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Case 

You are asked to see a 10-yo with intellectual disability (ID) due to problems with aggression at home and school. His aggression includes swearing, kicking others. Triggers include sensory issues, as well as teachers trying to ask him to follow the school routine. Unfortunately, his aggression is so severe that he is at risk of being suspended from school, which will cause extreme hardship to his mother, as she will then be at risk of losing her job. 

What are you going to do?

What is Intellectual Disability?

Intellectual disability (ID) is a chronic developmental disorder, with onset in the developmental period (i.e. before age 18), with impairment of general mental abilities which impacts adaptive functioning in three domains:

1. Conceptual domain, which includes skills such as:
   • Language
   • Reading
   • Writing
   • Math
   • Reasoning
   • Knowledge
   • Memory
2. Social domain, which are social and interpersonal skills such as:
   • Empathy
   • Social judgment
   • Communication skills
   • Ability to make and retain friendships
3. Practical domain, the ability to self-manage in areas such as:
   • Personal care, health and safety
   • Ability to function at school or work
   • Manage money and finances
   • Recreation and leisure

Impairment of mental abilities is defined as significantly below, i.e. 2 standard deviations below the population, which means an IQ score of 70 or below.

Terms

There is variation in terms across the Western world:

• Australia: 
  • Intellectual disability
• North America:
  • With the DSM-5, the term is now Intellectual disability (or intellectual developmental disorder).
  • With the DSM-IV, the previously used term was mental retardation.
• UK: 
  • Learning disabilities.

Developmental disability

• Refers to various developmental disabilities, which includes intellectual disability as well as autism spectrum disorders and other developmental disorders.

Red Flags

Infants with language delays

• No words by 12-months
• No 2-word phrases by age 2
• Parents concerned the child is deaf

Toddler with motor delays

• Delays in self-feeding, toileting, dressing
• Troubles with comprehension

Clinical Presentation

Borderline intellectual functioning

• If symptoms are not identified while in school, they may even remain unidentified as adults.

Mild ID

• Delays may not be noted in preschool years, but rather in school age.

Severe or profound ID

• Significant delays in motor, language and social milestones may be noted earlier on such as within first 2-years of life

Individuals with intellectual disability (ID) may have difficulty in numerous domains:

Presentation to Psychiatry

As a psychiatrist, you may encounter individuals with ID in various ways:

• The diagnosis has already been made and they have been referred to you for mental health issues (e.g. depression, anxiety) and/or behavioural issues.
• You are seeing a child/youth or adult for mental health issues, and you suspect they may have ID.

Epidemiology

Prevalence of intellectual disability

• 1% of the population

Gender

• Males > females (due to sex-linked genetic factors; male vulnerability to brain insult)
  • Mild ID M:F = 1.6 : 1
  • Severe ID M:F = 1.2 : 1

Etiology

There are many different causes of intellectual disability which include:

• Known causes 60% (Curry, 1997)
• Idiopathic (no specific known cause) 40% (Curry, 1997)

Known Causes

Prenatal (before birth)

Perinatal (around the time of birth)

Postnatal causes

Screening

Screen a child’s development at regular intervals (American Academy of Pediatrics), such as by using parental surveys:

• Parents' Evaluation of Developmental Status (PEDS),
• Ages and Stages Questionnaires (ASQ)
• Child Development Inventories (CDI).

Diagnostic Measures

Psychologists may use common psychological tests such as:

• Bayley Scales of Infant Development-III,
• Stanford-Binet Intelligence Scale,
• Wechsler Intelligence Scale for Children-IV,
• Wechsler Preschool and Primary Scale of Intelligence-Revised,

