Definition of Autism - Autism Awareness

Definition of Autism

Autism is a lifelong, nonprogressive neurological disorder typically appearing before the age of three years. The word “autism” means a developmental disability significantly affecting verbal and non-verbal communication and social interaction.

The classic form of autism involves a triad of impairments – in social interaction, in communication and the use of language, and in limited imagination as reflected in restricted, repetitive and stereotyped patterns of behavior and activities. It was in 1943 that Leo Kanner, a psychiatrist at Johns Hopkins University, created the diagnosis of autism.

Autism is a spectrum disorder. The symptoms and characteristics of autism can present themselves in a wide variety of combinations, from mild to severe. Although autism is defined by a certain set of behaviors, children and adults can exhibit any combination of the behaviors in any degree of severity. Two children, both with the same diagnosis, can act very differently from one another and have varying skills.

DSM-V Autism Diagnostic Criteria (2013)

A. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history (examples are illustrative, not exhaustive, see text):

-Deficits in social-emotional reciprocity, ranging, for example, from abnormal social approach and failure of normal back-and-forth conversation; to reduced sharing of interests, emotions, or affect; to failure to initiate or respond to social interactions.
-Deficits in nonverbal communicative behaviors used for social interaction, ranging, for example, from poorly integrated verbal and nonverbal communication; to abnormalities in eye contact and body language or deficits in understanding and use of gestures; to a total lack of facial expressions and nonverbal communication.
-Deficits in developing, maintaining, and understanding relationships, ranging, for example, from difficulties adjusting behavior to suit various social contexts; to difficulties in  sharing imaginative play or in making friends; to absence of interest in peers.

B. Restricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the following, currently or by history (examples are illustrative, not exhaustive; see text):

-Stereotyped or repetitive motor movements, use of objects, or speech (e.g., simple motor stereotypies, lining up toys or flipping objects, echolalia, idiosyncratic phrases).
-Insistence on sameness, inflexible adherence to routines, or ritualized patterns or verbal nonverbal behavior (e.g., extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, need to take same route or eat food every day).
-Highly restricted, fixated interests that are abnormal in intensity or focus (e.g, strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interest).
-Hyper- or hyporeactivity to sensory input or unusual interests in sensory aspects of the environment (e.g., apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement).

Specify current severity: Severity is based on social communication impairments and restricted, repetitive patterns of behavior. (See below.)

C. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities or may be masked by learned strategies in later life).

D. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning.

E. These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level.

Note: Individuals with a well-established DSM-IV diagnosis of autistic disorder, Asperger’s disorder, or pervasive developmental disorder not otherwise specified should be given the diagnosis of autism spectrum disorder. Individuals who have marked deficits in social communication, but whose symptoms do not otherwise meet criteria for autism spectrum disorder, should be evaluated for social (pragmatic) communication disorder.

Specify if:

-With or without accompanying intellectual impairment
-With or without accompanying language impairment(Coding note: Use additional code to identify the associated medical or genetic condition.)
-Associated with another neurodevelopmental, mental, or behavioral disorder(Coding note: Use additional code[s] to identify the associated neurodevelopmental, mental, or behavioral disorder[s].)
-With catatonia
-Associated with a known medical or genetic condition or environmental factor

Severity levels for autism spectrum disorder

Level 3 – “Requiring very substantial support”

Social Communication – Severe deficits in verbal and nonverbal social communication skills cause severe impairments in functioning, very limited initiation of social interactions, and minimal response to social overtures from others. For example, a person with few words of intelligible speech who rarely initiates interaction and, when he or she does, makes unusual approaches to meet needs only and responds to only very direct social approaches

Restricted, Repetitive Behaviors – Inflexibility of behavior, extreme difficulty coping with change, or other restricted/repetitive behaviors markedly interfere with functioning in all spheres. Great distress/difficulty changing focus or action.

Level 2 – “Requiring substantial support”

Social Communication – Marked deficits in verbal and nonverbal social communication skills; social impairments apparent even with supports in place; limited initiation of social interactions; and reduced or  abnormal responses to social overtures from others. For example, a person who speaks simple sentences, whose interaction is limited  to narrow special interests, and how has markedly odd nonverbal communication.

