In Focus: A Selective Mutism Primer

What It Is, How It’s Diagnosed, and Approaches to Treatment

In Focus: A Selective Mutism Primer

What It Is, How It’s Diagnosed, and Approaches to Treatment

By Rachel Merson, Psy.D.
Boston University Center for Anxiety and Related Disorders

What is Selective Mutism?

Although anxiety disorder diagnoses in youth have become increasingly common (Racine et al., 2021), selective mutism (SM) is an anxiety disorder that remains understudied and is often misunderstood. Individuals with SM are consistently unable to speak in certain social contexts (e.g., at school, with new people), despite generally demonstrating age-appropriate verbal communication abilities in environments in which they are comfortable (e.g., with a best friend, at home). A relatively uncommon disorder, data suggest that SM affects less than 1% of youth (Muris & Ollendick, 2015). In a large sample of elementary school children in the United States, Bergman and colleagues (2002) identified SM in approximately 1 out of 133 students (0.75%). SM typically first emerges in early childhood, but often is not identified and diagnosed until formal schooling begins (Kristensen, 2000). If untreated, it can persist into adolescence and even adulthood. Given the significant functional impairment associated with SM, the persistence of this disorder is associated with a range of negative sequelae including social isolation, academic and occupational underachievement, and increased risk of future psychopathology, including depression and other anxiety disorders (Steinhausen, 2006).

Correcting Misperceptions

Myths and misperceptions about SM abound. A frequent assumption is that a child’s lack of speech is due to trauma or maltreatment; however, the rates of trauma amongst youth with SM are comparable to that of the general population. SM also is commonly erroneously attributed to oppositionality and viewed as a behavior problem or matter of discipline. Though SM and externalizing disorders can co-occur, the comorbidity rate is relatively low, at only 10-15%. In fact, youth with SM often report wanting to be able to speak but feel unable to do so. It has been suggested that most oppositional behavior in SM can be conceptualized as a response to anxiety producing environmental demands, rather than reflecting a distinct disorder (Cohan et al., 2008). Furthermore, SM is not “just shyness” nor is it an extreme variant of social anxiety disorder. Whereas shyness is a normal personality trait, SM is a mental health condition that causes distress and impairment. When in situations in which they are comfortable, some individuals with SM do not present as shy at all – in contrast, they can be quite outgoing and socially engaged. That said, SM and social anxiety disorder are highly comorbid (60-80% of youth with SM also meet criteria for social anxiety disorder; Driessen et al., 2020), and many individuals with SM express cognitions related to negative evaluation and judgement (e.g., “I don’t speak because others might laugh at me,” and “I don’t speak because others might not understand me,” Vogel et al., 2019). However, despite this overlap, SM and social anxiety disorder have repeatedly been differentiated as distinct conditions (Keeton & Budinger, 2012; Milic et al., 2020; Poole et al., 2020). Finally, SM should not be viewed as something that a child will “outgrow.” While this may be the case for a subset of youth, in most treatment outcome studies, age (and by proxy, number of years symptomatic) is correlated with increased symptom severity and is a predictor of worse treatment outcomes (Oerbeck et al., 2014).

Assessing for Selective Mutism

A thorough SM assessment is multimodal, requiring the synthesis of information from various sources. Given both the young age at which many children seeking services for SM present, as well as the nature of their symptoms, conducting a child-focused clinical interview is generally not advised and even may be contraindicated. Instead, assessment should focus on gathering data from caretakers, teachers and school personnel, behavioral observations, and a review of previous evaluation reports, when available.

Clinical Interview

Using a caregiver-report semi-structured diagnostic interview like the Anxiety Disorders Interview Schedule for Children (Albano & Silverman, 1996) will allow a clinician to assess for the symptoms of SM, assist in differential diagnosis, and determine whether comorbid conditions are present. The Social Communication Anxiety Inventory (SCAI; Shipon-Blum, 2023) can provide a more nuanced understanding of communication abilities (e.g., non-verbally responsive; verbally initiative) in a range of contexts (e.g., school with primary teacher, school with peers, in a store with parents, in a store when addressed by an unfamiliar person). 