• Vineland Adaptive Behavior Scales-Second Edition (Vineland-II)
  • The “Vineland” is designed to measure adaptive behavior of individuals from birth to age 90.
  • Contains 5 domains
    • Communication
      • Receptive: How the individual listens and pays attention and what he or she understands.
      • Expressive: What the individual says, how he or she uses words and sentences to gather and provide information.
      • Written: What the individual understands about how letters make words, and what he or she reads and writes.
    • Daily Living Skills
      • Personal: How the individual eats, dresses, and practices personal hygiene.
      • Domestic: What household tasks the individual performs.
      • Community: How the individual uses time, money, the telephone, the computer, and job skills.
    • Socialization
      • Interpersonal Relationships: How the individual interacts with others.
      • Play and Leisure Time: How the individual plays and uses leisure time.
      • Coping skills: How the individual demonstrates responsibility and sensitivity to others.
    • Motor Skills
      • Gross Motor: How the individual uses arms and legs for movement and coordin
      • Fine Motor: How the individual uses hands and fingers to manipulate objects.
    • Maladaptive Behaviour (optional)
      • Any internalizing, Externalizing and other types of undesirable behavior that may interfere with the individual’s adaptive functioning.
  • Adaptive Behavior Composite: A composite of the communication, daily living skills, socialization, and motor skills domains.

Assessment / History of the Person with known (or suspected) ID

Ensure your physical space is safe, such as being mindful of sensory needs:

• Reduce visual overstimulation, e.g. keep waiting rooms tidy, try to avoid harsh fluorescent lighting; dim lights if possible; allow patient to wear baseball cap, hoodies, etc.
• Reduce auditory overstimulation, e.g. don’t have background radio in the waiting room.
• Consider booking individuals with ID during quieter periods, e.g. first or last appointment of the morning/afternoon.

Communication recommendations (Kelly, 2011; Sullivan, 2018):

• Is it an older youth or adult with ID?
  • Explain to caregivers that you will address patients directly (as opposed to simply turning to their caregivers) AND that you also want caregivers’ input as well.
• Is it a child with ID?
  • Address caregivers primarily, in the same way as you would with other children AND ask the child for input when appropriate (e.g. asking about their thoughts/feelings, sensory issues, triggers and stresses) as well as meeting alone (when screening for neglect / abuse).
• Engage the patient, e.g. around a preferred item that has been brought to the appointment; their clothing; ask about interests.
• Communication aids used by those with ID may include
  • Signing (such as American Sign Language)
  • Picture exchange communication systems (such as on tablet device)

A comprehensive assessment would include the following:

• Concerns
  • What are the main issues that are stressful, difficult, or troubling?
  • Any behaviours that are challenging for caregivers? (aka behaviours that challenge (BTC))?

• Goals
  • What are the patient’s best hopes from the visit? (if patient is able to articulate, such as with those with mild ID)
  • What are the caregiver's best hopes from the visit?

• Current services and supports
• Any stressful life events?
  • E.g. abuse, neglect, bullying, exclusion.
• Medication history
  • Review medications regularly (eg, every 3 mo), including the indication, when started / stopped, effectiveness, and any side effects (Sullivan, 2018)
• Caregiver needs (Sullivan, 2018)
  • Ask caregivers about how they are coping, and if they have any particular needs.

• Psychiatric review of symptoms including
  • Neurovegetative symptoms, e.g. sleep, energy, concentration, appetite.
  • Screening for abuse/trauma: Meet alone with the individual with IDD to screen for abuse, exploitation or neglect (Sullivan, 2018)

• School / Workplace history
  • What schools were attended in the past? Were these mainstream, or in a specific program?
  • With adults: What work/ employment in the past?

• Pregnancy history
   
• Birth history
   
• Developmental history
  • Language development
  • Sensory processing
  • Motor skills
  • Socialization
    • Any troubles with social skills
• Family medical history
  • Genetic conditions?
  • Mother
    • Infections during pregnancy?
    • Any possibility of prenatal exposure to toxins?
    • Any consanguinity?
    • Fetal loss
  • Premature?

Physical Examination

As a psychiatrist, either perform, or ensure that there is a primary care provider who can provide physical examinations as necessary.

Mental Status Examination (MSE)

Estimating Intellectual Disability Based on Level of Function

Spectrum of Intellectual Function

Intellectual Disability		Borderline intellectual functioning		Normal IQ
1% of the population		7% of the population		Majority of the population
IQ 50-55 to 70 (or below)		IQ 71-85
		Still face significant challenges compared to those with “normal” IQ. May perform daily activities and work without assistance but are more vulnerable to stressful life events and mental health concerns.

