If you’re wondering whether your child meets the criteria for an autism diagnosis, this guide will help you understand exactly what doctors are looking for during an assessment.

Across Canada, the USA, and many other parts of the world, healthcare professionals diagnose autism using the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders). While the assessment process may vary between provinces and clinicians, the diagnostic criteria themselves are the same.

The challenge is that the DSM-5 was written for healthcare professionals, not parents.

This article explains each autism criterion in plain English, with practical examples to help you understand what doctors are looking for during an assessment.

Understanding The Four Criterion for an Autism Diagnosis

To receive an autism diagnosis, a child must meet four requirements (called the Criterion) outlined in the DSM-5. These requirements help clinicians determine whether a child’s behaviours fit the pattern of autism rather than another developmental or medical condition.

They are:

1. Persistent differences in social communication and social interaction.
2. Restricted or repetitive behaviours, interests, or sensory experiences.
3. Symptoms were present in early childhood, even if they became more noticeable later.
4. The symptoms significantly affect everyday life and aren’t better explained by another condition.

We’ll look at each of these in plain English throughout this guide. Here’s a quick overview

Criterion A: Persistent Differences in Social Communication and Social Interaction

This is the first thing clinicians evaluate during an autism assessment. To meet the DSM-5 criteria for autism, a child must show differences in all three of the areas below.

That doesn’t mean every autistic child behaves the same way. It means these differences are consistently present, even if they look different from one child to another.

1. Social-Emotional Reciprocity

What Is Social-Emotional Reciprocity?

Social-emotional reciprocity is simply the natural back-and-forth that happens during everyday interactions.

It’s how children share experiences, respond to other people, take turns in conversations or play, and enjoy connecting with others.

Doctors aren’t looking at whether your child is friendly or affectionate. They’re looking at how naturally social interactions happen.

What Does A Lack Of Social-Emotional Reciprocity Look Like?

• Rarely bringing toys or objects to show you.
• Not pointing things out just to share interest.
• Not consistently responding when someone tries to start an interaction.
• Talking at people rather than having back-and-forth conversation.
• Having difficulty taking turns during conversations or play.
• Preferring interactions to revolve around their own interests.
• Having difficulty noticing or responding when someone else is excited or upset.

What Doctors Are Looking For

During an assessment, clinicians may observe things like:

• Does your child try to share enjoyment?
• Do they bring you into their play?
• Do they respond when someone interacts with them?
• Can they participate in simple back-and-forth exchanges?
• Do they seek interaction for reasons beyond getting something they want?

2. Differences in Nonverbal Communication

What does ‘Differences in Nonverbal Communication’ mean?

Communication isn’t just about words.

From the time they’re babies, children communicate using eye contact, facial expressions, gestures, body language, and tone of voice. These nonverbal cues help us share our thoughts, understand other people’s feelings, and navigate everyday social situations.

During an autism assessment, clinicians look at how well these different forms of communication work together.

What Do Differences in Nonverbal Communication Look Like?

• Limited or inconsistent eye contact.
• Not pointing to show you something interesting.
• Rarely using gestures like waving, nodding, or shrugging.
• Difficulty understanding other people’s facial expressions.
• Facial expressions that don’t always match what’s happening.
• Speaking in a voice that’s unusually flat, sing-song, or monotone.
• Standing unusually close to other people or having difficulty understanding personal space.
• Looking at an object without looking back to see if someone else is sharing the experience.

What Doctors Are Looking For

Doctors aren’t counting how many times your child makes eye contact. They’re looking at whether different forms of communication work together naturally.

For example:

• Does your child point at an airplane and then look back at you to make sure you saw it?
• When they smile, do they naturally look at the person they’re smiling with?
• Do they use gestures to support what they’re trying to communicate?
• Can they understand what someone else’s facial expression is telling them?

They’re looking for communication that feels connected and shared, rather than isolated.

3. Differences in Developing, Maintaining, and Understanding Relationships

What Does ‘Differences in Developing, Maintaining, and Understanding Relationships’ Mean?

As children grow, their social interactions become more complex.

They learn how to make friends, join games, understand social rules, adjust their behaviour in different situations, and use their imagination during play.

Children with autism often find these skills more difficult, even if they enjoy being around other people.

What Might This Look Like?

• Preferring to play alone most of the time.
• Having difficulty joining other children in play.
• Limited or repetitive pretend play.
• Wanting to play with other children but not knowing how.
• Difficulty understanding social rules that seem to come naturally to other children.
• Struggling to understand jokes, sarcasm, or figurative language (in older children).
• Finding it difficult to make or maintain friendships.
• Playing beside other children rather than with them.

