What Is the Difference Between ADHD and Autism?

Medically reviewed by Kira Graves, PhDMedically reviewed by Kira Graves, PhD

Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are the two most common kinds of neurodevelopmental disorders, which are conditions that develop during childhood that impact how you learn, think, communicate, and behave.

ADHD and autism can both affect your personal, social, school, and work life. However, the way they affect these areas of your life is different.

ADHD primarily affects attention and impulsivity, which can result in social rejection. ASD directly impacts social communication and interaction, which can prevent you from developing and maintaining relationships since you may be unable to adjust your behavior to various social settings.

In the United States, about 10% of children and 4% of adults have ADHD. About 2% or 3% of children and adults in the U.S. have ASD.

Symptoms of ADHD vs. Autism

While both ADHD and ASD affect your attention span, social interactions, speech, movement, self-control, and impulsivity, the specific ways they impact each area can differ. With both conditions, other people may perceive the symptoms as a lack of boundaries or social awkwardness, which may lead to social isolation or rejection.

Differences

Although ADHD and autism are the two most common developmental disorders, they are different in prevalence, severity, when they appear, how they are diagnosed, and how they are treated.

ADHD Is More Common

ADHD is the most common neurodevelopmental disorder in childhood that can persist into adulthood. ADHD affects around 10% of children and 4% of adults in the U.S.

Risk factors for ADHD include differences in temperament, low birth weight, history of child abuse and neglect, exposure to toxins that harm the nervous system, infections, or exposure to alcohol while in the womb. Research also indicates that genetics play a role in the development of ADHD.

According to the most recent data, about one out of every 36 children has ASD. That means about 2% or 3% of children and adults in the U.S. have autism.

Risk factors for ASD include having a sibling with autism, having certain genetic or chromosomal conditions, experiencing complications at birth, and being born to older parents.

ASD Is Usually Diagnosed Earlier

Although both disorders are diagnosable in children, ASD symptoms can typically be recognized earlier. Signs of autism can be seen when a child is as young as 12-24 months. Signs of ADHD can initially be noticed in the first 12 years of life, though ADHD is often diagnosed when a child is in elementary school.

This variance in age at diagnosis is due to the differences in the conditions’ symptoms. Autism can be identified in infants who aren’t meeting their developmental milestones for communication, social interaction, or motor and cognitive skills.

Meanwhile, ADHD is most often identified when a child starts elementary school since this is when inattention can be more obvious and impairing. If a child is diagnosed with ADHD earlier, such as in preschool, the main symptom leading to the diagnosis is usually hyperactivity.

Symptoms associated with autism can also be more obvious, such as delayed language and social skills. ADHD symptoms can appear in ways that some might consider normal behaviors in toddlers, such as excessive motor activity, so there might be a delay in diagnosis.

Healthcare Providers Use Different Diagnostic Tests

ADHD can be diagnosed by mental health professionals, like psychologists or psychiatrists, or by a primary care provider, like a pediatrician. Providers refer to criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) to identify symptoms for diagnosis. ADHD can also be diagnosed using a neuropsychological assessment, which assesses how the brain functions and may include tests on factors like memory.

Diagnosing autism can be more complex. Children are typically screened for developmental delays during their routine wellness check-ups. If delays are detected, they may be referred to a team of healthcare providers for further testing. This team could include child neurologists, developmental pediatricians, speech-language pathologists, child psychologists and psychiatrists, educational specialists, and occupational therapists.

The diagnostic evaluation for autism is often more wide-sweeping than it is for ADHD. The diagnostic process for autism can include medical and neurological examinations and observation of the child’s behavior. They might assess the child’s cognitive and language abilities, as well as age-appropriate skills needed to complete daily activities like eating and getting dressed.

The diagnostic process for autism will also likely include an in-depth conversation with the caregivers about the child’s behavior and development. The provider may also want to conduct blood and hearing tests.

If you’re an adult and think you may have signs of autism, you can ask your healthcare provider for a referral for an ASD evaluation. Although evaluation for autism in adults is still being developed, adults may be referred to a neuropsychologist, psychologist, or psychiatrist who has experience with ASD.

The Treatment Options for ADHD and Autism Aren’t the Same

While symptoms of ADHD and ASD can be managed through medication, ongoing therapy treatments vastly differ.

