What Is Autism Spectrum Disorder? A Guide for Parents

Many parents begin researching autism after noticing differences in their child’s development. Maybe your child is not speaking as expected, struggles with social interaction, or seems overwhelmed by sounds or textures.

If you are asking “What is autism spectrum disorder?”, you are not alone. Thousands of families search for information about autism each year as they try to better understand their child’s development.

Autism spectrum disorder (ASD) is a neurodevelopmental condition that affects how a person communicates, interacts socially, processes information, and experiences the world around them. Autism spectrum disorder affects children of all races and nationalities. Autism is called a spectrum because it can present differently in every individual. The term 'spectrum' in autism spectrum disorder refers to the wide range of symptoms and the severity of these symptoms.

At the Chicago Autism Testing Institute, we work with families across Chicago and the surrounding suburbs to provide comprehensive autism testing and autism evaluations for children. Understanding what autism is and how it presents in children is often the first step toward finding clarity and support.

The number of children diagnosed with autism spectrum disorder is rising, making early diagnosis and intervention increasingly important.

This guide explains what autism spectrum disorder is, how it affects children, the signs parents may notice, and how autism is diagnosed.

What Is Autism Spectrum Disorder?

Autism spectrum disorder is a developmental condition that affects how the brain processes information related to communication, behavior, and social interaction. It is classified as one of several developmental disorders, as outlined in authoritative sources like the DSM-5.

Autism spectrum disorder includes conditions that were once thought to be separate, such as autism and Asperger's syndrome.

Children with autism may experience differences in areas such as:

• Social communication
• Language development
• Emotional regulation
• Sensory processing
• Behavior patterns
• Play and interaction with others

Because autism exists on a spectrum, some children may need significant daily support, while others may have milder differences that become noticeable only in certain environments like school or social settings.

No two autistic individuals are exactly alike. Each child has their own unique strengths, interests, and challenges.

Although autism can be diagnosed at any age, it is described as a developmental disorder because symptoms generally appear in the first two years of life.

Why Is It Called a “Spectrum”?

The term autism spectrum disorder reflects the wide range of ways autism can appear.

No two autistic people are exactly alike. Autistic people show a diversity of traits, strengths, and challenges, and many prefer identity-first language to reflect their experiences and community preferences.

Some children with autism may:

• Have delayed speech or limited verbal communication
• Prefer independent play rather than social interaction
• Show repetitive behaviors or strong routines
• Experience sensory sensitivities

Other children may:

• Speak fluently but struggle with social communication
• Have intense interests in specific topics
• Experience anxiety related to change or unpredictability
• Have difficulty interpreting social cues

Because autism presents differently for every individual, evaluations must be comprehensive and individualized.

Common signs and autism symptoms often appear early in development, especially when there are obvious delays in language skills and social interactions.

What Causes Autism Spectrum Disorder?

Researchers do not point to a single cause of autism. Instead, autism is believed to result from a combination of genetic and environmental factors that influence early brain development.

Current research suggests that autism may involve differences in how certain areas of the brain communicate with each other. These differences affect how individuals interpret social cues, language, and sensory information.

Several risk factors have been identified for autism spectrum disorder. Having a sibling with autism increases the likelihood of a child being diagnosed with autism. Older parental age at the time of pregnancy is also linked with a greater risk of autism. Additionally, certain medications taken during pregnancy, such as valproic acid and thalidomide, have been associated with a higher risk of autism in offspring.

Importantly, autism is not caused by parenting style or vaccines. Scientific research has repeatedly confirmed that vaccines do not cause autism. Autism is simply one way that human brains can develop differently.

Signs of Autism in Children

Autism signs can appear as early as toddlerhood, although some children are diagnosed later.

Concerns about a child's behavior and child's development often prompt parents to seek evaluation. Parents, caregivers, or teachers may notice developmental differences in areas such as communication, social engagement, or behavior, which can lead to further assessment for autism spectrum disorder.

Monitoring developmental milestones is important for identifying developmental delays. Pediatricians and specialists use these milestones to evaluate a child's progress in language, social, and motor skills, helping to identify early signs of autism spectrum disorder and other developmental concerns.

