Studying SM and Understanding it.

Introduction

When four-year-old Chloe was told by her preschool teacher that she had finally spoken at school after nearly eight months of silence, her parents felt a profound mix of relief and confusion. Their daughter spoke perfectly at home—she was talkative, engaged, and articulate. Yet at school, she remained completely silent. This scenario describes selective mutism (SM), a complex childhood anxiety disorder that often goes unrecognised and misunderstood by both parents and educators.

Selective mutism is far more than shyness or stubbornness. It represents a persistent failure to speak in certain social situations despite possessing normal language abilities (Kearney & Rede, 2021). This blog post explores what selective mutism is, its underlying causes, how it's assessed, and the evidence-based treatments that can help affected children find their voices.

 (note * in this essay some findings used are highlights from secondary sources which already sythesised other information)

Defining Selective Mutism

Selective mutism is a psychiatric condition characterised by a consistent failure to speak in specific social situations where speaking is expected, even though the child demonstrates normal speech in other environments (American Psychiatric Association, 2013). The defining feature is that the mutism is truly "selective"—the child is not unable to speak, but rather unable to speak in particular contexts.

Children with selective mutism may communicate through gestures, nodding, pointing, or in some cases, whispering or speaking in one-syllable words in the non-speaking situations. However, in familiar environments like home with immediate family members, they typically demonstrate completely normal speech patterns and language development (Wong, 2010). This stark contrast between speaking and non-speaking contexts is what distinguishes selective mutism from other communication disorders or developmental delays.

The term "selective mutism" has replaced the earlier term "elective mutism," which was used when the condition was first described by German physician Adolf Kussmaul in 1877 as "aphasia voluntaria." The original terminology incorrectly suggested that children were deliberately withholding speech—a misconception that modern neuroscience and psychology have thoroughly refuted (Viana, Beidel, & Rabian, 2009).

Prevalence and Demographics

While selective mutism is a rare disorder, it is not uncommon enough to overlook. The prevalence of SM ranges from 0.18% to 1.9% of the child population, depending on the assessment methodology used (Koskela et al., 2023). In the United States, it is recorded to affect less than one percent of children, though the actual rate may be higher due to underdiagnosis and misdiagnosis (NORD, 2023).

The disorder appears slightly more common in females than in males, though the reasons for this gender difference remain unclear. Selective mutism typically emerges between the ages of two and four years, though the diagnosis is often not apparent until the child enters school or other structured social environments where the contrast between their silent behavior and expected communication becomes evident.

Classification as an Anxiety Disorder

Selective mutism was officially classified as an anxiety disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), marking an important shift in how clinicians understand and treat the condition (American Psychiatric Association, 2013). This classification was based on accumulating evidence showing that anxiety, particularly social anxiety, plays a central role in the presentation of selective mutism.

However, emerging research suggests that this classification may be incomplete. While anxiety is undoubtedly present in selective mutism, the heterogeneous (diverse) nature of the disorder indicates that it may be better conceptualised as a neurodevelopmental disorder rather than purely an anxiety disorder (Kearney & Rede, 2021). Children with selective mutism differ from those with social anxiety in key ways, including patterns of behavioral inhibition, speech-based fears, and the degree of trauma exposure.

Etiology: Understanding the Causes

The exact cause of selective mutism is not fully understood, but contemporary research points to a multifactorial etiology involving genetic, environmental, and neurodevelopmental factors (Koskela et al., 2023). Rather than a single cause-and-effect model, selective mutism likely results from complex interactions between these various domains over time.

Genetic and Familial Factors

There is evidence suggesting a genetic vulnerability or predisposition to selective mutism. Children with selective mutism often come from families with a history of anxiety disorders and/or shyness. Research using a developmental psychopathology perspective indicates that genetic, biological, neurological, cognitive, and interpersonal domains operate within multilevel, complex transactions between the individual and the environment over time (Viana et al., 2009).

Neurobiological Factors

While the neurobiological underpinnings of selective mutism are still being elucidated, some research has examined the role of inhibitory mechanisms in the brain. The observation that selective serotonin reuptake inhibitors (SSRIs) can be therapeutically effective has led to theoretical explanations involving serotonergic dysregulation and overactive inhibitory neural circuits. However, this neurochemical model remains incomplete, and more research is needed to fully understand the brain mechanisms involved.

Environmental and Psychological Factors

Environmental stressors, temperament characteristics such as excessive shyness, and learned anxiety responses may all contribute to the development and maintenance of selective mutism. Temperamental factors like negativism, behavioral inhibition, and social withdrawal are commonly observed in children with selective mutism. Some cases may be triggered or exacerbated by specific environmental stressors or social experiences, though the precise mechanisms remain unclear.

Associated Features and Comorbidities

Children with selective mutism frequently present with a complex clinical picture that extends beyond anxiety. Research has identified numerous associated features and comorbid conditions that must be considered for accurate assessment and treatment.

Selective mutism can present with various comorbidities including obsessive-compulsive disorder, depression, elimination disorders (enuresis and encopresis), and speech and language abnormalities (Wong, 2010). Additionally, developmental delays and autism spectrum disorder features have been noted in some individuals with selective mutism. The severity and specific manifestations of these comorbidities vary considerably from one child to another, underscoring the heterogeneous nature of the disorder.