What Doctors Are Looking For

Doctors are interested in more than whether your child has friends. They’re looking at how your child understands and navigates relationships.

For example:

• Do they enjoy pretend play with others?
• Can they take on different roles during play?
• Do they notice what other children are doing and join in appropriately?
• Can they adjust their behaviour depending on who they’re with?
• Do they understand basic social expectations, like taking turns or reading another person’s reactions?

Criterion B: Restricted or Repetitive Behaviours, Interests, or Sensory Differences

The second part of the DSM-5 criteria focuses on patterns of behaviour, interests, and sensory experiences.

To meet the criteria for autism, a child must show at least two of the following four areas. Some of these behaviours are easy to recognize, while others are much more subtle. Every autistic child is different, and not every child will show the same traits.

1. Repetitive Movements, Speech, or Use of Objects

What Does Repetitive Movements, Speech, or Use of Objects Mean?

Many autistic children repeat certain movements, sounds, words, or play patterns. These behaviours are often called “repetitive behaviours” or “stimming.”

While everyone repeats certain behaviours from time to time, clinicians are looking for patterns that are persistent, frequent, or noticeably different from what’s expected for a child’s age.

What might this look like?

• Hand flapping.
• Rocking back and forth.
• Spinning in circles.
• Walking on tiptoes.
• Repeating words or phrases (echolalia).
• Repeating lines from favourite TV shows or movies.
• Lining up toys instead of playing with them.
• Spinning the wheels on toy cars rather than driving them.
• Repeatedly opening and closing doors, drawers, or lids.
• Watching objects spin or fall over and over again.

What Doctors Are Looking For

Doctors aren’t simply checking whether your child flaps their hands or repeats words. They’re looking at how your child plays, moves, and communicates.

For example:

• Are repetitive movements used regularly?
• Does your child become focused on repeating the same action?
• Do they repeat language in a meaningful way, or simply echo what they’ve heard?
• Is their play flexible, or does it follow the same pattern every time?

These behaviours can serve many purposes. Some children repeat movements because they enjoy the sensation, while others use them to regulate emotions, express excitement, or cope with stress.

2. Insistence on Sameness and Inflexible Routines

What Does Insistence On Sameness And Inflexible Routines Mean?

Most children enjoy routines. They like familiar bedtime rituals, favourite foods, and knowing what comes next.

For autistic children, however, routines often provide a sense of predictability and security. Unexpected changes, even small ones, can be genuinely upsetting because they disrupt what the child was expecting to happen.

Clinicians aren’t looking for children who simply like routines. They’re looking for behaviours that are unusually rigid or distressing when things don’t go as expected.

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What Might This Look Like?

• Becoming very upset when plans change unexpectedly.
• Wanting to follow the exact same routine every day.
• Taking the same route to school or the grocery store.
• Eating foods in a particular order.
• Insisting on using the same cup, plate, or utensils.
• Difficulty transitioning from one activity to another.
• Becoming distressed if favourite objects are moved.
• Needing things to happen in a specific sequence.
• Repeating the same rituals before bedtime or leaving the house.

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What Doctors Are Looking For

Doctors want to understand how your child responds to change.

For example:

• Can they adapt when plans change?
• How do they handle transitions between activities?
• Do small changes cause mild frustration or significant distress?
• Are routines simply preferred, or do they feel necessary?

Many children are disappointed when something doesn’t go their way. Clinicians are looking for a pattern where changes consistently lead to distress or interfere with everyday life.

An Important Note

This isn’t about being stubborn or “just liking things a certain way.” For many autistic children, routines help make the world feel more predictable. When those routines change unexpectedly, it can feel genuinely overwhelming rather than simply disappointing.

3. Highly Restricted or Intense Interests

What Does Highly Restricted Or Intense Interests Mean?

It’s perfectly normal for children to have favourite toys, TV shows, or hobbies.

Autistic children, however, often develop interests that are unusually intense, highly focused, or consume much of their attention. These interests may be very specific and can become a major source of enjoyment, comfort, and learning.

Doctors aren’t looking for children who simply love dinosaurs or trains. They’re looking at how different the interest is from what’s typical for a child of the same age.

What Might This Look Like?

