Table of ContentsView AllTable of ContentsDefinitionSymptoms in ChildrenSymptoms in AdultsCausesDiagnosisRelated ConditionsParental Support
Table of ContentsView All
View All
Table of Contents
Definition
Symptoms in Children
Symptoms in Adults
Causes
Diagnosis
Related Conditions
Parental Support
Intellectual disability (ID) is impaired development of learning, reasoning, social, and life skills. It often becomes apparent at birth or during childhood and continues through adulthood.This condition occurs in varying degrees and can result from genetic, environmental, or unknown factors.
For many decades, the medical establishment and the general public unkindly referred to affected individuals as “feeble-minded,” “moron,” “idiot,” and “imbecile.” During the 1960s, the American Association on Intellectual and Developmental Disabilities (AAIDD) and lawmakers adopted the term “mentally retarded," which experts considered to be more sensitive at the time.
The term “intellectual disability” came about because of Rosa’s Law, passed in 2010 and named after a young girl with ID.
This article reviews ID, its causes, diagnosis, and related conditions. It also offers coping tips for parents.
Martinbowra / Getty Images
What Does Intellectual Disability Mean?
When someone has an intellectual disability, they have limitations in their ability to learn, practice good judgment, and problem-solve (intellectual functioning); they may have difficulty communicating or be unable to live independently.
In some cases, individuals may not show signs of ID in early childhood but develop symptoms during adolescence or adulthood.
Symptoms of Intellectual Disability in Children
Intellectual disability is the most common developmental disability. Approximately 439,000 affected children and youth ages 3 to 21 received support under theIndividuals with Disabilities Education Act (IDEA) in 2019.However, the number of affected children could be higher because data were unavailable for some states.
Children with disabilities may experience issues with:
Some children may always require assistance with these activities.
Symptoms of Intellectual Disability in Adults
The life expectancy of adults with intellectual disabilities has increased over recent decades.For these people, aging comes with additional health risks compared to their peers because they are at higher risk of developing certain health conditions at an earlier age.
These health conditions include:
They also face discrimination and exclusion, which trigger secondary mental health disorders, such as anxiety anddepression.Nevertheless, many adults with mild intellectual disabilities can thrive on their own or with minimal support.
Causes of Intellectual Disability
Intellectual disabilities arise from factors such as:
Intellectual and developmental disabilities also stem from cognitive disruption due to:
How Do You Know if Your Child Is Intellectually Disabled?The way in which an intellectual disability presents itself depends on the underlying cause and severity.Profound or severe cases are usually evident soon after birth. With milder forms, intellectual disability symptoms may include:Not meetingdevelopmental milestones, such as sitting, crawling, or walking later than most childrenDifficulty speaking clearly or at allLearning difficulties at schoolIf you suspect that your child has an intellectual disability, talk with your child’s healthcare provider. They can get you in touch with a developmental pediatrician. Reach out to a public school or anearly intervention programfor information and support.
How Do You Know if Your Child Is Intellectually Disabled?
The way in which an intellectual disability presents itself depends on the underlying cause and severity.Profound or severe cases are usually evident soon after birth. With milder forms, intellectual disability symptoms may include:Not meetingdevelopmental milestones, such as sitting, crawling, or walking later than most childrenDifficulty speaking clearly or at allLearning difficulties at schoolIf you suspect that your child has an intellectual disability, talk with your child’s healthcare provider. They can get you in touch with a developmental pediatrician. Reach out to a public school or anearly intervention programfor information and support.
The way in which an intellectual disability presents itself depends on the underlying cause and severity.Profound or severe cases are usually evident soon after birth. With milder forms, intellectual disability symptoms may include:
If you suspect that your child has an intellectual disability, talk with your child’s healthcare provider. They can get you in touch with a developmental pediatrician. Reach out to a public school or anearly intervention programfor information and support.
Diagnosing Intellectual Disability
Pediatricians and other child healthcare providers can screen for IDDs at your well-child visits and annual exams. You might complete a brief, standardized test that your pediatrician will score.A medical professional may interview you and observe your child for symptoms as well.
