Autism Spectrum Disorder (ASD) is medically classified as a neurodevelopmental disorder. Symptoms are usually observed within the first three years of life (although it’s not uncommon for a diagnosis to be made later in life). ASD changes the way the brain processes information (which is why you might see the term “neurodivergent” used to refer to people on the spectrum). The specific “cause” of ASD—such as genetic, environmental, developmental, etc.—has not been determined, and no single determining factor is common across every single case of ASD.[1] It’s also important to note that ASD is not a degenerative condition (i.e., one that gets progressively worse over time, such as Parkinson’s).
How does ASD affect people?
As the term “spectrum” implies, ASD can affect people in a wide variety of ways and within a range of different degrees of severity. Some of the most commonly observed challenges are in: socialization, speech, and communication (including non-verbal communication), repetitive/restrictive behaviours, and difficulties with sensory processing (i.e., an over- or under-sensitivity to smell, touch, vision, taste, and/or hearing).[2] Other symptoms have been noted to commonly appear in those on the spectrum (such as gastric issues, motor challenges, atypical sleeping/eating habits), but there is still debate among the medical community as to whether these symptoms are directly correlated to ASD, or if they are simply easier to observe in people on the spectrum.[3] It’s also worth noting that having ASD is not synonymous with having a low intelligence; a large part of ASD is related to differences in how a person processes information, but it’s just as likely that those differences can make it easier to grasp certain topics or concepts, depending on the individual and how the information is presented. The concept of this is related to a recent increased scrutiny over the validity of long-held assumptions about how intelligence and problem-solving ability is measured, as it is becoming increasingly apparent that assessment methods such as the IQ test are better at examining how a person solves problems rather than how well they can do so.[4]
The Prevalence of ASD
According to the Government of Canada’s 2018 report on ASD rates, 1 in 66 (1.5%) children have been diagnosed with ASD, with 80% of the diagnoses being for male children; it is currently unknown whether ASD is actually more common in boys than girls, or if there’s a diagnostic bias that results in girls not being recognized as being on the spectrum as often as their male peers.[5] Statistics for adults are less clear, in part due to the lack of an easy information-gathering system (the statistics for children were clearer due to school records kept for budgeting/programming reasons), but according to a 2017 report less that 1% of Canadian adults cite ASD as a contribution to difficulties in daily life.[6] Of course, the number is almost certainly larger than indicated here, as it does not include adults who didn’t voluntarily respond to the survey, adults unaware that they are on the spectrum due to a lack of an official diagnosis, and those adults on the spectrum who did not classify their ASD as a source of distress in their life.