• Wanting to talk about the same topic over and over again.
• Memorizing large amounts of information about a favourite subject.
• Becoming deeply interested in objects that other children don’t usually focus on, such as ceiling fans, elevators, vacuum cleaners, road signs, or washing machines.
• Playing with the same toy or activity for long periods while showing little interest in other toys.
• Becoming upset when unable to engage with a favourite interest.
• Collecting or organizing objects in very specific ways.
• Showing an unusually advanced knowledge of one topic compared to other children their age.

What Doctors Are Looking For

Doctors aren’t asking, “Does your child have a favourite interest?”

They’re asking questions like:

• Is the interest unusually intense?
• Does it dominate your child’s play or conversations?
• Is it difficult to redirect their attention?
• Does the interest interfere with other activities or social interactions?

Some autistic children have interests that change over time, while others stay passionate about the same topic for years.

An Important Note

Having a passionate interest doesn’t automatically mean a child is autistic. Many children go through phases where they love dinosaurs, princesses, or construction vehicles. What makes this criterion different is the intensity, focus, and impact of the interest, not simply the topic itself.

For some autistic children, these interests also become incredible strengths. They can lead to impressive knowledge, creativity, and lifelong passions that should be supported rather than discouraged.

4. Differences in Sensory Processing

What Does Differences In Sensory Processing Mean?

We all experience the world through our senses. We see, hear, touch, taste, smell, and notice things like movement, temperature, and pain.

Many autistic children experience these sensations differently. Some are much more sensitive than other people, while others don’t seem to notice certain sensations at all. Some children experience both, depending on the situation.

Doctors are looking for sensory differences that are persistent and have a noticeable impact on everyday life.

What Might This Look Like?

Increased sensitivity (hypersensitivity)

• Covering their ears during everyday noises.
• Becoming distressed by vacuum cleaners, hand dryers, or toilets flushing.
• Refusing certain clothing because of seams, tags, or fabrics.
• Avoiding bright lights.
• Strong reactions to certain smells.
• Eating only foods with specific textures.
• Resisting haircuts, nail trimming, or tooth brushing because they feel overwhelming.

Reduced sensitivity or sensory seeking (hyposensitivity)

• Not reacting to pain the way you would expect.
• Seeking deep pressure, tight hugs, or heavy blankets.
• Constantly spinning, jumping, climbing, or crashing into furniture.
• Watching spinning objects for long periods.
• Frequently smelling or touching objects.
• Putting non-food items in their mouth beyond the expected age.

What Doctors Are Looking For

Doctors aren’t simply asking whether your child dislikes loud noises. They’re looking at how your child experiences and responds to sensory information throughout the day.

For example:

• Do certain sounds, textures, or lights consistently cause distress?
• Does your child actively seek certain sensations?
• Do sensory differences affect eating, dressing, sleeping, or participating in everyday activities?
• Are these reactions noticeably different from what you’d expect for a child of the same age?

An Important Note

Sensory differences can affect almost every part of daily life. A child who refuses certain clothes may not be “being picky.” A child who avoids noisy birthday parties may not be shy. A child who constantly jumps, spins, or crashes into the couch may be seeking sensory input rather than simply having extra energy.

Understanding these behaviours through a sensory lens can help explain why certain situations feel much harder for some autistic children than others.

Criterion C: Symptoms Must Have Been Present During Early Development

What Does This Mean?

Autism is currently considered a neurodevelopmental condition, which means the differences associated with autism must begin early in childhood for a diagnosis, even if they aren’t recognized until much later.

Some children show signs during infancy, while others don’t become noticeably different until preschool or elementary school, when social interactions, communication, and everyday expectations become more complex.

This is why it’s possible for a child to receive an autism diagnosis later in childhood, despite having been autistic their entire life.

What Doctors Are Looking For

During the assessment, clinicians will ask about your child’s early development to understand whether autistic characteristics have been present since childhood.

They may ask questions like:

• When did your child begin smiling or making eye contact?
• Did they point to show you things that interested them?
• How did they communicate before they could talk?
• When did they begin using words or sentences?
• How did they play with toys as a toddler?
• Were there any developmental regressions or loss of skills?
• When did you first begin noticing differences?

Doctors are looking for a developmental history that supports the behaviours they’re seeing during the assessment today.

An Important Note

Not every autistic child shows obvious signs as a baby or toddler.

Some children learn to compensate for their differences, while others don’t begin struggling until social expectations become more demanding. This doesn’t mean the autism suddenly appeared. It simply means the differences became easier to recognize as your child grew and the world expected more complex communication, friendships, and independence.