Gold-standard tests for intellectual disability include the Autism Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview, Revised.
Evaluating Intellectual and Adaptive Functioning
Measuring Intellectual Functioning
Measuring Adaptive FunctioningAdaptive functioning is measured in these three areas:Conceptual: This includes reading, math, writing, knowledge, and memory.Social: This encompasses social skills, communications, the ability to follow rules, and making and keeping friends.Practical: This includes living independently, taking care of personal hygiene, and being able to hold down a job, manage money, and handle organizational tasks.
Measuring Adaptive Functioning
Adaptive functioning is measured in these three areas:Conceptual: This includes reading, math, writing, knowledge, and memory.Social: This encompasses social skills, communications, the ability to follow rules, and making and keeping friends.Practical: This includes living independently, taking care of personal hygiene, and being able to hold down a job, manage money, and handle organizational tasks.
Adaptive functioning is measured in these three areas:
Evaluating Severity
The AAIDD uses the Supports Intensity Scale (SIS) to assess the severity of ID. It focuses on the types of supports an individual requires to thrive, not just the limitations of the mentally challenged, and ranks them as follows:
Intellectual vs. Developmental DisabilitiesIntellectual disability is a type of developmental disability (DD). The Centers for Disease Control and Prevention (CDC) describes DD as a broader category of conditions due to an impairment in physical, learning, language, or behavior areas.“IDD” describes situations in which intellectual disability and other disabilities co-occur. Examples of intellectual and developmental disabilities include:ADHDAutism spectrum disorderCerebral palsyHearing lossVision impairmentSpina bifida
Intellectual vs. Developmental Disabilities
Intellectual disability is a type of developmental disability (DD). The Centers for Disease Control and Prevention (CDC) describes DD as a broader category of conditions due to an impairment in physical, learning, language, or behavior areas.“IDD” describes situations in which intellectual disability and other disabilities co-occur. Examples of intellectual and developmental disabilities include:ADHDAutism spectrum disorderCerebral palsyHearing lossVision impairmentSpina bifida
Intellectual disability is a type of developmental disability (DD). The Centers for Disease Control and Prevention (CDC) describes DD as a broader category of conditions due to an impairment in physical, learning, language, or behavior areas.
“IDD” describes situations in which intellectual disability and other disabilities co-occur. Examples of intellectual and developmental disabilities include:
Intellectual disability frequently co-occurs with other developmental, physical, medical, and psychiatric conditions. It can be challenging to identify these illnesses if the affected person has limited communication skills. Commonly related conditions include:
Other conditions associated with intellectual disability include:
Supporting People With Intellectual Disabilities
Both children and adults with intellectual disabilities need support.
Ways to support children with ID include the following:
Your pediatrician and local school can be your partner in caring for your child with ID. Federal laws provide for special education and accommodations in public schools. You can ask for an evaluation to determine your child’s needs and help develop an Individualized Education Program (IEP) for a successful learning journey.
There are also ways to support adults with ID:
Summary
Most affected people have mild ID, but disorders can also be moderate, severe, or profound. With early detection and intervention, you can connect with specialized services to enhance the well-being of your loved one living with ID.