Children with ADHD can be treated with behavior therapy, and their caregivers can go through behavior management training to help their child cope. Adults with ADHD can manage their symptoms with psychotherapy (talk therapy) and skills coaching. In their therapy sessions, children and adults can learn organizational skills and calming techniques.

ASD treatment is more varied. ASD treatment involves learning social, communication, and language skills. A mental healthcare provider may help you reduce behaviors that interfere with daily functioning and learn life skills for living independently.

ASD treatment can involve applied behavior analysis, where therapists encourage behaviors and skills that will help you cope with your ASD. Other forms of treatment, including speech and language therapy, occupational therapy (OT), and cognitive behavioral therapy (CBT) may also be involved.

OT is a form of rehabilitation therapy that helps you improve your ability to carry out daily tasks. CBT is a form of therapy that helps you identify thoughts and behaviors that may negatively affect your life and restructure them into positive and healthier patterns.

Similarities

ADHD and ASD are similar in when they develop, the demographic they impact, and their mental health risks. And while treatment is one of their differences, it’s also one of their similarities.

Both Start in Childhood and Are More Common Among Boys

ADHD and autism both begin in childhood. Sometimes these conditions are not diagnosed until adulthood—that doesn’t mean the condition was not present in childhood; it just means it went undiagnosed. In fact, one of the diagnostic criteria for ADHD is that the symptoms had to have been present before the age of 12.

While both conditions start in childhood, they also both continue through adulthood. However, for some people, ADHD symptoms may become milder over the years, which is why ADHD rates are lower among adults than children.

ADHD and autism are more often diagnosed in males than females. About 13% of boys and 6% of girls are diagnosed with ADHD. Meanwhile, autism is four times more common among boys than girls.

Medication Can Help Manage Symptoms

While there are no medications that can lead to a complete reversal of ADHD or ASD, medications are available to help manage symptoms.

ADHD may be managed with stimulants and non-stimulants. Stimulants have a calming effect on children with ADHD who are hyperactive. Non-stimulants can improve focus, attention, and impulsivity. Non-stimulants are usually prescribed if you have side effects from stimulants. They may also be prescribed in combination with stimulants to increase effectiveness.

Medications can’t treat the core symptoms of ASD, but they can help manage co-occurring symptoms. For instance, certain medications can help manage high energy levels, inability to focus, or self-harming behavior like head banging or hand biting. Medication can also help manage co-occurring conditions like anxiety or depression.

Both ADHD and Autism Have Negative Long-Term Effects if Undiagnosed

People with ADHD and autism report trouble with getting appropriate support, diagnosis, and treatment for difficulties associated with their conditions.

Research has shown that these troubles can lead to poorer outcomes for the person and their families.

For example, someone with ADHD or autism who doesn’t get the proper diagnosis or support can have academic struggles and an increased prevalence of depression and anxiety. They may also have higher rates of imprisonment, divorce, driving accidents, unemployment, suicidal thoughts and behaviors, and other mental health issues.

Can You Have Both ADHD and Autism?

It’s possible to have both ADHD and ASD. About 14% of children with ADHD also have autism, and 50-70% of people with autism also have ADHD.

Research suggests that people who have both conditions often experience more impairment in their lives than people who have just one of the conditions. This includes greater challenges with mental, emotional, and social factors.

However, research on how having the two conditions can affect people is still early. That’s because the previous version of the DSM—based on its exclusion criteria in the diagnosis of autism—didn’t allow for a dual diagnosis of ADHD and autism. Now that a dual diagnosis is allowed, more research can be done.

When To Seek Care and Who To Contact

If symptoms of ADHD or ASD impair your or your loved one’s daily functioning in areas of your life such as school, work, and relationships, you may want to consider setting up an appointment with a primary healthcare provider or mental health professional. Children might even be able to use services at school.

If your insurance or the medical office requires it, the primary care provider can refer you to a neurologist, psychologist, or psychiatrist. These specialists can help diagnose and manage your symptoms.

A Quick Review

ADHD and autism are two of the most common types of neurodevelopmental disorders that start in childhood and persist into adulthood. The conditions share several similarities and differences.

ADHD and autism can both affect the way you interact, focus, speak, and act. They are both more commonly diagnosed in boys, and their symptoms can be managed through therapy and medication. However, the age at which ADHD and autism are diagnosed, how they are diagnosed, and the specific symptoms they cause can be different.

It’s also possible to have both conditions. If you suspect you or a loved one has ADHD or autism, consider visiting a healthcare provider to talk about symptoms and potential next steps.

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