Autism spectrum disorder is a lifelong neurodevelopmental condition that affects social communication and is marked by restricted, repetitive patterns of behavior, interests, or activities. "Spectrum" reflects the wide range of abilities: some autistic people have intellectual disability and no spoken language, while others have average or above-average intelligence and fluent speech but struggle with social interaction.

Causes and risk factors — strongly genetic (high heritability; higher risk in siblings of autistic children), with contributions from prenatal factors: prematurity, older parental age, prenatal valproate exposure, and genetic syndromes such as fragile X syndrome and tuberous sclerosis complex. Large studies have found no link between vaccines (including MMR) and autism, and parenting style does not cause autism.

Frequency — CDC surveillance identified about 1 in 31 children aged 8 years (2022 data), with ASD more than 3 times more common in boys. Rising numbers largely reflect broader criteria and better detection.

DSM-5-TR criteria (summary)

1. Persistent deficits in social communication and social interaction across contexts — all three: social-emotional reciprocity, nonverbal communication (eye contact, gestures, facial expression), and developing and maintaining relationships
2. Restricted, repetitive patterns — at least two of four: stereotyped or repetitive movements, object use, or speech (e.g., hand flapping, lining up toys, echolalia); insistence on sameness and distress at small changes; highly restricted, intense interests; hyper- or hyporeactivity to sensory input
3. Present in the early developmental period (may not be fully apparent until social demands increase)
4. Clinically significant impairment
5. Not better explained by intellectual disability alone

Severity is rated separately for each domain as level 1 (requiring support), level 2 (substantial support), or level 3 (very substantial support), with specifiers for accompanying intellectual or language impairment.

Common co-occurring conditions — intellectual disability (a substantial minority), ADHD, anxiety, sleep problems, epilepsy, gastrointestinal problems and constipation, feeding selectivity, and self-injurious behavior.

Early signs (red flags for referral)

• No babbling, pointing, or waving by 12 months
• No single words by 16 months; no spontaneous two-word phrases by 24 months
• Any loss of language or social skills at any age
• Does not respond to name; limited eye contact or shared smiling
• Little joint attention — does not point to show interest or follow another's point
• Lack of pretend play; lines up or spins objects; intense attachment to unusual objects
• Unusual reactions to sounds, textures, lights, or smells; repetitive movements

Older children — difficulty with conversation and reading social cues, literal interpretation of language, rigid routines, intense focused interests, difficulty making friends, meltdowns with sensory overload or change.

Health and safety assessment

• Communication method (spoken words, signs, pictures, device)
• Sensory preferences and aversions, triggers, and calming strategies — ask the parents
• Sleep, diet (food selectivity), bowel pattern, dental health
• Wandering (elopement), pica, self-injury, aggression
• Pain may be expressed atypically (behavior change, self-injury) or seem under-reported

Screening

• Developmental surveillance at every well-child visit, with autism-specific screening at 18 and 24 months (AAP)
• M-CHAT-R/F (Modified Checklist for Autism in Toddlers, Revised with Follow-Up) — a 20-item parent questionnaire for children 16–30 months

A screen is not a diagnosis. A positive screen or parental concern → referral for diagnostic evaluation and early intervention at the same time — do not "wait and see."

Diagnostic evaluation (developmental pediatrician, child psychiatrist, psychologist, or team)

• Clinical observation and history using DSM-5-TR criteria; standardized tools such as the ADOS-2 (observation) and rating scales such as the Childhood Autism Rating Scale (CARS-2)
• Audiology — rule out hearing loss in every child with language delay
• Genetic testing: chromosomal microarray and fragile X testing (and others as indicated); EEG if seizures are suspected; lead level with pica
• Cognitive and adaptive testing to plan education and supports

There is no cure; the goal is to build communication, social, adaptive, and learning skills, reduce distress, and support the family. Earlier intervention gives better outcomes.

