Background: Studies on Selective Mutism (SM) often focused on young children rather than on adolescents. Emotion regulation difficulties likely play a role in the fear of speaking among children...Show moreBackground: Studies on Selective Mutism (SM) often focused on young children rather than on adolescents. Emotion regulation difficulties likely play a role in the fear of speaking among children with SM. Emotion regulation has been investigated in children and adolescents with anxiety disorders, but knowledge about emotion regulation among adolescents with SM is scarce. To fill this gap, the current mixed-methods study examined which emotion regulation strategies adolescents with SM use in anxiety-provoking situations. First, differences between adolescents with and without SM in the use of adaptive, maladaptive and external emotion regulation strategies were examined. Subsequently, it was investigated whether the use of emotion regulation strategies was related to and predicted SM symptoms in adolescents with SM. In addition, this study investigated in an exploratory qualitative way, which emotion regulation strategies adolescents themselves and parents of adolescents with SM reported in online focus groups. Methods: 33 adolescents with SM (SM-group) and 44 healthy adolescents (control group) were compared using the FEEL-KJ questionnaire on their use of different emotion regulation strategies. 79 parents filled in the Selective Mutism Questionnaire (SMQ) to confirm the SM diagnosis and to measure the severity of SM symptoms. Results: Adolescents with SM significantly used adaptive strategies less often and maladaptive strategies more often, compared to healthy adolescents. The adolescents with or without SM did not significantly differ from each other on external regulation strategies. In contrast, adaptive, maladaptive and external emotion regulation strategies did not relate to or predict the extent of SM symptoms in adolescents with SM. Quotes from the chat- and focus groups suggested that adolescents with SM use adaptive, maladaptive and external emotion regulation strategies, whereby withdrawal after freezing can be seen as an effective useful strategy for adolescents with SM. Conclusions: The results indicate emotion dysregulation among adolescents with SM. Limitations and strengths and suggestions of implications for treatment of adolescents with SM were discussed.Show less