The behaviors listed below are common early signs used to understand and identify autism spectrum disorder:

Common early signs of autism include:

• Limited eye contact
• Lack of response to name
• Delayed speech or language skills
• Repetitive movements or behaviors
• Intense interest in specific topics or objects
• Difficulty with social interactions

Children with autism spectrum disorder usually show some signs of delayed development before they're 3 years old. Signs of autism spectrum disorder often appear early in development when there are obvious delays in language skills and social interactions.

Communication Differences

Autistic children may have trouble communicating and may find it difficult to express emotions. They may:

• Have delayed speech development
• Use fewer gestures like pointing or waving
• Have difficulty responding to their name
• Repeat words or phrases
• Struggle with conversational turn-taking

Social communication deficits may include difficulties in understanding tone of voice, facial expressions, or body language.

Social Interaction Differences

Some autistic children may have delayed or limited social interactions. They may:

• Avoid or limit eye contact
• Prefer playing alone
• Have difficulty sharing attention with others
• Struggle to understand social cues or facial expressions
• Find peer relationships challenging

Repetitive Behaviors and Routines

Autistic children often display patterns of repetitive behavior or strong routines. These repetitive behaviors and routines are among the specific symptoms specialists look for when diagnosing autism spectrum disorder.

Examples include:

• Hand flapping or rocking
• Repeating actions or movements
• Intense interest in specific objects or topics
• Distress when routines change

Restricted interests and repetitive behaviors may include a strong attachment to specific objects or routines.

Sensory Sensitivities

Many autistic children experience sensory processing differences.

They may be especially sensitive to:

• Loud sounds
• Bright lights
• Certain textures
• Strong smells
• Busy environments

Some children may also seek sensory input, such as spinning, jumping, or deep pressure.

Impact on Child’s Development

Autism spectrum disorder (ASD) can have a significant influence on a child’s development, especially in the areas of social communication, social interaction, and repetitive behaviors. According to the Diagnostic and Statistical Manual (DSM-5), children with ASD may find it challenging to use and interpret both verbal and nonverbal communication, such as making eye contact, reading facial expressions, or understanding body language. These differences can make it harder for children to develop age-appropriate social skills and connect with peers.

The American Psychiatric Association emphasizes the importance of early intervention for children on the autism spectrum. Behavioral therapies and educational programs are key tools that help children improve their social communication, reduce repetitive behaviors, and learn new skills. By starting these supports early, families can help their children build on their strengths and make meaningful progress in their daily lives.

The Centers for Disease Control and Prevention (CDC) also highlight that early diagnosis and treatment can have a lasting positive impact on a child’s development and future opportunities. With the right support, children with autism spectrum disorder can continue to grow, learn, and thrive in their own unique ways.

When Should Parents Consider Autism Testing?

If developmental concerns persist, parents may want to consider autism testing for their child. Parents and caregivers should discuss any concerns about their child's behavior with their child's health care provider, who can help initiate the evaluation process.

Many families pursue autism testing in Chicago when they notice:

• Delayed language development
• Difficulty with social interaction
• Repetitive behaviors
• Sensory sensitivities
• Concerns raised by pediatricians or teachers

Diagnosing autism spectrum disorder often starts with routine well-checks at 18 and 24 months. The American Academy of Pediatrics recommends autism screenings at the 18-month and 24-month visits.

Autism evaluations can be conducted as early as 18 months of age, and early identification can help children access supportive services sooner.

How Autism Is Diagnosed

Autism spectrum disorder is diagnosed through a comprehensive developmental evaluation conducted by trained professionals. An accurate diagnosis is essential and involves a multi-step process, including thorough assessments, developmental history, and expert consultations.

The evaluation process typically includes:

• Parent interviews and developmental history
• Standardized autism assessment tools
• Direct observation of the child
• Behavioral and social communication evaluation
• Clinical interpretation of results, often using a diagnostic manual such as the DSM-5-TR, and may include input from a developmental pediatrician

If a pediatrician notices possible signs of autism, they will refer the child to a specialist for further evaluation. The diagnostic evaluation for autism may involve a team of healthcare providers, including child neurologists and developmental pediatricians.

At Chicago Autism Testing Institute, autism evaluations are designed to provide families with a thorough understanding of their child’s development.

Our clinicians use evidence-based assessment tools to ensure accurate and meaningful results.

