Symptoms of Autism Spectrum Disorder (ASD)

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Autism spectrum disorder (ASD) is a developmental condition that affects how individuals living with the condition behave and communicate.

It’s a condition that affects both children and adults. However, the symptoms vary from individual to individual. Symptoms of ASD also range in severity. Some people might only experience mild symptoms throughout the course of their lives, while some people might experience much more severe conditions. If left untreated, ASD could worsen in severity. 

In autistic children, the symptoms could begin very early on and persist into adulthood. In severe cases, symptoms might interfere with daily functioning

Signs & Symptoms 

While a lot of people living with this condition might share a host of similar signs and symptoms, they look a little different in children and adults. 

Symptoms of Autism in Children 

Symptoms of autism in children fall into two major categories: communication challenges and restricted and repetitive behaviors. Children may also experience sensory issues and might find themselves overstimulated or understimulated by sounds, light, smells, or pain. 

Communication Challenges

This is a symptom that is common in children and adults. For example, autistic people might struggle to speak, maintain eye contact, control their facial expressions, or repeat gestures.

These are some of the other ways communication challenges might reveal themselves in people with this condition: 

  • They may not respect people’s personal space. 
  • They don't respond to their name when it’s called, especially at a really young age.
  • They have a hard time playing with children of the same age.
  • They find it difficult to understand other people’s emotions and, in some cases, don't know they’ve hurt someone else’s feelings. 
  • They often get distracted in between conversations.
  • They might sometimes speak in a tone that is different from their regular tone of voice and keep this going for a while.
  • They may find it difficult to understand non-verbal cues.

Restricted and Repetitive Behaviors

Autistic children might engage in certain behaviors that might seem atypical if you aren’t familiar with them. They could also repeat these behaviors very often.

Some restricted and repetitive behaviors autistic children exhibit include: 

  • Lining up personal items in a particular order and getting upset when they are placed out of order 
  • Repeating a particular word or phrase several times 
  • Repeating certain gestures over and over again. For instance, they might spin in a circle several times or clap their hands together repeatedly.
  • Sticking to strict routines and getting upset when anyone or thing disrupts their routine 
  • They might get obsessive when they find a thing or activity that interests them. For instance, a child with ASD might refuse to go to bed or engage in any activities at all if they aren’t wearing their favorite hat.
  • Engaging in activities that could result in self-harm, like repeatedly banging their head against a wall 

Some other signs of ASD in children that don’t particularly fall under any of the above categories include: 

  • Experiencing a delay in the development of their language skills. This means they might start speaking much later than their peers. 
  • Exhibiting hyperactive and impulsive behaviors 
  • Experiencing mild to severe mood swings
  • Having an unusual sleep routine 
  • Having unusual eating habits. An autistic child might only eat at certain times, refuse to eat certain foods, or show such a strong preference for certain foods they need to be included in almost every meal. 

Symptoms of Autism in Adults 

Autism tends to look a little different in adults with the condition. Research also shows that autism looks a little different in men and women. Autistic women might be quieter and show fewer overt signs of the condition. This often makes it difficult for the condition to be diagnosed in adult women.

Some of the common symptoms autistic adults experience include: 

  • Sticking to a very strict routine and becoming upset at the slightest disruption of their routine 
  • Experiencing anxiety in even the smallest social situations and often preferring to be isolated 
  • They may take things very literally. For example, they may not understand or pick up on sarcasm.
  • Difficulty expressing themselves emotionally 
  • Difficulty controlling their tone of voice in situations that call for it. For instance, they might come off as rude or brash to people even when they don’t mean to.
  • Struggling to make or maintain eye contact with other people 

Complications & Comorbidities 

Research shows that people with autism have significant co-occurrences of mental and physical disorders such as ADHD and sleep disorders. These conditions might last throughout their lives or might diminish in severity at different stages of the condition.

It’s often difficult for many co-occurring disorders to be diagnosed because autistic people often have communication difficulties.

Some of the most common co-occurring conditions autistic people might experience include: 

  • Seizure disorders: Autistic people might also live with seizure disorders like epilepsy. Some research shows that up to 25% to 40% of autistic people live with seizure disorders.
  • Eating disorders: Obesity and anorexia brought on by eating disorders could sometimes occur with autistic people. This is typically a result of selective eating patterns, which is a common symptom of the condition.
  • Sleep disorders: Some research shows that up to 50% to 80% of autistic children live with sleep disorders. They might find it difficult to fall asleep or be unable to remain asleep all through the night.

Asperger Syndrome 

Asperger syndrome (AS) used to be classified separately from ASD by the Diagnostic and Statistical Manual of Mental Disorders. However, in the latest version of the manual, AS has been grouped with ASD. As a result, people formerly diagnosed with AS are now considered to be on the autistic spectrum.

As autistic children grow, some of these symptoms may disappear or lessen in severity with proper care. However, autism is a lifelong condition, and no cure currently exists for it.

If any of these signs and symptoms seem familiar either with your children or someone you know, it’s advisable to speak to a doctor about it. Sometimes symptoms of ASD might also be indicative of other developmental disorders. 

6 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention (CDC). Signs & symptoms of Autism Spectrum Disorder. March 29,2021

  2. NHS UK. Signs of Autism in Children. April 18, 2019

  3. NHS UK. Signs of Autism in Adults. April 10, 2019

  4. Besag FM. Epilepsy in patients with autism: links, risks and treatment challenges. NDT. 2017;14:1-10.

  5. Children's Hospital of Philadelphia. Autism’s clinical companions: frequent comorbidities with ASD. July 01,2017

  6. Cleveland Clinic. Asperger’s syndrome: management & treatment. January 02, 2021

By Toketemu Ohwovoriole
Toketemu has been multimedia storyteller for the last four years. Her expertise focuses primarily on mental wellness and women’s health topics.