Restricted, Repetitive Behaviors – Inflexibility of behavior, difficulty coping with change, or other restricted/repetitive behaviors appear frequently enough to be obvious to the casual observer and interfere with functioning in  a variety of contexts. Distress and/or difficulty changing focus or action.

Level 1 – “Requiring support”

Social Communication -Without supports in place, deficits in social communication cause noticeable impairments. Difficulty initiating social interactions, and clear examples of atypical or unsuccessful response to social overtures of others. May appear to have decreased interest in social interactions. For example, a person who is able to speak in full sentences and engages in communication but whose to- and-fro conversation with others fails, and whose attempts to make friends are odd and typically unsuccessful.

Restricted, Repetitive Behaviors – Inflexibility of behavior causes significant interference with functioning in one or more contexts. Difficulty switching between activities. Problems with organization and planning.

According to the 2018 National Autism Spectrum Disorder Surveillance System (NASS) Report, autism now effects at least 1 in every 66 Canadian children. This includes 1 in 42 boys and 1 in 189 girls. An estimated 50,000 teens with autism become adults – and lose school-based autism services – each year.

Causes of Autism

There is no known single cause for autism, but it is generally accepted that it is caused by abnormalities in brain structure or function. Brain scans show differences in the shape and structure of the brain in autistic versus non-autistic children. Researchers are investigating a number of theories, including the link between heredity, genetics and medical problems. In many families, there appears to be a pattern of autism or related disabilities, further supporting a genetic basis to the disorder. While no one gene has been identified as causing autism, researchers are searching for irregular segments of genetic code that autistic children may have inherited. It also appears that some children are born with a susceptibility to autism, but researchers have not yet identified a single “trigger” that causes autism to develop.

Other researchers are investigating the possibility that under certain conditions, a cluster of unstable genes may interfere with brain development resulting in autism. Still other researchers are investigating problems during pregnancy or delivery as well as environmental factors such as viral infections, metabolic imbalances, and exposure to environmental chemicals.

Autism tends to occur more frequently than expected among individuals who have certain medical conditions, including Fragile X syndrome, tuberous sclerosis, congenital rubella syndrome, and untreated phenylketonuria (PKU).


Children with ASD develop differently from other children. Children without ASDs develop at about the same rate in areas of development such as motor, language, cognitive, and social skills. Children with ASDs develop at different rates in different areas of growth. They might have large delays in language, social, and cognitive skills, while their motor skills might be about the same as other children their age. They might be very good at things like putting puzzles together or solving computer problems, but not very good at some things most people think are easy, like talking or making friends.

Children with ASD might also learn a hard skill before they learn an easy one. For example, a child might be able to read long words, but not be able to tell you what sound a “b” makes. A child might also learn a skill and then lose it. For example, a child may be able to say many words, but later stop talking altogether.

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  1. Karen says:

    Hello I was reading about your article and I am learning a lot, my nephew has Autism but, we do not exactly how help him to communicate with him, he ca not walk alone, he can not speak anything, hi is 4 years all, I will appreciate your comment.

  2. Maya says:

    Can an autistic child move between levels!? We were told our child is level 1 when diagnosed at age of one year and a half. But at age 4 we were told he is level 1 to 2. He has lots of words and can say simple sentences, counts to 200, knows all letters, shapes, body parts, animals but not very conversational. At the same time he also does not have narrow interest and he is flexible with changes and not so fixated. Our developmental pediatrician said he is smart and something will click where his speech will improve (we have been doing SLP since he was one year) 
    Many thanks in advance 

  3. Dr.Qasim Khan says:

    What is the management of autism

    • Dr. Khan, the big question is how do we support an autistic person to help them thrive. You would have to narrow your question down for me because this topic is huge and cannot be answered in a simple way. You want to look at best practices and what each individual needs as the needs and learning styles will vary. There is no “one” way to support an autistic person. I have two adults on the spectrum and each one requires different support because they are individuals with their own preferences, interests and way of doing things.

