Day # 73: Selective Mutism

Today we will continue our current theme of anxiety disorders as we discuss selective mutism. This will be the last anxiety disorder that we cover in this section.

Today's Content Level: Beginner, Intermediate

Introduction

• Selective mutism is a rare disorder characterized by failing to speak in specific social situations.

• Important: To be diagnosed they must have intact comprehension and use of language in other situations.

• Symptom onset typically during childhood.

• Although selective mutism is considered an independent disorder it is believed to be related to social anxiety disorder.

Diagnostic Criteria 1

• Consistent failure to speak in specific social situations (example: school, work, meetings) despite speaking in other scenarios.

• Interferes with and causes impairment to academic, occupational or social functioning.

• Duration ≥ 1 month (can't just be the first month of school)

• Mutism is not due to a communication disorder, lack of knowledge, and does not occur exclusively in autism or a psychotic disorder.

Epidemiology/Pathogenesis 2

• Rare in all age groups, but prevalence varies with age. Increased risk in young children.

• Prevalence estimates 0.03 - 1 % in children 4-7 years old with highest.

• More common in girls.

• Higher than expected proportion of children with the disorder have a history of speech delay, however symptoms typically are subtle and cannot fully account for the diagnosis.

• Shares many of the same etiologic factors leading to social anxiety disorder, and one survey found that 90% of children with selective mutism met criteria for social phobia. Some consider it a sub-type of social anxiety disorder.

• Clinical reports suggest that many young children with mutism remit spontaneously. Some studies demonstrate continued impairment suggesting that treatment intervention is preferable to "watchful waiting".

• Children who do note improve by 10 years old tend to have a long-term course with a worse prognosis.

Clinical Pearls

• Examples of screening questions: Does your child have difficulty speaking in any specific situations? Such as peers or teachers at school? Such as other children in social situations (clubs, teams, etc.)?

• Patients may remain completely silent, whisper, or use nonverbal communication such as writing or gesturing.

• The majority of these patients suffer from anxiety, particularly social anxiety. Screen for other anxiety disorders, especially social anxiety, separation anxiety, generalized anxiety disorder, and panic disorder. Also screen for depression.

• Optional questionnaire: Selective Mutism Questionnaire (SMQ).

• Ensure that speech/comprehension is normal in at least some other settings and that mutism is not secondary to a neurological or communication disorder. Some examples include dysphasia, speech-sound disorders, social (pragmatic) communication disorder, autism spectrum disorder and more. Communication delays or disorders may co-occur, but they cannot fully account for the selective mutism in order to receive the diagnosis.

• Most common setting is school. Cannot be diagnosed within the first month of school.

Treatment

• Treatment for all anxiety disorders are similar, so we have written a detailed post titled "Treatment of Anxiety Disorders" where we discuss treatment options in detail. Please refer to that post for a more thorough discussion.

• Psychotherapy: Therapy is the mainstay treatment for anxiety disorders in childhood including selective mutism. Evidence of large trials for psychotherapy in selective mutism is scant, however CBT is recommended as first-line management. Several small trials suggest CBT with exposure improved speaking behavior by 75% compared with the control group (waitlist) 3. Family therapy is also commonly used where therapists will intervene on parent-child interactions. Play therapy and/or a therapeutic nursery can be used in younger children.

• Pharmacotherapy: SSRIs are first-line medications for childhood anxiety disorders including selective mutism. Very small trials have found had mixed results with some showing no difference in symptoms and some showing modest improvement. Larger effect seen with comorbid social anxiety disorder.

CONCLUSION

We have now finished our discussion of the various anxiety disorder. Next up will be a review quiz before we transition to our discussion of anxiolytic medications.

Resources for today's post include: Kaplan and Sadock's Synopsis of Psychiatry, DSMV, and First Aid for the Psychiatry Clerkship.

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