ADHD vs. Autism: What’s the Difference?

If you feel like you hear people talk about attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) a lot more than you used to — and often in the same breath — you aren’t imagining things. There’s been a steady rise in both diagnoses over the past few decades.

And thanks to social media, there’s been an explosion of information sharing — including the firsthand experiences of autistic people and those with ADHD and ASD. If you aren’t familiar with these conditions, you can learn about them by hearing directly from people who have them.

As we broaden our horizons, questions are bound to come up. Is ADHD on the autism spectrum? Can you have both conditions? How can you tell the difference? We asked developmental pediatrician Mary Wong, MD, to help us understand the complicated history of (and relationship between) autism and ADHD.

“Autism spectrum disorder and attention-deficit/hyperactivity disorders are both neurodevelopmental disorders, which means something about the way your brain grew is different from that of a neurotypical person,” Dr. Wong explains. In both cases, the exact way your brain is different will vary from person to person. That variation changes both the severity of the condition and the impact it has on your day-to-day life.

ADHD and ASD share some common traits, but they’re distinct conditions. In order to understand the differences between them, you need to first understand why people so often conflate them. And that requires a short history lesson.

Diagnosing ADHD and ASD

We’ve become more familiar with ADHD and ASD over the past several decades, but that’s not the only reason we’re seeing more diagnoses. It’s also because the diagnostic criteria for both conditions changed.

ADHD and autism used to be mutually exclusive diagnoses: You couldn’t have both. That put providers in a real bind because it meant they had to choose what symptoms to treat and which to ignore. Finally, in 2013, the American Psychiatric Association released the fifth edition of their Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The DSM-5 changed the rules, allowing people who fit the criteria for both ADHD and ASD to get a dual diagnosis.

That change opened the floodgates. Turns out, ADHD is the most common co-occurring condition autistic people experience. When we say it’s a frequent dual diagnosis, we aren’t exaggerating. Researchers estimate that between 50% and 70% of autistic people also have ADHD.

The same isn’t true the other way around: Most people with ADHD aren’t autistic. But the numbers are still striking. A 2020 study estimates that 1 out of every 8 people with an ADHD diagnosis also have ASD.

They’re impressive statistics, but what do they mean, exactly? It’s a question that researchers are still trying to answer. And they’re doing it, in part, by examining the root causes of both conditions.

Shared causes

ADHD and ASD have a lot in common — including, researchers think, their origins.

Both conditions can be inherited, and some researchers believe they have some genetic overlap. We also know that both conditions can be the result of environmental exposure, which basically means an outside force is impacting fetal development. Think preterm birth, neonatal opioid withdrawal syndrome (NOWS) and lead poisoning, for instance.

So, ADHD and ASD aren’t the same condition, but — because they have so many similarities — it’s easy to confuse them. After all, it’s not like there’s a specific spot on the brain where ASD stops and ADHD begins. It’s more complicated than that.

Common characteristics

To add another layer of complexity, ADHD and ASD can manifest in similar ways.

“Children and adults with these conditions may experience problems focusing,” Dr. Wong shares. “Beyond the attention issues, autism and ADHD can also impact the way you interact with other people. For example, a child may have a hard time communicating or making friends. They can also have behavior issues.”

Some other overlapping features of ADHD and ASD include:

• Executive dysfunction.
• Neurodivergent thought patterns and logic.
• Difficulty interpreting one’s own bodily signals (interoception).
• Sensory processing difficulties.
• A tendency to hyperfocus.
• Masking (hiding neurodivergent traits in public).
• Self-control and emotional regulation issues.
• Self-stimulating (aka “stimming”) behaviors.
• Restricted or unconventional interests.
• High risk of mental health conditions.

In order to distinguish between ADHD and ASD — or diagnose both conditions — providers really have to drill down during the assessment process. That means examining both the subtleties of the symptoms and their broader context.

To illustrate the point, let’s imagine two children have been getting bad grades at school because they’re not doing their homework.

The first child starts their homework but gives up after 15 minutes. They can’t pay attention and keep losing their place, so they’re off to the playground.

The second child also bails after 15 minutes, but they only skip their math homework. Problem sets are boring, but they’ll happily spend hours reading for their literature class. And when they finish the book, they’ll go to the library to get another one.

In this example, both kids have issues with attention. But they aren’t the same issues — and providers shouldn’t address them the same way.

They also can’t make a diagnosis based on that anecdote alone. In isolation, the first child's attention issues seem to stem from ADHD, while the second child is displaying behavior that’s associated with ASD. But these are extremely complex conditions that look different from person to person.

The providers need to collect lots of different kinds of information to arrive at diagnoses. After hearing this story, for example, they may ask follow-up questions about areas where the two conditions differ, like the ability to read social cues or adapt to unexpected changes in daily routine.

There are many differences between ADHD and ASD. Here are some of the most notable:

Treatment differences

There isn’t a way to cure ADHD or autism because they aren’t diseases. These diagnoses simply mean your brain works differently in a specific way.

When providers talk about treating ADHD and ASD, their goal isn’t (or shouldn’t be) “fixing” you. They should be trying to lessen the impact those developmental differences have on your ability to live the life you want.

The path your care team takes will depend on a lot of factors, including any comorbidities you have. Depending on how much your condition affects your daily life, your providers may also recommend that you receive disability accommodations, benefits or government support.

In the case of ADHD, many people find prescription medications help them focus. It may take a while to find the right drug, or combination of drugs, for you. You may also benefit from psychotherapy or cognitive behavioral therapy. It can help you better understand and work with (not against) your condition. And your therapist can also teach you coping skills to get through challenging moments. It’s possible that your symptoms will fade or change with time, so learning how to adapt will serve you well.

Autism is a bit more complicated from a treatment perspective because the autism spectrum is so broad. When you’re diagnosed, providers will decide how much support you need to complete activities of daily living (ADLs). They use a scale of three levels (one, two and three). Level one means you need minimal support, while level three means you need extensive support.

Regardless of level, the goal of an autism treatment plan is always the same: Helping you make progress, whatever that means for you. And the earlier you’re diagnosed, the better. It means you’ll have more time to take advantage of the different behavioral and educational interventions that are available to you.

The bottom line

Autism spectrum disorder and attention-deficit/hyperactivity disorder are distinct neurodevelopmental conditions, but they have a lot in common. Both can be heritable and can develop as a result of pregnancy complications or exposures. And there’s even evidence that they have some genetic overlap. So, it isn’t surprising that ADHD and ASD can also look very similar.

ADHD and ASD used to be mutually exclusive (meaning you could only have one or the other). But a change to the diagnostic criteria in 2013 made it possible to get a dual diagnosis. If you think you might be neurodivergent, talk to your healthcare provider. They can perform assessments to determine whether you have ADHD, ASD, or both, or neither.