PART I: FOUNDATIONAL CONCEPTS AND DEFINITIONS
Introduction to Learning Disability
Understanding the psychiatry of learning disability (LD) is a core component of the MRCPSYCH curriculum. This field requires a shift from traditional psychiatric assessment, demanding an appreciation for developmental trajectories, atypical presentations of illness, and the profound impact of biological, psychological, and social factors. This document provides a structured overview of the key concepts, from fundamental definitions and epidemiology to the nuances of co-morbid conditions and their management.
Visualization: The IQ Bell Curve
Visual representation of IQ distribution in the general population, highlighting the threshold for Learning Disability.
According to standardized intelligence testing, what is the approximate IQ score that serves as the upper threshold for a diagnosis of Learning Disability?
Correct Answer (B): The diagnosis of a Learning Disability requires an impaired intelligence, which is operationally defined as an IQ score of approximately two standard deviations or more below the population mean. With a mean IQ of 100 and a standard deviation of 15, this corresponds to an IQ score of 70 or below.
1.0 Definitions, Terminology & Classification
To approach the psychiatry of learning disability, we must first establish a clear and precise vocabulary. The terms used to describe this condition have evolved over time, reflecting changes in societal attitudes and clinical understanding. For the MRCPSYCH exam, you are required to know the current terminology used by major classification systems (ICD and DSM) and understand the specific, multi-faceted definition of the condition.
1.1 Terminology and Synonyms
The language used in this field is important. While several terms exist, they converge on a single core concept.
- Learning Disability (LD): This is the current and preferred term in the United Kingdom, promoted by governmental bodies like the Department of Health and advocacy groups. It is considered less stigmatising and is the term you should be most familiar with for the exam, as it will be used in UK-based clinical vignettes.
- Intellectual Disability (ID) / Intellectual Developmental Disorder: This is the term adopted by the American Psychiatric Association in DSM-5 and is due to be used in the forthcoming ICD-11. It is the internationally accepted clinical term. For all practical and diagnostic purposes, 'Intellectual Disability' is synonymous with 'Learning Disability'.
- Mental Retardation (MR): This was the term used in ICD-10 and previous editions of the DSM. While you will still encounter it in older literature and in the ICD-10 classification system (which remains examinable), it is now considered outdated and potentially offensive. You must recognise it as the historical equivalent of LD/ID.
A crucial point of distinction is between a 'learning disability' and a 'learning difficulty'. These are not interchangeable.
- Learning Disability (LD): Refers to a significant, global impairment of intellectual and adaptive functioning with a developmental onset. The IQ is below 70.
- Learning Difficulty: Refers to a specific problem in a particular area of learning, such as reading, writing, or mathematics, in an individual with a normal or even high overall intelligence. Examples include dyslexia, dyspraxia, and dyscalculia.
Table: Terminology Summary
| Term | System / Region | Status & Key Features |
|---|---|---|
| Learning Disability (LD) | United Kingdom (Current) | Preferred term. Refers to global impairment (IQ < 70 + adaptive deficits). |
| Intellectual Disability (ID) | DSM-5 / ICD-11 (International) | Synonymous with LD. The standard international clinical term. |
| Mental Retardation (MR) | ICD-10 / Older Literature | Outdated/Historical term. Functionally equivalent to LD/ID. |
| Learning Difficulty | General (e.g., Dyslexia) | Specific deficit in one area of learning with normal overall intelligence. Not the same as LD. |
Clinical Example: Student Assessment
Two 15-year-old students are referred for educational assessment.
• Student A has an IQ of 65. He struggles across all academic subjects, finds it difficult to follow multi-step instructions, and needs support with managing his daily schedule and travel to school. He has a Learning Disability.
• Student B has an IQ of 115. He excels in mathematics and verbal reasoning but has profound difficulty with reading and spelling, which are significantly below the level expected for his age and overall intelligence. He has a specific Learning Difficulty (dyslexia).
