What Is… Selective Mutism

In this series, I dig a little deeper into the meaning of psychology-related terms. This week’s term is selective mutism.

Selective mutism is a rare disorder that begins in childhood and is characterized by an inability to speak in select social contexts (hence the “selective” part of the name). It used to be called elective mutism, but perhaps the DSM folks realized that sounded a bit too blame-y.

Symptoms

In the DSM-5, selective mutism is classified as an anxiety disorder. Symptoms include:

• consistent failure to speak in specific social situations where speaking is expected, despite being able to speak in other situations
• the speech disturbance interferes with achievement at school or with social communication
• the duration is at least 1 month, although it can’t only occur in the first month of school
• the disturbance in speech isn’t related to language comprehension issues or lack of knowledge
• it doesn’t occur solely in the context of autism spectrum disorder or a psychotic disorder (someone can have both selective mutism and autism diagnoses if they appear to manifest independently, but not if they seem to be two sides of the same coin)

There may also be behaviours associated with social anxiety, such as decreased eye contact, freezing, and hiding. Avoidance behaviours can include avoiding public toilets (which happens in another form of social phobia known as paruresis or shy bladder syndrome). Physical symptoms of anxiety may also occur.

Assessment before making the diagnosis involves ruling out physical or cognitive deficits, hearing loss, or tics that may be impairing speech.

Risk factors

Risk factors include a family history of either selective mutism or other anxiety disorders (social anxiety in particular). Children who develop the disorder tend to have shy, inhibited temperaments, and they may have overactive threat detection going on in the amygdala (something that also occurs in other disorders, like OCD).

There appears to be a higher risk among immigrant and language-minority children. This may be related to a fear of being ridiculed or ignored based on their speech.

Some of the theories around the development of selective mutism are:

• Behavioural: negatively reinforced learning (avoidance by the child and subsequent rescue by a parent) leads to behavioural inhibition (i.e. mutism) as an adaptive response to anxiety
• Freudian/psychodynamic: children became fixated in the oral or anal stage of development, and selective mutism is a way of displaying anger and punishing the parents
• Family systems: the disorder arises when there is extreme interdependency in attachments and distrust of the outside world
• The disorder is a form of social phobia.
• The disorder can be an attempt to cope with trauma (traumatic mutism may also occur, but that would tend to occur across all contexts rather than selective contexts).

Other characteristics

Selective mutism occurs most often in children, and the average age of onset is between age 3 and 6. The prevalence is less than 1%. It appears to be slightly more common in females than males. It begins in childhood but can persist into adulthood.

A variety of other co-occurring conditions may occur, including bedwetting, sensory processing disorder, OCD, depression, dissociative disorders, and autism spectrum disorder. Most children with selective mutism have social phobia (90% according to one source).

Some children may outgrow the disorder on their own, although social phobia may persist. The disorder can be self-reinforcing, i.e. the longer you go without speaking in certain contexts, the more difficult it becomes.

Treatment

Treatments include psychodynamic therapy (in the form of play therapy), family therapy, behavioural therapy, cognitive behavioural therapy (in teens or adults) or medication, which typically involves antidepressants. There are also various speech-language pathology interventions that can be used.

Behavioural treatments can include:

• stimulus fading: have the child start talking one-on-one with a trusted individual, and then gradually bring others into the room
• shaping: facilitate communication. by starting with strategies like gestures or whispering
• self-modelling: record the child communicating effectively in a comfortable setting, and then have them watch the recording to boost self-confidence

Most of what I came across was focused on children since that’s when it develops, but it does occur in adults, especially if they didn’t receive any treatment as children. In the DSM-IV, selective mutism fell under the hodgepodge category of disorders that begin in childhood, but in the DSM-5, it was shifted over to the anxiety disorders category. To me, at least, it makes a great deal of sense that this would be a way for social anxiety to manifest itself.

Had you heard of selective mutism before?

References

• American Speech-Language-Hearing Association: Selective mutism
• Cedars-Sinai Health Library: Selective mutism
• SMART Center: What is selective mutism?
• Wikipedia: Selective mutism
• Wong, P. (2010). Selective mutism: A review of etiology, comorbidities, and treatment. Psychiatry (Edgemont), 7(3), 23-31.