Is there an ADHD spectrum?

Q. I’ve heard people talk about having mild ADHD or severe ADHD. Is there such a thing as an ADHD spectrum?

A. This is a great question, and the short answer is “yes.” ADHD symptoms exist on a spectrum or a continuum. But the longer answer is a little bit more complicated. There are two important factors to consider: the type of symptoms a person has and how intense the symptoms are.

The main signs of ADHD are inattention, hyperactivity, and impulsivity. Some people have trouble in all three of those areas. Some primarily have problems with inattention. And others may primarily have problems with impulsivity and hyperactivity.

People often think of ADHD as being just one thing. To some it might mean the stereotype of the hyperactive boy who can’t sit still in school. To others, it might mean the friend who never seems to pay attention.

But no two people with ADHD are exactly alike. Their symptoms can vary in type and severity. For instance, one person with hyperactivity might squirm in their seat. Another might get up and walk around the room, touching everything in sight. So, you might think of the first person as having “mild” ADHD and the other as having “severe” ADHD.

This is why diagnosing ADHD can be tricky. ADHD isn’t an all-or-nothing thing. And sometimes, what looks like ADHD might not be a sign of an issue at all.

All people have times when they’re forgetful, struggle to wait their turn, or are easily distracted. That doesn’t mean they have ADHD, though.

People with ADHD don’t just have this behavior sometimes. They constantly have it. And for a diagnosis of ADHD, their behavior must be severe enough to interfere with their ability to function at home and in school or at work. That’s why I say there’s an ADHD spectrum.

A good evaluator will be thinking about the spectrum of symptoms that define ADHD. The challenge is to separate typical behavior from problems that can have a mild impact or a major one.

That can also help determine what type of ADHD treatment a person might need. Those whose symptoms fall on the more significant end of the spectrum might receive multiple treatments. These might include ADHD medication and behavioral strategies. People with milder symptoms may receive only behavioral strategies.

Imagine a fifth grader with severe ADHD symptoms. He has serious difficulty paying attention in school. He’s frequently out of his seat in the classroom, blurts out answers to questions, and is so distracted by even the slightest noise that he has trouble doing almost anything in class.

For that reason, his doctor has prescribed medication for ADHD. The school has given him IEP services and supports. He gets classroom accommodations and works with a specialist to improve executive function skills.

Now imagine a young adult who has difficulty staying organized and getting work done on time. Her symptoms of inattention are significant enough to cause difficulty at work. But they’re so mild that she wasn’t diagnosed with ADHD until she was in her 20s.

She works with an organizational coach to build skills. She talked with her doctor about medication. But she decided her symptoms were mild enough that behavioral strategies would be enough to help her cope.

Recent genetic studies have looked at attention skills in the general population. They found that there’s a natural spectrum of functioning, with ADHD at one extreme.

Someday, genetic analysis may help us predict who will be at high risk for ADHD. For now, a diagnosis still depends on how severe the symptoms are. Evaluators use their clinical judgment to make that determination. And professionals consider where symptoms fall on the continuum to determine how to best help a person with ADHD.

• Check out ADHD Aha! to hear stories about how ADHD impacts people.

• Listen to Season 2 of Understood Explains to learn about the process for diagnosing ADHD in adults.

• Parents and caregivers: Read more about what to do if your child was recently diagnosed with ADHD.