NEW YORK (CBSNewYork) — As Americans grow older, doctors are seeing more coming in with symptoms that look like early dementia or Alzheimer’s, but is it really?

CBS2’s Dr. Max Gomez said they may actually be suffering from an undiagnosed childhood problem known as Attention Deficit Hyperactivity Disorder.

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A few years ago, Dennis McGrath started having problems with his memory.

“I was concerned about it, do I have Alzheimer’s?” he said.

The 71-year-old said he felt as if he was aging overnight. Gary Olson, 62, was also having problems, which were work-related.

“As far as getting projects done — missing deadlines, late for appointments, all that kind of thing,” he said.

Both men had symptoms that at first glance resemble early cognitive decline, the possible beginnings of dementia.

“We’re starting to see more adults in their 60s and even 70s come in saying that they’re having attention problems,” Dr. Len Adler of New York University Langone Medical Center said. “So that’s an important differential to make between having Alzheimer’s disease or dementia and having ADHD. And sometimes people will come in having had a dementia work-up. It hasn’t shown anything.”

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While adult ADHD is common, it’s also under-diagnosed and under-treated. Like Olson, sufferers know something is wrong, but don’t necessarily know what it is.

“I never really knew what it was or I couldn’t put my finger on it. I just thought that something just wasn’t right,” Olson said.

It’s especially important to differentiate between early dementia and ADHD because there are good treatments for the disorder, medications and cognitive talk therapy.

There’s a World Health Organization 18-symptom checklist that provides a doctor with a kind of roadmap for ADHD versus dementia. Taking note of a patient’s history is particularly important.

“If the issues of attention, concentration, distraction, restlessness, impulsivity, have been present going back to earlier in life and presumably some of them back to at least before middle school, then we’re dealing with a longitudinal problem and that’s not necessarily a cognitive decline where that would start in older life,” Adler explained.

Adults aren’t suddenly developing ADHD, they’ve had it since childhood but were never diagnosed or treated, Dr. Gomez said.

Proper diagnosis and treatment is critical because they may have higher rates of smoking, divorce, and lower academic and employment success.

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To learn more about adult ADHD, please visit the New York University Langone Medical Center website.