Autism Spectrum Disorder (ASD) is a neurodevelopmental condition affecting 1-2% of the population. It is characterised by a different way of perceiving the world, establishing social relationships and processing information, with extraordinarily wide clinical heterogeneity. The DSM-5 unified the former categories (classic autism, Asperger syndrome, PDD-NOS) under a single "spectrum" in 2013, recognising the dimensional continuity of the condition.
Complete Guide
ASD / Autism
Autism Spectrum Disorder (ASD): the complete guide
In this section:
- Early signs of ASD: when and how to detect autism
- ASD Level 1: characteristics, diagnosis and support (formerly Asperger syndrome)
- ASD and inclusive schooling: practical strategies for teachers and families
- ASD and sensory processing: understanding hypersensitivity in autism
- ASD in girls: the invisible female profile of autism
- Asperger syndrome: the high-functioning autistic profile and its current diagnosis
- Social skills in ASD: a critical look at what really helps
What is ASD? Neurobiological and clinical basis
ASD is a neurodevelopmental condition with complex genetic basis affecting neural circuits involved in social communication, sensory processing and cognitive flexibility. Fundamentally, it is a condition of atypical social learning: people with ASD do not learn social rules and codes implicitly and automatically, but must learn them explicitly and laboriously — which does not mean they cannot learn them, only that they need specific support to do so.
1-2%Global prevalence
4:1Boys/girls ratio (diagnostic bias reduces the real ratio)
36mOptimal diagnostic age
DSM-5 diagnostic criteria: the two core domains of ASD
The DSM-5 describes two diagnostic domains: Domain A (deficits in social communication and interaction: socioemotional reciprocity, nonverbal communicative behaviours, developing/maintaining relationships) and Domain B (restricted, repetitive patterns of behaviour, interests or activities: stereotyped movements, insistence on sameness, restricted interests, sensory hyper/hyporeactivity). The 3 DSM-5 support levels describe the amount of support required, not fixed disorder severity.
Early signs: when to be concerned?
Early detection is one of the most important prognostic factors. Key red flags by age: at 6-9 months (reduced social smile, poor eye contact); at 12 months (no pointing, no communicative gestures, skill regression — refer urgently); at 18 months (no meaningful words, no joint attention); at 24 months (no two-word phrases, absent functional play). Any regression of previously acquired skills at any age warrants immediate referral.
Evidence-based interventions for ASD
ASD is not a disease to be "cured" — it is a different form of neurology. Effective interventions improve quality of life, adaptive functioning and communication skills: early intensive behavioural intervention (naturalistic ABA, ESDM), speech and language therapy including augmentative communication systems, sensory integration therapy, social skills programmes (PEERS, Lego Therapy), and intensive family support.
ASD and education: inclusion with specialist support
All students with ASD need, regardless of educational setting: structure and predictability (visual schedules, anticipating changes), sensory adaptation, alternative communication systems when oral language is limited, and explicit social skills support. Curriculum adaptations should be based on individual cognitive profiles — typically with visual-spatial strengths and difficulties with abstract verbal comprehension.
Frequently asked questions
ASD is not a disease to be "cured" — it is a different form of neurology with specific strengths and difficulties. Appropriate interventions aim to maximise quality of life, adaptive functioning and wellbeing, not to eliminate ASD. Many people with ASD (especially ASD Level 1) lead full, autonomous and rewarding lives.
No. This hypothesis, published by Wakefield in 1998, has been completely refuted by dozens of rigorous studies involving millions of children. The original article was retracted from The Lancet for scientific fraud. There is no credible scientific evidence of a causal relationship between vaccines and ASD.
Both conditions share symptoms, but their nature differs. In ASD, social difficulties stem from atypical understanding of social codes. In ADHD, they stem from impulsivity and inattention, but basic social understanding is intact. Both diagnoses can coexist in 50-70% of cases.
Want personalised guidance?
Take our free assessment and get a personalised neuropsychological profile in about 15 minutes.
Start free assessment