What Do the Three Subtypes of ADHD Mean?
You might have heard that there are three subtypes of ADHD. When you hear "type," it sounds like they're completely different from each other or that they need different treatments. But that's not really the case. The DSM-5 (which is like the bible of mental health diagnoses) lists three presentations (not subtypes) of ADHD: primarily inattentive, combined, and primarily hyperactive-impulsive. But these categories don't tell us much about how much someone is struggling, and they don't give us any clues about which treatments might work best. So, while it's good to know about these presentations, they're not super helpful in understanding what's going on with someone's ADHD.
When it comes to figuring out which ADHD presentation someone has, clinicians look at how many symptoms the person has in two different categories: inattentive symptoms and hyperactive-impulsive symptoms. For adults, if someone has five or more symptoms from either the inattentive or hyperactive-impulsive categories, that's enough to be considered to have that presentation. But if someone has five or more symptoms from both categories, they'll be given the "combined" presentation label. Basically, the idea is to see which symptoms are most strongly affecting the person and use that to help guide treatment.
In my experience assessing adults with ADHD, most of them meet the criteria for the combined presentation, which means they have significant symptoms of both inattention and hyperactivity/impulsivity. The rest have an inattentive presentation. I've never met an adult who meets only the hyperactive-impulsive criteria, and honestly, I'm not convinced that the hyperactive-impulsive presentation is very useful. Research has shown that most people who meet the hyperactive-impulsive criteria are preschool-aged children, and as they get older and are reassessed, almost all of them end up meeting enough inattentive symptoms to be classified as combined presentation. It's not surprising that inattentive symptoms are harder to spot in young kids - I even wondered about my own son when he was little since his hyperactive and impulsive symptoms were so prominent, and now he clearly displays all 18 symptoms of ADHD. From what I've seen, inattentive symptoms are really the core of ADHD, and most people also have significant hyperactive and/or impulsive symptoms.
In my experience, I've come across individuals with the inattentive presentation of ADHD who are just as, if not more, impaired in their daily lives compared to those who meet the criteria for the combined presentation. It's not necessarily the case that having fewer total symptoms means that a person is less impaired than someone with more symptoms. That's why I use a severity rating (mild, moderate, and severe) to indicate how much impairment the symptoms are causing. The number and type of symptoms a person has are just one piece of the puzzle, and it's important to look at the bigger picture to truly understand the impact of ADHD on a person's life.
Another reason why naming different presentation types may not be particularly useful is that medications for ADHD can work well on all symptoms of the disorder, even ones that aren't officially considered symptoms. For example, most people I see with ADHD also experience difficulties with emotional regulation, which isn't listed as a core symptom of the disorder, but still significantly impacts their lives. Whether someone has an inattentive presentation or the combined presentation of ADHD, it's important to know that treatment options are available and effective. Don't worry that having a specific presentation means that you won't receive the right treatment or that it won't work for you. Any symptoms of ADHD can be improved with proper treatment, and there's hope for a better quality of life.