DSM-5 Intellectual Disabilities

DSM-5 Intellectual Disabilities are the following:

1. Intellectual disability (aka intellectual developmental disorder)

• Previously known as mental retardation in DSM-IV

2. Global developmental delay (GDD)

• The term GDD is used when a person is < 5 years of age and has significant deficits in learning and function, however reliable (IQ testing) assessment is not possible
• GDD requires reassessment after a period of time (DSM-5)
• A child with GDD will not necessarily test in the ID range when older.

3. Unspecified intellectual disability (ID)

• The term “Unspecified ID” is used when a person is > 5 years age, and reliable assessment is not possible.

DSM-5 Intellectual Disability (Intellectual Developmental Disorder)

DSM-5 Criteria for ID 

A. Deficits in intellectual function

• Deficits (reasoning, problem- solving, planning, abstract thinking etc) confirmed by clinical assessment and individual standardized testing (IQ: 70 ± 5).

B. Deficits in adaptive function

• The person’s intellectual deficits lead to deficits in adaptive function, i.e the person is unable to meet socio-cultural standards for activities in daily life (at home, school, work, community) without ongoing support.

C. Age of onset is during the developmental period.

Note:

• A diagnosis of ID is not made only on basis of IQ score (i.e. IQ ≤ 70) -- it requires troubles with adaptive functioning as well.

Specifiers

• Severity for ID
  • Mild IQ 50-55 to 70
  • Moderate IQ 35-40 to 50-55
  • Severe IQ 20-25 to 35-40
  • Profound IQ < 20-25

Differential Diagnosis of Intellectual Disability: DSM-5 Differential

Differential Diagnosis of Intellectual Disability: Medical Causes

Consider the following in those with otherwise unexplained developmental delay or intellectual disability:

Comorbidity

People with ID are at a higher risk of having numerous conditions (Oeseburg et al., 2011) such as:

Medical isssues

Psychiatric (and neuropsychiatric) conditions

Investigations

Has a psychoeducational assessment been done, with full-scale IQ? If not, then refer to psychology for psychoeducational assessment.		Psychoeducational Assessment
Does child have unexplained MR/DD, even in the ab-sence of dysmorphic facial features, other clinical features or positive family history.” (Shaffer, 2005)		Psychoeducational assessment Refer to genetics (Shaffer, 2005)
Is there a possibility of metabolic condition?		Refer to pediatrics who can consider metabolic screening
Any structural differences noted, e.g. microcephaly, macrocephaly? Any neurologic symptoms (e.g. spasticity, ataxia, dystonia, seizures, loss of motor skills, abnormal reflexes)		Refer to neurology Consider neuroimaging
Is there possible seizure disorder?		Refer for EEG
Are there any medical issues suspected? (E.g. hypothyroidism)		Do testing as indicated

Management / Treatment

Psychoeducation

• When providing education to the individual with ID about conditions or other issues, use appropriate resources targeted for those with ID such as
  • Easy Health (from the UK) has a wide range of handouts on various topics including healthy living, as well as anxiety, depression, and autism.
    http://www.easyhealth.org.uk.

Education

• Attending school is essential for individuals with ID to learn academics as well as life skills; most school boards have specialized programs for those with ID.
• Recommendation
  • Liaise with the school.
  • Ensure that the student with ID has an IEP in place, as well as appropriate support, such as educational assistant (EA), or specialized classroom.
  • Those with mild ID tend to be integrated in the mainstream school setting, whereas those with severe ID will likely be in a specialized classroom.

Occupational therapy (OT) and physiotherapy (PT)

• Are there ongoing sensory / motor / self-regulation issues?
  • Occupational therapy (OT) can help, as well as with day-to-day function at home and school, such as life skills.
  • Physiotherapists (PT) can help with motor issues such as low muscle tone, problems with coordination.

Speech language therapy (SLP)

• Are there difficulties with communication?
  • SLP may help improve the ability to communicate (Wilkinson, 2007).

