Selective Mutism and IQ: Typical Scores, Language Gaps and How Silent Children Are Tested

Most children with selective mutism have an IQ in the average range when they are tested with methods that do not require speech. A sizable minority have weaknesses in language or other developmental delays, and there is no good evidence for the common claim that children with selective mutism are unusually intelligent.

This article covers what selective mutism is, what IQ and language studies show, where the "high IQ" idea comes from, how psychologists assess a child who will not speak to them, and what happens over time.

Selective mutism is a consistent failure to speak in certain social settings, most often school, while the child speaks normally at home or with familiar people. It usually begins in the preschool years. Since 2013 the American diagnostic manual (DSM-5) has listed it among the anxiety disorders, a change reviewed by Muris and Ollendick, who noted that anxiety is prominent in most affected children.

Estimates of how common it is depend on the age group and the method:

• A US school district: Bergman and colleagues asked kindergarten to second-grade teachers in a large public school district to identify pupils who met the criteria and found a prevalence of 0.71% (16 of 2,256 children).

• Göteborg, Sweden: Kopp and Gillberg screened children aged 7 to 15 in Göteborg and found 18 per 10,000 (0.18%), with many more children who were shy and reticent without meeting the criteria.

• A teacher survey of second-graders: Kumpulainen and colleagues reported 2%, using a questionnaire completed by teachers.

Anxiety is the core feature. In a pilot study by Black and Uhde, 97% of 30 children with selective mutism were diagnosed with social phobia or avoidant disorder. Our article on IQ and anxiety covers how anxiety relates to test scores more generally.

Very few studies give children with selective mutism a full IQ test, mainly because many of them will not speak to an examiner. The studies that use nonverbal measures find average reasoning ability:

• Nonverbal IQ near 100: In a Norwegian treatment study of 24 children aged 3 to 9, Oerbeck and colleagues reported a mean nonverbal IQ of 98 (standard deviation 10) and a mean receptive vocabulary score of 95, both within the average range. That study excluded children with an IQ below 50, so it says nothing about the small group with severe intellectual disability.

• School achievement: Cunningham and colleagues compared 52 children with selective mutism with 52 community controls and found that their reading and math skills did not differ.

Language is where differences appear. Manassis and colleagues compared 44 children with selective mutism aged 6 to 10 with 28 children with other anxiety disorders and 19 typical controls. The children with selective mutism scored significantly lower on standardized language tests than both other groups. Better receptive grammar predicted less severe mutism, while higher social anxiety predicted more severe mutism. In a series of 100 cases, Steinhausen and Juzi found that speech and language disorders before the mutism began played a role in about a third of the children.

The broadest comparison comes from a case-control study in which Kristensen assessed 54 children with selective mutism and 108 matched controls. Of the children with selective mutism, 68.5% met criteria for a developmental disorder or delay, compared with 13.0% of controls, and 46.3% had both an anxiety disorder and a developmental disorder or delay. A later review by Shorer lists language and motor coordination problems, mild intellectual disability and autism among the developmental conditions reported in this group. In another study, Kristensen and Oerbeck found that children with selective mutism had a shorter auditory-verbal memory span than controls, while their visual memory was not different once IQ, language and motor skills were taken into account.

The picture, then, is average nonverbal reasoning in most children, with a subgroup whose language skills are weaker than their reasoning. Because the mutism hides speech, those weaknesses can go unnoticed unless someone looks for them. A child who also has a stutter or speech-sound errors may have one more reason to stay silent.

Parents and some websites often describe children with selective mutism as unusually bright and perceptive. Individual children certainly can be, but the research does not show a group advantage. The best nonverbal data point to an average of about 100, and achievement in reading and math matches that of classmates. In the second-grade teacher survey, teachers rated about a third of the children as performing below average at school.

Two things may feed the impression. Children who say nothing in class still understand what is going on, and adults who discover what the child knows at home can be surprised by how much that is. And parents who seek out specialist clinics and online communities may differ from the wider population of affected families. Neither is evidence of a higher IQ.

Standard IQ tests rely heavily on spoken answers, so assessing a child with selective mutism takes planning. Shorer's 2025 review describes several approaches:

• Nonverbal batteries: Tests that let the child respond by pointing, arranging or drawing can measure reasoning without speech. The Leiter test and the Universal Nonverbal Intelligence Test are built for exactly this situation, because both are given and answered without words.

• Comparing verbal and nonverbal subtests: If a child does much better on a nonverbal task such as block design than on a verbal one such as similarities, anxiety may be suppressing the verbal score, or verbal language may need support. The pattern is a clue to follow up, and it does not settle which explanation is right.

• Parents, recordings and written answers: Some clinicians test at home, record the child speaking with a parent, or accept written answers. In a study by Klein and colleagues, parents were trained to present language test items while a professional scored them, and Shorer reports that the children did significantly better when parents supported the testing.

• Timing: Shorer suggests it may sometimes be better to wait for some symptom relief, because asking a child early in treatment to speak to an unfamiliar examiner could set back gradual exposure to speaking.

Parent and teacher reports also matter, since the child may show very different abilities in different places. The assessment is usually led by a child psychologist or psychiatrist, with a speech-language pathologist checking language skills.

Many children improve, though not always completely. In a follow-up of 45 patients an average of 12 years later, Remschmidt and colleagues found complete remission in 39% of those with sufficient data, while the rest still had some communication problems. In a study of 33 young adults, Steinhausen and colleagues found that symptoms had improved considerably, but phobic disorders were still more common than in controls. There is no evidence that IQ changes as speech returns, but language skills that went unpractised may need direct support.

