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Psych Topicsintellectual-disability

Psych · intellectual-disability

Psychiatric disorders in intellectual disability

Also known as Dual diagnosis intellectual disability · Mental ill-health in learning disability · Psychiatric comorbidity in ID · DC-LD psychiatry · Learning disability mental illness

Exam-exhaustive fellowship reference on psychiatric disorders in intellectual disability — diagnostic overshadowing, modified/pathoplastic presentation, DC-LD and DM-ID frameworks, Cooper/Smiley epidemiology, differential of behaviour that challenges versus mental illness versus physical illness, adapted assessment, treatment adaptations, Tyrer/Sheehan/Deb psychotropic evidence, NICE and multiagency care. FRANZCP-primary, globally tagged.

high16 referencesUpdated 26 July 202611 min readVerification in progress

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FRANZCPMRCPsychABPNMD-DNBNEET-SS

Red flags

  • Sudden behavioural change in a person with ID — exclude pain, constipation, dental disease, infection, epilepsy, medication toxicity before labelling 'challenging behaviour'
  • Attributing all psychiatric symptoms to intellectual disability (diagnostic overshadowing) — mental illness is common and treatable
  • Long-term antipsychotics for aggression without diagnosed mental illness, functional analysis, or review plan — overprescribing risk
  • New self-injury, withdrawal, sleep/appetite collapse, or loss of skills — assess for depression, anxiety, psychosis, abuse, and medical causes
  • Assumed global incapacity — capacity is decision-specific; support decision-making
  • Placement breakdown with high risk of harm — escalate specialist ID psychiatry and safeguarding, least restrictive safety plan
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Your progress

Saved on this device.

Practise this topic10 MCQs with explanations

Target exams

FRANZCPMRCPsychABPNMD-DNBNEET-SS

Red flags

  • Sudden behavioural change in a person with ID — exclude pain, constipation, dental disease, infection, epilepsy, medication toxicity before labelling 'challenging behaviour'
  • Attributing all psychiatric symptoms to intellectual disability (diagnostic overshadowing) — mental illness is common and treatable
  • Long-term antipsychotics for aggression without diagnosed mental illness, functional analysis, or review plan — overprescribing risk
  • New self-injury, withdrawal, sleep/appetite collapse, or loss of skills — assess for depression, anxiety, psychosis, abuse, and medical causes
  • Assumed global incapacity — capacity is decision-specific; support decision-making
  • Placement breakdown with high risk of harm — escalate specialist ID psychiatry and safeguarding, least restrictive safety plan
The one-line answer

People with intellectual disability have substantially elevated rates of mental ill-health, and diagnostic overshadowing is the bias that hides it. Use adapted assessment with collateral and DC-LD or DM-ID thinking when standard criteria under-detect, exclude physical illness and environmental causes first, treat diagnosed mental illness with psychological and pharmacological adaptations — start low, go slow — and avoid routine long-term antipsychotics for aggression without a formulation. Tyrer showed limited advantage over placebo; Sheehan showed prescribing exceeds recorded mental illness.[1][4][6][8]

Meet the patient

A 45-year-old man with moderate intellectual disability is referred for "worsening aggression." He has hit two staff this week. His baseline is cheerful and sociable. The GP letter asks for "something to calm him." Your first question is not which drug — it is what has changed, and since when?[1][5]

The registrar wants to start an antipsychotic. The consultant wants the bowel chart, the dental review, the medication list and a week of ABC data. Nine times out of ten the "aggression" is pain, constipation, or an unrecognised mood disorder wearing a behavioural disguise — and the right first prescription is paracetamol, laxatives, and an adapted assessment, not risperidone.[5][7][8]

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References16ShowHide
  1. [1]Cooper SA, Smiley E, Morrison J, Williamson A, Allan L Mental ill-health in adults with intellectual disabilities: prevalence and associated factors Br J Psychiatry, 2007.PMID 17197653
  2. [2]Smiley E, Cooper SA, Finlayson J, et al. Incidence and predictors of mental ill-health in adults with intellectual disabilities: prospective study Br J Psychiatry, 2007.PMID 17906241
  3. [3]Cooper SA, Melville CA, Einfeld SL Psychiatric diagnosis, intellectual disabilities and Diagnostic Criteria for Psychiatric Disorders for Use with Adults with Learning Disabilities/Mental Retardation (DC-LD) J Intellect Disabil Res, 2003.PMID 14516368
  4. [4]Reiss S, Szyszko J Diagnostic overshadowing and professional experience with mentally retarded persons Am J Ment Defic, 1983.PMID 6829617
  5. [5]Ali A, Hassiotis A Illness in people with intellectual disabilities BMJ, 2008.PMID 18340045
  6. [6]Sheehan R, Hassiotis A, Walters K, Osborn D, Strydom A, Horsfall L Mental illness, challenging behaviour, and psychotropic drug prescribing in people with intellectual disability: UK population based cohort study BMJ, 2015.PMID 26330451
  7. [7]Deb S, Kwok H, Bertelli M, et al. International guide to prescribing psychotropic medication for the management of problem behaviours in adults with intellectual disabilities World Psychiatry, 2009.PMID 19812757
  8. [8]Tyrer P, Oliver-Africano PC, Ahmed Z, et al. Risperidone, haloperidol, and placebo in the treatment of aggressive challenging behaviour in patients with intellectual disability: a randomised controlled trial Lancet, 2008.PMID 18177776
  9. [9]Einfeld SL, Ellis LA, Emerson E Comorbidity of intellectual disability and mental disorder in children and adolescents: a systematic review J Intellect Dev Disabil, 2011.PMID 21609299
  10. [10]Hassiotis A, Serfaty M, Azam K, et al. Cognitive behaviour therapy (CBT) for anxiety and depression in adults with mild intellectual disabilities (ID): a pilot randomised controlled trial J Intellect Disabil Res, 2011.PMID 21492437
  11. [11]Willner P, Rose J, Jahoda A, et al. Group-based cognitive-behavioural anger management for people with mild to moderate intellectual disabilities: cluster randomised controlled trial Br J Psychiatry, 2013.PMID 23520220
  12. [12]Cooper SA, van der Speck R Epidemiology of mental ill health in adults with intellectual disabilities Curr Opin Psychiatry, 2009.PMID 19535982
  13. [13]Munir KM The co-occurrence of mental disorders in children and adolescents with intellectual disability/intellectual developmental disorder Curr Opin Psychiatry, 2016.PMID 26779862
  14. [14]Deb S, Unwin GL Psychotropic medication for behaviour problems in people with intellectual disability: a review of the current literature Curr Opin Psychiatry, 2007.PMID 17762588
  15. [15]Cooper SA, Smiley E, Morrison J, Williamson A, Allan L Mental ill-health in adults with intellectual disabilities: prevalence and associated factors (DC-LD subtype rates) Br J Psychiatry, 2007.PMID 17197653
  16. [16]Deb S, Kwok H, Bertelli M, et al. International guide to prescribing psychotropic medication for the management of problem behaviours in adults with intellectual disabilities (monitoring principles) World Psychiatry, 2009.PMID 19812757

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