What Is Autism?

1. Deficits in social communication and interaction
2. Restricted, repetitive patterns of behavior, interests, or activities

Historical Classification

• Autistic Disorder (classic autism)
• Asperger Disorder (milder, no language delay)
• Childhood Disintegrative Disorder (normal development, then regression)
• Rett Syndrome (predominantly females, stereotyped hand movements)
• Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS)

Core Features

Social Communication Deficits

• Reduced eye contact, facial expressions, and gestures
• Difficulty understanding and maintaining relationships
• Lack of sharing of interests or emotions with others
• Delayed or absent language development (in some)

Restricted & Repetitive Behaviors

• Stereotyped movements (hand-flapping, toe-walking, rocking)
• Intense, narrow, idiosyncratic interests
• Insistence on sameness and resistance to change
• Unusual sensory responses (hypersensitivity or hyposensitivity)

When Does It Appear?

• ASD is typically evident during the second year of life
• In severe cases, lack of social interest may be noted even in the first year
• In milder cases (like former Asperger's), it may not be recognized until middle childhood when academic and social demands increase
• In up to 25% of cases, some language develops first and is then lost
• Average age of diagnosis: ~3.1 years for classic autism, ~7.2 years for the former Asperger type

Causes & Risk Factors

• Genetics: ASD has polygenic heritability - many genes contribute, not a single gene
• Prenatal factors: Certain prenatal environmental exposures have been associated with increased risk (see recent review in BMC Medicine)
• NOT caused by vaccines: There is no relationship between childhood immunizations and ASD - this has been thoroughly studied and disproven
• Males are diagnosed significantly more often than females

Prevalence

• Approximately 1 in 36 children in the United States (recent CDC data; earlier estimates were ~1 in 68)
• The increase in prevalence over recent decades is largely attributed to improved detection and broader diagnostic criteria, not a true increase in cases

Associated Features

• About 1 in 3 children with ASD also have an intellectual disability
• Sensory sensitivities are very common
• Co-occurring conditions include ADHD, anxiety, epilepsy, and sleep disorders
• Some children show normal intellectual function with social and communication challenges only

Diagnosis

• ADOS-2 (Autism Diagnostic Observation Schedule)
• ADI-R (Autism Diagnostic Interview - Revised)
• DSM-5 criteria require symptoms to be present from the early developmental period and cause significant impairment

Treatment & Management

Key Takeaways

• ASD is a lifelong condition, but many individuals lead independent, fulfilling lives with the right support
• Early diagnosis and intervention are the most important factors for better outcomes
• The condition is not caused by parenting style or vaccines
• Each person with autism is unique - the spectrum is genuinely broad