Research also demonstrates that children with selective mutism often exhibit other behavioral and emotional characteristics including oppositional behaviors, social isolation, withdrawal, temper tantrums, excessive shyness, and difficulties with social skills. Some children display speech-based fears and specific anxieties about being heard or evaluated by others (Kearney & Rede, 2021).

Assessment and Diagnosis

Accurate assessment of selective mutism requires a comprehensive, multimodal approach that goes beyond simple observation of the child's silence. Assessment should include information about the specific social contexts where the child fails to speak, communication methods used in non-speaking situations, any articulation or language difficulties, and language differences if the child is multilingual (Oerbeck et al., 2018).

Parental and Teacher Input

Information from parents and teachers is critical, as they observe the child in different contexts. Parents can describe home behavior and language abilities, while teachers can document school-based communication patterns, peer interactions, social situations the child avoids, and any threats or incidents that might be relevant. Teachers can also report on the child's academic performance in verbal and non-verbal tasks.

Formal Assessments

Formal assessment tools include the Selective Mutism Questionnaire (SMQ), which has demonstrated acceptable to excellent internal consistency and provides quantitative measures of the child's functioning across different contexts (Bergman et al., 2008). School-based assessments should evaluate intellectual and achievement levels, speech and language abilities, performance on non-verbal tasks, receptive language skills, written narratives, and academic records.

Comprehensive Evaluation

A thorough developmental, medical, and psychiatric history is essential, as selective mutism can overlap with or be complicated by other conditions such as autism spectrum disorder, language disorders, developmental delays, and other psychiatric conditions. The assessment should clarify whether the child truly has the ability to speak in at least some contexts and whether the mutism is truly situation-specific rather than pervasive.

Long-Term Outcomes

For many years, little was known about what happens to children with selective mutism as they grow older. Recent research has begun to address this important gap in understanding. A systematic literature review examining long-term outcomes found that most subjects with selective mutism recovered from the disorder during adolescence (Koskela et al., 2023). However, this recovery does not mean the disorder's effects simply disappear.

Among adults with a childhood history of selective mutism, anxiety disorders remain common, occurring in approximately 57% of cases (Koskela et al., 2023). Some longitudinal research found that persisting communication problems were noted in a substantial portion of children with selective mutism at mean 12 years after treatment, with 39% considered to be in full remission (Kristensen, 2000). These findings underscore the importance of early detection and intervention.

Predictors of poorer outcomes include older age at treatment initiation and greater severity of initial selective mutism symptoms. Interestingly, mutism within the core family (complete silence with even immediate family members) predicted poorer outcomes in one study, suggesting that the breadth of the child's selective mutism contributes to prognosis.

Evidence-Based Treatments

The recommended approach for selective mutism is cognitive behavioral therapy (CBT), with emerging evidence supporting various behavioral and multimodal treatment packages. Treatment options are diverse because the manifestations of selective mutism itself are multifaceted.

Behavioral Interventions

Behavioral approaches form a cornerstone of selective mutism treatment. These include stimulus fading (gradual exposure to feared speaking situations), contingency management (positive reinforcement of speaking behavior), and response initiation techniques (Oerbeck et al., 2023). In contingency management approaches, the aim is to identify and specifically reward verbal behavior while not reinforcing silent behavior. Stimulus fading involves gradually increasing exposure to social speaking situations through carefully structured progressions.

Response initiation is a specialised behavioral technique in which the therapist spends dedicated one-on-one time with the child, and the child is required to speak before leaving the session. The therapist rapidly develops rapport using nonverbal play and empathetic statements, providing encouragement and clearly stating the expectation that the child speak at least one word prior to leaving. If the child remains silent, the therapist ignores the child and prolongs the encounter until the child speaks.

Integrated Behavior Therapy

Integrated Behavior Therapy for Selective Mutism (IBTSM) combines multiple behavioral approaches with attention to the specific triggers and contexts maintaining the child's selective mutism. One study involving 21 children ages 4 to 8 with primary selective mutism found that those randomised to 24 weeks of IBTSM showed significantly increased functional speaking behavior post-treatment as rated by parents and teachers, with a 75% high rate of treatment responders (Viana et al., 2009). In contrast, children in a waitlist control group did not experience significant improvements in speaking behaviors.

School-Based Interventions

Research has also demonstrated the efficacy of school-based cognitive behavioral therapy approaches. In a 5-year follow-up study of children who completed school-based CBT interventions, sustained improvements were found at follow-up periods. The intervention included psychoeducation about selective mutism delivered jointly to teachers and parents, behavioral interventions applied during school-based sessions, and structured progression through defined modules as the child's speaking increased (Oerbeck et al., 2023).

Pharmacological Treatment

While behavioral interventions form the primary treatment approach, pharmacological interventions may be considered as adjunctive treatments. The use of selective serotonin reuptake inhibitors (SSRIs), particularly fluoxetine, has shown promise. The theoretical rationale is that SSRIs' disinhibitory effects may enhance effectiveness in treating selective mutism, which is conceptualised as an inhibitory behavior (Wong, 2010).