Criterion D: Symptoms Must Significantly Affect Everyday Life

What Does This Mean?

To receive an autism diagnosis, it’s not enough for a child to have autistic traits. Those differences must have a meaningful impact on their everyday life.

That impact may be seen at home, at school or daycare, in friendships, or during everyday activities like getting dressed, eating meals, or transitioning between tasks.

Every autistic child is different. Some children need very little support, while others need significant support. The question isn’t how severe the autism is. It’s whether the characteristics of autism are affecting your child’s ability to function in daily life.

What Doctors Are Looking For

Doctors want to understand how your child’s differences affect their everyday experiences.

They may ask questions like:

• Does your child struggle to make or maintain friendships?
• Do communication differences make it difficult to express their needs?
• Do sensory sensitivities interfere with eating, dressing, or participating in activities?
• Does your child become extremely distressed when routines change?
• Do repetitive behaviours interfere with learning, play, or family life?
• Does your child require more support than other children of the same age?

The goal is to understand how these challenges affect your child’s daily functioning, not simply whether they exist.

An Important Note

Having one or two autistic traits doesn’t necessarily mean a child is autistic. Many children dislike loud noises, have favourite routines, or develop strong interests. An autism diagnosis is based on the overall pattern of behaviours and whether those differences have a meaningful impact on everyday life.

Could Another Condition Better Explain These Differences?

How Doctors Rule Out Other Conditions

When doctors assess a child for autism, they also consider whether another condition could better explain the behaviours they’re seeing.

Some conditions share characteristics with autism, including language disorders, hearing loss, intellectual disabilities, ADHD, and anxiety. It’s also possible for a child to have autism and one or more of these conditions.

Rather than focusing on a single behaviour, clinicians look at your child’s overall developmental history, communication, social interaction, behaviour, and strengths to determine which diagnosis, or combination of diagnoses, best explains what they’re observing.

What Happens During an Autism Assessment?

By the time your child attends an autism assessment, the clinician has likely already reviewed questionnaires or referral information. The assessment itself is about understanding how your child communicates, interacts, plays, behaves, and experiences the world.

Rather than checking off a list of behaviours, clinicians look for patterns that fit the DSM-5 criteria. Every assessment is a little different, but most include some combination of the following.

Talking With Parents

Parents play an important role in the assessment. You’ll likely be asked questions about your child’s early development, communication, social interactions, play, behaviour, sensory differences, and everyday routines.

Some of the questions may seem unrelated, but each one helps build a picture of your child’s development over time.

Observing Your Child

Much of the assessment involves simply watching your child interact. Depending on their age, the clinician may play games, read books together, offer different toys, or create situations that encourage communication and social interaction.

They aren’t testing whether your child is “good” or “bad.” They’re observing how your child naturally communicates, responds, and engages with other people.

Looking for Patterns

One behaviour on its own rarely tells the whole story. For example, a child who dislikes loud noises isn’t automatically autistic. Neither is a child who loves dinosaurs or repeats phrases from their favourite TV show.

Instead, clinicians look at the overall pattern.

Do the social communication differences and repetitive behaviours fit together in a way that meets the DSM-5 criteria? Have these differences been present since early childhood? Do they affect everyday life? It’s the combination of these factors, not a single behaviour, that leads to an autism diagnosis.

An Important Note

Many parents leave an assessment surprised by some of the questions they were asked. That’s because clinicians aren’t just interested in what your child can do. They’re interested in how your child communicates, plays, solves problems, adapts to change, and connects with other people.

The goal isn’t to catch your child doing something “wrong.” It’s to better understand how they experience the world so the right supports can be recommended.

FAQ About the DSM-5 criteria

Final Thoughts

If you’ve made it this far, you probably know much more about the autism assessment process than you did when you started.

The DSM-5 isn’t meant to be a mystery. It’s simply a framework that helps clinicians consistently identify autism based on a child’s communication, behaviour, development, and everyday functioning.

Whether your child ultimately receives an autism diagnosis or not, understanding the criteria can help you walk into the assessment feeling more prepared and confident. You’ll have a better idea of the questions being asked, the behaviours being observed, and how doctors bring all of those pieces together to understand your child.

And remember, an assessment isn’t about finding reasons why your child is different. It’s about understanding how they experience the world so they can receive the support they need to thrive.

Wondering what to do next? You can read the complete guide – What To Do After An Autism Diagnosis – to learn more.

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