The Examiner's Focus:
The examiner will expect you to know that the terms Learning Disability (UK), Intellectual Disability (DSM-5/ICD-11), and Mental Retardation (ICD-10) all refer to the same fundamental condition defined by deficits in both IQ and adaptive functioning. A common trap is to confuse 'Learning Disability' with a specific 'Learning Difficulty' like dyslexia. You must be able to differentiate between a global impairment (LD) and a specific one (difficulty).
1.2 Core Definition of Learning Disability
A diagnosis of Learning Disability is not based on an IQ score alone. It is a tripartite definition, meaning three core criteria must be met. The definition from the 2001 English government White Paper Valuing People is a standard reference and encompasses these three elements.
A learning disability includes the presence of:
- A significantly reduced ability to understand new or complex information or to learn new skills (Impaired Intelligence).
- A reduced ability to cope independently (Impaired Social/Adaptive Functioning).
- An impairment that started before adulthood, with a lasting effect on development (Developmental Onset).
Let's break down each component.
A 30-year-old man presents with an IQ of 65 and has required lifelong support for daily living. He was diagnosed after a traumatic brain injury at age 22. Which criterion for Learning Disability is NOT met?
Correct Answer (D): The diagnosis of Learning Disability requires that the intellectual and adaptive deficits begin during the developmental period, which is defined as before the age of 18. Since this man's impairments began at age 22, he has an Acquired Brain Injury, not a Learning Disability.
1.2.1 Component 1: Impaired Intelligence
This refers to a global deficit in cognitive functioning. It is operationally defined by performance on a standardised, individually administered intelligence test, where the score is approximately two standard deviations or more below the population mean. Since the mean IQ is 100 and the standard deviation is 15, this translates to an IQ score of approximately 70 or below. This impairment is not limited to one area (like mathematics) but affects reasoning, problem-solving, planning, abstract thinking, and learning from experience.
Clinical Example: Vocational Assessment
A 20-year-old man is undergoing a vocational assessment. When asked to learn a new three-step task on a computer, he requires multiple repetitions, simple language, and visual prompts. He struggles to generalise the learned skill to a slightly different task. This demonstrates a reduced ability to learn new skills and understand complex information.
1.2.2 Component 2: Impaired Social/Adaptive Functioning
This is the "real-world" component of the diagnosis. It refers to a person's failure to meet the standards of personal independence and social responsibility expected for their age and cultural group. Deficits must be present in one or more of three domains:
- Conceptual (Academic) Domain: Competence in memory, language, reading, writing, math, practical knowledge, and judgement.
- Social Domain: Awareness of others' thoughts and feelings (empathy), interpersonal communication skills, friendship abilities, and social judgement.
- Practical Domain: Self-management in areas like personal care, job responsibilities, money management, recreation, and organising school or work tasks.
Clinical Example: Adaptive Functioning Deficit
A 30-year-old woman has an IQ of 68. She requires daily support from her family to ensure she washes, dresses appropriately for the weather, and eats regular meals. She cannot manage her own finances, use public transport alone, or hold a job without direct, constant supervision. This demonstrates significant deficits in the practical domain of adaptive functioning.
1.2.3 Component 3: Developmental Onset
The onset of these intellectual and adaptive deficits must be during the developmental period, which is defined as before the age of 18 years. This criterion is critical as it distinguishes a lifelong neurodevelopmental condition from cognitive impairments acquired later in life due to other causes.
- Case A: A 25-year-old man has a documented history of developmental delays, special educational needs throughout his schooling, and has always required support with daily living. His IQ is 60. He has a Learning Disability.
- Case B: A 25-year-old man was an unimpaired university student until he sustained a severe traumatic brain injury in a car accident. He now has an estimated post-injury IQ of 60 and requires significant support for daily living. He has an Acquired Brain Injury, not a Learning Disability, because the onset was after the developmental period.
The Examiner's Focus:
A diagnosis of Learning Disability requires that ALL THREE criteria are met: low IQ, impaired adaptive functioning, and onset before age 18. Questions may present a vignette where only one or two criteria are met (e.g., a person with a low IQ but good adaptive skills, or a person who acquires deficits in adulthood). You must recognise that these cases do not meet the full diagnostic criteria for Learning Disability. The principles of supporting independence, as highlighted in policy documents like Valuing People, are also a key examinable concept.
