Recognizing the Signs: Understanding Autism Spectrum Symptoms in Children

Like Attention Deficit Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD) is a very common neurodevelopmental disorder. In fact, about 1 in 36 children have ASD, according to the Centers for Disease Control. The American Psychiatric Association describes Autism as a complex developmental condition. It involves ongoing symptoms of social communication and interaction differences, restricted interests, and repetitive behaviors.

Part of why Autism might be considered complex is that these symptoms can present in many ways. Differences in how Autism looks from person to person, which may veer outside of stereotypes, can make it harder to detect ASD in some kids than others. Understanding the diverse ways symptoms of Autism Spectrum Disorder might present in childhood can help.

This article will give parents a more thorough idea of ASD and how to recognize the signs. First, we'll give an overview of ASD symptoms and examples of the symptoms that may lead to an Autism diagnosis. Then, we'll talk about what symptoms may look like in a child's early years, from infancy to preschool age, and the importance of early intervention.

Overview of Autism Spectrum Symptoms

Autism Spectrum Disorder is diagnosed using the most recently updated Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria. Over time, the way providers diagnose Autism has changed, as has our overall understanding of the condition. Let's go over examples of what Autism symptoms might look like.

Social communication difficulties

As of 2024, DSM criteria requires that individuals experience persistent symptoms in the following three areas of social communication and interaction for a diagnosis of ASD to occur. Note that the examples below aren't exhaustive.

• Challenges in verbal and nonverbal communication, which could include poor eye contact, trouble understanding facial expressions, body language, or gestures from others, exaggerated body language and expression, or a personal lack of facial expressions and gestures.
• Trouble with social-emotional reciprocity. For example, unusual ways of initiating or engaging in social interactions, not responding to one's name, tangential speech (e.g., may go on about special interests), and poor pragmatic or social use of language.
• Increased difficulty developing, maintaining, or understanding relationships. For example, not understanding that one needs to adjust one's behavior to suit different social contexts, having low interest in peers, or having difficulties sharing imaginative play.

These symptoms will occur alongside at least two out of four symptoms of restricted, repetitive patterns of behavior, interests, and activities and developmental considerations (e.g., child’s age) will also be taken into account.

Repetitive behaviors and restricted interests

Similar to differences in social interaction and communication, repetitive behaviors and restricted interests can vary extensively in kids with Autism. Here are some common examples.

Engaging in repetitive movements or actions

Kids with Autism may engage in repetitive or unusual body movements such as:

• Repetitive hand movements (flapping, clapping, twisting, or flicking fingers)
• Rocking, swaying, or stepping from foot to foot
• Repeating words or phrases (echolalia)
• Hair twirling
• Lining up toys and objects
• Pacing 

Some kids may also turn light switches off and on, open and close doors, speak in a usually formal way, or have noticeable differences in body posture. These symptoms can sometimes mimic other disorders as well (e.g., OCD) which is why consulting with a qualified health provider is so important.

Insisting on sameness

Kids with Autism Spectrum Disorder frequently have difficulty with transitions or change beyond what is typically seen in other children their age. For example, kids may have intense emotional reactions to changes in certain routines and patterns in their lives, whether it is changes to a daily routine, changes to where people are seated at the family dinner table, or an object being out of its typical place. Some kids have verbal rituals, like having one or more sentences they may say in the exact same way, with the same words and tone, each time. Children may be more rigid or inflexible than others.

Fixation on specific topics or objects

Many people with ASD have special interests. A special interest refers to intense interest in a certain topic, such as horses, fish, cars, medicine, or a specific movie, book, or TV series. Whether it is a common or uncommon interest, the child will often obtain extensive information regarding the interest. Kids may also form atypical attachments to unusual objects.

Sensory sensitivities

Sensory processing differences or sensory sensitivities are one of the ways restricted, repetitive behaviors, activities, or interests can manifest. Like other ASD symptoms, what they can look like might surprise you.

Over or under-sensitivity to sensory stimuli

Autistic children may be over or under-reactive to sensory stimuli. Many experience a combination of both. Due to sensory differences, a child could under-react when hurt or injured, have difficulty wearing certain fabrics, have trouble with tags in clothing or sock seams, or eat a limited number of foods.

Unusual reactions to sensory input

Examples of unusual reactions to sensory input may include but aren't limited to:

• Indifference to heat or cold
• Abnormally high pain tolerance
• Adverse reactions to specific sounds
• Excessive smelling or touching of objects
• Sensitivity to certain textures (e.g., food textures, fabric textures)
• Visual fixation on things like lights, water, or spinning objects

More than 90% of autistic children experience atypical sensory behaviors or responses, so this is considered a very common symptom.

Early Signs of Autism Spectrum Symptoms in Children

How is Autism detected earlier in life, before kids are in situations where certain symptoms might be more apparent? Here are some of the hallmark symptoms providers look for in infancy, toddlerhood, and preschool-aged kids.

Infancy

Differences in social interaction and communication can show up in early signs of Autism. Here are two common Autism Spectrum Disorder symptoms parents may notice in infancy.

Lack of eye contact or social smiling

Research indicates that babies who later get diagnosed with Autism start to make less eye contact as young as around two months old. If your child's eye contact declines, speak to a healthcare provider. Lack of social smiling (for example, a baby may not smile back at parents) is another common symptom.

