March 2026

What You Should Know About Autism

The Kids Mental Health Foundation Icon
Morgan Wright, PhD; A. Dawn Greathouse, PhD

Article Summary

 
  • Autism is a condition that affects how a child communicates and interacts with others. Every person with autism is different.
  • Doctors look for signs like difficulty with social interaction, repetitive behaviors, or unusual reactions to sounds or textures.
  • There is no blood test or medical lab test for autism.
  • If a parent is worried about their child’s development, they should talk to a doctor early and ask for screening or an evaluation so the child can get support as soon as possible.

What is autism? 

Autism spectrum disorder, or autism, is a condition that affects the way a child communicates and interacts with others and the world around them. In 2013, “autism spectrum disorder” replaced several older diagnoses, such as autistic disorder and Asperger’s syndrome.

Autism is called a spectrum disorder because every child with autism has different strengths and weaknesses. Some children may require more support in daily life, while others may need less.

What causes autism?

There is no single known cause of autism. Research shows that a combination of genetic and environmental factors can increase the risk for autism. Just because someone has some of these risk factors does not mean they will develop autism. Research has shown that vaccines and Tylenol do not cause autism.

What are the symptoms of autism?

Autism is defined by two core symptom categories:

  1. Difficulty interacting with others in these three areas:
  • Back-and-forth interactions (like conversations)
  • Nonverbal communication (such as maintaining eye contact)
  • Making and keeping friends and understanding social relationships
  1. At least two of the following restricted or repetitive behaviors:
  • Repetitive speech, play and body movements (repeating phrases, flapping arms)
  • Inflexible thinking and/or behavior (distress with small changes)
  • Intense and/or highly focused interests
  • Under or overreaction to sounds, textures, lights or other sensory input

What are the early signs of autism by age?

Learning the early signs and tracking developmental milestones helps families act early if there are concerns.

By 6 months:

  • Limited eye contact
  • Not smiling at others

By 9 months:

  • Lack of back-and-forth interaction (e.g., lack of interest in games like peek-a-boo)


Around 12 months:

  • Lack of babbling
  • Few gestures like pointing, showing, reaching or waving
  • Inconsistent or limited response to name when called


Around 24 months:

  • May prefer to play alone
  • Plays with toys in unexpected or repetitive ways
  • May not engage in pretend play

Not all children with autism show all these behaviors. Some children without autism show some of these behaviors, so it is important to talk to your child’s pediatrician if you notice any of these behaviors.

How is autism diagnosed?

There is no blood or medical lab test for autism. Children can be checked for autism as early as 12 months old, but screening often happens at well child appointments between 18 and 24 months.

You will need to meet with trained health professionals who understand child development and autism, such as:

  • Psychologists
  • Developmental and behavioral pediatricians
  • In some cases - primary care physicians, psychiatrists or neurologists

 
What happens during an evaluation?

After this step, you may be referred for an evaluation, where trained professionals:

  • Look at the child’s development (how they grow, learn and communicate)
  • Watch how the child behaves
  • Talk with people (caregivers, teachers, others) who know your child
  • Use special screening and testing tools, such as:
    • Structured observations
    • Questionnaires

No single test alone can diagnose autism. Professionals look at all the information together before making a diagnosis.

What should I do if I’m worried that my child has autism?

If you are worried about your child’s development, it’s important to act early. You do not need to “wait and see.”

  1. Track your child’s development.
  1. Contact your child’s doctor.
  1. Request a referral for an evaluation.
  • Your doctor can refer to an evaluation or see if self-referral is available.
  • Because waiting lists are long, it’s best to schedule as soon as possible.
  1. Contact other supports or your local school.

Your concerns matter. Reaching out early gives your child access to support during the years when development is happening. Early intervention is lifechanging.

Resources:

References:

American Psychiatric Association. (2022). Neurodevelopmental disorders. In Diagnostic and statistical manual of mental disorders (5th ed., text rev.). 

Hirota T. King BH. (2023). Autism Spectrum Disorder: A Review.Journal of the American Medical Association, 329(2), 157–168.

Hodges H, Fealko C, Soares N. Autism spectrum disorder: Definition, epidemiology, causes, and clinical evaluation. Transl Pediatr. 2020 Feb;9(Suppl 1):S55-S65.

Lord C. Risi S. DiLavore PS. Shulman C. Thurm A. Pickles A. (2006). Autism from 2 to 9 years of age. Archives of general psychiatry, 63(6), 694–701.

https://doi.org/10.21037