Description

• 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:
  • DSM-IV previously included autistic disorder, Asperger disorder, Rett disorder, childhood disintegrative disorder, and pervasive developmental disorder, not otherwise specified within overall category
  • DSM-5 has eliminated these separate diagnoses due to insufficient evidence.
  • DSM-5 added severity levels (1 to 3) based on the level of support required.
• Associated with specific known genetic disorder (e.g., fragile X) in a minority (15%) of cases
• Behaviors exist along continuum with unclear boundaries between trait and disorder.

Epidemiology

Risk Factors

• Strong genetic influence: risk in 1st-degree relatives 2–18%; identical twins 35–95%
• Multiple genes implicated (>100), suggesting polygenic risk. Approximately 15% 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 unknown but may be associated with abnormalities in cortical laminar architecture during prenatal brain development

Commonly Associated Conditions

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