Questionnaire Data

A clinical interview should be accompanied by a review of data gathered through objective assessment measures. Whereas questionnaires like the Child Behavior Checklist (CBCL) and the Behavior Assessment System for Children (BASC) can provide a helpful big picture overview of a child’s social-emotional functioning, these should be complemented with SM-specific assessment. The most widely used SM questionnaire is aptly named the Selective Mutism Questionnaire (SMQ; Bergman et al. 2008). This 23-item tool assesses a child’s speech in three settings: at school, at home/with family, and in the community, and allows for a comparison of speech between a target child and other children with SM as well as with typically developing peers. Bergman and colleagues also developed the School Speech Questionnaire (SSQ), which can easily be completed by a child’s teachers for further assessment of speech in the classroom setting. More recently published, the Frankfurt Scales of Selective Mutism (FSSM; Gensthaler et al., 2020), includes both a diagnostic scale and a severity scale as well as cut-offs to distinguish SM from social anxiety. There are three versions of the FSSM, for youth of different ages. The SMQ, SSQ, and FSSM are all available within the public domain (see links below).

Behavior Observations

Direct observation of a child’s speech and engagement in different contexts is critical in informing diagnostic decision making and developing an individualized treatment plan. The Selective Mutism Baseline Observation Task (SM-BOT; Kurtz, 2023), provides a systematic framework for assessing speech when a child is 1) one-on-one with a caregiver; 2) with a caregiver, in the presence of a new person; 3) prompted to speak by a new person in front of a caregiver; and 4) alone with a new person. Variables of interest include the frequency of a child’s response to different types of questions (e.g., open ended versus forced choice), rate of spontaneous speech (i.e., how often a child speaks without direct questioning or prompting), speech volume, response latency (i.e., how long it takes for the child to respond), eye contact, and use of non-verbal communication strategies. In addition, clinicians are encouraged to have caregivers share a video sample of the child speaking comfortably (e.g., a video taken at home) to provide a more thorough understanding of the child “at their best.”

Evidence-Based Treatment

The preponderance of data suggests that treatment approaches that combine behavioral therapy techniques (e.g., shaping, fading, exposure, contingency management) and systems interventions (e.g., involvement of caregivers, school consultation) lead to the most robust treatment outcomes (Zakszeski & Paul, 2017). Specific SM treatment packages include integrated behavior therapy (Bergman et al., 2013), defocused communication and behavioral therapy (Oerbeck et al., 2014; Oerbeck, et al., 2018), social communication anxiety therapy (SCAT; Klein, et al., 2017), parent-child interaction therapy for selective mutism (PCIT-SM; Catchpole et al., 2019), and intensive group behavioral therapy (IGBT; Cornacchio et al., 2020). A 2021 meta-analysis (Steains et al., 2021) found a large effect for psychological treatment versus control at post-treatment (Hedges g = 0.87). Across studies, diagnostic remission rates have ranged from 45-70%, clinically significant increases in speech on the SMQ have been consistently documented, and treatment response rates, based on the CGI-I, reached 50-88% of participants. That said, RCTs for SM have been limited in number, have included relatively small sample sizes, and typically have only utilized waitlist control groups. Thus, there remains a need for larger treatment outcome studies, particularly those comparing the relative efficacy of active treatments, in order to allow mental health professionals to optimally support these youth and their families.

For more information about Selective Mutism including resources for families, professionals, and educators, please visit: https://www.selectivemutism.org/

Links:

https://www.selectivemutism.org/resources/archive/online-library/selective-mutism-questionnaire/

https://www.selectivemutism.org/resources/archive/online-library/school-speech-questionnaire/

https://www.selectivemutism.org/resources/archive/online-library/frankfurt-scale-selective-mutism/

References

Albano A., & Silverman, W. (1996). Anxiety Disorders Interview Schedule for DSM-IV-Child Version: Clinician Manual. Psychological Corporation.

Bergman, R. L., Gonzalez, A., Piacentini, J., & Keller, M. (2013). Integrated Behavior Therapy for Selective Mutism: A randomized controlled pilot study. Behaviour research and therapy, 51, 680-689.

Bergman, R. L., Keller, M., Piacentini, J., & Bergman, A. (2008). The development and psychometric properties of the Selective Mutism Questionnaire. Journal of Clinical Child and Adolescent Psychology, 37, 456-464.

Bergman, R. L., Piacentini, J., & McCracken, J. (2002). Prevalence and description of selective mutism in a school-based sample. Journal of the American Academy of Child and Adolescent Psychiatry, 33, 1000-1006.

Catchpole, R., Young, A., Baer, S., & Salih, T. (2019). Examining a novel, parent-child interaction therapy informed behavioral treatment of selective mutism. Journal of Anxiety Disorders, 66, 102-112.

