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Selective Mutism


Selective mutism (SM) is an anxiety-based disorder primarily among young children, but also affecting older children and adolescents, who are typically fearful and unable to speak or speak very little. The disorder is primarily characterized as being freely verbal and comfortable at home (with family or close friends), but being mostly nonverbal in social settings (school, birthday parties, to familiar adults or close friends) or in the community.  

This fear of speaking causes significant impairment in daily functioning, academic performance and/or social relationships. Children are unable to ask to have their needs met nor communicate when they are in pain or to fully participate in school or social activities. 

Anyone can develop SM, but it is typically first diagnosed in early childhood, childhood or adolescence. It affects:

  • Roughly 7 per 1,000 children; or 1 out of 140 elementary-aged children
  • Average age of onset is age 5, though parents or teachers often notice signs as early as ages 3-4
  • Slightly more prevalent among girls than boys

While SM itself is not genetic, some evidence suggests a genetic link between children with SM and anxious parents or family members. Those with the disorder may also be shy and have social anxiety. By avoiding speaking situations, this avoidant behavior gets reinforced over time. 

SM can persist for months or years. If left untreated, it is more likely to persist and can have negative consequences on a child’s life, including: 

With appropriate and early treatment, SM can be overcome. Evidence shows children with SM have a “decreased threshold of excitability in the brain’s amygdala,” which receives and processes potential threats (see Selective Mutism Association or SMA). In addition:

Those with SM have changes in anxiety level and level of functioning from one setting to another. 

  • An inability to speak effectively in some but not other settings does not indicate a deliberate refusal to speak. 
  • It would be inappropriate to punish or withhold privileges for not speaking.

The difference between SM and simple shyness: 

  • Typically, most children will grow out of shyness, a normal personality trait that does not tend to interfere with daily functioning. 
  • In contrast, SM is a diagnosable mental health disorder, requiring treatment to overcome symptoms and function at an adaptable level. 

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