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Diagnosing Autism

Diagnosing Autism

Published: Sep. 7, 2022Updated: Apr. 17, 2024

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Autism (also referred to as autism spectrum disorder, or ASD) is a developmental disability that can cause delays or deficits in social-emotional skills and communication. How autism presents in each person is different, which is why autism is considered to be a “spectrum.” You can read about this and much more in our article Autism 101. Here, we’ll cover who can diagnose autism, the diagnostic tools they may use, and the pros and cons of seeking a diagnosis for your child.

For insights, we sat down with Dr. Hitha Amin, neurodevelopmental neurologist at Children’s Hospital Orange County, Dr. Emily Haranin, child and adolescent psychologist at Children’s Hospital Los Angeles and clinical assistant professor of pediatrics at Keck School of Medicine at USC, and Dr. Stephen Kanne, a clinical pediatric neuropsychologist and director of New York-Presbyterian’s Center for Autism and the Developing Brain.

Diagnosis under the new DSM-5

Note to our readers: In this article, we explore autism as a medical diagnosis, which is distinct from qualifying for an IEP through assessment for autism at school. To learn more about school assessments for autism, read our article Getting a Child with Autism the School Supports They Need. To read about IEPs, check out our article What is an IEP?

Autism as a spectrum

The latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published in 2013, made some big changes to the way autism is defined and diagnosed. Autism is now recognized as being a spectrum: not one condition but a “collection of related neurological conditions.” The DSM-5 has folded autism, Asperger syndrome, pervasive developmental disorder-not otherwise specified (PDD-NOS), and childhood disintegrative disorder into the single label of autism spectrum disorder (ASD). The DSM-5 also added a new condition called social communication disorder (SCD), which can be diagnosed in those who do not meet the criteria for autism (for example, the presence of social deficits but no repetitive behaviors that previously might have been diagnosed as Asperger syndrome or PDD-NOS).

The intention behind the changes is to allow for a more “individualized, dimensional approach” to diagnosing autism.

Sensory processing

Another change in the DSM-5’s diagnostic criteria for autism was the addition of sensory-related symptoms: “Hyper- or hypo-reactivity to sensory input or unusual interest 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).”

Differences in girls

The latest DSM-5 criteria for a diagnosis of autism also includes this specifier, which may help girls with autism: “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).” This one line can help older girls who may be told, “If you had autism, you would have been diagnosed by now.” It also identifies the use of masking, which is more common in girls with autism than boys with autism. Read more in our article Autism in Girls.

What are the DSM-5 criteria for autism?

The DSM-5 criteria for autism consist of two main categories (A and B), three separate criteria (C–E), and a measure of symptom intensity and needed support (levels 1–3). Here’s a brief overview:

  • Category A: Persistent deficits in social communication and social interaction (deficits in reciprocity, nonverbal communication such as body language and eye contact, and forming relationships)
    • Having all three meets the diagnostic criteria.
  • Category B: Restricted, repetitive patterns of behavior, interests, or activities (stimming, inflexibility to change, fixated interests, or hyper/hypo-sensitivity to sensory input)
    • Having two out of four meets the diagnostic criteria.
  • Criterion C: Symptoms must be present since childhood.
  • Criterion D: Symptoms cause clinically significant impairment in social, occupational, or other important areas of function.
  • Criterion E: Symptoms are not better explained by an intellectual disability.
  • Model of support levels/needs:
    • Level 1: requires support
    • Level 2: requires substantial support
    • Level 3: requires very substantial support

For a thorough and thoughtful breakdown of the autism criteria, check out Embrace Autism’s Decoding autism in the DSM-5.

How is a child evaluated for the signs and symptoms of autism?

Screening questionnaires

In order to identify if a child has developmental delays, providers will often use screening questionnaires. In fact, pediatricians use screening questionnaires during routine check-ups in order to identify early signs of a disorder. These can evaluate for a specific disorder or assess more broadly, identifying factors such as motor and language skills. When it comes to screening questionnaires that assess for autism, you may see either type of screening.

While questionnaires may seem one-dimensional or impersonal, Dr. Amin reminds us that parent input on the challenges their child is experiencing — “whether there is difficulty with the social communication aspect, any difficulty with repetitive, restricted interests, or repetitive behaviors” — is invaluable.