In a trial by Black and Uhde among six children with selective mutism, those actively administered fluoxetine over 12 weeks showed improved ratings on mutism and anxiety, although other symptoms remained unchanged. In one notable case report, a 12-year-old girl who had never spoken at school was treated successfully with fluoxetine. Although psychotherapy, behavioral therapy, and other medications had failed to demonstrate efficacy for this individual, fluoxetine for one month resulted in her speaking freely with teachers and peers, with normal social communication and interactions confirmed at seven-month follow-up (Wong, 2010).

Multimodal Approaches

Given the heterogeneous nature of selective mutism and the variety of associated features and comorbidities, most effective treatment packages are multimodal. These may include individual therapy, family involvement, educational components, peer-based interventions, and coordination between parents, teachers, and mental health professionals. The specific combination of treatments is tailored to address the unique presentation and needs of each child.

Implications for Parents, Teachers, and Clinicians

Early detection and intervention are crucial. Parents who notice that their child speaks normally at home but is persistently silent in school or other social situations should seek professional evaluation rather than attributing the behavior to shyness or stubbornness. Similarly, teachers who encounter children who are selectively mute should inform parents and recommend professional assessment.

Clinicians must approach selective mutism with nuance and avoid applying a simplistic anxiety disorder framework. The heterogeneity of selective mutism requires individualised assessment and case conceptualisation to identify appropriate, personalised treatment approaches. Understanding the child's specific clinical profile—including associated features, comorbidities, and the breadth of their selective mutism—is essential for designing effective interventions.

Teachers and peers can play critical roles in treatment success. Many behavioral approaches require their involvement and support to reinforce speaking behavior and gradually expose the child to speaking situations in a supportive, non-threatening manner. School-based interventions that coordinate with parents and mental health professionals have demonstrated particular promise.

Conclusion

Selective mutism is a complex, multifactorial childhood anxiety disorder that presents with significant heterogeneity in its clinical manifestations, causes, and treatment needs. While the exact etiology remains incompletely understood, contemporary research points to genetic, environmental, and neurodevelopmental factors operating in complex interaction over time.

Despite its rarity, selective mutism deserves recognition and appropriate clinical attention because of its significant impact on children's functioning, academic achievement, and social-emotional development. The good news is that evidence-based treatments—particularly cognitive behavioral therapy and behavioral interventions—have demonstrated efficacy in helping children overcome selective mutism and reclaim their voices.

Most children with selective mutism recover during adolescence, but early intervention appears critical for achieving better long-term outcomes and preventing the development of persistent anxiety disorders in adulthood. With proper identification, comprehensive assessment, and tailored multimodal treatment involving collaboration between mental health professionals, schools, and families, children with selective mutism can develop the ability and confidence to communicate successfully across social contexts.

For children like Chloe, whose journey to finding her voice took months of patience and appropriate intervention, selective mutism is not a character flaw or a matter of willfulness—it is a treatable psychiatric condition that, with the right support, can be overcome.

References

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596

Bergman, R. L., Keller, M. L., Piacentini, J., & Bergman, A. J. (2008). The development and psychometric properties of the Selective Mutism Questionnaire. Journal of Clinical Child & Adolescent Psychology, 37(2), 456–464. https://doi.org/10.1080/15374410801955805

Kearney, C. A., & Rede, M. (2021). The heterogeneity of selective mutism: A primer for a more refined approach. Frontiers in Psychology, 12, 700745. https://doi.org/10.3389/fpsyg.2021.700745

Koskela, M., Ståhlberg, T., Yunus, W. M. A. W. M., & Sourander, A. (2023). Long-term outcomes of selective mutism: A systematic literature review. BMC Psychiatry, 23(1), 779. https://doi.org/10.1186/s12888-023-05279-6

Kristensen, H. (2000). Selective mutism and comorbidity with developmental disorder/delay, anxiety disorder, and elimination disorder. Journal of the American Academy of Child & Adolescent Psychiatry, 39(2), 249–256. https://doi.org/10.1097/00004583-200002000-00026

National Organization for Rare Disorders (NORD). (2023). Mutism, selective - symptoms, causes, treatment. Retrieved from https://rarediseases.org/rare-diseases/mutism-selective/

Oerbeck, B., Stein, M. B., Wentzel-Larsen, T., Langsrud, O., & Kristensen, H. (2018). Treatment of selective mutism: A 5-year follow-up study. European Child & Adolescent Psychiatry, 27(8), 997–1009. https://doi.org/10.1007/s00787-018-1110-7

Viana, A. G., Beidel, D. C., & Rabian, B. (2009). Selective mutism: A review and integration of the last 15 years. Clinical Psychology Review, 29(1), 57–67. https://doi.org/10.1016/j.cpr.2008.09.009

Wong, P. (2010). Selective mutism: A review of etiology, comorbidities, and treatment. Psychiatry (Edgmont), 7(3), 23–31. https://pubmed.ncbi.nlm.nih.gov/20436772/