Similarities and differences between young children with selective mutism and social anxiety disorder

A growing body of evidence points to a strong overlap between selective mutism (SM) and social anxiety disorder in children, specifically with regard to characteristics such as social reticence and anxiety. Yet few studies have directly compared these populations, especially with young children. This study compared 25 children (aged 3-7 years) with a primary diagnosis of SM, 17 children with a primary diagnosis of social anxiety disorder and 15 non-clinical controls using interviews and questionnaires on expressions of social anxiety and behavioural inhibition. Results showed that children with SM or social anxiety disorder were more anxious than non-clinical controls and did not significantly differ from each other on either non-verbal social anxiety or non-social forms of anxiety. Both children with SM and social anxiety disorder had fewer friends and experienced greater difficulties forming friendships than non-clinical controls. However, children with SM scored higher than children with social anxiety disorder and non-clinical controls on a few measures of inhibition (both verbal and nonverbal). The results support assertions of strong similarities between SM and social anxiety disorder, but suggest that children with SM may show even greater severity in certain symptoms at a young age. These findings point to the need for treatment to include both cognitive behavioural skills to manage social anxiety and structured practice of social skills in order to improve treatment efficacy for children with SM.