In Canada, autism prevalence is informed by the National Autism Surveillance System (NASS). NASS is a collaboration of federal, provincial and territorial governments, working to build a comprehensive picture of autism among children and youth in Canada. Based on 2015 data, it is estimated that 1 in 66 Canadian children and youth ages 5-17 have been diagnosed with autism. It is estimated that males are diagnosed with autism four times more frequently than females.
There is not one autism but many subtypes, most influenced by a combination of genetic and environmental factors. Because autism is a spectrum disorder, each person with autism has a distinct set of strengths and challenges. The ways in which people with autism learn, think and problem-solve can range from highly skilled to severely challenged. Some people with autism may require significant support in their daily lives, while others may need less support and, in some cases, live entirely independently.
Several factors may influence the development of autism, and it is often accompanied by sensory sensitivities and medical issues such as gastrointestinal (GI) disorders, seizures or sleep disorders, as well as mental health challenges such as anxiety, depression and attention issues.
Signs of autism usually appear by age 2 or 3. Some associated development delays can appear even earlier, and often, it can be diagnosed as early as 18 months. Research shows that early intervention leads to positive outcomes later in life for people with autism.
In 2013, the American Psychiatric Association merged four distinct autism diagnoses into one umbrella diagnosis of autism spectrum disorder (autism). They included autistic disorder, childhood disintegrative disorder, pervasive developmental disorder-not otherwise specified (PDD-NOS) and Asperger syndrome.