Autism Spectrum Disorder (ASD)

Autism spectrum disorder (ASD) is a neurodevelopmental condition — it arises from how a child's brain develops. It is defined by persistent differences in two broad areas: social communication and interaction, and restricted or repetitive patterns of behavior, interests, and activities. These differences cause real functional impact in social, school, and daily life.

Core features

A. Social communication and interaction differences:

• Social-emotional reciprocity — sharing interests, back-and-forth conversation, seeking and giving attention, imitation
• Non-verbal communication — eye contact, gestures, facial expression, posture, pointing
• Developing and maintaining relationships appropriate to developmental level

B. Restricted, repetitive patterns of behavior, interests, or activities:

• Repetitive speech, movements, or object use — echolalia, hand-flapping, rocking, lining up toys
• Inflexible adherence to routines and strong resistance to change
• Intense, narrow interests, unusual in intensity or focus
• Sensory hyper- or hypo-reactivity — aversion to loud noises, sensory-seeking, defensiveness

In everyday terms, parents report: less sharing of interests, difficulty appreciating their own and others' emotions, discomfort with eye contact, literal interpretation of abstract language, and difficulty making or keeping friends.

Why "spectrum"

Autism looks different in every child. One child may struggle most with social skills and show few repetitive behaviors; another may be consumed by routines while socializing more easily. Each trait sits on a continuum, and abilities vary enormously — some autistic children have intellectual disability, while others are highly capable yet still struggle with abstract thinking, organization, and applying skills across settings. There is often nothing about a child's appearance that sets them apart.

Diagnosis

There is no blood test or brain scan for autism. Diagnosis is behavioral: a trained clinician observes and plays with the child, takes a detailed developmental history from parents, and typically uses standardized tools such as the ADOS (a play-based diagnostic observation), developmental and adaptive scales, plus speech/language and motor evaluations. Early signs can sometimes be noticed before age one and are typically consistent by ages 2–3; in milder cases they may only become obvious once the child starts school and is among peers.

One note on labels: older materials use the old subtypes — Autistic Disorder, Asperger's Syndrome, and PDD-NOS. Under DSM-5 these were merged into the single diagnosis of ASD, with support levels (1–3) describing how much help a person currently needs — see Autism support levels.

Co-occurrence is the rule

Around 85% of children with autism carry at least one additional diagnosis:

• ADHD — estimated in 50–70% of the ASD population (the most common companion)
• Anxiety disorders — roughly 30%
• Depression — roughly 26%

Also common: speech and language differences (often the first concern that leads families to evaluation), sensory processing differences, sleep and GI problems, and about 10% with an identifiable genetic condition.

What parents should know

• The diagnosis doesn't change your child. It's a label that describes characteristics and unlocks services — not a verdict on potential.
• Medical diagnosis ≠ school eligibility. Schools determine an educational eligibility separately, and the criteria differ by country/state. A child can have one without the other — and either can be the doorway to support.
• No medication treats the core features of autism, but medication can help co-occurring conditions so the child gets more out of therapy and school.
• Support is usually a mix: behavioral, developmental (speech, occupational, physical therapy), social-relational, psychological, and pharmacological approaches. Combinations are the norm.
• Feelings are normal. Many families move through grief stages after diagnosis — shock, sadness, guilt, anger, denial, loneliness, acceptance — and siblings and grandparents grieve too. See Family & Wellbeing for the post-diagnosis journey.

Not medical advice. This page is a parent-compiled summary. If this sounds like your child, consult a developmental pediatrician or licensed clinician for an individualized evaluation.