A woman insists on living independently despite her intellectual disability. Her family supports this goal. Which principle underpins this approach?
Correct Answer (C): Normalisation is the foundational principle that people with disabilities should be supported to live lives as close as possible to the "normal" patterns of mainstream society. This includes living in their own homes in the community, having choice over their daily routines, and accessing ordinary facilities, rather than being segregated. The woman's goal of living independently is a core tenet of normalisation.
1.3 Classification by Severity (IQ-Based)
While the diagnosis of LD requires deficits in adaptive functioning, the severity of the condition is formally graded according to the level of intellectual impairment as measured by an IQ test. You must memorise these brackets and their corresponding labels.
Table: Learning Disability Severity Levels
| Severity Level | IQ Range | Prevalence in LD Population | Support Needs Level |
|---|---|---|---|
| Mild Learning Disability | 50–69 | ~85% | |
| Moderate Learning Disability | 35–49 | ~10% | |
| Severe Learning Disability | 20–34 | ~3-4% | |
| Profound Learning Disability | < 20 | ~1-2% |
Visualization: Distribution of Learning Disability Severity
Borderline Intellectual Functioning:
This term is used for individuals with an IQ in the 70-85 range. This is not formally classified as a learning disability, but it is recognised that these individuals may struggle with complex academic or vocational demands and may require support, especially under stress.
Clinical Examples of Severity Levels:
• Mild LD (IQ 62): A 35-year-old man lives in a supported living flat. He works part-time as a cleaner with supervision. He can manage his own personal care and prepare simple meals but needs help with budgeting, reading official letters, and making complex appointments. He communicates in full sentences.
• Moderate LD (IQ 41): A 28-year-old woman lives with her parents. She communicates using simple phrases and gestures. She can follow basic hygiene routines with verbal prompts but cannot cook or clean independently. She attends a day centre where she participates in supervised craft and music activities.
• Severe LD (IQ 28): A 19-year-old man is non-verbal and communicates his needs through sounds and by leading carers to objects. He requires physical assistance with all aspects of personal care, including feeding and toileting. He has associated epilepsy and motor coordination problems.
• Profound LD (IQ < 20): A 40-year-old woman is non-ambulatory and has multiple physical health problems requiring 24-hour nursing care in a residential facility. She has no recognisable speech and interacts with her environment in very limited ways, such as by turning her head towards a familiar sound.
The Examiner's Focus:
You must have the four severity brackets (Mild, Moderate, Severe, Profound) and their corresponding IQ ranges memorised. The exam will test this directly or via vignettes where you must classify an individual based on a stated IQ or a description of their functional level. Remember that the vast majority (85%) of individuals with a learning disability fall into the Mild category.
A 35-year-old man requires assistance with cooking and financial planning but can manage basic self-care. His intellectual disability is best classified as:
Correct Answer (A): The description perfectly matches the functional profile of an individual with Mild Learning Disability. They are typically independent in basic activities of daily living (self-care) but require support for more complex instrumental activities (cooking, managing finances). This corresponds to an IQ in the 50-69 range.
1.4 Adaptive Functioning
As previously established, an IQ score below 70 is a necessary but not sufficient condition for a diagnosis of Learning Disability. The second, equally important criterion is a significant deficit in adaptive functioning. This concept moves the diagnosis from the abstract testing environment into the reality of a person's daily life.
Definition: Adaptive functioning refers to how effectively an individual meets the standards of personal independence and social responsibility expected for their chronological age and sociocultural background. It is about the ability to apply cognitive skills to real-world situations.
Assessment of adaptive functioning is not based on a single test but on clinical evaluation and information gathered from multiple sources, such as parents, carers, teachers, and the individual themselves. Standardised scales are used to structure this assessment, with the Vineland Adaptive Behavior Scales being the most widely recognised.
