Autism Spectrum Disorder

Descriptive text is not available for this imageBASICS

DESCRIPTION

  • A neurodevelopmental disorder characterized by:
    • Delays/impairments in development of social communication and social interaction
    • Restricted, repetitive patterns of behavior, interests, or activities
    • Symptoms present in early childhood
    • Significant impairment in functioning
  • Diagnostic criteria changes since 2013:
    • Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) (DSM-IV) previously included autistic disorder, Asperger disorder, Rett disorder, childhood disintegrative disorder, and pervasive developmental disorder, not otherwise specified within overall category.
    • Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-5) has eliminated these separate diagnoses due to uncertain distinctions.
    • DSM-5 added severity levels (1 to 3) based on the level of support required.
  • Behaviors exist along continuum with unclear boundaries between trait and disorder.
  • Associated with specific known genetic disorder (e.g., fragile X) in 15–30% of cases

EPIDEMIOLOGY

Prevalence

  • Approximately 1 in 44 (23 per 1,000) of 8-year-old children, according to the Centers for Disease Control and Prevention (CDC) 2021 report
  • Rate rising over past decades
  • 4 times more common in males than females
  • Females and male are equally likely to also have intellectual disability.

RISK FACTORS

  • Strong genetic influence: risk in 1st-degree relatives 2–18%; identical twins 35–95%
  • Several hundred genes implicated, suggesting polygenic risk. Approximately 15–30% of children with autism have identifiable genetic anomaly.
  • Other risk factors: closer spacing of pregnancies, advanced maternal or paternal age, extreme premature birth (<26 weeks), possible maternal inflammation in utero
  • Link to vaccinations not supported by scientific evidence

PATHOPHYSIOLOGY

Pathophysiology is not well understood but may be associated with abnormalities in cortical laminal architecture during prenatal brain development or errors in synaptic pruning during development.

COMMONLY ASSOCIATED CONDITIONS

  • Intellectual disability
  • Gastrointestinal (GI) problems
  • Epilepsy
  • Sleep disorders
  • Attention-deficit/hyperactivity disorder (ADHD)
  • Anxiety, depression, mood disturbances
  • Aggression and self-injury

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