Silencing Anxiety: A Case Study with Cognitive-Behavioral Intervention and a Theoretical Perspective from ACT in Selective Mutism

Abstract This case study describes the assessment and therapeutic intervention of a 9-year-old boy diagnosed with Selective Mutism, combining a structured Cognitive-Behavioral Therapy (CBT) approach with pharmacological treatment using sertraline. The psychotherapeutic plan was multimodal, involving individual sessions with the child, parental intervention, and collaboration with the school context. In parallel, the theoretical relevance of Acceptance and Commitment Therapy (ACT) was explored, given the conceptual overlap between Selective Mutism and Social Anxiety. Throughout 24 sessions, progressive improvements were observed in verbal communication, social functioning, and academic engagement, along with a reduction in overall anxiety. Nonetheless, behavioral inhibition and cognitive rigidity remained present. This case suggests that, beyond cognitive-behavioral intervention, ACT may offer a useful perspective for understanding patterns of experiential avoidance and for promoting psychological flexibility in both the child and their caregivers.