Late-Onset ADHD: Recent Research and Remaining Questions

ADHD Section Editor and Psych Congress Steering Committee member Vladimir Maletic, MD, MS, discusses recent research developments regarding late-onset ADHD and questions that remain unanswered.

Dr. Maletic is Clinical Professor of Psychiatry, University of South Carolina School of Medicine, Greenville. He is presenting "Trees or the Forest? Advances in Neurobiological Understanding of ADHD and Novel Treatments," at the 2021 Psych Congress Regionals meeting series, which continues April 9-10, 2021.

Read the transcript:

There have been some very interesting discussions about late-onset ADHD. It is something that was speculated about for a long period of time. Finally, in the last 5 years, we're now getting some relevant answers. We're getting these answers because longitudinal prospective study results are being published.

Here's what we're finding out. Individuals who have met criteria for adulthood ADHD diagnosis quite often would not have met criteria for ADHD in their childhood and adolescence.

Exactly how often? About 65 to 90 percent of the time, individuals who are diagnosed with ADHD in adulthood would not have met criteria for ADHD at ages younger than 12. This is definitely not something that we anticipated.

A little bit more refined research took place. What was noted is that although these individuals who meet criteria for ADHD in adulthood but not earlier in their life do have manifestations of ADHD. In their childhood and adolescence, they may have had inattentiveness, distractibility, impulsivity, and hyperactivity. But they did not meet clinical threshold nor did they result in sufficient functional impairment in order to be diagnosed as a disorder.

So it is not that ADHD emerged out of nothing. There were symptoms earlier in childhood and adolescence, yet they did not meet the threshold to be diagnosed as such.

What are some of the remaining open questions? Are the individuals who have adult onset of ADHD neurobiologically and genetically different than individuals who have ADHD that emerges up to age 12? Is there a different treatment approach that may be more effective for these individuals?

Unfortunately, we don't have data to answer these questions, but there is at least some effort now to provide answers and tell us, are there neurobiological differences via looking at biological markers, and functional structural neuroimaging studies, and genome-wide association studies? Are these individuals biologically different than the ones who have more typical onset of ADHD?

More Expert Insights on Adult ADHD:
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Using Computational Models to Improve ADHD Diagnosis and Treatment
Recent Developments in Genetic Studies Examining ADHD