For examples of various screening questionnaires that a provider may use, you can check out the CDC’s website for a detailed breakdown. Some clinics, such as the Boone Fetter Clinic at Children’s Hospital of Los Angeles, may also offer virtual autism assessments.

Dr. Kanne tells us that the gold standard screening tool for children up to age three is the Modified Checklist for Autism in Toddlers (M-CHAT). However, he notes that in order for this tool to be effective, it must be accompanied by a follow-up interview to get insight into each individual child.

He also cautions that age matters when considering which screening tool is appropriate. Screeners such as the Social Communication Questionnaire may be used for older children around age four. But, he says, there is a gap between three and four years old where there isn’t really a great screener to use. There is the Social Responsiveness Scale for preschoolers (SRS), but many of the psychometrics are still being developed.

So, what makes a quality screening questionnaire? Listen to Dr. Kanne’s explanation in this clip:

Another diagnostic tool, the Autism Diagnostic Observation Schedule, or the ADOS-2, created by Catherine Lord, PhD, is play-based and consists of four modules that accommodate a range of children of different developmental and language levels. During an ADOS assessment, the specialist interacts directly with the child in social and play activities to observe how they play, interact socially, and communicate. The ADOS is unique in that it isn’t based on developmental data and only looks at current behaviors and skills that may be characteristic of autism.

A more recent tool is the Monotropism Questionnaire, which looks at the tendency to hyper-focus on special interests and tasks. Monotropism is a common trait among individuals with autism and ADHD, although the authors of the questionnaire did not design it to diagnose autism.

A note about screenings

Screening tools and questionnaires cannot be used alone to determine a diagnosis. In fact, many professionals in the field acknowledge that there are weaknesses within screening and diagnosis processes for autism. It is widely acknowledged that no tool should be used on its own to make a diagnosis. There are several reasons for this.

First, the way the examiner interacts with the child can bias the results, and the examiner will get second-hand observations from the caregiver based on their memory and understanding. Second, many social-communication skills and repetitive behaviors do not emerge until later in a child’s developmental process; some behaviors may be normal during infancy but become concerning only if they persist past that age.

If a child shows signs in their screening that a condition like autism might be present, the provider should recommend that the child sees a specialist who can make a diagnosis.

Dr. Kanne cautions that sometimes a physician may detect a positive screening for a disorder and then neglect to refer a patient to a specialist. If your pediatrician does a screening and a potential disorder is detected, you should not wait for a referral — ask about seeing a specialist for further testing right away.

Cognitive testing

The evaluation process may also include neuropsychological or cognitive testing, which includes thinking, memory, attention, executive function, organizational skills, problem solving, social cognition, as well as a child’s strengths and weaknesses in learning and communicating.

In any screening, it’s important to remember that every child is unique, with their own strengths, traits, and needs. As Dr. Haranin explains, following diagnostic criteria like those in the DSM-5 can appear like “trying to put human beings in little boxes.” She says, “It's always really important, when we’re thinking about diagnoses, that we recognize that while it can be helpful to describe patterns we see in children that are similar to patterns we see in a group of children or a group of adults, ultimately, kids or adults are never going to fit perfectly into those boxes. And so our job as mental health professionals is to try to identify which boxes best fit and best capture what a child is presenting with at any given time because that can help us make recommendations about treatment or intervention that might be helpful.”

Research is still ongoing. For example, eye-tracking tools are sometimes used to diagnose autism in children as young as 16 months old, but eye gaze tests may actually reflect alexithymia, a condition that appears to be common in individuals with autism.

Who can diagnose autism?

While your pediatrician may provide a screening for autism and/or other disorders, a referral to a specialist such as a clinical child psychologist, developmental psychologist, neurologist, neuropsychologist, or developmental pediatrician should be made if a screening shows that a disorder may be present.

A comprehensive evaluation should use multiple screening and diagnostic tools to consider all behavioral, social, and environmental factors, and it should be specific to your child’s needs. For example, Dr. Amin says that some children “may need a more extensive evaluation, which might include having a speech therapist and an occupational therapist as part of the assessment,” while others “may need an assessment just from the psychologist and the neurologist together.”