Behavioral and developmental interventions

• Applied behavior analysis (ABA) and naturalistic developmental behavioral interventions (e.g., Early Start Denver Model) — structured teaching with positive reinforcement
• Speech-language therapy and augmentative and alternative communication (AAC) — picture exchange (PECS), sign, speech-generating devices. AAC supports, not blocks, spoken language
• Occupational therapy for self-care, fine motor, and sensory needs
• Social skills training; parent training; special education supports

Medications — treat target symptoms, not autism itself

Avoid unproven and harmful therapies — chelation, hyperbaric oxygen, and restrictive diets without medical need have no proven benefit, and chelation has caused deaths.

Listed in priority order.

1. Safety
   • Elopement prevention — secure doors, close supervision; drowning is a leading cause of injury death in autistic children who wander
   • Self-injury and aggression — protective equipment as ordered, remove hazards, identify triggers
   • Physical restraint only as a last resort for imminent danger, per policy, with the least restrictive method
2. Reduce anxiety and sensory overload in hospital
   • Private, quiet room, dim lights, fewer alarms and interruptions; consistent caregivers
   • Keep home routines and familiar objects; involve parents in all care
   • Visual schedules and social stories to show what will happen next and increase predictability
   • Prepare the child before each procedure and change, step by step; warn before touching
   • Allow self-soothing repetitive behaviors unless harmful
3. Communication
   • Use the child's name first, short, concrete, literal sentences, one instruction at a time; give time to respond
   • Use the child's own system (pictures, PECS, device, signs)
   • Avoid overwhelming verbal input; do not insist on eye contact
4. Assess the child's individual sensory profile — which sounds, textures, lights, or smells cause distress and which calm; adapt the environment (headphones, weighted blanket if used at home, fragrance-free products)
5. Pain and illness assessment — behavior changes, self-injury, and sleep disturbance may be the only signs; ask parents about usual pain behaviors
6. Nutrition and elimination — respect food preferences while offering new foods gradually; monitor weight; constipation management
7. Medication monitoring — weight, BMI, glucose, lipids, prolactin symptoms, movement disorders with antipsychotics
8. Promote development and health maintenance — routine immunizations, dental care (desensitization visits), vision and hearing checks, sleep hygiene
9. Team approach — consistent strategies across home, school, therapists, and hospital so skills generalize

• Listen to parental concerns without judgment; a screening result is a reason to get help early, not a label
• Early intervention works best when started early — begin services while waiting for a formal diagnosis
• Teach self-care skills with visual supports and task analysis; praise success immediately; avoid punishment
• Keep routines predictable and prepare the child for changes with pictures or stories
• Wandering safety: door alarms or locks, identification bracelet, swimming lessons, alert neighbors; call emergency services immediately if the child is missing and check nearby water first
• Antipsychotic medicines: healthy diet and activity to limit weight gain; keep lab appointments; report stiffness or abnormal movements
• Be cautious of therapies promising a cure; discuss any new treatment with the health team
• Vaccinate on schedule — vaccines do not cause autism
• Care for the whole family: respite, parent support groups, sibling support
• Adolescents: puberty education, self-advocacy, transition to adult services and employment

• ASD core features: social communication deficits + restricted, repetitive behaviors, present early in development
• Red flags: no babbling or pointing by 12 months, no words by 16 months, no two-word phrases by 24 months, any loss of skills
• Autism-specific screening at 18 and 24 months; M-CHAT-R/F for 16–30 months
• M-CHAT-R: 0–2 low; 3–7 follow-up interview; 8–20 refer immediately
• Always check hearing in a child with language delay
• Vaccines do not cause autism
• Hospital care: quiet room, consistent staff, routines, visual schedules, advance preparation
• Communication: short, literal sentences; PECS/AAC — not excessive verbal stimulation
• Assess the child's sensory preferences and aversions before adapting care
• Physical restraint is a last resort
• Risperidone/aripiprazole for irritability — monitor weight, glucose, lipids, movements
• Most common co-occurring conditions: intellectual disability, ADHD, anxiety, epilepsy