Autism Spectrum Disorder (ASD)
Summary
Autism Spectrum Disorder (ASD) is a lifelong neurodevelopmental condition characterised by difficulties in social communication and interaction, together with restricted, repetitive patterns of behaviour, interests, or activities. It is a spectrum condition, meaning there is wide variation in how it presents — from individuals who need significant support in daily life to those who live independently but may experience challenges in social situations. ASD is typically identified in early childhood, though diagnosis may occur at any age. There is no cure, but early intervention with speech and language therapy, educational support, and behavioural strategies can significantly improve outcomes.
Key Facts
- Core Domains: Social communication difficulties + Restricted/repetitive behaviours
- Spectrum: From high support needs to minimal support needs
- Prevalence: ~1 in 100 (increasing recognition)
- M:F Ratio: 3-4:1 (females may be underdiagnosed)
- Assessment: ADOS-2, comprehensive developmental assessment
- No cure: Support and intervention tailored to individual
Clinical Pearls
"Triad to Dyad": DSM-5 changed from the previous "triad of impairments" to two core domains: (1) Social communication and (2) Restricted/repetitive behaviours.
"Girls Are Different": Girls may present differently (better social camouflaging) and are often diagnosed later. Consider ASD in girls with anxiety or social difficulties.
"Regression is a Red Flag": Loss of previously acquired skills (especially language) warrants investigation for Rett syndrome, Landau-Kleffner, or metabolic conditions.
"Sensory Issues Are Common": Many individuals with ASD have sensory sensitivities (to noise, light, textures) that cause significant distress.
Prevalence
- ~1 in 100 people (UK)
- Increasing — likely due to widened diagnostic criteria and better recognition
Demographics
- M:F = 3-4:1 (may reflect underdiagnosis in females)
- Presents in early childhood (typically by age 2-3)
- Diagnosis may be delayed until school age or adulthood
Risk Factors
| Factor | Notes |
|---|---|
| Genetic | Strong heritability (80-90%); often polygenic |
| Family history | Siblings 10-20x higher risk |
| Older parental age | Slight increase in risk |
| Prematurity | Associated |
| Male sex | More commonly diagnosed |
Neurobiology
- Differences in brain development and connectivity
- Increased local connectivity, reduced long-range connectivity
- Alterations in prefrontal cortex, amygdala, cerebellum
Genetics
- Highly heritable
- Many genes implicated (hundreds); often de novo mutations
- Associated syndromes: Fragile X, Tuberous Sclerosis, Rett syndrome
Core Domain 1: Social Communication and Interaction
| Feature | Examples |
|---|---|
| Reduced social-emotional reciprocity | Difficulty with back-and-forth conversation; reduced sharing of interests |
| Reduced nonverbal communication | Poor eye contact; limited gestures; flat affect |
| Difficulty with relationships | Struggles to make/keep friends; lack of interest in peers |
Core Domain 2: Restricted/Repetitive Behaviours
| Feature | Examples |
|---|---|
| Stereotyped behaviours | Hand flapping, spinning, rocking |
| Insistence on sameness | Distress at routine changes |
| Restricted interests | Intense focus on narrow topics (trains, dinosaurs) |
| Sensory differences | Hypersensitivity to noise, texture, light; or seeking sensory input |
Other Associated Features
Behavioural Observation
- Eye contact
- Response to name
- Pointing (joint attention)
- Play (functional vs repetitive)
- Interaction with examiner
Developmental Assessment
- Communication (verbal and nonverbal)
- Motor skills
- Adaptive functioning
Physical Examination
- Dysmorphic features (consider genetic syndromes)
- Skin (café-au-lait spots — Tuberous Sclerosis)
- Hearing test (essential to exclude hearing impairment)
Diagnostic Assessment
- ADOS-2 (Autism Diagnostic Observation Schedule): Gold standard observational assessment
- ADI-R (Autism Diagnostic Interview-Revised): Structured parent interview
- Multidisciplinary assessment (paediatrician, psychologist, SALT)
Additional Investigations
| Test | Indication |
|---|---|
| Hearing test | All children referred for ASD |
| Genetic testing (chromosomal microarray, Fragile X) | If dysmorphism, ID, or regression |
| EEG | If seizures suspected |
| MRI brain | If focal neurological signs or regression |
Management Approach
┌──────────────────────────────────────────────────────────┐
│ AUTISM SPECTRUM DISORDER MANAGEMENT │
├──────────────────────────────────────────────────────────┤
│ │
│ EARLY INTERVENTION (Best evidence): │
│ • Speech and Language Therapy (SALT) │
│ • Social communication interventions │
│ • Occupational Therapy (sensory needs) │
│ • Behavioural support (ABA modified; EIBI) │
│ │
│ EDUCATIONAL SUPPORT: │
│ • Education, Health and Care Plan (EHCP) │
│ • Mainstream with support or specialist school │
│ • Visual timetables, structured environment │
│ │
│ CO-MORBIDITY MANAGEMENT: │
│ • Melatonin for sleep problems │
│ • SSRIs (sertraline) for anxiety (cautious) │
│ • Stimulants (methylphenidate) for ADHD │
│ • Risperidone/Aripiprazole for severe aggression │
│ (specialist only) │
│ │
│ FAMILY SUPPORT: │
│ • Parent training programmes │
│ • Respite care │
│ • Support groups (National Autistic Society) │
│ │
│ TRANSITION TO ADULTHOOD: │
│ • Supported employment │
│ • Independent living skills │
│ • Adult mental health services │
│ │
└──────────────────────────────────────────────────────────┘
Of ASD
- Social isolation
- Bullying
- Mental health problems (anxiety, depression)
- Underemployment
- Exploitation and safeguarding risks
Co-morbidities
- ADHD (50%)
- Anxiety disorders (40%)
- Depression
- Epilepsy (20-30%)
- GI problems
Childhood
- Early intervention improves outcomes
- Many children make significant progress with support
Adulthood
- Wide variation in outcomes
- Some live independently with successful careers
- Others require lifelong support
- Mental health issues common
Key Guidelines
- NICE CG170: Autism Spectrum Disorder in Under 19s (2011, updated 2017)
- NICE CG142: Autism in Adults (2012, updated 2021)
Key Evidence
Early Intervention
- Meta-analyses support early behavioural and communication interventions
Medication
- No medication for core ASD symptoms
- Treat co-morbid conditions
What is Autism?
Autism Spectrum Disorder (ASD) is a lifelong difference in how the brain works. It affects how a person communicates and interacts with others, and they may have intense interests or need routines.
What Are the Signs?
- Difficulty making friends or understanding social cues
- Not responding to their name or avoiding eye contact
- Repetitive movements (like hand flapping)
- Very focused interests
- Sensitivity to sounds, lights, or textures
- Upset by changes in routine
Is It Different in Everyone?
Yes — that's why it's called a "spectrum." Some people need a lot of support, while others live independently and may only need help in certain situations.
Is There a Cure?
There is no cure, and autism is not something that needs to be "fixed." Many autistic people see it as part of who they are. Support focuses on helping with communication, learning, and managing challenges.
How is It Supported?
- Speech and language therapy
- Occupational therapy (for sensory issues)
- Educational support
- Help with social skills
- Medication for sleep problems or anxiety if needed
Primary Guidelines
- NICE. Autism Spectrum Disorder in Under 19s: Support and Management (CG170). 2013, updated 2017. nice.org.uk/guidance/cg170
Key Studies
- Lord C, et al. Autism spectrum disorder. Lancet. 2018;392(10146):508-520. PMID: 30078460