Table of Contents

What is Autism?

Autism, or autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by challenges with social skills, communication, and restricted and repetitive behaviors.

What is Autism Testing?

Autism symptoms most commonly appear by age two or three, with most children receiving a diagnosis by age five. However, autism testing can be completed beyond childhood into adolescence and adulthood. Identifying autism early may help individuals access services and support that aim to promote their development. For some individuals, the characteristics of autism may be more noticeable or problematic early on, while for others, characteristics may not be fully apparent or may not interfere significantly with functioning until demands increase. Thus, it is important to recognize that it can be normal for older children, teenagers, and adults to seek autism testing later in life.

Diagnosing autism can be challenging because there is not a specific or single medical test, like imaging or a lab test, to make the diagnosis. Instead, a diagnosis of autism comes from a specialist with extensive knowledge of developmental conditions including autism who must examine developmental history, social skills, language, and behavior to identify autism.

How Autism Evaluations are Conducted

Because autism is a developmental disorder, the evaluation will usually include a range of skills that are mastered as people mature. The evaluation looks for discrepancies or differences in areas that are often delayed in autism. An autism evaluation often includes tests of intelligence, language, memory, behavior, and adaptive functioning such as daily living skills and activities. Additional information is obtained through clinical interviews and forms completed by parents, teachers, family members, or caregivers.

The length and components of autism evaluations vary based on the age and developmental level of the individual being assessed, the purpose or function of the evaluation, and the type of clinician administering the tests. While the specific measures may vary, an autism assessment often includes the following, regardless of the patient’s age:

  • Detailed interviews with the patient and others who know them well (e.g., caregiver, family member, friend, or spouse)
  • A thorough understanding of the patient’s medical, developmental and social history
  • Consideration of family history, particularly developmental disorders, genetic and metabolic conditions
  • Identification of sensory processing differences, if present
  • An assessment of cognitive and intellectual functioning
  • An assessment of language and communication skills
  • An assessment of cognitive functioning
  • Structured evaluation of adaptive (day to day) functioning
  • Direct observation

What to Expect for Autism Testing with Younger Children

Autism symptoms are typically evaluated through parent/caregiver interviews, activities that assess developmental skills, and direct observation.

Parents/caregiver interviews gather information about the child’s development from birth to the time of evaluation, explore pregnancy and birth history, health history, school history, behavioral and emotional health, and other details that may affect the child’s behavior or development.

Activities may be standardized or structured play or tasks that are used to assess a child’s developmental level in specific areas such as language, visual, motor, sensory, and social skills. These activities are appropriate for the age of the child and consider developmental milestones that the child is working towards.

Direct observation is used to better understand how the child behaves in one of their typical environments or an office setting. It gives the clinician an opportunity to observe expected and unexpected responses, as well as symptoms.

In many cases, the above methods are enough to evaluate a child for autism. In some situations, it may be helpful to also interview the child’s teacher or other adults who know the child well. The goal is to have enough information about the child to understand how they function in different environments and with their peers.

The clinician conducting the evaluation compiles all this information and applies their training and experience to determine the diagnosis. They objectively consider other possible diagnostic explanations or conditions that may happen along with, or in place of, autism, while ultimately looking to answer the question “Does this child have autism?”

What to Expect for Autism Testing for School-aged Children and Teens

Autism testing for teens uses similar methods that are used for younger children but typically involve less play and more structured tasks and questions. In addition to interviewing parents or caregivers, reviewing developmental history, and administering structured activities, clinicians will ask for completion of questionnaires to better understand symptoms, development, and socialization.

What to Expect for Autism Testing for Adults

Similar to testing with older children and teenagers, an adult evaluation for autism will include review of developmental, medical and psychological history, structured activities to assess cognitive functioning, and completion of questionnaires to understand symptoms and social skills. An important part of an evaluation with an adult is having information on the adult’s childhood and developmental history. This could involve the participation of someone such as a parent, sibling, or relative who can report on early developmental history. Occasionally, a spouse or friend may participate if that individual is able to offer additional insight. Though this information can be more difficult to obtain for adults, it can help the completeness and speed of the process.

Many adults report that finding someone to diagnose them with autism can be difficult. Some professionals feel less qualified to diagnose adults, as autism may present itself differently, or it may be complicated by the person’s life history and co-occurring mental health conditions. Many individuals begin by speaking with their primary care physician, who may be able to refer them to a qualified specialist. Additionally, it may be beneficial to seek treatment with a mental health provider, like a therapist, who can help address the concerns and also offer a referral to a specialist who can test for autism.