Service Navigation

• Ensure that the family is connected to community organizations that support those with intellectual disabilities (and their families), such as a case worker.

Healthy activities for a sense of connection, belonging and purpose

• Persons with ID may benefit from the usual activities for others such as sports and recreational activities; spiritual-based activities, etc.
• Persons with more severe ID may need more specific services geared to those with ID.

Family Support

• What are the family’s needs?
  • Information / knowledge about the diagnosis, or related issues
  • Emotional support
  • Help with practical issues, e.g. finances
  • Peer support with other families?

Sleep Challenges

Are there problems with sleep?

• Start with sleep hygiene and behavioural strategies including limiting screen time 1-2 hrs before bedtime 

Are there still problems with sleep? 

• Consider melatonin, which has been specifically studied in people with autism and shown considerable benefit (Cortese, Wang, Angriman, Masi & Bruni, 2020)
• Note: 
  • Off-label use of antipsychotics for sleep issues is common but unfortunately not evidence-based 
  • The American Academy of Child & Adolescent Psychiatry (Findling, Drury, Jensen, Rapoport, & AACAP Committee on Quality Issues, 2011) recommends AGAINST the usage of antipsychotics for sleep.

Behaviours that Challenge (BTC)

Behaviours that challenge (BTC) (aka challenging behaviour) include:

• Self-injurious behaviour
• Anger, aggression, irritability
• Property destruction
• Pica

Assessment

• Understand what is beneath the challenging behaviour, as there may be many different causes for the behaviour such as:
  • Health related reasons, e.g. pain; constipation.
  • The person is sensory overloaded (e.g. too much sound)
  • The person is reacting to stressful life circumstances such as a loss or change (e.g. change in caregiver)
  • The person is aggressive because they do not yet have the skills to express their feelings or wishes in a more appropriate way, e.g. not yet able to express that they are frustrated, sad, angry, anxious.
  • Mental health related reason, e.g. depression, anxiety, adjustment problems

Management of challenging behaviour (CB)

• Address the underlying cause (rather than simply using positive/negative reinforcement strategy for the behaviour)
  • Example
    • If the person is aggressive because they are constipated, it will be more effective deal with their constipation (as opposed to punish them for being aggressive).
• Consider referral to behaviorist if available
  • Behaviorists uses multiple interventions including
    • Functional assessment
    • Antecedent-behaviour-consequence (ABC) charts

• Are there challenging behaviours that persist despite exhausting non-medication strategies? Is the severity sufficient to warrant medication trial? (e.g. person at risk of losing their placement or housing, etc.)
  • Options
    • Second generation antipsychotics for problem behaviours (Snyder, 2002)
      • Note a lack of evidence for medications in ID, and thus, much evidence is extrapolated from studies in those with ASD. 
      • Start low and go slow -- people with ID generally have more comorbid medical issues, and may be more sensitive to side effects
      • Antipsychotic medications appear to be effective in the short-term, though they carry significant side effects (McQuire C et al., 2015).
    • Is there comorbid ADHD?
      • Consider stimulant medication for ADHD 
        • Evidence for the use of methylphenidate first-line for ADHD with comorbid ID -- note lower effect size than in children with ADHD and average intelligence (Arnold, 2013). 
        • First-line
          • Methylphenidate, given that
            • More evidence for methylphenidate (than amphetamine) for ADHD in the context of ASD (Mahajan et al., 2012; Rodrigues et al. [in press]) and ID (Arnold, 2013)
            • Methylphenidate is better tolerated (than amphetamine) in children and adolescents (Cortese et al., 2018)
        • Watch for paradoxical effects such as worsening behaviours, irritability and insomnia (DeFlllipis & Wagner, 2016)
    • Is there self-injurious behaviour?
      • Consider Naltrexone (Revia)
    • Are there mood/anxiety issues?
      • Consider SSRIs

Antipsychotic Medication Table for Adolescents and Adults

NOTE:

• CAMESA Monitoring Guidelines recommend: 
  • Height, weight, waist circumference, blood pressure
  • Bloodwork: fasting plasma glucose, insulin, total cholesterol, LDL, HDL, triglycerides, prolactin. 
• Ideally, values are monitored at baseline, three months, six months, and every six months thereafter (Pringsheim, Panagiotopoulos, Davidson, Ho & CAMESA guideline group, 2011).