Domains of Adaptive Functioning
The deficits must be significant enough to require ongoing support in one or more of the following three domains:
- Conceptual Domain:
This domain involves cognitive skills used in academic settings and for independent thought.
- Deficits include: Difficulties with language (receptive and expressive), reading, writing, mathematical reasoning, general knowledge, memory, and problem-solving. In adults, it relates to the ability to understand abstract concepts like time and money.
- Social Domain:
This domain involves the skills needed for social interaction and understanding social rules.
- Deficits include: Naivety in social situations, difficulty understanding social cues (like body language or tone of voice), poor empathy or perspective-taking, problems making and maintaining friendships, and vulnerability to manipulation or exploitation.
- Practical Domain:
This domain covers the skills of daily living needed to function independently.
- Deficits include: Difficulties with personal care (hygiene, dressing), domestic tasks (cooking, cleaning), managing money, using a telephone, travelling independently, and maintaining safety. In an occupational context, it involves the ability to manage a job and follow workplace rules.
The Examiner's Focus:
You must remember that adaptive functioning is a mandatory component of the diagnosis. A vignette describing a person with an IQ of 65 who is married, employed full-time without support, and manages their own finances does not have a Learning Disability, as their adaptive functioning is not impaired. The deficits must be clinically significant and require support. Examiners will test your understanding of the three domains (Conceptual, Social, Practical) and how they manifest in a person's life.
An 18-year-old with an IQ of 68 has difficulty understanding sarcasm and is easily led by peers, demonstrating poor social judgement. In which domain of adaptive functioning are these deficits most prominent?
Correct Answer (C): Difficulty understanding social cues like sarcasm, naivety, and poor social judgement are hallmark features of impairment in the Social Domain of adaptive functioning.
1.5 Characteristic Features by Severity Level
The IQ-based severity levels directly correlate with an individual's expected level of adaptive functioning. You should be able to form a mental picture of a person at each level of severity.
- Mild Learning Disability (IQ 50-69):
- Conceptual: May achieve academic skills up to a late primary school level (approx. age 11). Can read and write for practical purposes. Struggles with abstract thinking and executive functions (planning, prioritising).
- Social: Communication is usually effective for everyday conversations. May be immature in social interactions and misinterpret social cues. Vulnerable to manipulation. Can form meaningful relationships and friendships.
- Practical: Can manage basic personal care independently. Can live semi-independently with support for complex tasks like managing a budget, grocery shopping, legal decisions, and healthcare. Can often hold unskilled or semi-skilled employment.
- Moderate Learning Disability (IQ 35-49):
- Conceptual: Marked developmental delays. Language is often limited to simple phrases or single words. Academic skills are rudimentary (e.g., recognising some sight words or numbers).
- Social: Makes friends but has significant difficulty with social conventions and communication. Social judgement is poor.
- Practical: Requires considerable support and teaching to learn basic self-care skills. Will need lifelong support in a supervised setting (e.g., with family or in a group home). Can perform simple, routine tasks in a supervised work setting.
- Severe Learning Disability (IQ 20-34):
- Conceptual: Very limited understanding of language or numbers. Speech is often restricted to single words or is absent.
- Social: Communication is primarily non-verbal (gestures, sounds). Social interaction is limited to familiar family and carers.
- Practical: Requires support for all activities of daily living, including eating, dressing, bathing, and toileting. Requires 24-hour supervision to ensure safety. Often has significant co-occurring motor impairments.
- Profound Learning Disability (IQ < 20):
- Conceptual: May understand simple gestures and instructions but has no symbolic understanding of concepts like speech or numbers.
- Social: Interaction is limited to non-verbal, emotional responses to highly familiar people.
- Practical: Fully dependent on others for all aspects of physical care, health, and safety. Usually has significant co-morbid neurological and physical disabilities (e.g., immobility, epilepsy, sensory impairments).
1.6 Key Conceptual Frameworks
Beyond the core definitions, several key concepts are essential for understanding the clinical and social context of learning disability.
1.6.1 Diagnostic Overshadowing
This is a critical concept and a frequent source of examination questions.