Note that speech therapists, occupational therapists, physical therapists, social workers, school professionals, and others may contribute to the evaluation for the diagnosis, but they are not qualified to provide a holistic diagnosis.

Regional Centers

Regional Centers in California are able to provide assessments and a diagnosis for autism. They work with vendored and contracted providers who are qualified to provide these services.

Autism clinics

One advantage of pursuing a diagnosis at an autism center is that these clinics often employ speech therapists, occupational therapists, psychologists, neurologists, and other providers on their clinical team, all of whom specialize in autism. These specialists typically have weekly case meetings to communicate about their patients, which means that your child’s care team can stay informed about nearly every aspect of their care.

Because autism centers act as a “one-stop shop” for autism diagnosis and treatment, appointments with them are often highly coveted, leading to long waitlists. Dr. Kanne recommends that if your child is showing symptoms of developmental delays while you are on the waitlist for an autism center, you should not wait to pursue the appropriate evaluations and treatments elsewhere. For example, if your child is showing signs of speech or language delays, you should see a speech therapist for an evaluation. Any outside evaluations you receive will be considered by autism centers when they are making their diagnosis.

Dr. Amin assures us that if you can’t access an autism center, you can still get the same quality of care elsewhere, it just might take a bit more work to identify the right providers in your community.


Schools are qualified to assess whether a student meets the qualifying criteria for eligibility for special education services. However, schools are not permitted to medically diagnose a child. For more information on assessment for special education in school, read our article Getting a Child with Autism the School Supports They Need.

Downloadable guide to parenting a child with autism

When should families pursue a diagnosis?

Children are typically diagnosed with autism between the ages of two-and-a half and six years old. While most children are diagnosed around three years of age, they can be diagnosed as early as one year old. However, diagnoses are more reliable if given after a child is fourteen months of age. Dr. Amin adds that if parents have concerns such as expecting more social behavior around the 18-month mark, the pediatrician may pick up on this in the MCHAT and refer the child to a specialist.

It is more common for a diagnosis to be missed than for it to be overturned as a child ages. However, if a child is showing fewer symptoms or their symptoms are less pervasive, a child may not be diagnosed with autism until they are older. Caregiver input can help prevent a missed diagnosis because a child’s immediate caregivers may notice signs of autism within their routine and daily behavior that other people in the child’s life (such as teachers) may miss.

What are the pros and cons of pursuing a diagnosis?

The most important reason to pursue a diagnosis is that it can unlock services that may otherwise not be available; studies show that only about half of children with autism access therapies before age 3. However, while a diagnosis can open doors to the critical services a child needs — particularly when it comes to funding sources — parents should keep in mind that getting their child the services they need is the first priority. This is especially critical during the first few years of life. Early intervention services such as speech therapy and occupational and physical therapies support young children during a critical neurodevelopmental period when they can make great gains. You can hear why Kathryn Smith (RN, MN, DrPH, associate director for policy at UCEDD and nurse care manager at the Boone Fetter Clinic at CHLA) feels it can sometimes be more important to emphasize services over getting a diagnosis in our article The 4 Ws of Early Intervention: WHEN Should You Start Evaluations and Therapies?

Many providers note that if a child comes in with an existing autism or developmental delay diagnosis, they are more easily able to provide the appropriate interventions. While most providers see an autism diagnosis as a “descriptive” part of connecting a child to the interventions they need, it is widely acknowledged that a more holistic view is necessary, including psychological and social factors alongside the diagnosis when useful.

Here’s one perspective from Undivided parent Michelle:

“A diagnosis is just a pathway to services. It gives you more information, access, and different resources through your insurance, Regional Center, local support groups, and your child’s school. I think a lot of people tend to forget that no matter what diagnosis your kid gets, it's still the same child [you had] before the diagnosis.”
Michelle also shares why it can be important to be prudent about who you share your child’s diagnosis with:

Why are screening, early detection, and early intervention important?

Naturally, the earlier your child can be screened for autism, the earlier a care plan can be established to help your child meet their full potential. Early detection can allow for early interventions even prior to when a formal diagnosis is received.

Early interventions are typically pursued prior to a child entering schooling. This is a critical age in a child’s neurodevelopment, which is why these interventions often have positive outcomes in helping a child develop appropriate social, behavioral, communication, and language skills.

