Parents and caregivers who notice particular changes or challenges in a 3-year-old may wonder if these could indicate autism.

Autism spectrum disorder (ASD) affects approximately 1 in 59 children. ASD covers a range of conditions that doctors used to believe were different, including autism and Asperger’s syndrome.

Behavioral symptoms often develop in early childhood, with research suggesting that parents and caregivers tend to notice some of these behaviors before a child’s first birthday.

Despite this, the Centers for Disease Control and Prevention (CDC) report that most autistic children do not receive a diagnosis until after 4 years of age.

In this article, we discuss the possible signs and symptoms of autism in 3-year old children.

What is autism?

signs of autism in 3 year old lonely

Autistic people may have difficulty developing friendships and understanding other people’s feelings.

Autism is one of the more commonneurodevelopmental disorders. It is characterized by challenges with social interaction, communication, and flexibility in thinking and behavior.

Autistic people may have difficulty relating to those around them, developing friendships, and understanding other people’s feelings. They may also have repetitive thoughts and perform repetitive behaviors.

Autistic people often have higher rates of co-occurring, or comorbid, conditions than the general population. Some of these conditions include:

  • seizures
  • digestive disorders
  • psychiatric issues, such as anxiety or depression

According to some research, 70% of autistic children have one co-occurring condition, while 41% have two or more, including attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder, or social anxiety.

There is no “cure” for autism, and many autistic people feel that ASD is an integral part of their identity. Doctors and therapists can help people manage their symptoms and maintain a happy, healthy life.

Signs and symptoms in a 3-year-old

Some signs of autism in a 3-year-old might include:

Social detachment

Autistic children may not play with others. They may:

  • play alone
  • have no interest in socializing
  • avoid sharing toys
  • not understand turn-taking play
  • not respond to their name
  • not understand make-believe or “pretend” play

Differences in emotional expression

Autistic people experience a full range of emotions, but they typically read and express them differently from others.

An autistic 3-year old may:

  • have difficulty discussing or expressing their feelings
  • have trouble understanding the feelings of others
  • struggle to be soothed or comforted
  • make facial expressions that may not match internal feelings
  • avoid physical contact with others
  • become rigid when hugged
  • show no emotion when a parent leaves the room

Communication difficulties

Autism is characterized by difficulty communicating. At 3 years of age, an autistic child may:

  • demonstrate delays or regression in speech and language skills
  • speak in a flat or sing-song manner
  • not speak at all
  • avoid eye contact
  • appear expressionless
  • not answer questions appropriately
  • repeat the words of others
  • use words, phrases, or sounds repeatedly, which doctors call echolalia
  • use the wrong pronouns, for example, “you” instead of “I”
  • not use gestures, such as pointing or waving
  • not respond to pointing
  • not understand age-appropriate humor


Autistic children often display seemingly unusual or repetitive behaviors. They may:

  • flap their hands repeatedly
  • spin around
  • rock back and forth
  • appear fascinated with a particular toy or activity
  • have obsessive behaviors
  • line up toys in an ordered fashion
  • be hyperactive in certain situations
  • have a short attention span
  • insist on specific routines or rituals
  • display agitation, anger, or frustration when someone disturbs their routine or ritual

Other signs

Additional potential signs of autism in children include:

  • aggression
  • impulsivity
  • self-injuring
  • intense reactions to sounds, smells, textures, colors, or tastes
  • temper tantrums
  • unusual eating habits

Not all autistic children show all these signs, and many neurotypical children occasionally demonstrate some of them. For this reason, a professional diagnosis is essential.

Signs of autism as children get older

signs of autism in 3 year old toys

Autistic children may have a preference for being alone as they get older.

Autistic children may experience more or different challenges with communication, socialization, and behavior as they age. This is partly due to increasing social demands at school and in the community.

School-age children and teenagers may display some of the following:

  • a need for routine
  • a preference for being alone
  • a lack of friendships
  • aggression
  • agitation or frustration when routines are disturbed
  • anxiety
  • difficulty making conversation and taking turns in a conversation
  • heightened or lowered sense of smell, taste, touch, vision, and hearing
  • obsession with specific topics or activities
  • problems interpreting nonverbal and social cues
  • rigidity when following rules in school and sports
  • unusual posture or movements, such as biting or flicking of the fingers
  • unusual speech patterns and tone

SOURCE: Article by By Jayne Leonard Reviewed by Timothy J. Legg, PhD, CRNP in Medical News Today