Neurodevelopmental Disorders
These conditions manifest early in development and involve cognitive, motor, social, or academic impairments. They frequently co-occur and may be lifelong.
1. Autism Spectrum Disorder (ASD) – see below
- Core Features:
- Deficits in social communication and interaction
- Restricted, repetitive behaviours or interests
2. Attention-Deficit/Hyperactivity Disorder (ADHD)
- Core Features:
- Persistent inattention and/or hyperactivity-impulsivity
- Signs/Symptoms (present in ≥2 settings):
- Inattention: distractible, disorganised, forgetful, poor follow-through
- Hyperactivity: fidgeting, excessive talking, unable to wait turns
- Key Notes:
- Onset before age 12
- Subtypes: Predominantly Inattentive, Predominantly Hyperactive-Impulsive, or Combined
- High comorbidity with ODD, learning disorders, ASD
3. Developmental Coordination Disorder (DCD / Dyspraxia)
- Core Features:
- Motor skill impairment that interferes with daily life or school
- Signs/Symptoms:
- Clumsiness, poor handwriting, difficulty with dressing, sports, tying shoelaces
- Key Notes:
- Diagnosed when motor issues are not due to intellectual disability, visual impairment, or neurological disorder
- Often coexists with ADHD, SLD, and ASD
4. Specific Learning Disorder (SLD)
- Core Features:
- Difficulties learning and using academic skills
- Signs/Symptoms (persist for ≥6 months despite intervention):
- Impaired reading (dyslexia), writing (dysgraphia), or mathematics (dyscalculia)
- Key Notes:
- Diagnosed via educational testing
- Not explained by low IQ, poor schooling, or sensory deficits
- Can co-occur with ADHD, DCD, ASD
Asperger’s Syndrome
- Asperger’s Syndrome (DSM-IV, 1994–2013):
- A subtype of Pervasive Developmental Disorders (PDD).
- Core Features:
- Difficulties with social interaction and communication.
- Restricted and repetitive behaviours.
- No significant language delay (normal speech milestones).
- No intellectual disability (often average or above-average IQ).
- Often diagnosed later (e.g. in school-age children) due to subtle language and social difficulties.
- Autistic Disorder (DSM-IV):
- Also under PDD umbrella.
- Characterised by:
- More obvious language delays.
- Intellectual disability may be present.
- Similar social/communication and behavioural difficulties as Asperger’s, but generally more pronounced.
DSM-5 (2013–Present): Unified Diagnosis
- DSM-5 eliminated separate Asperger’s diagnosis.
- All previous subtypes (including Asperger’s) are now diagnosed under: Autism Spectrum Disorder (ASD)
- Diagnosed based on:
- Persistent deficits in social communication/interaction, and
- Presence of restricted/repetitive behaviours/interests, with
- Severity specifiers and language/intellectual ability descriptors.
Why Was Asperger’s Removed?
- High overlap with autism → poor inter-rater reliability between diagnoses.
- Wide variability in functioning and symptoms.
- Emphasis shifted to diagnosing autism as a spectrum, rather than discrete subtypes.
What Does This Mean Clinically?
- Individuals previously diagnosed with Asperger’s would now meet criteria for ASD without intellectual/language impairment.
- Diagnosis includes:
- Severity levels (1–3), indicating required support.
- Descriptive specifiers (e.g. with/without language delay, cognitive impairment).
- In Australia (e.g. SA): clinicians use DSM-5 for ASD diagnosis; Asperger’s no longer separately recognised.
Autism Spectrum
The Autism Spectrum refers to a range of neurodevelopmental conditions characterised by differences in:
- Social communication and interaction, and
- Restricted, repetitive behaviours, interests, or activities.
Under the DSM-5 (2013–present), all previously separate diagnoses are grouped into Autism Spectrum Disorder (ASD). The term “spectrum” highlights the wide variability in:
- Symptom severity
- Functional abilities
- Language and cognitive development
Autism Spectrum: Core Domains
ASD is defined by persistent deficits in two domains:
1. Social Communication and Interaction (across contexts)
- Difficulties with:
- Social-emotional reciprocity (e.g. back-and-forth conversation)
- Nonverbal communication (e.g. eye contact, body language)
- Developing, maintaining, and understanding relationships
2. Restricted and Repetitive Patterns of Behaviour, Interests, or Activities
- Stereotyped or repetitive movements/speech
- Insistence on sameness or routines
- Highly restricted, fixated interests
- Hyper- or hypo-reactivity to sensory input
Spectrum of Presentation: Clinical Variability
| Subtype / Descriptor | Key Features | Previous DSM-IV Label (Now under ASD) |
|---|---|---|
| High-functioning autism | Normal IQ, intact language, subtle social challenges | Asperger’s Syndrome |
| Classic autism | Language delay, intellectual disability, obvious repetitive behaviour | Autistic Disorder |
| PDD-NOS | Atypical autism traits not meeting full criteria | PDD-NOS (Pervasive Developmental Disorder – Not Otherwise Specified) |
| Nonverbal autism | No functional verbal language | Autistic Disorder |
| Regressive autism | Normal early development, then loss of skills (typically age 15–30 months) | Often classified as ASD in DSM-5 |
DSM-5 Specifiers for ASD Diagnosis
ASD is diagnosed with the following specifiers:
- Severity level (1–3) based on support needs:
- Level 1: Requires support
- Level 2: Requires substantial support
- Level 3: Requires very substantial support
- With/without intellectual impairment
- With/without language impairment
- Associated conditions (e.g. epilepsy, ADHD, anxiety)
Related Conditions (can co-occur but are not within ASD)
| Condition | Notes |
|---|---|
| ADHD | Common comorbidity; affects attention, impulse control |
| Language disorder | Affects expressive/receptive language without core ASD traits |
| Intellectual disability | Can co-occur with ASD but not all individuals with ASD have it |
| Social (pragmatic) communication disorder | Impaired social use of language without restricted/repetitive behaviours |
| Global developmental delay | Diagnosed in children <5 when ASD can’t yet be clearly determined |