ADHD vs. Autism: What These Different Disorders Look Like in Children

When the Diagnostic and Statistical Manual of Mental Disorders (DSM-5)—a.k.a. the diagnostic bible for psychiatry—was updated in 2013, it marked the first time that a person could be diagnosed with both ADHD and autism.

“The conditions themselves look very different on paper, but there’s confusion between the two of them because they can sometimes co-exist,” says Elisa I. Muniz, MD, developmental behavioral pediatrician and assistant professor of pediatrics at the Rose F. Kennedy Children’s Evaluation and Rehabilitation Center at Einstein/Montefiore in New York City. “Though estimates vary widely, it has been reported that up to 50 percent of children with autism have symptoms of ADHD.  And approximately 14 percent of children with ADHD have autism. A child can be diagnosed with both conditions because distinguishing between the two can be challenging, especially in younger children.”

According to the Centers for Disease Control and Prevention, 9.4 percent of children in the U.S., or almost 1 in 10, have ADHD, while 1 in 59 has autism. ADHD is a disorder that can affect adults and children and is characterized by trouble with attention (the ability to focus), hyperactivity (the ability to sit still), and impulsivity (the ability to control impulsive actions).

Autism spectrum disorder, on the other hand, is a developmental disability that affects an individual’s ability to communicate, interact socially, and form relationships. It’s a lifelong, complicated condition that can range from mild to severe, and may include an inability to speak or delayed speech, repetitive movements, and repetition of sounds and phrases, among other symptoms.

Social interactions

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“A child with ADHD is interested in making friends, seeks out attention from others, and is generally motivated to interact with others,” says Dr. Muniz. That child “is usually persistent in engaging others, utilizing their ability to make good eye contact, and use facial expressions and gestures to engage others in activity. However, someone with ADHD may have trouble keeping friends. They may face challenges such as having trouble waiting their turn, difficulty participating in an activity that doesn’t capture their attention, and interrupting when others are speaking.”

Children with autism, on the other hand, often “struggle with initiating social interactions and in maintaining those relationships over time,” says Dr. Muniz. “They may avoid eye contact when spoken to, and at times, appear to avoid people and social situations. A child with autism may be contently playing alone or even alongside another child, but may struggle to make attempts to engage the other child in their activity.”

Energy levels and focus

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The classic high energy level of someone with ADHD differentiates them from someone with autism. “Children with ADHD are more likely to be distractible, having trouble finishing tasks, and can be overly active,” says Geraldine Dawson, PhD, professor of psychiatry and behavioral sciences at Duke University in Durham, North Carolina. “Many children with autism can be unusually focused on a task and have trouble transitioning from one activity to another. Children with autism also tend to have more challenges understanding social cues and interacting with other children.” Girls are often underdiagnosed for ADHD, in fact, because they don’t always have those classic hyperactive qualities.

Sensitivity

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A main symptom of autism is an extreme sensitivity to tastes, smells, textures, and sounds—especially loud noises. Many people with the disorder are hypersensitive to bright lights or certain light wavelengths (fluorescent lights, for example). And certain types of touch (light or deep) can feel extremely uncomfortable. Discover other autism symptoms you may not realize.

Organizational skills

Here’s where the two conditions’ differences can be very apparent: Children with autism are very precise and hyper-organized—making sure there’s a place for everything and everything in its place—whereas a child with ADHD struggles with organization. “Although both autism and ADHD are associated with some difficulties in organizational skills, children with ADHD are more likely to become distracted and have trouble following through with instructions,” says Dr. Dawson. “Children with autism, on the other hand, have more difficulty flexibly changing their learning strategies to adapt to different tasks.”

Interests and hobbies

Someone with ADHD may have a bunch of varied interests, whereas those with autism will show a restrictive, hyper-focused interest in one particular topic. But that’s not always true. “ADHD describes the pattern of behavior of inattention and/or hyperactivity and impulsivity that is inconsistent with developmental level and causes challenges in functioning,” says Elizabeth Harstad, MD, developmental behavioral pediatrician at Boston Children’s Hospital in Boston, Mass. “Autism describes significant challenges with social communication and restrictive, repetitive patterns of behavior or functioning.” And yet, adds Dr. Harstad, “it’s hard to make a universal statement about how hobbies and interests differ among kids with ADHD versus autism. While some children with autism fixate on certain interests, others have a broad range of interests and hobbies. Additionally, some children with ADHD have a broad range of hobbies and interests, while others prefer only a few things.”

Speech development

While both conditions develop in childhood, it’s evident earlier in children with autism. “Autism generally presents itself in the first few years of life with a child having difficulty communicating, challenges with understanding others’ perspectives, and repetitive or rigid behaviors or movements,” says Dr. Harstad. “ADHD often presents by early- to mid-elementary school age.” (Learn what you should try to avoid saying to a parent of child with autism.)

Early development

Just as with speech, other areas of early development may look different in children with autism versus those with ADHD. “Many of my parents of children with autism say they knew something was different early on,” says  Deborah A. Pearson, PhD, professor of psychiatry and behavior sciences at The University of Texas Health Science Center at Houston, in Houston, Texas. “I had one parent, for example, who said, ‘When he was a baby he wouldn’t look me in the eye.’ On the other hand, ADHD doesn’t usually become evident until they’re going to preschool and are compared to other children.”

Nonverbal behavior

“Those with ADHD display pretty typical nonverbal behavior—they make good eye contact, use gestures, and have a normal range of facial expressions, but in autism, this isn’t the case,” says Dr. Pearson. “With autism, you’ll see inconsistent or nonexistent eye contact, they may not use gestures, and they may have a limited range of expressions or very exaggerated or neutral facial expressions.” (Watch out for these persistent autism myths.)