What is Autism?

Autism Spectrum Disorder (ASD), commonly known as autism, refers to a broad range of conditions characterized by difficulties with social skills, repetitive behaviours, speech and nonverbal communication. Signs and characteristics of ASD typically appear within the first three years of life; however, it can also be first diagnosed in adulthood. ASD affects individuals differently and to varying degrees.

There is no known single cause for autism but there are observed differences in the autistic brain. Early, evidence-based interventions can improve an individual’s prognosis over the course of their life.

ASD is a lifespan neurodiversity that needs to be understood, accepted, and accommodated for in the social and physical environment.

Brief History of the Autism Diagnosis

The term ‘autism’ was first used by Swiss psychiatrist Eugen Bleuler in 1908, which drew from the Greek word ‘autós’ meaning ‘self’. In 1943, Austrian-Amercian psychiatrist Leo Kanner of the Johns Hopkins University published a study on a group of 11 children and introduced the label ‘infantile autism’ into the English language. This label described a set of behaviours that he observed among these young children. In 1944, Austrian physician, Hans Asperger, described autism-like behaviours among children that he observed. He termed this ‘autistic psychopathy’, which was later changed to ‘Asperger’s syndrome’.

The Diagnostic and Statistical Manual Second Edition (DSM-2, 1952) defined autism as a psychiatric condition – a form of childhood schizophrenia. When this theory was refuted, the DSM-3 (1980) established autism as a separate diagnosis under the term ‘pervasive developmental disorder’, which was revised to include a mild end of the spectrum in 1987 (DSM-3-TR). The release of the DSM-4 (1994) and DSM-4-TR (2000) categorized autism as a spectrum containing five distinct conditions including ‘autism’, ‘pervasive developmental disorder’, ‘pervasive developmental disorder not otherwise specified’, ‘Asperger’s disorder’ and ‘childhood disintegrative disorder’.

Today, most of these labels are no longer listed in the DSM-5-TR (2013) but are described within the term ‘Autism Spectrum Disorder’. In the DSM-5-TR, ASD is characterized by varying degrees of impairment in communication skills, social interactions, and restricted, repetitive and stereotyped patterns of behavior. There are three levels of ASD described: Level 1 – requires support; Level 2 – requires substantial support and Level 3 – requires very substantial support.

For a deeper dive into the levels of ASD visit: https://www.youtube.com/watch?v=DYf6-lEh2fI

Prevalence in Children

The World Health Organization estimates that 1 in 100 children are autistic, globally. The Centers for Disease Control and Prevention (CDC) estimates that 1 in 44 children has been identified with ASD. Autism is now more common in the pediatric population than diabetes, spinal bifida, or Down’s syndrome.

Parents are usually the first to notice autism in their child. In some cases, parents notice their babies are unresponsive to people or focusing intently on one item for long periods of time. The first signs of autism can also appear in children who seem to be otherwise developing ‘normally’ (neurotypically). This may be observed when an engaging, babbling toddler suddenly becomes silent, withdrawn, self-abusive or indifferent to social overtures. Any significant changes in behaviour must be investigated, and research shows that parents are usually correct about noticing developmental problems, although they may not know the specific nature or degree of the problem.

Early Warning Signs

Social communication and social interaction characteristics related to ASD can include:

  • Avoidance or fleeting eye contact
  • Unresponsiveness to name by 9 months
  • Lack of facial expressions such as, happiness, sadness, anger, and surprise by 9 months
  • Lack of play in interactive games like, peek-a-boo by 12 months
  • Few or no social gestures such as, waving by 12 months
  • No shared interests with others by 15 months (Example: showing an object they like)
  • No pointing to show something interesting by 18 months
  • Does not seem to notice when others are hurt or upset by 24 months
  • Does not seem to notice other children and join them in play by 36 months
  • Does not pretend to be someone else by 48 months (Example: a teacher or superhero)

Restricted or repetitive behaviours and interests related to ASD can include:

  • Lining up toys or objects and becoming upset when the order changes
  • Repeating words or phrases over and over (Echolalia)
  • Playing with toys the same way every time
  • Focusing on parts of objects (Example: wheels)
  • Upset by minor changes
  • Strong interests that appear obsessive
  • Needing to follow a certain routine
  • Flapping hands, rocking body, or spinning in circles
  • Unusual reactions to sounds, smells, tastes and the way things look or feel

Other related characteristics can include:

  • Delayed language skills
  • Delayed movement skills
  • Delayed cognitive or learning skills
  • Hyperactivity, impulsivity, and/or inattentive behavior
  • Epileptic or seizure disorder
  • Unusual eating and sleeping habits
  • Gastrointestinal issues (Example: constipation or sensitivity)
  • Unusual mood or emotional reactions
  • Appearance of anxiety, stress, or excessive worry
  • Lacking fear or more fear than expected for a situation