Definition: Diagnostic overshadowing is a cognitive bias where a clinician attributes all of a person's symptoms or behaviours (especially new ones) to their pre-existing learning disability, thereby failing to explore or diagnose a co-existing physical or mental health condition.
This is a major contributor to the health inequalities experienced by people with LD. A change in behaviour is often the primary way a person with limited communication can express distress from pain, fear, or psychosis. Dismissing this change as "just their learning disability" can lead to missed diagnoses and untreated suffering.
Clinical Example: Diagnostic Overshadowing
A 45-year-old non-verbal man with severe LD begins repeatedly hitting his head against the wall and becomes aggressive during mealtimes. His carers attribute this to a "challenging behaviour" inherent to his disability. A specialist LD psychiatrist insists on a physical examination, which reveals a severe, painful dental abscess. After treatment with antibiotics and dental extraction, the head-banging and aggression resolve completely. The carers had overshadowed the physical pain with the diagnosis of LD.
A man with Down's syndrome describes “butterflies in his stomach” before a job interview. Staff attribute this to his intellectual disability. What is this phenomenon called?
Correct Answer (B): The man is expressing a clear symptom of anxiety ("butterflies in his stomach") in a context-appropriate situation (a job interview). The staff are dismissing this valid emotional experience and attributing it to his underlying diagnosis of Down's syndrome and intellectual disability. This is a perfect example of diagnostic overshadowing, where a co-morbid and treatable condition (anxiety) is missed because it is subsumed under the primary diagnosis.
A 28-year-old woman with intellectual disability is observed head-banging. Staff attribute this to her disability. What is this phenomenon called?
Correct Answer (C): This is another classic scenario. Head-banging is a non-specific behaviour that can signal many different underlying problems: physical pain (headache, earache, toothache), sensory overload, frustration due to communication difficulties, or symptoms of a mental illness like depression or psychosis. Attributing it solely to the intellectual disability without further investigation is the definition of diagnostic overshadowing.
PART II: SERVICES, ASSESSMENT, AND MANAGEMENT
4.0 Community Services for Learning Disability
The approach to supporting people with learning disabilities has undergone a radical transformation over the past century. The historical model, rooted in segregation and control, has been replaced by a modern framework emphasising community presence, individual rights, and inclusion. Understanding this evolution and the principles that guide current services is fundamental to the practice of LD psychiatry.
4.1 Historical Context and Guiding Principles
To appreciate the current system of care, one must first understand the system it replaced.
- The Era of Institutionalisation: During the late 19th and early 20th centuries, the prevailing societal view was that people with learning disabilities (then termed 'feeble-minded' or 'idiots') were a source of social problems like crime and poverty. This led to a policy of segregation, where large numbers of individuals were confined to long-stay institutions, often for life. These institutions were typically isolated from the community, and residents were 'dehumanised'—stripped of individuality, choice, and personal relationships.
- Normalisation: This is arguably the most important principle guiding modern disability services. First developed in Scandinavia in the 1960s by Bengt Nirje, normalisation is the principle of enabling people with disabilities to experience patterns of life and conditions of everyday living which are as close as possible to the regular circumstances and ways of life of their society.
- Social Role Valorisation (SRV): Developed by Wolf Wolfensberger, SRV is an extension of the normalisation principle. The goal of SRV is to actively counter this by creating opportunities for individuals to hold valued social roles.
- UK Government Policy: Valuing People (2007): This key government white paper translated these principles into a concrete policy framework for England, based on four key tenets for people with learning disabilities: Rights, Independence, Choice, and Inclusion.
- Deinstitutionalisation: This is the process by which the principles of normalisation and SRV were put into practice. Starting in the 1980s in the UK, it involved the systematic closure of long-stay institutions and the movement of residents into community-based care settings.
The principle of enabling people with disabilities to experience life patterns as close as possible to mainstream society is known as:
Correct Answer (C): Normalisation is the guiding philosophy focused on ensuring that people with disabilities have access to the same patterns and conditions of everyday life that are available to other citizens.
2.0 Epidemiology
Epidemiology provides the "big picture" of learning disability, covering how common it is, who is affected, and what other conditions frequently co-occur.