Most do not. Studies using nonverbal tests find average reasoning, with a mean near 100, although some children have weaker language skills or other developmental delays.

No good evidence shows that. Children with selective mutism span the usual range of ability, and their school achievement in reading and math is similar to their classmates'.

Psychologists use nonverbal tests answered by pointing or arranging, compare verbal and nonverbal scores, and sometimes use recordings, written answers or parent-presented items.

No. A child with selective mutism speaks normally in comfortable settings, but some children have a language weakness as well, so both should be checked.

A child psychologist or psychiatrist experienced with anxiety disorders, working with a speech-language pathologist, can separate anxiety, language and reasoning.

Selective mutism is an anxiety disorder of speech in certain settings. It does not reflect a child's reasoning ability. Nonverbal studies put most children in the average range, a subgroup has language or other developmental weaknesses that the silence can hide, and the "high IQ" reputation is not backed by data. A good assessment uses tasks that do not depend on speaking to a stranger. Adults curious about how general reasoning is measured on tasks that need no spoken answers can try an online IQ test built by psychometricians.

1. Muris, P., & Ollendick, T. H. (2015). Children who are anxious in silence: A review on selective mutism, the new anxiety disorder in DSM-5. Clinical Child and Family Psychology Review, 18(2), 151-169. [doi.org/10.1007/s10567-015-0181-y](. doi.org

2. Bergman, R. L., Piacentini, J., & McCracken, J. T. (2002). Prevalence and description of selective mutism in a school-based sample. Journal of the American Academy of Child & Adolescent Psychiatry, 41(8), 938-946. [doi.org/10.1097/00004583-200208000-00012](. doi.org

3. Kopp, S., & Gillberg, C. (1997). Selective mutism: A population-based study: A research note. Journal of Child Psychology and Psychiatry, 38(2), 257-262. [doi.org/10.1111/j.1469-7610.1997.tb01859.x](. doi.org

4. Kumpulainen, K., Räsänen, E., Raaska, H., & Somppi, V. (1998). Selective mutism among second-graders in elementary school. European Child & Adolescent Psychiatry, 7(1), 24-29. [doi.org/10.1007/s007870050041](. doi.org

5. Black, B., & Uhde, T. W. (1995). Psychiatric characteristics of children with selective mutism: A pilot study. Journal of the American Academy of Child & Adolescent Psychiatry, 34(7), 847-856. [doi.org/10.1097/00004583-199507000-00007](. doi.org

6. Oerbeck, B., Stein, M. B., Pripp, A. H., & Kristensen, H. (2015). Selective mutism: Follow-up study 1 year after end of treatment. European Child & Adolescent Psychiatry, 24(7), 757-766. [doi.org/10.1007/s00787-014-0620-1](. doi.org

7. Cunningham, C. E., McHolm, A., Boyle, M. H., & Patel, S. (2004). Behavioral and emotional adjustment, family functioning, academic performance, and social relationships in children with selective mutism. Journal of Child Psychology and Psychiatry, 45(8), 1363-1372. [doi.org/10.1111/j.1469-7610.2004.00843.x](. doi.org

8. Manassis, K., Tannock, R., Garland, E. J., Minde, K., McInnes, A., & Clark, S. (2007). The sounds of silence: Language, cognition, and anxiety in selective mutism. Journal of the American Academy of Child & Adolescent Psychiatry, 46(9), 1187-1195. [doi.org/10.1097/chi.0b013e318076b7ab](. doi.org

9. Steinhausen, H. C., & Juzi, C. (1996). Elective mutism: An analysis of 100 cases. Journal of the American Academy of Child & Adolescent Psychiatry, 35(5), 606-614. [doi.org/10.1097/00004583-199605000-00015](. doi.org

10. 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. [doi.org/10.1097/00004583-200002000-00026](. doi.org

11. Shorer, M. (2025). Multi-faceted assessment of children with selective mutism: Challenges and practical suggestions. Behavioral Sciences, 15(4), 472. [doi.org/10.3390/bs15040472](. doi.org

12. Kristensen, H., & Oerbeck, B. (2006). Is selective mutism associated with deficits in memory span and visual memory? An exploratory case-control study. Depression and Anxiety, 23(2), 71-76. [doi.org/10.1002/da.20140](. doi.org

13. Klein, E. R., Armstrong, S. L., & Shipon-Blum, E. (2013). Assessing spoken language competence in children with selective mutism: Using parents as test presenters. Communication Disorders Quarterly, 34(3), 184-195. [doi.org/10.1177/1525740112455053](. doi.org

14. Remschmidt, H., Poller, M., Herpertz-Dahlmann, B., Hennighausen, K., & Gutenbrunner, C. (2001). A follow-up study of 45 patients with elective mutism. European Archives of Psychiatry and Clinical Neuroscience, 251(6), 284-296. [doi.org/10.1007/pl00007547](. doi.org

15. Steinhausen, H. C., Wachter, M., Laimböck, K., & Metzke, C. W. (2006). A long-term outcome study of selective mutism in childhood. Journal of Child Psychology and Psychiatry, 47(7), 751-756. [doi.org/10.1111/j.1469-7610.2005.01560.x](. doi.org

Hero image: Empty classroom with chairs on table in Har Nof, by Yitzilitt, licensed CC BY-SA 4.0 (creativecommons.org/licenses/by-sa/4.0). Via Wikimedia Commons.