If you are noticing differences in how your child communicates, plays, or responds to the world around them, it is worth talking to your pediatrician sooner rather than later. Autism screening typically starts with a brief questionnaire at your child's 18 and 24 month well visits, and if concerns are flagged, the next step is a comprehensive developmental evaluation. You do not need to wait for a formal diagnosis to seek answers, and reaching out early makes a meaningful difference.

From the moment children are born, they begin to engage with the world around them. How your child interacts with the environment, particularly the people in their environment, provides important clues about his or her neurodevelopment.

If you are wondering whether your child might be showing some early signs of autism, there are many resources that can help you get the answers you need. Assistance early on from qualified healthcare professionals can bring reassurance, clear steps, and strategies to support every aspect of your child’s health and development. It is never too early to reach out.

What are some early signs of autism?

Children can grow and develop in many different ways. There is no single right developmental path. What might be considered an early sign of autism varies depending on a child's age. For example, many nine month old children do not yet imitate others in waving bye. In a two year old child, however, the absence of this developmental milestone is a potential early sign of autism.

Some infants may show early signs in their first months of life, while other children may not show signs until later. Not all children with autism will show all the same signs, and many children who do not have autism may have a few of the signs. It is also important to rule out other neurodevelopmental differences with similar symptoms. For example, delays in imitating movements could point to problems in the visual or motor systems, and delayed language could be a sign of hearing loss. These complexities of early child development make professional evaluation an essential step toward an accurate diagnosis.

By six months of age:

  • Longer and more extreme periods of irritability compared to other infants. You might find that common strategies for consoling and calming infants don’t seem to work for your child. Your child might need to be swaddled tightly, rocked, or bounced for an extended period of time in order to settle down.

  • Conversely, some children show less need for attention. You may find that your infant does not mind being left alone for long periods of time that would cause most infants to start to fuss or cry.

  • Differences in the motor system and how your child moves, such as abnormal muscle tone, asymmetry in the lying position, atypical rolling patterns, or increased head lag when being pulled from the lying to the sitting position. These symptoms may be subtle and require a specialized evaluation by a pediatric neurologist, pediatric occupational therapist, or pediatric physical therapist.

  • Limited or no smiles or positive facial expressions

  • Limited or no eye contact

By nine months:

  • Little or no back-and-forth sharing of sounds, smiles, or other facial expressions

  • Atypical sitting posture (e.g., asymmetric)

By 12 months:

  • Little or no babbling

  • Little or no back-and-forth gestures such as pointing, showing, reaching, or waving

  • Little or no response to name

  • Atypical patterns of crawling

By 16 months:

  • No one-word communications

  • Atypical posture for standing or walking

What Is the M-CHAT Screening Tool?

Research studies have identified a set of early signs of autism in children 16 to 30 months of age. These are captured in a questionnaire called the Modified Checklist for Autism in Toddlers (M-CHAT), which is increasingly used as an autism screening tool by pediatricians.

A “no” response to the following questions may be an early sign of autism in a child between the ages of 16 to 30 months:

  • If you point at something across the room, does your child look at it? (For example, if you point at a toy or an animal, does your child look at the toy or animal?)

  • Does your child point with one finger to show you something interesting? (For example, pointing to an airplane in the sky or a big truck in the road?)

  • Is your child interested in other children? (For example, does your child watch other children, smile at them, or go to them?)

  • Does your child show you things by bringing them to you or holding them up for you to see – not to get help, but just to share? (For example, showing you a flower, a stuffed animal, or a toy truck?)

  • Does your child respond when you call his or her name? (For example, does he or she look up, talk or babble, or stop what he or she is doing when you call his or her name?)

  • When you smile at your child, does he or she smile back at you?

A “yes” response to the following questions may be an early sign of autism in a child between the ages of 16 to 30 months:

  • Does your child make unusual finger movements near his or her eyes? (For example, does your child wiggle his or her fingers close to his or her eyes?)

  • Have you ever wondered if your child might have trouble hearing?

  • Does your child get upset by everyday noises? (For example, does your child scream or cry to noises such as a vacuum cleaner or loud music?)

Seeking an evaluation from a professional is an essential step toward an accurate diagnosis.

How is autism diagnosed?

The diagnosis of autism is based on a child's behavior and development. There is currently no medical test, like a blood test or a brain scan, to diagnose autism. The term autism describes a specific set of behavioral symptoms, including difficulties with communication and social interactions and repetitive patterns of behavior. These symptoms can have a broad range of severity, which is why autism is often described as a spectrum.

Often, the first signs are observed by a parent and brought to the pediatrician. Whether concerns are brought by the parent or detected during a routine visit, the next step is to pursue a formal diagnostic evaluation. This can be done by a clinical psychologist, a nurse practitioner, a pediatric neurologist, or a developmental pediatrician with expertise in neurodevelopment.

What makes a diagnosis of autism official?

A diagnosis of autism is considered official if your child meets the criteria of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association. To meet these criteria, a child must show challenges with communication and social interaction. In addition, there must be the presence of unusual patterns of behavior, interests, or activities that are considered repetitive or restricted. Once a psychologist or physician has completed a diagnostic evaluation and documented that the DSM-5 criteria have been met, the diagnosis is considered official.

Because children grow and change over time, it is possible that some children who meet the diagnostic criteria at one point in time may not meet the criteria at a later point in time. In those instances, an evaluating physician or psychologist may determine that the diagnosis of autism is no longer appropriate, and the label can be removed.

Who can make the diagnosis?

To make an official diagnosis of autism, a professional must be either a licensed clinical psychologist or a physician with expertise in child development, such as a pediatric neurologist, developmental pediatrician, or child psychiatrist.

When can a diagnosis of autism be made?

For some children, a diagnosis of autism can be made at 18 months or earlier. For most children, the diagnosis can be made by two years of age. Some providers prefer to diagnose younger children as being “at-risk” of autism and will defer a definite diagnosis until age three or later. However, studies have shown that early diagnostic impressions are very stable in this age range, and it’s important to start therapeutic services as early as possible.

When should you consult with a medical provider?

It’s never too early to share your concerns with your provider. In the past, evaluation by a specialist was delayed until the signs of autism were very clear. Because of the importance of early diagnosis and early intervention, parents and pediatricians are now encouraged to seek an autism evaluation much earlier - as soon as early signs appear.

What is the difference between screening and diagnosis?

Screening and diagnosis are two different steps. A screening, like the M-CHAT questionnaire your pediatrician uses at well visits, is a brief tool designed to flag children who may benefit from a closer look. It is not a diagnosis. A positive screen means further evaluation is recommended, not that your child is autistic.

A full diagnostic evaluation is the step that comes after screening if concerns are identified. It is more comprehensive, involves direct observation of your child, and is conducted by a specialist with expertise in neurodevelopmental conditions. The evaluation is what leads to an official diagnosis.

What medical or laboratory testing should be done?

In the past, many children diagnosed with autism did not receive a medical evaluation and greater focus was placed on behavioral assessments. Many children receiving behavior services for autism today still have not had appropriate medical testing. Autism is a medical condition and there are many known medical causes that contribute to the brain differences that underly autism symptoms. Many of these are treatable. Medical testing that should be considered for any child with autism includes:

Why is it important to diagnose autism early?

Early diagnosis can make a big difference in the lives of children with autism and their families. A thorough neurodevelopmental evaluation is the first step in understanding your child’s unique developmental profile and the areas that would benefit from additional support through medical and other therapies. If you’ve observed any of the early signs of autism, seek a diagnostic evaluation with a qualified specialist as soon as you can. The therapies that your child receives early on can make a positive difference for a lifetime.