  4. Mike Lethby says:

    I’ve just seen this article about autism, and am wondering whether I should be assessed to determine if this is in my makeup?
    It may be too late in life to make a difference, and has never been discussed or even, as far as I know, thought about, but it could be. So I thought I should ask the question.
    I’m a 65 year old British male, quite well educated at grammar school, and had been brought up to love reading, and learned to write well by about 8 years old.
    I have had a life long struggle with myself, with a tough mixture of body dysmorphia, very poor memory and a level of shyness so acute that as a child I found it immensely difficult to make friends. I had no conversation with any female apart from my sister, mother and other family members and teachers until I was 19, when I met a young woman on an overland trip from England to India in 1976 after leaving a boys-only grammar school.
    My mental capacity is a little unusual. A reasonable writer and creative person, but always plagued by having the memory of a colander, and with a shyness so acute that I couldn’t face meeting my then wife-to-be’s family when she first took me to Wales to meet them. Shyness that was only reluctantly overcome to work as a journalist and interview strangers.
    Looking at your article, these caught my eye: “Without supports in place, deficits in social communication cause noticeable impairments. Difficulty initiating social interactions, and clear examples of atypical or unsuccessful response to social overtures of others. May appear to have decreased interest in social interactions. For example, a person who is able to speak in full sentences and engages in communication but whose to- and-fro conversation with others fails, and whose attempts to make friends are odd and typically unsuccessful.” Those definitely describe me.
    You go on [in part]: “Difficulty switching between activities. Problems with organization and planning.” This is partly true, in that I am capable of being organised and am willing to learn the tools needed: I used to be known as “Mr Spreadsheet” when as a magazine editor I was involved organising and budgeting trade show events such as press conferences.
    So essentially I’m at a crossroads, stuck in a place that I can’t escape from, and with the prospect of very little future. Yet with a brain that still has cognitive function and would be wasted if I can’t deal with whatever is holding me back.
    Any thoughts very welcome!
    Kind regards

  5. Kara Joanna says:

    Hi, our baby is almost 2 and he is talkative but the words are understandable. He has fine motor skills he learned to walk at aal very young age. My only worry is that when I call out his name he doesn’t look or respond and when I am trying to ask him do something he takes longer to do it sometimes he doesn’t do anything at all. Should I be worried?

    • Kara, I want you to have a look at our newest article on autism in young children – Here is one of the key takeaways – If your child just has one or two of these symptoms and is developing normally, chances are they do not have autism; however, there may still be challenges present such as a speech delay or sensory issues. These can be addressed with the appropriate professional who can help your child.

      It is so hard for me to comment when I have not seen your son as I may notice something different from what you do. If you have concerns on his development, please talk to your doctor. One thing you could be describing is problems with receptive language (understanding what is being said). A speech pathologist would have to do an assessment to determine if there is something to be concerned about.

  6. Sirisha says:

    Hi , my kid 6 years, she is unable to walk, bcoz she has cp problem, but she has speaking, listening , eye contact ,all are good, but she is not writing ..she is not concentrate the writing plz help me and give
    suggestion for this issue..
    Thank you ..

  7. Shanice says:

    Thank you I have a 3 year old son he does not talk  and I was worried why until I see this 

    • Shanice, if you son is 3 and not talking he needs to be assessed right away. You can start with getting a referral to see a speech language pathologist (SLP) who can assess your son’s needs. You can also visit the Hanen Centre’s website which is one of the best sites to learn more about supporting a child’s communication needs –

  8. Amanuel matewos says:

    i was with an assignment and I found ur work so great! thank u1

  9. Omilaja Adekunle says:

    Very educative

  10. Rowayda says:

    I loved the infomation provided. My best friend has a daughter with autism and I wanted more information to understand her better to explain to my kids.She is such a doll and I really enjoy time with her.

  11. Hijab zahra says:

    Much needed information.

  12. Linda twinamasiko says:

    Thanks for the information I always wanted to know why am like this why am l different from the others ..I have all the signs of autism….thanks

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