2.1 Prevalence and Incidence
- Overall Prevalence: The prevalence of learning disability in the general population is estimated to be between 1% and 3%. In the UK, a figure of 20-30 per 1000 people is often cited.
- Prevalence of Severe LD: The prevalence of more severe learning disability (IQ < 50) is much lower and more consistent across studies, at around 3-4 per 1000 people.
- Incidence: The highest incidence is seen in school-aged children, peaking between the ages of 10 and 14.
- Gender Ratio: Learning disability is approximately 1.5 times more common in males than in females.
2.2 Co-morbidity of Mental Health Problems
This is one of the most important areas in the psychiatry of learning disability. People with LD have a significantly higher rate of mental health problems than the general population.
- Overall Rate: The total prevalence of mental health problems (including challenging behaviour) in adults with LD is estimated to be between 30% and 50%.
- Correlation with Severity: The risk of psychopathology increases with the severity of the learning disability.
Visualization: Mental Health Co-morbidity in LD Population
Table: Prevalence of Psychiatric Disorders in Adult LD Population
| Disorder | Prevalence in LD Population | Comparison to General Population |
|---|---|---|
| Schizophrenia | 3 - 4% | Approx. 3-4 times higher (vs. ~1%) |
| Affective Disorders (Total) | ~6% | Similar or slightly higher |
| Anxiety Disorders | ~4% | Higher rates of GAD and phobias |
| Autism Spectrum Disorder | ~7.5% (up to 40% in severe LD) | Massively higher (vs. ~1%) |
| Problem Behaviour | ~10 - 22.5% | A major clinical issue |
The Examiner's Focus:
You must know that the prevalence of mental illness in the LD population is significantly higher than in the general population (30-50%). The single most important figure to memorise is the prevalence of schizophrenia, which is approximately 3-4 times higher than the 1% rate in the general population. Questions will frequently test this specific fact.
What is the approximate prevalence of schizophrenia in adults with learning disabilities (LD)?
Correct Answer (B): As stated in epidemiological research and major textbooks, the prevalence of schizophrenia in the adult LD population is consistently found to be around 3-4%. Therefore, 3.5% is the most accurate figure provided. This represents a threefold increase compared to the general population risk of ~1%.
2.3 Physical Health Co-morbidity and Health Inequalities
One of the most profound and concerning findings in the study of learning disability is the stark reality of physical health inequality. Individuals with LD experience significantly poorer health outcomes and a shorter lifespan compared to the general population.
- Premature Mortality: The Confidential Inquiry into Premature Deaths of People with Learning Disabilities (CIPOLD) found that, on average, men with a learning disability die 13 years earlier and women die 20 years earlier than their peers in the general population.
- Barriers to Healthcare: People with LD face numerous obstacles including communication difficulties, diagnostic overshadowing, and a lack of training among healthcare professionals.
- Specific Physical Co-morbidities:
- Epilepsy: Prevalence is around 20-25% in the LD population (vs. <1% general pop), reaching as high as 50% in those with profound LD.
- Sensory Impairments: Hearing loss is found in 25-42% and significant vision problems affect around 19%.
- Obesity: Rates of being overweight (28.8%) and obese (23.6%) are very high.
What is the most significant neurological co-morbidity in individuals with Learning Disability, with prevalence increasing dramatically with the severity of the disability?
Correct Answer (C): Epilepsy is the most significant neurological co-morbidity, affecting 20-25% of the LD population and up to 50% in those with severe/profound LD.
3.0 Aetiology and Prevention
The causes of learning disability are numerous and complex, involving an intricate interplay between genetic and environmental factors. In approximately 30% of severe LD cases and 50-75% of mild LD cases, no cause can be identified.
3.1 Aetiological Factors
- Genetic Factors: The largest single group of identifiable causes.
- Autosomal Chromosome Disorders: e.g., Down's Syndrome (Trisomy 21).
- Sex Chromosome Disorders: e.g., Fragile X Syndrome, Turner's Syndrome.