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Types of Autism Tests

While there are no lab tests, there are a number of different psychological and neuropsychological measures administered to support a diagnosis of autism. It is important to use tests that researchers and health professionals trust to help identify this condition.

The Autism Diagnostic Observation Schedule, Second Edition (ADOS®-2) is considered by many to be the “gold standard” autism testing, when used as part of a comprehensive evaluation. The ADOS-2 is a powerful tool for many cases, but not necessary or useful in every case. The clinician will make the determination on which test(s) will be used as part of the autism evaluation. There are several commonly used tests that may be used with or without the ADOS-2.

For example:

  • Ages and Stages Questionnaire (ASQ)
  • The Modified Checklist for Autism in Toddlers (M-CHAT)
  • Autism Diagnostic Interview–Revised (ADI®-R)
  • Childhood Autism Rating Scale, Second Edition (CARS™2)
  • Monteiro Interview Guidelines for Diagnosing the Autism Spectrum, Second Edition (MIGDAS™-2)
  • Social Communication Questionnaire
  • Social Responsiveness Scale – 2nd Edition (SRS-2)
  • Gilliam Autism Rating Scale, Third Edition (GARS-3)
  • Tele-ASD-Peds (for telehealth assessments)

What Causes Autism?

There is no single cause of autism. Research suggests that autism develops a combination of genetic and nongenetic or environmental influences. It is important to keep in mind that an increased risk does not mean that someone will have autism. For example, some gene changes associated with autism can also be found in people who don’t have the disorder. Similarly, most people exposed to an environmental risk factor for autism will not develop the disorder.

Autism’s Genetic Risk Factors

Autism does tend to run in families. Changes in certain genes increase the risk that a child will develop autism. If a parent carries one or more of these gene changes, they may get passed to a child (even if the parent does not have autism). Other times, these genetic changes arise spontaneously in an early embryo or the sperm and/or egg that combine to create the embryo. Again, the majority of these gene changes do not cause autism by themselves. They simply increase the risk for developmental disorders.

Autism’s Environmental Risk Factors

Research also shows that certain environmental influences may further increase – or reduce – the risk of developing autism in people who are genetically predisposed to the disorder. However, the increase or decrease in risk appears to be small for any one of these risk factors:

Increased Risk

  • Advanced parent age (in either parent)
  • Pregnancy and birth complications such as extreme prematurity (before 26 weeks), low birth weight, or multiple pregnancies
  • Pregnancies spaced less than one year apart

Decreased Risk

  • Prenatal vitamins containing folic acid, taken before, at conception and through pregnancy have been shown to decrease the risk of a baby developing autism.

No Effect On Risk

    • Vaccines. Scientists have conducted extensive research over the last two decades to debunk the myth that there is a link between childhood vaccinations and autism. The result of this research is clear: vaccines do not cause autism.

Symptoms and Signs of Autism by Category

Social Communication and Interaction Skills

  • Avoids or does not keep eye contact
  • Does not respond to name by 9 months of age
  • Does not show facial expressions like happy, sad, angry or surprised by 9 months of age
  • Does not play simple interactive games like patty cake by 12 months of age
  • Uses few or no gestures by 12 months of age (for example, does not wave goodbye)
  • Does not share interests with others by 15 months of age (for example, shows you an object that they like)
  • Does not point to show you something interesting by 18 months of age
  • Does not notice when others are hurt or upset by 24 months of age
  • Does not notice other children and join them in play by 36 months of age
  • Does not pretend to be something else, like a teacher or superhero, during play by 48 months of age
  • Does not sing, dance or act for you by 60 months of age

Restricted or Repetitive Behaviors or Interests

  • Lines up toys or other objects and gets upset when order is changed
  • Repeats words or phrases over and over
  • Plays with toys the same way every time
  • Hyper-focus on parts of objects (for example, wheels)
  • Gets upset by minor changes
  • Must follow certain routines
  • Flaps hands, rocks body, or spins self in circles
  • Unusual reactions to the way things sound, smell, taste, look or feel