Capacity and Consent in Emerging Adults with Intellectual Disability

With children/youth with intellectual disabilities, ensure that informed consent is obtained for any interventions especially medications.

• Discuss risks, benefits, and alternative treatments with parents (and ideally, the child/youth is providing assent).
  

As children become youth and emerging adults however, they may make increasingly assert their autonomy and also decisions that their parents disagree with, e.g. a youth with intellectual disability who wants to stop taking necessary medications; who wants to date an older boyfriend and move out with him, etc.

For more information about capacity and consent in emerging adults with developmental disabilities 

• Capacity and Consent As Your Child/Youth with Developmental Disabilities Becomes an Adult: Information for Parents
  https://docs.google.com/docume...
  

Outcome / Prognosis of Intellectual Disability

High mortality rates

• Individuals with severe/profound ID have higher mortality rates because of complications associated with physical disease.
• Accidental injury rates may be increased due to lack of awareness of risk/danger.
• There is increased risk for suicide, presumably because life is more challenging and difficult for them.

Victimization by others

• Gullibility and lack of awareness of risk may result in exploitation by others, victimization, fraud, unintentional criminal involvement, false confessions, risk for physical/sexual abuse.

Outcomes vary, depending on the severity of the intellectual disability. One estimate is the following:

Clinical Practice Guidelines

Shaffer L: American College of Medical Genetics guideline on the cytogenetic evaluation of the individual with developmental delay or mental retardation,

Nov/Dec 2005, Genetics in Medicine 7(9):650-654.

https://www.acmg.net/PDFLibrary/Developmental-Delay-Cytogenetic-Evaluation.pdf

Szymanski L, King B: Practice parameters for the assessment and treatment of children, adolescents, and adults with mental retardation and comorbid mental disorders, JAACAP, Dec 1999, 38(12): 5S-31S (supplement).

NOTE - these Practice Parameters are out of date, but are provided for historical information.

https://www.jaacap.org/article/S0890-8567(99)80002-1/fulltext

Sullivan W et al.: Primary care of adults with intellectual and developmental disabilities

2018 Canadian consensus guidelines. Canadian Family Physician, 64: Apr 2018.

https://www.cfp.ca/content/cfp/64/4/254.full.pdf

Kishore M et al.: Clinical Practice Guidelines for Assessment and Management of intellectual disability. Indian J Psychiatry. 2019 Jan; 61(Suppl 2): 194–210.

doi: 10.4103/psychiatry.IndianJPsychiatry_507_18

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6345136/

Resources for Clinicians

Kelly M. Communicating effectively with people with developmental disabilities. In: Sullivan WF, Developmental Disabilities Primary Care Initiative Scientific and Editorial Staff, editors. Tools for the primary care of people with developmental disabilities. Toronto, ON: Surrey Place Centre, MUMS Guidelines Clearinghouse; 2011. p. 18-20. http://ddprimarycare.surreyplace.ca/tools/general-health/communicating-effectively/ .

Treatable-ID.org

Website with an interactive tool for the clinician and scientist, both expert and trainee, in order to identify 81 treatable causes of intellectual disability. Based on a systematic literature review published in “Molecular Genetics and Metabolism” in Mar 2012.

http://www.treatable-id.org

Marrus N, Hall L. Intellectual Disability and Language Disorder. Child Adolesc Psychiatr Clin N Am. 2017;26(3):539–554. doi:10.1016/j.chc.2017.03.001

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5801738/

References

Arnold, L. E. (2013). Commentary: Filling out the evidence base for treatment of attention-deficit hyperactivity disorder symptoms in children with intellectual and developmental disability: conclusions for clinicians—a response to Simonoff et al. (2013). Journal of Child Psychology and Psychiatry, 54(6), 701-703. doi: 10.1111/jcpp.12097

Curry CJ, Stevenson RE, Aughton D, Byrne J, et al. Evaluation of mental retardation: Recommendations of a Consensus Conference: American College of Medical Ge- netics. Am J Med Genet 1997;72:468–477.