- Deletions and Duplications: e.g., Prader-Willi Syndrome, Angelman Syndrome.
- Single Gene Disorders: e.g., Tuberous Sclerosis, Phenylketonuria (PKU).
- External Prenatal Factors (During Pregnancy):
- Infections (TORCH): Toxoplasmosis, Other (Syphilis), Rubella, Cytomegalovirus (CMV), Herpes.
- Substance Exposure: Alcohol (leading to FASD), medications (e.g., sodium valproate).
- Perinatal Factors (Around Birth): Prematurity, low birth weight, and birth asphyxia.
- Postnatal Factors (In Early Childhood): CNS infections (meningitis), head injury, and severe psychosocial deprivation.
The strongest established risk factor for autism spectrum disorder (ASD) is:
Correct Answer (C): Twin and family studies consistently demonstrate very high heritability for ASD, with genetic factors accounting for the vast majority of the risk (heritability estimates of 80-90%). While other factors may contribute, genetics is overwhelmingly the strongest established risk factor.
A 40-year-old woman is pregnant. What is the estimated risk of having a child with Down’s syndrome?
Correct Answer (C): As maternal age increases, the risk of non-disjunction during meiosis rises significantly. At age 40, the risk of having a child with Down syndrome is approximately 1 in 100. This is a crucial figure to memorise.
A clinician is assessing a child with known Fragile X syndrome. Which of the following behavioural features is most likely to be present in this condition?
Correct Answer (C): A core feature of the Fragile X behavioural phenotype is profound social anxiety. This manifests as shyness, poor peer relationships, and, most characteristically, avoidance of eye contact or gaze avoidance.
Which enzyme deficiency leads to Lesch–Nyhan syndrome?
Correct Answer (C): Lesch-Nyhan syndrome is caused by a deficiency of the enzyme HGPRT, which is crucial for purine metabolism. This leads to the characteristic neurological and behavioural symptoms, as well as hyperuricaemia.
A 14-year-old girl with loss of purposeful hand use, autistic features, and seizures. Genetic testing reveals a mutation in the MECP2 gene. What is the diagnosis?
Correct Answer (A): The combination of regression after normal early development, loss of purposeful hand skills, autistic features, seizures, and a mutation in the MECP2 gene is diagnostic of Rett syndrome.
A non-verbal man with ASD self-injures by head-hitting when transitioning between activities. What is the FIRST-line approach in behavioural intervention prioritisation?
Correct Answer (B): The first and most crucial step in managing self-injurious behaviour, especially when it is linked to a specific trigger like transitions, is to understand its function. An ABC (Antecedent-Behaviour-Consequence) analysis is the primary tool for this.
A 32-year-old woman with mild intellectual disability (ID) presents with escalating challenging behavior, including punching her abdomen during periods of distress. Which first-line pharmacological intervention is MOST appropriate?
Correct Answer (C): While behavioural interventions are always the first step, if pharmacological intervention is deemed necessary for severe challenging behaviour after behavioural strategies have failed, low-dose antipsychotics (like risperidone) have the strongest evidence base for reducing aggression and self-injury in individuals with ID.
A core feature of autism spectrum disorder (ASD) is difficulty integrating discrete elements into a coherent whole. This deficit is termed:
Correct Answer (D): "Central coherence" is the ability to integrate details into a meaningful whole. The deficit, known as "weak central coherence," means individuals with ASD tend to focus on details rather than the overall context, which impacts social understanding and abstract reasoning.
A 34-year-old man with mild learning disability has gastrointestinal bleeding and refuses blood tests, believing they may worsen the bleeding. What is the most appropriate management strategy?
Correct Answer (C): The most appropriate first step is to address the man's misunderstanding through clear explanation and allow him time to reconsider. This respects his autonomy and is the least restrictive approach.
Which tool is MOST appropriate for diagnosing autism in a non-verbal 7-year-old child?
Correct Answer (B): The ADOS is a standardised observational assessment. Module 1 is specifically designed for children who are non-verbal or have very limited language, making it the most appropriate diagnostic tool in this scenario.