Signs Of Autism In A 3-Year-Old: Symptoms, Diagnosis & Treatment

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Medically reviewed by Kimberly Langdon, MD

Signs Of Autism In 3-Year-Olds (1)

Looking for signs of autism in a 3-year-old may seem too early. After all, a child is still developing at that age, after all. However, research suggests that symptoms of Autism Spectrum Disorder may appear as early as 12 months old. Additionally, the earlier problems can be identified, the sooner a child can be helped. 

Most healthcare professionals won’t diagnose a child with Autism Spectrum Disorder until the child is at least 3 years old, however. Even at that young age, the challenges and disabilities that children with Autism Spectrum Disorder face can affect their lives. Helping them face and manage those challenges can also have a real impact on how they continue to develop.

Knowing some of the signs of autism in 3 year olds is an important thing for parents and childcare professionals to understand. With that understanding, it’s possible to put a child onto a more successful, more satisfying path through life.

Signs of Autism in 3 Year Olds

It can be difficult to sort out what is a symptom and what is just a kid being a 3 year old. However, there are a few key indicators that you can look for. Signs of autism in 3-year-olds include:

  • Problems with eye contact
  • Delayed development in language skills
  • Difficulty processing non-verbal communication
  • A flat or emotionless expression
  • Not waving, pointing, or using other gestures
  • Flapping hands, spinning circles, and repetitive motions
  • Limited, but focused interests
  • A preference for solitude

Any child might display some of these behaviors, depending on the situation. Three year olds are often shy around new people. They may spin around or find other physical ways of burning off energy.

That means that you’re not just looking for the symptoms in that list. You’re looking for those symptoms to persist over a longer period of time. You’re also looking for behaviors that appear frequently. Also, if behavior regularly interferes with a child’s happiness or success, it can be a symptom of Autism Spectrum Disorder. It’s the combination of the symptoms on the list and these other factors that point to a possible diagnosis of Autism Spectrum Disorder.

It’s also possible that some children may regress. That means that they developed some language and social skills, but that as they grow older they lose those skills or are less proficient in them.

Symptoms of Autism Spectrum Disorder generally fall into two categories: challenges in communication and repetitive behavior. These are, to some extent, what defines Autism Spectrum Disorder. As a result, it can be helpful to understand both of those two issues in more depth.

Difficulties in Communication and Social Interaction

Children with Autism Spectrum Disorder often find social interactions difficult to follow and understand. They experience challenges on both sides of communication, expressing themselves and understanding others.

First, they will experience difficulties in expressing their own ideas and emotions. This can be a physical disability, meaning that they may speak slowly or even struggle to produce words at all. They may point or gesture when words fail them. 

Children with Autism Spectrum Disorder may have difficulties monitoring their own emotional and physical states, as well. Things like level of hunger and body temperature may cause them distress without them understanding why.

Autism Spectrum Disorder also involves challenges in understanding others. They will usually have a hard time with jokes, even the sort of humor that usually sets a 3 year old giggling. Children that young may generally have a hard time with sarcasm and abstractions, but children with Autism Spectrum Disorder may have an even harder time. As a result, they may not play pretend.

They may also just show a general disinterest in other people, preferring to spend time on their own. Instead, the children with Autism Spectrum Disorder may focus on a particular toy or game, or develop a profound focus regarding one or two specific topics.

Repetitive Behavior and Restricted Interests

The other aspect of Autism Spectrum Disorder is a tendency toward repetitive behavior. We don’t fully understand Autism Spectrum Disorder or the brain chemistry behind it. However, it seems likely that familiar and repetitive actions are soothing in circumstances when children with Autism Spectrum Disorder become distressed.

There are also some indications that repetitive behavior is the result of certain parts of the brain being overactive. In particular, the system that gives us a positive boost when we do something ‘good’ may kick into overtime when a child with Autism Spectrum Disorder is pursuing their interests. The focus on a few topics or objects, to the point of excluding entirely other pursuits, is called restricted interests. 

People with Autism Spectrum Disorder often also perform repetitive behavior. That actually covers a wide range of things. It can be the more obvious meaning, in which they make a gesture repeatedly. For example, it’s very common for children with Autism Spectrum Disorder to flap their hands or spin circles. Repeating words is also common.

The tendency towards repetition may also include broader behaviors. They may need to follow the same routine for dinner everyday or become upset. Other routines may be important for their mental health. If these routines are disturbed, the child may become very distressed.

New surroundings, new people, or other changes may also cause distress.

Signs of Autism In Older Children

The behaviors that are developed as children will often define how we behave for the rest of our lives. For that reason, older children or adults with Autism Spectrum Disorder will show many of the indicators that we’ve already discussed. However, additional signs of autism in older children may include:

  • Further focus on restricted interests
  • More organized than is typical for children
  • Anger and frustration with their disability
  • Self harm
  • Aggression
  • Inappropriate or disproportionate emotional reactions
  • Depression
  • Anxiety
  • Short attention span

As they grow older, the symptoms may grow worse, particularly if left untreated. Difficulties with social interaction will become more pronounced. Repetitive motions will continue, even when you might expect older kids to settle down or develop other interests.

They may be very organized in a way children usually aren’t. Children with Autism Spectrum Disorder that display restricted interests may become very knowledgeable about the one or two topics they have focused on.

Other symptoms may also become apparent. Some will fit in the categories we’ve already discussed. Any child may have a hard time with sarcasm, but even older children with Autism Spectrum Disorder will continue to find it hard to understand. 

Other signs won’t fit as neatly into the two categories we’ve discussed. Anger, frustration, and anxiety are all common. Depression is also likely, as older children begin to experience more and greater challenges as they get older. The frustration they experience can also result in aggression or even self harm.

Autism Spectrum Disorder may not have a cure, but very effective treatments of different kinds have been developed. We mentioned that the behaviors we develop as children will tend to stay with us as we age. That is just as true of children with Autism Spectrum Disorder. That can also be a good thing, however. When young children receive the right therapy at a young age, they can learn to cope in healthy ways and still live full lives.


+ 4 sources

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  1. https://www.nichd.nih.gov/. (2017). When do children usually show symptoms of autism? [online] Available from: https://www.nichd.nih.gov/health/topics/autism/conditioninfo/symptoms-appear
  2. CDC (2020). What is Autism Spectrum Disorder? [online] Centers for Disease Control and Prevention. Available from: https://www.cdc.gov/ncbddd/autism/facts.html
  3. Autism Speaks. (2021). Learn the Signs of Autism | Autism Speaks. [online] Available from: https://www.autismspeaks.org/signs-autism
  4. Otsimo Editorial (2020). Signs of Autism In Different Age Groups and Genders. [online] Otsimo. Available from: https://otsimo.com/en/10-early-signs-of-autism-in-different-age-groups/

Medically reviewed by:

Sean Newton has nearly ten years of experience as a health and fitness writer, focusing on diet and its effects on your health. He also is an avid athlete and martial artist, specializing in bodyweight exercises and movement training. Together with an evidence-based approach to good health, his goal is to lay out the facts for readers, so they can make informed choices.

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