Cohan, S. L., Chavira, D. A., Shipon-Blum, E., Hitchcock, C., Roesch, S. C., and Stein, M. B. (2008). Refining the classification of children with selective mutism: a latent profile analysis. Journal of Clinical Child and Adolescent Psychology, 37(4), 770-784.

Cornacchio, D., Furr, J. M., Sanchez, A. L., Hong, N., Feinberg, L. K., Tenenbaum, R., Del Busto, C., Bry, L. J., Poznanski, B., Miguel, E., Ollendick, T. H., Kurtz, S. M. S., & Comer, J. S. (2019). Intensive group behavioral treatment (IGBT) for children with selective mutism: A preliminary randomized clinical trial. Journal of Consulting and Clinical Psychology, 87, 720–733

Driessen, J., Blom, J., Muris, P., Blashfield, R., Molendijk, M. (2020). Anxiety in children with selective mutism: A meta-analysis. Child Psychiatry and Human Development, 51, 330-341.

Gensthaler, A., Dieter, J., Raisig, S., Hartman, B., Ligges, B., Kaess, M., Freitag, C., & Schwenck, C. (2020). Evaluation of a novel parent-rated scale for selective mutism. Assessment, 27, 1007-1015.

Keeton, C., & Crosby Budinger, M. (2012). Social phobia and selective mutism. Child and Adolescent Psychiatric Clinic of North America, 21, 621–641 

Klein, E., Armstrong, A., Skira, K, Gordon, J. (2017). Social Communication Anxiety Treatment (S-CAT) for children and families with selective mutism:  A pilot study. Clinical Child Psychology and Psychiatry, 21, 90-108.

Kristensen, H. (2000). Selective mutism and comorbidity with developmental disorder/delay, anxiety disorder, and elimination disorder. Journal of the American Academy of Child and Adolescent Psychiatry, 39, 249–256.

Kurtz, S. (2023). Selective Mutism Baseline Observation Task.  Presented as part of the panel discussion Assessing Selective Mutism: Tools for Gathering Information, Making Diagnoses, and Monitoring Progress, sponsored by the Selective Mutism Association. 

Milic, M., Carl, T., & Rapee, R. (2010). Similarities and differences between young children with selective mutism and social anxiety disorder. Behaviour Research and Therapy 133, 1-11. 

Oerbeck, B., Overgaard, K.R., Stein, M.B., Pripp,  A.H., & Kristensen, H. (2018). Treatment of selective mutism: A 5-year follow-up study. European Child & Adolescent Psychiatry, 27(8), 997–1009.

Oerbeck, B., Stein, M. B., Wentzel-Larsen, T., Langsrud, Ø., & Kristensen, H. (2014). A randomized controlled trial of a home and school-based intervention for selective mutism—Defocused communication and behavioural techniques. Child and Adolescent Mental Health, 19, 192–198.

Poole, K., Cunningham, C., McHolm, A., Schmidt, L. (2021). Distinguishing selective mutism and social anxiety in children: A multi-method study. European Child and Adolescent Psychiatry, 30(7), 1059-1069.

Racine, R., McArthur, B., Cooke, J., Eirich, R., Zhu, J., & Madigan, S. (2021). Global prevalence of depressive and anxiety symptoms in children and adolescents during COVID-19: A meta-analysis. JAMA Pediatrics, 175(11), 1142-1150.

Steains, S., Malouff, J., & Schutte, N. (2021). Efficacy of psychological interventions for SM in children: A meta-analysis of randomized controlled trials. Child: Care, Health, and Development, 1-11. 

Shipon-Blum, E. (2023). Assessment: Social Communication Anxiety Inventory. Presented as part of the panel discussion Assessing Selective Mutism: Tools for Gathering Information, Making Diagnoses, and Monitoring Progress, sponsored by the Selective Mutism Association.

Steinhausen, H., Wachter, M., Laimbock, K., & Metzke, C. (2006). A long-term outcome study of selective mutism in childhood. Journal of Child Psychology and Psychiatry, 47(7), 7451-756.

Steains, S. Y., Malouff, J. M., & Schutte, N. S. (2021). Efficacy of psychological interventions for selective mutism in children: A meta‐analysis of randomized controlled trials. Child: Care, Health and Development, 47(6), 771-781.

Zakszeski, B., & Paul, G. (2017). Reinforce, shape, expose, and fade: A review of treatments for selective mutism (2005–2015). School Mental Health, 9,1–15