Other Related Characteristics

  • Delayed language skills
  • Delayed movement skills
  • Delayed cognitive or learning skills
  • Low muscle tone
  • Sensory processing issues
  • Hyperactive, impulsive, and/or inattentive behavior
  • Unusual eating and sleeping habits
  • Gastrointestinal issues (for example, constipation or diarrhea)
  • Unusual mood or emotional reactions
  • Anxiety, stress, or excessive worry
  • Lack of fear or more fear than expected

Common Comorbidities

  • Intellectual disability
  • Learning Disorder
  • ADHD
  • Depression
  • Obsessive Compulsive Disorder (OCD)
  • Schizophrenia
  • Bipolar Disorder
  • Down Syndrome (DS)
  • Epilepsy or seizure disorder

References:

Almandil NB, Alkuroud DN, AbdulAzeez S, AlSulaiman A, Elaissari A, Borgio JF. Environmental and Genetic Factors in Autism Spectrum Disorders: Special Emphasis on Data from Arabian Studies. Int J Environ Res Public Health. 2019 Feb 23;16(4):658. doi: 10.3390/ijerph16040658. PMID: 30813406; PMCID: PMC6406800.

Centers for Disease Control and Prevention. (2025, April 15). Clinical screening for autism spectrum disorder. https://www.cdc.gov/autism/hcp/diagnosis/screening.html

Chaste P, Leboyer M. Autism risk factors: genes, environment, and gene-environment interactions. Dialogues Clin Neurosci. 2012 Sep;14(3):281-92. doi: 10.31887/DCNS.2012.14.3/pchaste. PMID: 23226953; PMCID: PMC3513682. https://www.ncbi.nlm.nih.gov/medgen/1840226

Gabis LV, Attia OL, Goldman M, Barak N, Tefera P, Shefer S, Shaham M, Lerman-Sagie T. The myth of vaccination and autism spectrum. Eur J Paediatr Neurol. 2022 Jan;36:151-158. doi: 10.1016/j.ejpn.2021.12.011. Epub 2021 Dec 22. PMID: 34996019; PMCID: PMC8694782. https://pmc.ncbi.nlm.nih.gov/articles/PMC8694782/

Pflumm, MIchelle, PhD (n.d.). Genetics and Genomics: A blood test for autism. Boston Children’s Hospital. https://www.childrenshospital.org/research/divisions/genetics-and-genomics-research/genetics-and-genomics-stories/blood-test-autism

Shaw, K. A., Williams, S., Patrick, M. E., Valencia-Prado, M., Durkin, M. S., Howerton, E. M., … Maenner, M. J. (2025, April 17). Prevalence and early identification of autism spectrum disorder among children aged 4 and 8 years — Autism and Developmental Disabilities Monitoring Network, 16 sites, United States, 2022 (Surveillance Summaries, 74(2), 1-22). Centers for Disease Control and Prevention. https://www.cdc.gov/mmwr/volumes/74/ss/ss7402a1.htm

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Carolyn Certilman, PsyD
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Dr. Certilman is a clinical neuropsychologist and serves as LifeStance’s Director of Evaluation Services for New York State. Dr. Certilman evaluates patients across the lifespan, from school-aged children through older adults, to conceptualize and treat cognitive, behavioral, emotional, and/or functional challenges. Dr. Certilman has specialized interest and training in working with adults and older adults with neurological illness or disease, such as concussion/ traumatic brain injury, stroke, epilepsy, Parkinson’s disease, multiple sclerosis, Lyme disease, and mild cognitive impairment and/or dementia. Dr. Certilman also enjoys working with children and their families to not only address the child’s areas of difficulty, but also identify strengths that might bolster the child’s success. Dr. Certilman believes in a holistic approach to evaluation and treatment planning that incorporates data on brain-behavior relationships with relevant psychological, academic/occupational, and social history to optimize patient outcomes. Dr. Certilman received her doctorate degree in clinical psychology from the University of Indianapolis. Her predoctoral internship was at St. Vincent Neuroscience Center where she completed rotations in outpatient neuropsychological assessment, inpatient neurorehabilitation, and adolescent behavioral health. She completed a two-year post-doctoral fellowship in clinical neuropsychology at Stony Brook University Medical Center where she evaluated children and adults in an outpatient setting. Previous research interests include performance validity and the impact of transient factors on assessment of attention. In her free time, Dr. Certilman enjoys hiking, cooking, traveling and spending time with her partner and son.