32 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institutes of Health.About intellectual and developmental disabilities (IDDs).Federal Register.Rosa’s law.American Association on Intellectual and Developmental Disabilities.Definition of intellectual disability.American Psychiatric Association.What Is intellectual disability?National Center for Education Statistics.Fast facts: Students with disabilities.Centers for Disease Control and Prevention.Facts about intellectual disability in children.Population Reference Bureau.U.S. adults with intellectual and developmental disabilities are living longer, but COVID threatens to erase recent gains.Wang H, Lee PMY, Zhang J, et al.Association of intellectual disability with overall and type-specific cardiovascular diseases: a population-based cohort study in Denmark. BMC Med. 2023 Feb 6;21(1):41. doi: 10.1186/s12916-023-02747-4Liao P, Vajdic C, Trollor J, et al.Prevalence and incidence of physical health conditions in people with intellectual disability – a systematic review. Taheri S, ed. PLoS ONE. 2021;16(8):e0256294. doi: 10.1371/journal.pone.0256294National Disability Navigator Resource Collaborative.Population-specific fact sheet – intellectual disability.Ilyas M, Mir A, Efthymiou S, Houlden H. The genetics of intellectual disability: advancing technology and gene editing. F1000Res. 2020;9:22. doi:10.12688/f1000research.16315.1Patel DR, Cabral MD, Ho A, Merrick J.A clinical primer on intellectual disability. Transl Pediatr. 2020;9(S1):S23-S35. doi: 10.21037%2Ftp.2020.02.02Lipkin PH, Macias MM.Promoting optimal development: identifying infants and young children with developmental disorders through developmental surveillance and screening.Pediatrics. 2020;145(1):e20193449. doi:10.1542/peds.2019-3449McCarty P, Frye RE.Early detection and diagnosis of autism spectrum disorder: why is it so difficult?Seminars in Pediatric Neurology. 2020;35:100831. doi: 10.1016/j.spen.2020.100831Sun F, Oristaglio J, Levy SE, et al.Genetic testing for developmental disabilities, intellectual disability, and autism spectrum disorder. Rockville (MD): Agency for Healthcare Research and Quality (US); 2015 Jun. (Technical Briefs, No. 23.)Nationwide Children’s Hospital.Microarray analysis test.National Library of Medicine.Mental disorders and disabilities among low-income children. 2015 Oct 28. Ch. 9: Clinical Characteristics of Intellectual Disabilities.Jonker F, Didden R, Goedhard L, Korzilius H, Nijman H. The ADaptive Ability Performance Test (ADAPT):A new instrument for measuring adaptive skills in people with intellectual disabilities and borderline intellectual functioning.J Appl Res Intellect Disabil. 2021;34(4):1156-1165. doi:10.1111%2Fjar.12876American Association on Intellectual and Developmental Disabilities.Supports intensity scale.Centers for Disease Control and Prevention.Developmental disabilities.Medline Plus.Apert syndrome.Merck Manual.Kernicterus.Medline Plus.Prader-Willi syndrome.National Institutes of Health.Phenylketonuria.Specht S, Straub V.Intellectual disability in paediatric patients with genetic muscle diseases. Neuromuscular Disorders. 2021;31(10):988-997. doi: 10.1016/j.nmd.2021.08.012Sarongku T, Trisnawati SY, Samatra DPGP.Intellectual disability as a comorbidity in Tourette syndrome: a case report. Postep Psychiatr Neurol. 2022 Dec;31(4):178-182. doi: 10.5114/ppn.2022.125074Medline Plus.Williams syndrome.Center for Parent Information & Resources.Intellectual disability.Reichow B, Lemons CJ, Maggin DM, Hill DR.Beginning reading interventions for children and adolescents with intellectual disability.Cochrane Developmental, Psychosocial and Learning Problems Group, ed.Cochrane Database of Systematic Reviews. 2019;2019(12). doi:10.1002/14651858.cd011359.pub2American Academy of Child & Adolescent Psychiatry.School services for children with special needs: Know your rights.American Academy of Family Physicians.Caring for a person who has intellectual or developmental disabilities.Special Olympics.How to speak with people with intellectual disabilities.Additional ReadingThe arcCenter for Parent Information and ResourcesSpecialOlympics.org.What Is Intellectual Disability?