DeFilippis, M., & Wagner, K. D. (2016). Treatment of autism spectrum disorder in children and adolescents. Psychopharmacology Bulletin, 46(2), 18-41.

Ke X, Liu J. Intellectual disability. In Rey JM (ed), IACAPAP e-Textbook of Child and Adolescent Mental Health. Geneva: International Association for Child and Adolescent Psychiatry and Allied Professions 2012.

https://iacapap.org/content/uploads/C.1-Intellectual-Disability.pdf

Kelly M. Communicating effectively with people with developmental disabilities. In: Sullivan WF, Developmental Disabilities Primary Care Initiative Scientific and Editorial Staff, editors. Tools for the primary care of people with developmental disabilities. Toronto, ON: Surrey Place Centre, MUMS Guidelines Clearinghouse; 2011. p. 18-20. Available from: http://ddprimarycare.surreyplace.ca/tools/general-health/communicating-effectively/ . Accessed 2019 Oct 14.

Lamberti, M., Siracusano, R., Italiano, D., Alosi, N., Cucinotta, F., Di Rosa, G., ... & Gagliano, A. (2016). Head-to-Head Comparison of Aripiprazole and Risperidone in the Treatment of ADHD Symptoms in Children with Autistic Spectrum Disorder and ADHD: A Pilot, Open-Label, Randomized Controlled Study. Pediatric Drugs, 18(4), 319-329. doi: 10.1007/s40272-016-0183-3.

Results: Aripiprazole and risperidone appeared to have similar benefits with efficacy and tolerability; prolactin levels decreased in aripiprazole compared to risperidone.
 

McQuire C, Hassiotis A, Harrison B, Pilling S: Pharmacological interventions for challenging behaviour in children with intellectual disabilities: a systematic review and meta-analysis, BMC Psychiatry, 2015 Nov.
https://doi.org/10.1186/s12888-015-0688-2

Nash A, Davis L: Fetal Alcohol Spectrum Disorders: What pediatric providers need to know. J Pediatr Health Care. 2017 Sep-Oct; 31(5): 594-606. Doi: 10.1016/j.pedhc.2017.04.002.

https://www.ncbi.nlm.nih.gov/pubmed/28838601

Pringsheim, T., Panagiotopoulos, C., Davidson, J., Ho, J. & Canadian Alliance for Monitoring Effectiveness and Safety of Antipsychotics in Children (CAMESA) guideline group. (2011). Evidence-based recommendations for monitoring safety of second-generation antipsychotics in children and youth. Paediatrics & Child Health,

16(9), 581-589. doi: 10.1093/pch/16.9.581.

Oeseburg B, Dijkstra GJ, Groothoff JW et al (2011). Prevalence of chronic health conditions in children with intellectual disability: a systematic literature review. Intellectual and Developmental Disabilities, 49:59-85.

Snyder R, Turgay A, Aman M et al (2002). Effects of risperidone on conduct and disruptive behavior disorders in children with subaverage IQs. Journal of the American Academy of Child & Adolescent Psychiatry, 41:1026- 1036.

Sullivan W et al.: Primary care of adults with intellectual and developmental disabilities 2018 Canadian consensus guidelines. Canadian Family Physician, 64: Apr 2018.
https://www.cfp.ca/content/cfp/64/4/254.full.pdf

Vedi K, Bernard S: The mental health needs of children and adolescents with learning disabilities Curr Opin Psychiatry, 2012, 25-353-358.

Wilkinson KM, Hennig S (2007). The state of research and practice in augmentative and alternative communication for children with developmental/ intellectual disabilities. Mental Retardation and Developmental Disabilities Research Reviews, 13:58-69.

Authors

Written by the child psychiatrists at CHEO at uOttawa. 

Conflicts of Interest: No competing interests declared.

Disclaimer

This information is offered ‘as is' and is meant only to provide general information that supplements, but does not replace the information from a qualified expert or health professional. Always contact a qualified expert or health professional for further information in your specific situation or circumstance.

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