ADHD Diagnosis in Adults

Adults: Are You Part of the 85 Percent?

Up to 85 percent of adults have ADHD and don’t know it. Learn why going undiagnosed can be dangerous and what to do if you think you have ADD.

A doctor evaluates his patient for ADHD by talking with her. Diagnosis requires more than just brain imaging.
A doctor evaluates his patient for ADHD by talking with her. Diagnosis requires more than just brain imaging.

There is no arguing with the facts. Nine million adults in the United States have ADHD. Unbelievably, eighty-five percent of them don’t know that they do. What does that mean for the undiagnosed millions?

“Untold personal misery, in many cases,” says Alan Brown, founder of ADD Crusher, a program of videos and tools to help adults deal with symptoms. Brown was once part of the 85 percent. He was a drug dealer and did cocaine. It wasn’t pretty.

It isn’t pretty for many adults with undiagnosed ADHD either. They have an increased chance of becoming an alcoholic or a drug user, of being fired from a job (many jobs, actually), of getting divorced, of committing a crime and going to prison. In women, undiagnosed ADHD increases the chances of developing an eating disorder and, most sadly, taking their life.

Cultural forces have something to do with the legion of undiagnosed adults. Many doctors, and a good portion of the public, think that ADHD is only a childhood disorder. In fact, in most cases, ADHD in childhood sticks around in adulthood. Millions of adults are at a dead end in their job and their relationships, with no hope of turning their life around. And they don’t know why.

If you think you may have ADHD (taking our self-test is a good first step in finding out), get evaluated by a good ADHD doctor and start a solid treatment plan. If you wind up not having attention deficit, no harm done. If you do, diagnosis and treatment could very well change your life.

Updated on March 24, 2021

4 Comments & Reviews

  1. Hello
    One slight correction: up to 85% of adults WITH ADHD don’t know they have it. At first I was quite surprised to read that up to 85% of adults have ADHD and don’t know it, because I thought it meant adults in general. Tee hee, that can happen.

  2. Still, if this were true that 85% of those who have ADHD are not diagnosed, (and the best number I’ve found is 7.2% of the population is diagnosed)… that would mean that 40.8% of the population actually has ADHD. … but that wouldn’t include this 85% you say is undiagnosed. So that would mean a total of 48% of the population has ADHD (with 40.8% of the population having it but not knowing). This seems really high. I’ve heard numbers like 1/5 people have it… but these numbers change with every article. Are there any good citations estimating the prevalence of ADHD? I’m trying to argue that as teachers we should have training on this topic, but can’t find citations to make the claim that is a common enough phenomenon to address. Anyone have any leads? ADDitude Mag, do you have any way to include further reading or citations to back up claims you make in articles like this? THANKS for all the great resources you provide this community!!

    1. That 7.2 number came from CHADD’s website:

      “A meta-analysis of 175 research studies worldwide on ADHD prevalence in children aged 18 and under found an overall pooled estimate of 7.2% (Thomas et al. 2015). The US Census Bureau estimates 1,795,734,009 people were aged 5-19 worldwide in 2013. Thus, 7.2% of this total population is 129 million—a rough estimate of the number of children worldwide who have ADHD.

      Based on DSM-IV screening of 11,422 adults for ADHD in 10 countries in the Americas, Europe and the Middle East, the estimates of worldwide adult ADHD prevalence averaged 3.4% (Fayyad et al. 2007)”

  3. In Australia the percentage of undiagnosed adults is as high as 95%. Now I am in the 5%; diagnosed at 40 years old. When the diagnosis came I thought ‘finally.. this explains ALOT’. How it happened: I was in an AA meeting and another guy said to me “it’s not alcoholism, it’s ADHD”. So I got checked out & he was right. I read books, watched videos & am now very familiar with the signs of ADHD. I see it quite a lot in family and friends. It baffles me just how many are undiagnosed. It baffles me that despite my diagnosis no-one else in my family will even look at the possibility that they may have it too. They just keep struggling… I’ve only ever met 2 other adult males that have a diagnosis and seen loads of people undiagnosed & struggling with symptoms.

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