32 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institutes of Health.About intellectual and developmental disabilities (IDDs).Federal Register.Rosa’s law.American Association on Intellectual and Developmental Disabilities.Definition of intellectual disability.American Psychiatric Association.What Is intellectual disability?National Center for Education Statistics.Fast facts: Students with disabilities.Centers for Disease Control and Prevention.Facts about intellectual disability in children.Population Reference Bureau.U.S. adults with intellectual and developmental disabilities are living longer, but COVID threatens to erase recent gains.Wang H, Lee PMY, Zhang J, et al.Association of intellectual disability with overall and type-specific cardiovascular diseases: a population-based cohort study in Denmark. BMC Med. 2023 Feb 6;21(1):41. doi: 10.1186/s12916-023-02747-4Liao P, Vajdic C, Trollor J, et al.Prevalence and incidence of physical health conditions in people with intellectual disability – a systematic review. Taheri S, ed. PLoS ONE. 2021;16(8):e0256294. doi: 10.1371/journal.pone.0256294National Disability Navigator Resource Collaborative.Population-specific fact sheet – intellectual disability.Ilyas M, Mir A, Efthymiou S, Houlden H. The genetics of intellectual disability: advancing technology and gene editing. F1000Res. 2020;9:22. doi:10.12688/f1000research.16315.1Patel DR, Cabral MD, Ho A, Merrick J.A clinical primer on intellectual disability. Transl Pediatr. 2020;9(S1):S23-S35. doi: 10.21037%2Ftp.2020.02.02Lipkin PH, Macias MM.Promoting optimal development: identifying infants and young children with developmental disorders through developmental surveillance and screening.Pediatrics. 2020;145(1):e20193449. doi:10.1542/peds.2019-3449McCarty P, Frye RE.Early detection and diagnosis of autism spectrum disorder: why is it so difficult?Seminars in Pediatric Neurology. 2020;35:100831. doi: 10.1016/j.spen.2020.100831Sun F, Oristaglio J, Levy SE, et al.Genetic testing for developmental disabilities, intellectual disability, and autism spectrum disorder. Rockville (MD): Agency for Healthcare Research and Quality (US); 2015 Jun. (Technical Briefs, No. 23.)Nationwide Children’s Hospital.Microarray analysis test.National Library of Medicine.Mental disorders and disabilities among low-income children. 2015 Oct 28. Ch. 9: Clinical Characteristics of Intellectual Disabilities.Jonker F, Didden R, Goedhard L, Korzilius H, Nijman H. The ADaptive Ability Performance Test (ADAPT):A new instrument for measuring adaptive skills in people with intellectual disabilities and borderline intellectual functioning.J Appl Res Intellect Disabil. 2021;34(4):1156-1165. doi:10.1111%2Fjar.12876American Association on Intellectual and Developmental Disabilities.Supports intensity scale.Centers for Disease Control and Prevention.Developmental disabilities.Medline Plus.Apert syndrome.Merck Manual.Kernicterus.Medline Plus.Prader-Willi syndrome.National Institutes of Health.Phenylketonuria.Specht S, Straub V.Intellectual disability in paediatric patients with genetic muscle diseases. Neuromuscular Disorders. 2021;31(10):988-997. doi: 10.1016/j.nmd.2021.08.012Sarongku T, Trisnawati SY, Samatra DPGP.Intellectual disability as a comorbidity in Tourette syndrome: a case report. Postep Psychiatr Neurol. 2022 Dec;31(4):178-182. doi: 10.5114/ppn.2022.125074Medline Plus.Williams syndrome.Center for Parent Information & Resources.Intellectual disability.Reichow B, Lemons CJ, Maggin DM, Hill DR.Beginning reading interventions for children and adolescents with intellectual disability.Cochrane Developmental, Psychosocial and Learning Problems Group, ed.Cochrane Database of Systematic Reviews. 2019;2019(12). doi:10.1002/14651858.cd011359.pub2American Academy of Child & Adolescent Psychiatry.School services for children with special needs: Know your rights.American Academy of Family Physicians.Caring for a person who has intellectual or developmental disabilities.Special Olympics.How to speak with people with intellectual disabilities.Additional ReadingThe arcCenter for Parent Information and ResourcesSpecialOlympics.org.What Is Intellectual Disability?
