Symptoms of selective mutism beyond failure to speak in children and adolescents

Understanding the symptoms of a mental disorder is essential for accurate diagnosis or selecting appropriate treatment targets. Despite this, there is a surprising lack of systematic research on the symptoms of selective mutism (SM). While the DSM-5 defines failure to speak as the only core symptom of SM, sparse research suggests that children with SM may experience additional symptoms. Previous studies have been limited in their identification of symptoms of SM, either by using a predefined set of symptoms or by only asking for anxiety-specific symptoms. This may have resulted in important symptoms being overlooked. In this study, we provided n = 86 parents of children and adolescents with SM (3-18 years) with a symptom definition appropriate for the target group. Additionally, parents were asked an open-ended question about any other symptoms they had observed in their children, beyond the failure to speak. The symptoms reported were categorized using qualitative content analysis (QCA) and examined for frequency and association with symptom severity. Ten different symptom categories were identified, with fear, freezing, and avoidance/security behaviors being the most prevalent. On average, parents reported M = 4.74 (SD = 2.37) symptoms from different symptom categories. Only fear was found to be related to symptom severity of SM. As the findings suggest that SM encompasses various symptoms beyond failure to speak, a more sophisticated understanding of SM as a mental disorder with multiple symptoms seems essential. The clinical implications of this are discussed in further detail.