Presenting Challenges

Social interaction:

Many autistics seem to have tremendous difficulty engaging in the give-and-take of everyday human interaction. In the first few months of life and into adulthood, many do not interact typically and may avoid eye contact. To other people, autistics may appear indifferent and may seem to prefer being alone. This might look like resistance to receiving attention or passively accepting hugs and cuddling. Research suggests that although autistic individuals are attached to their parents, friends and family, their expression of this attachment can be atypical and difficult to read for someone who is neurotypical.

Autistics may have difficulty learning to interpret what others are thinking and feeling. Subtle social cues – a smile, a wink, or a frown – may be challenging to process and interpret accurately. For example, “Come here!” might mean the same thing, whether the speaker is smiling and extending arms for a hug or frowning with fists on hips. The social world can seem bewildering for someone struggling to interpret gestures and facial expressions at a fast pace. This also affects an autistic person’s ability to predict or understand other people’s actions.


Although spoken language is a cornerstone of neurotypical communication, some people with autism do not speak throughout their lives. Some infants who later show signs of autism might coo and babble during the first few months of life, but this might eventually cease. Autistics who are non-verbal can learn to use augmentative and alternative communication systems such as pictures, sign language and speech-generating devices.

People on the spectrum who develop speech, may still experience delays with spoken language in childhood. Additionally, autistics may continue to have difficulty combining words into sentences. Some might speak using single words, while others may repeat the same phrase over and over (echolalia). Autistic people are also known to have precocious language and unusually large vocabularies but have great difficulty in sustaining a conversation.

Other difficulties can occur in understanding body language, tone of voice or phrases of speech. For example, “it is raining cats and dogs” might be interpreted literally rather than figuratively.

Communication can be difficult for autistic people and their tone of voice may fail to reflect felt emotions. Without appropriate gestures or the language to ask for things, autistics are at a loss to let others know what they need. This can lead to behavioural responses such as, screaming or grabbing what they want. Autistic people benefit from being taught meaningful ways to express their needs so they can become more independent and understood.


Although people on the spectrum usually appear physically typical, repetitive and/or odd motions may set them apart from others. These behaviours might be highly apparent or more subtle. Some children and older individuals on the spectrum might repeatedly flap their arms or walk on their toes. Some might suddenly freeze in position.

Autistics might spend hours lining up their toy cars and trains in a certain way, rather than using them for pretend play. Accidentally moving one of the toys might trigger tremendous, upset feelings. Autistics strongly benefit from consistency in their environment, as changes in any routine—mealtime, dressing, taking a bath, going to school at a certain time and by the same route—can be disturbing. Perhaps order and sameness lends some stability in a world of confusion. Autistic individuals must be prepared for change.

Autistics might hold strong interests such as, learning all about vacuum cleaners, train schedules, comic book characters, or even numbers, symbols and science topics.

Although not universal, people with autism can have difficulty regulating their emotions. This can take the form of behaviors such as crying or verbal/physical outbursts that appear inappropriate to those around them. Autistics might also appear disruptive and respond with aggression if they are in a strange or overwhelming environment. This can include hurting themselves or potentially harming others in moments of frustration.

Some Conditions that may accompany Autism

Sensory processing disorder:

People learn from what they see, feel or hear. If there is difficulty with processing and integrating sensory input, a person’s experience of the world can be confusing, and learning can be challenging. Additionally, there may be challenges with movement and balance.

Many people with autism are highly attuned or even painfully sensitive to certain sounds, textures, tastes and smells. Some autistics may find the feel of clothing almost unbearable. For some, sounds of a vacuum cleaner, a lawn mower, a ringing telephone, a sudden storm or even the sound of waves lapping the shoreline, may cause a strong disturbance. On the other hand, some autistics may appear oblivious to sensory input such as, pain. For example, an autistic child may be injured, yet never cry.

It is useful to explore sensory processing in a person with autism to better support their needs.


These may be present in people with autism. Examples can include skin conditions, asthma, food allergies, ear infections, gastro-intestinal issues, epilepsy and mental health conditions.


Some of the information on this page is reproduced from a range of fact sheets and online articles available at www.autism-help.org, http://www.nimh.nih.gov/health/publications/autism/complete-index.shtml , www.autism-society.org, https://www.cdc.gov/ncbddd/autism/signs.htm, https://www.spectrumnews.org/news/evolution-autism-diagnosis-explained/ and others.