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Institutes of Health.About intellectual and developmental disabilities (IDDs).Federal Register.Rosa’s law.American Association on Intellectual and Developmental Disabilities.Definition of intellectual disability.American Psychiatric Association.What Is intellectual disability?National Center for Education Statistics.Fast facts: Students with disabilities.Centers for Disease Control and Prevention.Facts about intellectual disability in children.Population Reference Bureau.U.S. adults with intellectual and developmental disabilities are living longer, but COVID threatens to erase recent gains.Wang H, Lee PMY, Zhang J, et al.Association of intellectual disability with overall and type-specific cardiovascular diseases: a population-based cohort study in Denmark. BMC Med. 2023 Feb 6;21(1):41. doi: 10.1186/s12916-023-02747-4Liao P, Vajdic C, Trollor J, et al.Prevalence and incidence of physical health conditions in people with intellectual disability – a systematic review. Taheri S, ed. PLoS ONE. 2021;16(8):e0256294. doi: 10.1371/journal.pone.0256294National Disability Navigator Resource Collaborative.Population-specific fact sheet – intellectual disability.Ilyas M, Mir A, Efthymiou S, Houlden H. The genetics of intellectual disability: advancing technology and gene editing. F1000Res. 2020;9:22. doi:10.12688/f1000research.16315.1Patel DR, Cabral MD, Ho A, Merrick J.A clinical primer on intellectual disability. Transl Pediatr. 2020;9(S1):S23-S35. doi: 10.21037%2Ftp.2020.02.02Lipkin PH, Macias MM.Promoting optimal development: identifying infants and young children with developmental disorders through developmental surveillance and screening.Pediatrics. 2020;145(1):e20193449. doi:10.1542/peds.2019-3449McCarty P, Frye RE.Early detection and diagnosis of autism spectrum disorder: why is it so difficult?Seminars in Pediatric Neurology. 2020;35:100831. doi: 10.1016/j.spen.2020.100831Sun F, Oristaglio J, Levy SE, et al.Genetic testing for developmental disabilities, intellectual disability, and autism spectrum disorder. Rockville (MD): Agency for Healthcare Research and Quality (US); 2015 Jun. (Technical Briefs, No. 23.)Nationwide Children’s Hospital.Microarray analysis test.National Library of Medicine.Mental disorders and disabilities among low-income children. 2015 Oct 28. Ch. 9: Clinical Characteristics of Intellectual Disabilities.Jonker F, Didden R, Goedhard L, Korzilius H, Nijman H. The ADaptive Ability Performance Test (ADAPT):A new instrument for measuring adaptive skills in people with intellectual disabilities and borderline intellectual functioning.J Appl Res Intellect Disabil. 2021;34(4):1156-1165. doi:10.1111%2Fjar.12876American Association on Intellectual and Developmental Disabilities.Supports intensity scale.Centers for Disease Control and Prevention.Developmental disabilities.Medline Plus.Apert syndrome.Merck Manual.Kernicterus.Medline Plus.Prader-Willi syndrome.National Institutes of Health.Phenylketonuria.Specht S, Straub V.Intellectual disability in paediatric patients with genetic muscle diseases. Neuromuscular Disorders. 2021;31(10):988-997. doi: 10.1016/j.nmd.2021.08.012Sarongku T, Trisnawati SY, Samatra DPGP.Intellectual disability as a comorbidity in Tourette syndrome: a case report. Postep Psychiatr Neurol. 2022 Dec;31(4):178-182. doi: 10.5114/ppn.2022.125074Medline Plus.Williams syndrome.Center for Parent Information & Resources.Intellectual disability.Reichow B, Lemons CJ, Maggin DM, Hill DR.Beginning reading interventions for children and adolescents with intellectual disability.Cochrane Developmental, Psychosocial and Learning Problems Group, ed.Cochrane Database of Systematic Reviews. 2019;2019(12). doi:10.1002/14651858.cd011359.pub2American Academy of Child & Adolescent Psychiatry.School services for children with special needs: Know your rights.American Academy of Family Physicians.Caring for a person who has intellectual or developmental disabilities.Special Olympics.How to speak with people with intellectual disabilities.
National Institutes of Health.About intellectual and developmental disabilities (IDDs).
Federal Register.Rosa’s law.
American Association on Intellectual and Developmental Disabilities.Definition of intellectual disability.
American Psychiatric Association.What Is intellectual disability?
National Center for Education Statistics.Fast facts: Students with disabilities.
Centers for Disease Control and Prevention.Facts about intellectual disability in children.