Co-Occurring Conditions

Many children with autism spectrum disorder (ASD) experience additional challenges known as co-occurring conditions. These can include mental health conditions like anxiety, depression, or attention-deficit/hyperactivity disorder (ADHD), as well as sleep disorders and certain genetic disorders. In fact, research shows that about 70% of children with autism have at least one co-occurring condition.

Some genetic conditions, such as Fragile X syndrome and Tuberous Sclerosis, are more common in children with ASD. These genetic disorders can affect a child’s development and may require specialized care. It’s important for healthcare providers to consider these co-occurring conditions when creating a care plan, as addressing them can improve a child’s overall well-being and quality of life.

Tools like the Autism Diagnostic Observation Schedule (ADOS) are often used not only to diagnose autism spectrum disorder but also to help identify other conditions that may be present. By taking a comprehensive approach, families and providers can ensure that children with autism receive the support they need for all aspects of their health.

Why Early Diagnosis Matters

Early autism diagnosis can open the door to supportive services that help children build important skills.

Early intervention may support development in areas such as:

• Communication and language
• Social interaction
• Emotional regulation
• Daily living skills
• Play and learning

Research shows that when children receive therapy early, they often make significant progress in communication and social development.

Early diagnosis also provides families with clarity and guidance during an uncertain time.

Support Services After an Autism Diagnosis

After an autism diagnosis, families may receive recommendations for therapies that support their child’s development. People with autism spectrum disorder may be referred to health care and service providers who specialize in various intervention approaches, including behavioral, psychological, educational, occupational, physical, or speech-language therapy.

Because Chicago Autism Testing Institute is part of North Shore Pediatric Therapy, families have access to a wide range of services across Chicagoland.

A health care provider may also prescribe medication to treat specific symptoms associated with autism spectrum disorder.

Recommended services may include:

Applied Behavior Analysis (ABA Therapy)

ABA therapy focuses on developing communication, social, and adaptive skills while supporting positive behavior.

Speech Therapy

Speech therapists help children develop language skills, improve communication, and build social interaction abilities.

Occupational Therapy

Occupational therapy supports sensory processing, motor development, and daily living skills.

Mental Health Support

Some children benefit from counseling or emotional support services that help them navigate social and emotional challenges.

These therapies work together to help children build independence and confidence.

Navigating the Healthcare System

For families of children with autism spectrum disorder (ASD), navigating the healthcare system can feel overwhelming. Working closely with your child’s healthcare provider is essential to developing a care plan that addresses your child’s unique needs. This plan may include behavioral therapies, educational programs, and other interventions tailored to support your child’s development.

Families should also be aware of the many resources available, such as genetic testing, referrals to pediatric neurologists, and local support groups. The Diagnostic and Statistical Manual (DSM-5) provides a framework for understanding spectrum disorder and can help guide conversations with your child’s doctor or specialists.

Being proactive—by recognizing early signs, seeking autism treatment, and addressing mental health conditions—can make a significant difference in your child’s developmental journey. By advocating for your child and staying informed, you can help ensure they receive the best possible care and support as they grow.

Strengths and Potential in Autistic Children

While autism can present challenges, it is also associated with many strengths.

Recognizing a child's strengths and understanding each child's unique qualities are essential for developing individualized recommendations and interventions for children with autism spectrum disorder.

Many autistic people demonstrate:

• Strong attention to detail
• Deep focus on interests
• Unique problem-solving abilities
• Creativity and innovation
• Honest and direct communication

Understanding autism as a neurological difference helps families support children in ways that honor their strengths while addressing areas of difficulty.

Supporting Families Through the Autism Journey

Learning that your child may have autism can bring many emotions — relief, uncertainty, concern, and hope. Family members, including caregivers, siblings, and other family members, play a crucial role in supporting children with autism throughout the diagnosis, therapy, and intervention processes.

For many families, the most helpful first step is gaining a clear understanding of their child’s development through a comprehensive evaluation.

At the Chicago Autism Testing Institute, our mission is to provide compassionate, evidence-based autism evaluations for children in Chicago and the surrounding suburbs.

We work closely with families to ensure they understand the evaluation process and feel supported every step of the way.

If you are searching for autism testing in Chicago or want to learn more about autism evaluations for your child, our team is here to help. Contact us today to schedule an evaluation and begin the journey toward clarity, understanding, and support.