Note: members of the autism spectrum disorder (ASD) community have different preferences on the use of person-first (“person with ASD”) and identity-first (“autistic person”) language. For this article, we have used a mix of person-first and identity-first language.
What is autism spectrum disorder?
Autism spectrum disorder (ASD) is a neurodevelopmental condition that affects how people communicate, socially interact and behave. ASD is a spectrum and its characteristics can vary from person to person.
Each autistic person will have their own unique set of strengths and challenges and the degree to which these differences affect their daily lives can also vary widely. There can be some autistic people who need regular close support to get through their daily tasks, whereas other autistic people may need no-to-minimal or intermittent supports. The level of support required for an individual can change over time as well.
Autistic people have a range of abilities. Many autistic people have average or above-average intelligence, though they may also have learning difficulties or an intellectual disability. Many autistic people have restricted patterns of interest and may exhibit a relatively high degree of knowledge or ability related to that specific interest. A small percentage of autistic people have savant skills. Autistic individuals may have strong skills in one area of development, though challenges in another. For example:
- One child may have difficulty holding a pencil but have a strong memory for the words of songs or movies. On the other hand, they could be fabulous artists or have perfect pitch.
- Another child may have difficulty knowing how to play a game with a peer but may have a very good understanding of how computers work.
- Another child who does not speak may be able to build complex structures out of Lego.
Autistic people will always have some characteristics of ASD throughout their lives, but many autistic people can achieve their goals and dreams. Autistic adults may need different types of support throughout their lives, such as education, employment, housing, transportation or health care. Many autistic adults can live independently, work, study, socialize and contribute to society.
What are the characteristics of ASD?
While every autistic child is unique, common characteristics include effects on social-communication and behavioural patterns.
Social communication differences
Autistic children may have limitations in their ability to communicate with others. This may include reduced eye contact, the inability to understand facial expression in others, and challenges having back and forth play and interactions with others. Autistic children may struggle with working, playing and learning to interact with others. When they are talking to others, they may not realize that other people also need to be able to talk about their interests. They may also have difficulty with social cues, eye contact, body language or tone of voice. This can make them seem uninterested but that is not their intention. Many autistic people do want to socialize and form relationships, but they may have different preferences and boundaries for social interactions. Autistic children may also have difficulty adapting their behaviour to different social contexts.
Autistic people have emotions, just like anyone else. They can feel happy, sad, angry, scared and everything in between. However, they may have trouble understanding, expressing, or showing their own emotions, or recognizing or responding to the emotions of others.
Restricted, repetitive behaviour, restrictions of interests or activities and need for sameness
A common characteristic of autistic individuals is demonstrated in repetitive behaviours of either words or actions. Autistic children may have strong interests in certain objects, or become experts on limited topics, such as maps of transportation systems or country music. They may learn detailed information about a topic and repeat it without being aware that other people might not have the same level of interest.
Autistic children may also exhibit repetitive behaviours. For example, they may repeatedly flap their hands, jump, or walk on tiptoes. This is common. It is something that many parents talk about when they describe their children. An autistic child may be doing these things to help calm themself during stressful situations or to help occupy or entertain themself. The patterns are not harmful, unless they interfere with daily functioning or cause injury. Trying to stop or prevent repetitive behaviours can be stressful, frustrating or even traumatic for autistic people.
Autistic children may play with toys in different or unusual ways. For example, they may be able to tell you everything you need to know about car engines. Or they may be able to sit for hours spinning the wheels on a toy vehicle, though have difficulty playing a make-believe game with cars.
Some autistic children have an under- or over-reaction to their senses (e.g., sight, touch, smell, taste, hearing). Some children may be sensitive to sound or texture, and others may have restricted food preferences. Others may be overwhelmed by crowds, or find particular sounds upsetting. Some children like to seek out sensations such as strong hugs or putting objects in their mouth. Many children may be bothered by these things, but children with ASD often have a stronger reaction to them.
How is ASD diagnosed?
There is no single test that can confirm the diagnosis of ASD. A health-care provider or health-care team that specializes in ASD may diagnose a child based on what they observe and learn about a child’s current and past behaviour and development. More information about diagnosis is available in Autism spectrum disorder (ASD): Diagnostic criteria.
How common is ASD?
ASD is common. In Canada, approximately 2% of children (or 1 in 50) have been diagnosed with ASD. About half are diagnosed by age five. ASD affects children of all genders. There is a 1:4 female to male ratio with ASD diagnosis, although it is thought that some female children are not being diagnosed as their symptoms present differently than in some male children. ASD affects people from all parts of the world. It affects people of every social economic background and race.
ASD is not a new disorder. It was first described in the 1940s, but it has likely existed for much longer. More autistic people are seen today because screening methods, diagnosis and awareness have all improved. The criteria for ASD diagnosis have also been expanded to include a wider range of symptoms and abilities. This means that more people who were previously undiagnosed or misdiagnosed can now receive the services and supports they need.
What causes ASD?
There are many studies looking at the causes of ASD. Although no one specific cause is known, current studies suggest that ASD may be related to differences in the brain. There are ongoing studies identifying genetic differences associated with ASD. Currently, there are hundreds of genes found to be associated with ASD, though individuals who pursue genetic testing for ASD have normal testing 80-90% of the time.
What does NOT cause ASD?
We now know that the brain of a child with ASD develops differently. Several older ideas about the cause of ASD have now been proven NOT to be true. We know that:
- ASD is not a mental illness.
- Autistic children are not unruly kids who choose to misbehave.
- “Bad” parenting does not cause ASD. ASD is not caused by parents who have difficult relationships with their children.
- Vaccines do not cause ASD. There is no scientific link between vaccines and ASD. The myth was based on a published paper that was later retracted. The author of this paper admitted that he made up details and the studies were deemed to be fraudulent, and data was misrepresented. In fact, many studies have confirmed that there is no link between vaccines and ASD. Vaccines do not cause ASD, but they can protect children and others from harmful diseases.
- Currently, studies have not established a direct cause-and-effect relationship between acetaminophen used during pregnancy and ASD. Please refer to the Parent Handout from Autism Speaks for more information.
Common conditions that may occur in autistic individuals
There are other conditions that may be more frequently diagnosed in autistic children and adults. These include:
- sleep problems
- feeding and nutrition problems
- constipation
- attention-deficit hyperactivity disorder (ADHD)
- anxiety
- depression
- seizures and epilepsy
When to see a health-care provider
If you are concerned about your child’s development, their social or communication skills or about specific behaviours, discuss them with your child’s health-care provider. If your think your child may be autistic, be open and direct with your child’s health-care provider. Voicing your concerns can help expedite screening and diagnosis.
More information on diagnosis is available in Autism spectrum disorder (ASD): Diagnostic criteria.
If you are waiting for a diagnostic assessment for your child, visit our page on what to do while you wait for an autism spectrum disorder (ASD) diagnostic assessment for your child.