Population Reference Bureau.U.S. adults with intellectual and developmental disabilities are living longer, but COVID threatens to erase recent gains.
Wang H, Lee PMY, Zhang J, et al.Association of intellectual disability with overall and type-specific cardiovascular diseases: a population-based cohort study in Denmark. BMC Med. 2023 Feb 6;21(1):41. doi: 10.1186/s12916-023-02747-4
Liao P, Vajdic C, Trollor J, et al.Prevalence and incidence of physical health conditions in people with intellectual disability – a systematic review. Taheri S, ed. PLoS ONE. 2021;16(8):e0256294. doi: 10.1371/journal.pone.0256294
National Disability Navigator Resource Collaborative.Population-specific fact sheet – intellectual disability.
Ilyas M, Mir A, Efthymiou S, Houlden H. The genetics of intellectual disability: advancing technology and gene editing. F1000Res. 2020;9:22. doi:10.12688/f1000research.16315.1
Patel DR, Cabral MD, Ho A, Merrick J.A clinical primer on intellectual disability. Transl Pediatr. 2020;9(S1):S23-S35. doi: 10.21037%2Ftp.2020.02.02
Lipkin PH, Macias MM.Promoting optimal development: identifying infants and young children with developmental disorders through developmental surveillance and screening.Pediatrics. 2020;145(1):e20193449. doi:10.1542/peds.2019-3449
McCarty P, Frye RE.Early detection and diagnosis of autism spectrum disorder: why is it so difficult?Seminars in Pediatric Neurology. 2020;35:100831. doi: 10.1016/j.spen.2020.100831
Sun F, Oristaglio J, Levy SE, et al.Genetic testing for developmental disabilities, intellectual disability, and autism spectrum disorder. Rockville (MD): Agency for Healthcare Research and Quality (US); 2015 Jun. (Technical Briefs, No. 23.)
Nationwide Children’s Hospital.Microarray analysis test.
National Library of Medicine.Mental disorders and disabilities among low-income children. 2015 Oct 28. Ch. 9: Clinical Characteristics of Intellectual Disabilities.
Jonker F, Didden R, Goedhard L, Korzilius H, Nijman H. The ADaptive Ability Performance Test (ADAPT):A new instrument for measuring adaptive skills in people with intellectual disabilities and borderline intellectual functioning.J Appl Res Intellect Disabil. 2021;34(4):1156-1165. doi:10.1111%2Fjar.12876
American Association on Intellectual and Developmental Disabilities.Supports intensity scale.
Centers for Disease Control and Prevention.Developmental disabilities.
Medline Plus.Apert syndrome.
Merck Manual.Kernicterus.
Medline Plus.Prader-Willi syndrome.
National Institutes of Health.Phenylketonuria.
Specht S, Straub V.Intellectual disability in paediatric patients with genetic muscle diseases. Neuromuscular Disorders. 2021;31(10):988-997. doi: 10.1016/j.nmd.2021.08.012
Sarongku T, Trisnawati SY, Samatra DPGP.Intellectual disability as a comorbidity in Tourette syndrome: a case report. Postep Psychiatr Neurol. 2022 Dec;31(4):178-182. doi: 10.5114/ppn.2022.125074
Medline Plus.Williams syndrome.
Center for Parent Information & Resources.Intellectual disability.
Reichow B, Lemons CJ, Maggin DM, Hill DR.Beginning reading interventions for children and adolescents with intellectual disability.Cochrane Developmental, Psychosocial and Learning Problems Group, ed.Cochrane Database of Systematic Reviews. 2019;2019(12). doi:10.1002/14651858.cd011359.pub2
American Academy of Child & Adolescent Psychiatry.School services for children with special needs: Know your rights.
American Academy of Family Physicians.Caring for a person who has intellectual or developmental disabilities.
Special Olympics.How to speak with people with intellectual disabilities.
The arcCenter for Parent Information and ResourcesSpecialOlympics.org.What Is Intellectual Disability?
The arc
Center for Parent Information and Resources
SpecialOlympics.org.What Is Intellectual Disability?
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
