Autism Spectrum Disorder (ASD), is a complex lifelong neurodevelopmental disorder that typically appears within the first three years of life. It is considered to be a spectrum disorder meaning the primary symptoms can be expressed in varying degrees of severity. Individuals with autism will have difficulties with verbal and non-verbal social communication, social interactions, and can display a range of rigid or stereotyped, repetitive behaviors, often with insistence on a specific routine that they will show resistance to changing. Hyper- or hypo-sensitivity to sensory stimuli is also often observed.
The diagnostic criteria for ASD was recently revised in May 2013 in the Fifth Edition of the Diagnostic and Statistical Manual (DSM-V) produced by the American Psychiatric Association (APA). The edition immediately preceding it, the DSM-IV, had ASD or Autistic Disorder as one of five disorders under the umbrella of Pervasive Developmental Disorders (PDD): Autistic Disorder, Asperger’s Disorder, Childhood Disintegrative Disorder (CDD), Rett’s Disorder, and Pervasive Development Disorder-Not Otherwise Specified (PDD-NOS). Each of these disorders had specific diagnostic criteria but shared the primary symptoms of deficits in social communication, social interaction and rigid, stereotypical behaviors.
WHO IS AFFECTED?
- According to the 2019 Canadian health survey on children and youth, 1 in 50 children/youth aged 1 to 7 years were diagnosed with ASD: https://www.canada.ca/en/public-health/services/publications/diseases-conditions/autism-spectrum-disorder-canadian-health-survey-children-youth-2019.html
WHAT CAUSES AUTISM?
Exactly what causes ASD is still unknown. Current research suggests that a predisposition to autism might be inherited. Researchers have not found a specific “autism gene” but instead a nonspecific factor, which may increase the likelihood of having cognitive impairments. Over the last five years, scientists have identified a number of rare gene changes, or mutations, associated with autism. Researchers have also found neuro-biological differences in the brains of individuals with autism. The current theory is that ASD is caused by a combination of “risk genes” and environmental factors in the early brain development period.