selective mutism

DEFINITION / DSM-5 CRITERIA: (1) Consistent failure to speak in specific social situations where speaking is expected (e.g., school) despite speaking in other situations. (2) Disturbance interferes with educational/occupational achievement or social communication. (3) Duration ≥1 month (not limited to the first month of school). (4) Not due to lack of knowledge of, or comfort with, the spoken language required in the social situation. (5) Not better explained by a communication disorder (e.g., childhood-onset fluency disorder/stuttering) and does not occur exclusively during autism spectrum disorder, schizophrenia, or another psychotic disorder. DSM-5 classifies it under ANXIETY DISORDERS.

EPIDEMIOLOGY: Rare (<1%). Onset typically before age 5, but often recognized when the child starts school and is expected to speak. Slightly more common in girls. Risk factors: family history of anxiety/social anxiety disorder, behavioral inhibition temperament, bilingualism or immigration (a risk factor but not a cause; the language-unfamiliarity exclusion still applies), and speech/language delays.

PATHOPHYSIOLOGY: Considered a manifestation of extreme social anxiety. Highly comorbid with social anxiety disorder (up to ~90%), other anxiety disorders, and sometimes communication disorders. It is not willful defiance or oppositional behavior, and it is not caused by trauma (an outdated view). Patients are physically capable of speech, and nonverbal communication (gesturing, nodding, writing) is often preserved.

CLINICAL PRESENTATION: A child who talks freely at home with family but is silent at school or with strangers. Associated features include shyness, clinginess, social withdrawal, freezing, and stiff posture/blank facial expression in triggering settings. Can lead to academic and social impairment and is hard to assess in school.

DIAGNOSIS: Clinical. Rule out hearing loss, language/communication disorders, autism spectrum disorder, and psychosis; confirm the child speaks the language adequately.

MANAGEMENT: First-line is behavioral/psychosocial therapy: CBT with graded exposure, stimulus fading, shaping, and positive reinforcement, plus parent and school involvement. Avoid pressuring the child to speak. Pharmacotherapy (SSRIs, e.g., fluoxetine) may be added in moderate-to-severe or refractory cases. Prognosis is good with early intervention, but social anxiety often persists.

HIGH-YIELD BOARD DISTINCTIONS: - Selective mutism: speaks in some settings, not others, anxiety-related. - Elective/oppositional refusal: not the DSM-5 concept; the "selective" name replaced "elective" because the child is not choosing to be silent. - Autism spectrum disorder: deficits in social reciprocity, restricted/repetitive behaviors, and impaired communication across all settings. - Language barrier in an immigrant child ("silent period") does not count as selective mutism. - Mutism in catatonia (schizophrenia, mood disorder) occurs with other catatonic signs (posturing, waxy flexibility, negativism). - Conversion disorder (functional neurological symptom disorder) can present with aphonia/mutism, usually with an acute stressor and in all settings. - Stuttering (childhood-onset fluency disorder): disrupted speech flow, not absence of speech.