ADHD and Autism Overlap: How Often Do They Coincide?

And while there is still some stigma in today’s society, the stereotyping of people with ADHD and ASD is not as prevalent as it once was. That may be due in part to the fact that diagnoses for both disorders are on the rise, with early screenings and increased awareness helping people better understand their own behaviors or those of their loved ones.

However, there’s still one area that’s not widely understood across the general population: the connection between ADHD and autism. Many people are curious about the potential overlap between these disorders, and whether having one makes you more likely to have the other as well. In this article, we’ll take a closer look and what connections exist between these disorders and what that means for you if you’ve been diagnosed with ADHD.

How Frequently Do ADHD and Autism Coincide?

The overlap between autism and ADHD may be much larger than you think. According to certain estimates:

About 20% to 50% of children with ADHD also meet the criteria for autism
About 30% to 80% of children with autism also meet the criteria for ADHD

With figures that overwhelming, it’s surprising to discover that, for many years, psychiatry guidelines only allowed for an individual to be diagnosed with one disorder or the other. In fact, the dual diagnosis of ADHD and ASD only became permissible with the release of the latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in 2013.

Interestingly, a dual diagnosis of ADHD and autism is not as common in adults. There’s a clear reason for this distinction, however. ASD is considered a lifelong disorder, while ADHD only persists into adulthood in about one-third to two-thirds of cases.

Some studies estimate that these disorders coexist in adults at a rate of about 20% to 37%. With growing awareness of the potential for a dual diagnosis, many clinicians screen for both at the same time.

Autism and ADHD Symptom Overlap

Both ADHD and ASD are neurodevelopmental disorders affecting the central nervous system, which controls our language, memory, movement, focus, and social abilities. The fact that these same areas are affected in both disorders makes it easy to see how there might be some similarity in the symptoms for ADHD and autism.

For instance, social skills can be affected with both disorders. Some common symptoms that may appear with both ADHD and ASD are trouble picking up on social cues and avoiding eye contact.

Focus is another area that can be affected. With ADHD and ASD, the tendency to intensely focus attention on a single object or topic is fairly common.

A few other symptoms that commonly occur with both ADHD and ASD include:

Impulsivity
Difficulty managing emotions
Learning differences
Sensory challenges
Problems with executive function (organizing, planning, multitasking, etc.)

The way ADHD presents can be affected by autism, and vice versa. This is one reason why thorough screenings are important if you think you may have both disorders.

How ADHD and Autism Differ

While there may be plenty of similar areas where ADHD and ASD have some overlap, there are just as many where these two disorders differ. These distinctions can help healthcare professionals to make an accurate diagnosis, and are important for making sure that people with ADHD and autism receive the supports they need.

Some ADHD symptoms which do not overlap with autism include:

Being easily distracted
Frequently changing tasks or becoming bored with activities quickly
Hyperactivity and fidgeting

On the other hand, some autism symptoms which don’t overlap with ADHD include:

Repetitive movements, like rocking
Withdrawn behaviors
Delayed developmental milestones
Unresponsive to common stimuli

Is There a Genetic Link Between ADHD and ASD?

While there isn’t a conclusive link between these two disorders, there is a growing body of research which supports the strong likelihood of a genetic link. For example, a 2014 study found that the firstborn child of a woman with ADHD has six times the risk of having ADHD and more than twice the risk of having autism compared to the general population. However, the complex nature of genetic influences makes it difficult to pin down the exact genetic connection.

Complicating matters is the way that environmental factors are also thought to influence the development of both ADHD and ASD. For example, studies have found that some people are at a greater risk of having ADHD if they’re exposed to certain environmental toxins in utero or as a child. And with autism, contributing environmental factors may include prenatal exposure to air pollution and advanced parental age at the time of conception.

The environmental links, however, are not as strong as those tied to genetics. Environmental factors are not thought to cause ADHD or autism, but rather potentially increase a child’s risk for developing a disorder when combined with genetic factors.

Recognizing Individual Differences

So, why do some people with ADHD also have ASD, while others don’t? It’s important to remember that even when looking solely at ADHD as a diagnosis, symptoms can vary widely from one person to the next. In fact, there are three different types of ADHD, each of which can present with mild or severe symptoms:

Predominantly hyperactive-impulsive
Predominantly inattentive
Combination (both hyperactive-impulsive and inattentive)

Similarly, it’s important to remember that ASD stands for autism spectrum disorder. Along that spectrum, there are many different ways that autism can present. Symptoms can be quite severe in some, while other people with ASD go years or even decades without a diagnosis because their symptoms are very mild.

Treatment Options

There are a number of recommended treatments for individuals with both ADHD and ASD, including:

Cognitive behavioral therapy (CBT)
Therapies for executive functioning
Prescription medication
Organizational supports

Finding the right combination of treatments may require some trial and error. What works and what doesn’t is based on a number of factors, so it’s important to work closely with psychiatrists, therapists, and healthcare professionals to find what is most effective on an individual level.

If you’re currently struggling with ADHD, or if you’re wondering if you meet the requirements for an ADHD diagnosis, reach out to a licensed practitioner to learn about your options.

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