Delayed babbling or gestures

Speech delays, when present, are some of the first symptoms parents may notice, alongside lack of eye contact or social smiling. Infants with Autism may not coo or babble. They may make fewer gestures (like pointing) than other children. At six months old, kids usually respond to their name. Some, but not all, infants and young children with Autism may not.

Toddlerhood

Although many kids don't get diagnosed until later, kids usually start showing signs in toddlerhood, whether those signs are very apparent or more subtle. Here are some common Autism Spectrum Disorder symptoms in toddlers.

Lack of interest in pretend play

Some, but not all, autistic children may lack interest in or have trouble with pretend play, also called make-believe. Since pretend play is common in this age group, parents who have a child with this symptom may notice it.

Difficulty with transitions or changes in routine

You may notice that your child has a harder time with change than other kids in their toddler years. For example, you may notice that your child gets upset or frustrated by small changes in life or daily routines. They may also have unique routines of their own and show distress when unable to carry them out.

Preschool age

When children are around four years old and enter preschool, parents may notice marked differences in communication skills or social interactions, repetitive patterns, or restricted interests. Some of these could be more prevalent because their child is now around other kids, which allows parents to observe how they interact.

Difficulty with social interactions and making friends

Difficulty with social interactions and making friends can manifest in very different ways. At around four years old or younger, you may notice that your child:

• Has less interest than peers their own age
• Has atypical social skills, even if they want to interact or make friends
• Exaggerated body language or facial expression
• Flat affect or fewer facial expressions
• Does not initiate social interaction or contact with others
• Does not understand social norms
• Prefers solitary play

Some kids will have strong language skills and may even speak in an overly formal way. Other kids may show little to no verbal communication.

Repetitive behaviors or obsessions with specific topics

Many parents start to notice special interests in kids with Autism around preschool-elementary school age, whereas younger kids who will later develop one may not have found theirs yet. Kids may seem obsessed with the topic and obtain all the information they can. You might also notice repetitive behaviors like repeating words and phrases or repetitive body or hand movements.

Importance of Early Intervention and Diagnosis

The American Academy of Pediatrics (AAP) recommends that all youth be screened for Autism at 18 months and 24 months. Not all autistic people are diagnosed at this time. When possible, early intervention and diagnosis are important for more than one reason.

Benefits of early intervention for children with ASD

When kids get an ASD diagnosis, they can access a range of specialized services for the diagnosis. For example, kids and parents can get referrals for occupational therapy, speech therapy, social skills training, sensory integration therapy, applied behavior analysis (ABA), and opportunities to work with other providers. Kids may be able to access special education services with an Autism diagnosis, including a 504 plan or individualized education plan (IEP). These can include classroom or assignment modifications, which may be helpful for kids coping with sensory issues, differences in their understanding of instructions, and other symptoms.

An accurate Autism diagnosis can also help children understand themselves better. While it's common for autistic people to have at least one co-occurring condition, research shows that undiagnosed Autism is associated with increased mental health problems, including anxiety, depression, and various other social or emotional problems. Rates of post-traumatic stress disorder and some types of trauma or abuse can also be higher. Once aware that a child is autistic, parents can teach kids to speak up about their experiences, identify dangerous situations, and understand or verbalize their emotions. They may be more able to access coping skills and tools that support their mental health.

Challenges in diagnosing ASD in young children

All autistic people present differently. Sometimes, providers who don't have an extensive understanding of Autism will not know how to detect Autism symptoms in kids, which can cause challenges for parents and children. This is especially common for kids with an atypical presentation (e.g., hyper-expressive children with strong language skills) or who meet certain developmental milestones.

Research shows that women and girls are more likely to go undiagnosed, which we hope to change with an increased understanding of how Autism can present. Another possible barrier is cultural and linguistic differences. Providers should have training in cultural sensitivity so that they can help a child get a thorough and appropriate Autism evaluation.

Resources and support available for families of children with ASD

It can be overwhelming and difficult to find the right resources. Whether you want to learn about Autism, find resources and support, or learn more about ways to get your child an evaluation, here are some resources that can help:

• Learn about early intervention and how to ask for an evaluation for kids aged 3+ here. 
• Support groups for families who have kids with disabilities, like Parent-to-Parent or the Joon ADHD Parent Support Group on Facebook.
• Learn about Autism and get resources from the Autism Society of America (ASA).

Parents with children under three can obtain an evaluation through their local early intervention system. Find early intervention information for kids under age three in your US state here. 

Conclusion

Recognizing and understanding Autism Spectrum Disorder symptoms in children is important because it helps parents understand how to best support their child and provides access to resources. When a provider diagnoses ASD, they'll use the symptom criteria in the DSM and will look for symptoms like social communication differences, repetitive behaviors, restricted interests, and sensory sensitivities.

It's important to seek help if you're concerned about your child's development. Getting an accurate diagnosis means that kids can access school or classroom accommodations and therapies or treatments they might benefit from. It can also qualify children for SSI benefits and may help parents understand how to accommodate a child's needs or support them at home.  

Autism is a complex neurodevelopmental disorder that may present in unexpected ways. Resources like the CDC's early intervention services by state and guidance on how to seek an Autism evaluation can be helpful for parents who suspect that their child may have ASD.