What’s most important is that your child is able to receive the services and interventions they need. This means establishing a care team with professionals such as developmental-behavioral pediatricians, speech therapists, occupational therapists, and other providers who can help identify your child’s specific needs.

What about diagnosing co-occurring conditions?

Data shows that co-occurring conditions are much more prevalent in children with autism than in the general population, with research from the CDC showing that 95% of autistic children have at least one co-occurring condition in addition to autism, with more than half having four or more conditions.

To learn more, check out our article Autism and Co-Occurring Conditions.

What can parents do if they feel their child is being missed or misdiagnosed?

Parents know their children better than anyone, and they have the ability to observe their child in their daily environment. As Dr. Kanne says in this clip, if you are observing unusual behaviors in your child, trust your gut!

Studies have shown that misdiagnosis can occur if there is difficulty distinguishing between autism and other conditions, such as ADHD. There are also significant racial, ethnic, and gender disparities in autism diagnoses. If you’re having concerns, make sure you voice them at the start of your visit with your pediatrician. Be ready to share as much information about what you’ve observed in confident, succinct phrases. The Connecticut Health Foundation has a great guide written by a developmental-behavioral pediatrician on how to talk to your child’s doctor about your concerns.

Talking to your child about their diagnosis

Something else to consider is how to talk with your child about their diagnosis. You might feel that telling them about their diagnosis will cause them to feel different or open doors to bullying or stigma. Some parents tell their children early on as soon as the child starts to feel different or ask questions; others wait until the child is older and will understand the diagnosis better. But research shows that “telling a child that they are autistic at a younger age empowers them by providing access to support and a foundation for self-understanding that helps them thrive in adulthood.”

Of course, how and when to tell your child is a personal choice and will depend on your child’s ability to understand the diagnosis, age, and emotional maturity. Here are a few tips on sharing the news:

  • Be mindful of your child’s ability to process information and speak to them at their level.
  • Speak positively and choose a moment where you and your child are both feeling good. Remember that highlighting their strengths — things they excel at, things that make them unique — is important.
  • Respect their style of processing and stress that you’re there for them. Some children may ask tons of questions, others may want to read every book on autism, and others may need more space to process.
  • Be wary of talking about “overcoming” autism. Focus on what they’re good at, what makes them unique, and how you can support them in living their best life.

What happens after a diagnosis?

Getting a diagnosis is just one step toward the ultimate goal of appropriate interventions. As Dr. Kanne explains, finding support after a diagnosis is just as important as the diagnosis process itself.

For parents, finding a good support system can help you better support your child as you navigate their diagnosis. “If you’re not in the right space, you’re not going to be able to help your child,” says Elissa Green Kaustinen, director of the Families, Agencies and Schools Together (FAST) program at the CHOC Thompson Autism Center.

Becoming a supportive advocate for your child is important as well. Rachel Kopito, who speaks as an advocate at Autism Society LA’s trainings and events, tells us that parent advocacy is key when it comes to teaching our children to listen to, understand, and respect themselves, and in helping them feel like they belong: “It really takes advocating for your children and then teaching them to advocate for themselves.”

To learn more about autism, check out our articles Autism 101, Getting a Child with Autism the School Supports They Need, and Autism and Co-Occurring Conditions.



Diagnosis under the new DSM-5

What are the DSM-5 criteria for autism?

How is a child evaluated for the signs and symptoms of autism?

Who can diagnose autism?

When should families pursue a diagnosis?

What are the pros and cons of pursuing a diagnosis?

Why are screening, early detection, and early intervention important?

What about diagnosing co-occurring conditions?

What can parents do if they feel their child is being missed or misdiagnosed?

Talking to your child about their diagnosis

What happens after a diagnosis?

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Claire BryanUndivided Writer

A fierce believer in curiosity and connectivity. Energized by friends, research, advocacy, and rearranging her home every few months.

Reviewed by


  • Dr. Stephen Kanne, clinical pediatric neuropsychologist and director of New York-Presbyterian's Center for Autism and the Developing Brain
  • Dr. Emily Haranin, Child and adolescent psychologist at Children’s Hospital Los Angeles and clinical assistant professor of pediatrics at Keck School of Medicine at USC
  • Dr. Hitha Amin, Neurodevelopmental neurologist at Children’s Hospital Orange County

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