Selective mutism

A child who talks freely at home but is silent at school is a case-exam classic: the task is to recognize selective mutism as an anxiety disorder, rule out language and developmental explanations, and choose a graded behavioral plan rather than pressure or waiting it out.

Criteria at exam depth. The child consistently fails to speak in specific social situations where speech is expected (most often school) while speaking in other settings (usually home with close family). The silence interferes with educational achievement or social communication, lasts at least 1 month, and that month cannot be limited to the first month of school, when shyness is common. The silence is not due to lack of knowledge of, or comfort with, the spoken language required, is not better explained by a communication disorder such as childhood-onset fluency disorder, and does not occur only during autism spectrum disorder or a psychotic disorder. Children often use gestures, nodding, or whispering in place of speech and may show marked social anxiety.

Hinge differentials.

• Speech or language disorder: impairs speech in every setting; in selective mutism the child speaks fluently at home with age-appropriate language.
• Autism spectrum disorder: look for restricted, repetitive behaviors and social-communication deficits that persist even with comfortable people; selective mutism shows normal reciprocity where the child feels safe.
• Recent immigrant or second-language learner: a silent period while acquiring a new language is expected and excludes the diagnosis.
• Social anxiety disorder: frequently co-occurs; both may be diagnosed when criteria for each are met.
• Adjustment to school entry: silence confined to the first month of school does not count.

On the NCMHCE. Gather history from parents and teachers about where, and with whom, the child speaks, and confirm language competence. Recommend a hearing and speech-language evaluation when language skills are in doubt. First-line work is behavioral and exposure-based: stimulus fading (gradually adding a new person or setting while the child is speaking), shaping (reinforcing successive approximations from mouthing to whispering to full speech), graduated exposure, and contingency management, delivered with parents and school staff. Coach adults to stop accommodating (answering for the child) and to avoid forcing or punishing silence. Consider culture, bilingual households, and family patterns of shyness. Medication, when it is considered, is a referral question for a prescriber.

Clinical Pearl: Speaks normally at home + silent at school for at least 1 month (not just the first month) + language is intact = selective mutism. Treat it as anxiety with stimulus fading and shaping, not as defiance.