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Children With ADHD 40 Years Later

What will childhood ADHD symptoms mean forty years later? There aren’t a lot of studies that give us data on that question.

For obvious reasons, doing a study that spans four decades is difficult. Still, that’s exactly what researchers in Finland did as part of a study that tracked hundreds of people from birth into adulthood.

One challenge with such a project is that when data collection began, in the early 1970s, our understanding of mental health conditions was much less advanced, and ADHD as we know it wasn’t even a diagnosis that was being made.

HourglassSo the researchers didn’t have ADHD questionnaires to determine study participants’ levels of childhood ADHD symptoms. But they did have other behavior reports, interviews, and assessments of attention problems, which they were able use to make reasonably accurate retrospective evaluations of ADHD.

Using that data, they divided study participants into three groups: those who would’ve qualified for an ADHD diagnosis, those who had subthreshold ADHD symptoms not meeting the clinical cutoff, and those without elevated ADHD symptoms.

Besides considering ADHD symptoms at ages 5 and 9, the researchers invited participants back for an ADHD assessment and series of surveys at age 40. Altogether, the study started off with 1,196 births and ended with 318 participants who still met the eligibility requirements and agreed to do the followup at age 40 – of whom 37 were childhood ADHDers and 64 had been children with subthreshold symptoms.

If those numbers seem high to you, it might be because the study was originally designed to follow infants with certain risk factors at birth, such as low birth weight. So the people in the study aren’t necessarily representative of the overall population. That said, the results can still give us some data on what implications childhood ADHD symptoms will have 40 years later.

When those who met the cutoff for childhood ADHD came back and completed the followup surveys, it turned out that 22 percent of them met the cutoff for an adult ADHD diagnosis, a figure that was much higher than for the other groups.

The exact number isn’t important, since there are the possible issues with retrospective childhood diagnosis and population representativeness that I mentioned above. But the general pattern is consistent with what we know about ADHD: not all children with ADHD will meet the cutoff for an ADHD diagnosis as adults, but many children with ADHD will go on to be adults with ADHD.

The researchers also found that childhood ADHD predicted two key differences in outcomes as adults: children with ADHD went on to have lower education levels and more drug use at age 40.

It’s worth noting that even for the “lucky” children with ADHD who didn’t meet the cutoff for diagnosis as adults, their childhood ADHD symptoms still potentially had lifelong effects if those symptoms caused educational underachievement. And for those children who did become adults at ADHD, we can expect that the consequences of childhood ADHD were even more significant.

In other words, you can consider this another exhibit on a well-worn theme: ADHD symptoms are associated with multiple negative outcomes that have real implications for people’s lives. Even in cases where the symptoms themselves decrease over time, the effects of those symptoms are evident 40 years later. All of which goes to underscore the importance of diagnosing and managing both childhood and adult ADHD!

Image: Flickr/Crispin Semmens

Children With ADHD 40 Years Later

Neil Petersen

Neil Petersen writes regularly on psychology, ADHD and education. In addition to ADHD Millennial, he writes about psychology at Psych Central's AllPsych blog and about ADHD at He can be found on Twitter at @ADaptHD_blog

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APA Reference
Petersen, N. (2019). Children With ADHD 40 Years Later. Psych Central. Retrieved on October 22, 2020, from


Last updated: 8 Oct 2019
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