consequently children receive no or inadequate treatment, with negative consequences for school and social functioning. If left untreated, SM can result in complex, chronic anxiety and/or mood disorders in adolescence and impaired working careers in adulthood. Currently, no evidence-based treatment for SM is available in the Netherlands, therefore this study aims to [1] test the effectiveness of a treatment protocol for SM that is carried out at school, and to [2] identify baseline predictors for treatment success. This article presents the design of a randomized controlled trial into the effectiveness of a behavioral therapeutic protocol for selective mutism in children (age 3-18). The expected study population is n = 76. Results of the treatment group (n = 38) will be compared with those of a waiting list control group (WCG) (n = 38). Pre and post treatment assessments will be conducted at comparable moments in both groups, with baseline assessment at intake, the second assessment at 12 weeks and post-assessment at the end of treatment. If proven effective, we aim to structurally implement this protocol as evidence-based treatment for SM.