By Linda Carroll, Kate Snow and Meghan Frank, NBC News

As a little girl, Bonnie Ihme had big plans. Bright and artistically talented, she dreamed of becoming an architect.

But the older she got, the more distant that dream seemed. By third grade, school had become a struggle. She felt easily distracted and found it impossible to focus in class. Eventually she abandoned her plan to be an architect. Ihme got married, had two kids and began cleaning houses and helping her husband with his business.

But even that simpler life felt impossibly difficult. The Michigan mom had trouble keeping track of all the threads of her life. She’d send her kids to school without sneakers on gym day. She’d forget to bring library books back. She felt more overwhelmed than ever before.

“I really would try hard to pull it all together,” Ihme told NBC’s Kate Snow in an interview airing on Rock Center Friday. “But when … you’re late for a Christmas concert that your daughter was really looking forward to going to and we get there and her class is walking back to the classroom and the tears in her eyes… you try harder.”

Ihme saw history repeating itself in her 10-year-old son, Jacob, who began struggling with school, just as she had. Jacob would spend hours doing his homework, only to forget to bring it to school the next morning. Ihme’s heart ached for her son.

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She decided to do something for him that no one had thought to do for her. She brought Jacob to a specialist in search of answers. After a battery of tests, the specialist diagnosed her son with ADHD – attention deficit hyperactivity disorder. He then told Ihme that the disorder was often inherited. That was when she began to wonder if ADHD had been her problem, too.

“I knew I was bright,” she told Snow. “And on some things that they were teaching I was higher than the rest of the class. But then I’d struggle with a lot of the other things and wonder what was wrong with me.”

Ihme went through the same testing her son did, and at age 42, was diagnosed with ADHD.

While many people think of ADHD as a childhood disorder -- something that kids eventually grow out of – long term studies have shown that ADHD sometimes lasts a lifetime. In fact, a report published in the April edition of Pediatrics found that nearly 30 percent of kids diagnosed with ADHD still suffered severe symptoms well into adulthood.

In the prospective study, researchers from the Boston Children’s Hospital and the Mayo Clinic tracked 5,718 children born between 1976 and 1982 for several decades. Among the children were 367 who’d been given a diagnosis of ADHD. Out of that number, 232 agreed to participate in the study.

As it turned out, life was a lot harder for ADHD sufferers than it was for their peers. They were at higher risk for death and suicide, with nearly 60 percent suffering from an additional psychiatric disorder.

In a similar longitudinal study, researchers from New York University started out following 207 boys who’d been diagnosed with ADHD between ages 6 and 12 and 178 boys without ADHD. By the time the boys had reached their 40s and 50s, there were big differences between the two groups, according to the report published in December in the Archives of General Psychiatry.

Clinical psychologist Rachel Klein, lead author of the New York University study and a pioneer in the field of ADHD, put it this way.

“Compared to the kids without ADHD, these children had more often died,” said Klein, Director of the Anita Saltz Institute for Anxiety and Mood at the NYU Child Study Center. “Many more had been in jail. Many more had been hospitalized for psychiatric reasons, mostly drug abuse.”

But the bad news didn’t stop there.

Almost a third of the ADHD boys had dropped out of high school and, on average, they made less money and experienced a higher divorce rate than their peers who didn’t have the disorder.

Much of that resonates with Frank South, who, at 49, discovered he had ADHD.

Professionally successful, South wrote for such hit TV shows as Hill Street Blues, Cagney & Lacey, and Melrose Place. But over the years he’s struggled in his personal life. He’s been married three times and can find the details of daily life challenging.

In fact, he says he’s so easily distracted that a simple trip to pick up a 12-pack of paper towels for his daughter’s basketball team can turn into Mission Impossible.

“You end up in the Costco going through things that you’re not even going to buy and the time goes right by because you find it so interesting,” he told Snow.

From freeze-dried granola to flat screen TVs, anything and everything becomes so alluring that hours later, the basketball team is still without paper towels.

“It’s debilitating,” he told Snow. “But the thing is, before your diagnosis, before you understand these things, you think, ‘I’m a jerk.’ And you feel like, ‘I’m also not very bright if I can’t just go and get a 12 pack of paper towels and bring them to the basketball coach without being two hours late."

After years of berating himself for such mishaps, and drinking hard to shut out the negative thoughts, South, like Ihme, finally spoke with a psychiatrist after his son Harry was diagnosed with ADHD and he started thinking he too might have the disorder.

Going undiagnosed as an adult is not that unusual.

 “I think … that there are still many people walking around who have ADHD who are being impaired by it, and they don’t even know it,” said study co-author Dr. Xavier Castellanos, director of the Center for Neurodevelopmental Disorders at the New York University Child Study Center.

Despite this, Castellanos acknowledges that some doctors may be over diagnosing ADHD. In fact, a New York Times story published last week concluded that over the last decade there’s been a 53 percent jump in the number of kids diagnosed with the disorder. Experts quoted in the story said they feared that the powerful stimulants used to treat ADHD might harm kids who don’t really need them.

But for those who do have ADHD, taking medication can be life changing.

South remembers when he first started taking medication for his ADHD.

“It was like a window, a big window, opening up on my brain,” he said. “You know, sunlight coming in and being able to breathe and be calm enough to understand. And the fear and the anxiety level went down.”

For those who still doubt that ADHD is a real brain disorder, Castellanos points to brain scans he’s done in some of the study volunteers. The scans of those who had been diagnosed with ADHD as children are thinner in areas that are known to control attention and govern emotion.

“These are differences of less than a tenth of a millimeter,” Castellanos explained. “And yet, a tenth of a millimeter is a lot of brain cells.”

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