Autism Symptoms and Signs: What Parents Should Look For
Published November 2, 2026 · Last updated November 2, 2026
If you are searching for autism symptoms, you are probably noticing something about your child that you cannot quite explain. This guide covers the two main groups of signs, the age-by-age signs the CDC lists, simple activities that show you more about how your child connects, and what to do next.
Autism symptoms fall into two groups: differences in social communication and interaction, and restricted or repetitive behaviors, interests or sensory reactions. The CDC lists signs by age, such as not responding to name by 9 months or not pointing by 15 to 18 months. One sign is not enough, so talk to your pediatrician about patterns.
- Two groups: Social communication differences, and repetitive behaviors, interests or sensory reactions.
- By age: The CDC lists signs from 9 months to 5 years, such as not pointing by 15 to 18 months.
- One sign is not enough: Look for a pattern across settings that affects daily life.
- Next step: Write it down, record short videos, and ask your pediatrician for a developmental screening.
What Are the Symptoms of Autism?
Autism shows up in two main areas, described in the diagnostic manual known as the DSM-5: differences in social communication and interaction, and restricted or repetitive behaviors, interests or activities, which include unusual reactions to sensory input. Signs usually appear in early childhood, but they look different in every person, and the CDC notes children may not show all or any of the example behaviors.
Signs by Age: What the CDC Lists
The CDC lists signs to watch for at specific ages. Use them as a prompt to talk to your pediatrician, not as a test.
Under 12 Months: What to Watch and What to Play
At this age you are looking at whether your baby responds to you. Signs the CDC lists include not responding to their name or not showing expected facial expressions by about 9 months, and not playing simple interactive games or waving by about 12 months.
| Try this | How | Why it helps you learn more |
|---|---|---|
| Name game | Call your baby's name from the side while they play, and note whether they turn | Shows how your baby responds to your voice |
| Peekaboo | Cover your face with a cloth, then reveal it with a smile and a sound | Shows interest in back-and-forth play and shared joy |
| Mirror play | Sit with a baby-safe mirror and make faces | Shows how they look at and copy faces |
| Wave and clap | Wave "bye-bye" at the door every day | Shows when gestures start to be copied |
12 to 36 Months: Pointing, Play and Language
This is the age most parents start to worry. The CDC lists not pointing to show things by 15 to 18 months, and not noticing others' distress or joining other children in play by 24 to 36 months. Repeating words or phrases over and over (echolalia) and strong distress over small changes are also listed.
| What you may notice | What to try | Why |
|---|---|---|
| Takes your hand to get things instead of pointing or looking at you | Hold a favorite toy up high and wait. Say "want?" and point to it yourself | Gives your child a reason to look at you and ask |
| Lines up cars or blocks and gets upset if they are moved | Join the line. Add one car and say "my turn." Do not take over | Joining their play builds connection. Small changes build flexibility |
| Plays with only one part of a toy, such as the wheels | Copy what they do, then add a small new move, such as rolling the car down a ramp | Copying shows you are connecting, and new moves widen play |
| Does not respond when you call | Get close, get down to their level, say their name and give a gentle touch | Lets you check hearing and attention. Ask for a hearing test either way |
| Distress at certain sounds, textures or foods | Offer a choice of two. Introduce new things next to preferred ones | Lowers pressure while keeping options open |
Toys that often work well for observing and building interaction are simple ones with a quick response: bubbles, a ball to roll back and forth, a pop-up toy, musical instruments, and wind-up toys. They give you many chances to pause, wait and see whether your child looks at you or asks for more.
Preschool and School Age
The CDC lists not engaging in pretend play, singing, dancing or acting by 48 to 60 months. In school, signs can also include difficulty making friends, taking things literally, strong reaction to change, trouble in noisy classrooms, or intense interests. Some children, especially those with strong language, are not noticed until school.
| Where | What you might see | What to try |
|---|---|---|
| Playground | Stands to one side, repeats the same game, or wants to control rules | Pick one peer for a short play date. Rehearse a script such as "Can I play too?" |
| Classroom | Covers ears, stays rigid when schedule changes, struggles in group work | Ask for advance notice of changes and a visual schedule |
| Home | Fine at school, melts down at home | Allow quiet time right after school before asking questions |
| Meals | Very limited foods, strong reaction to textures | Keep one safe food on the plate and add small steps. Talk to a feeding specialist if growth is a concern |
Other Things That Often Go With Autism
The CDC notes that most autistic people have other related characteristics, which may include delays in language, movement or learning skills, hyperactive or inattentive behavior, epilepsy, unusual eating or sleeping habits, stomach issues such as constipation, anxiety, and unusual fears or mood reactions. These are not required for a diagnosis, but they matter for planning support. Tell your doctor about all of them.
Autism Symptoms in Adults
Adult signs include difficulty with social conversations, strong need for routine, sensory overload, intense interests, and exhaustion after social time. The DSM-5 criteria state that symptoms may not be fully evident until social demands exceed a person's abilities, or may be masked by learned strategies in later life. That is why many adults are diagnosed after their own child is diagnosed.
What Is Not Autism
Late talking, shyness, a strong will, or being very active do not automatically mean autism. Hearing loss, language delay, anxiety, ADHD and other conditions can look similar or occur together with autism. A proper evaluation looks at the full picture.
What to Do If You See Signs
- Write it down. Note what you see, when, and how often. Short phone videos of play, talking and routines are very helpful to a clinician.
- Talk to your pediatrician. Ask for a developmental screening and a hearing check. If you are in the US, you can also read our guide to the autism evaluation process.
- Do not wait. Early support can start before a diagnosis. Speech therapy, play-based coaching and daily routine changes help whatever the final answer is.
- Use a screening tool as a starting point. Our free tool helps you organize what you see, but it does not diagnose.
Frequently Asked Questions
What are the first signs of autism in babies?
The CDC lists not responding to their name or not showing typical facial expressions by about 9 months, and not playing simple interactive games or using gestures like waving by about 12 months. These are prompts to talk to your pediatrician.
What are the main symptoms of autism?
Differences in social communication and interaction, and restricted or repetitive behaviors, interests or activities, which include unusual reactions to sensory input. Symptoms vary a lot between people.
Can a child have autism without all the signs?
Yes. The CDC says children with autism may not have all or any of the behaviors listed as examples. A clinician looks at the overall pattern and how it affects daily life.
What are autism symptoms in a 2 year old?
Examples include not pointing to show things, little interest in other children, not noticing others' distress, repeating words or phrases, lining up objects, and strong distress at small changes. Not every child shows all of them.
What are autism symptoms in adults?
Difficulty with social interaction, a strong need for routine, sensory overload, intense interests and tiredness after social time. Adults may have learned to mask their traits, so signs can be easy to miss.
Is hand flapping always a sign of autism?
No. Hand flapping and other repetitive movements are listed as possible signs of autism, but many children do them at times. It is the overall pattern that matters.
Can a hearing problem look like autism?
Yes. A child who does not respond to their name may have a hearing difficulty, so it is a good idea to ask for a hearing test as part of any evaluation.
Who can diagnose autism?
A qualified clinician, such as a developmental pediatrician, child psychologist, psychiatrist or other trained specialist. Screening tools and checklists are not a diagnosis.
Sources
- CDC: Signs and Symptoms of Autism Spectrum Disorder
- Interagency Autism Coordinating Committee: DSM-5 Diagnostic Criteria for Autism Spectrum Disorder
Not sure what you are seeing?
Our free tool helps you organize what you notice into a clear profile, a helpful starting point for talking to your pediatrician.
Free Sensory Profile & Support Tool for Parents →