They have less education and lower income, on average, and higher rates of divorce and substance abuse, according to findings released today in the Archives of General Psychiatry.
"A lot of them do fine, but there is a small proportion that is in a great deal of difficulty," said Rachel Klein, a professor of child and adolescent psychiatry at NYU Langone Medical Center in New York. "They go to jail, they get hospitalized."
Klein and her colleagues followed 135 white men who had been rated hyperactive by their school teachers back in the 1970s and referred to the hospital. According to Klein, the children did not have aggressive or antisocial behaviors and would have been diagnosed with attention deficit hyperactivity disorder today.
They all came from ordinary middle-class homes, Klein said, and had "well-meaning" parents. When the boys were 18, the researchers established a comparison group of age-matched white boys who had visited their medical center for unrelated reasons and had not had any problems at school.
Based on interviews done when the men were 41 years old, on average, Klein's team found that those who'd had ADHD symptoms as kids left school 2.5 years before the comparison group. Only four percent had higher degrees versus 29 percent of their peers.
In both groups, salaries went as high as $1.5 million a year. But in the comparison group, the average salary was about $175,000, compared to $93,000 in the troubled children.
More than one in five of the hyperactive boys were diagnosed with ADHD three decades later, versus one in 20 in the comparison group. And about a third had been in jail at some point - about three times the comparison rate.
They were also more likely to be divorced, abuse drugs and be labeled with antisocial behavior disorder. However, they weren't more likely to have mood or anxiety disorders.
It's not clear from the study that ADHD, per se, puts people at risk. But Klein said it's likely to be a slippery slope, with ADHD-linked impulsiveness making youngsters more likely to use drugs and spiral downward into crime and other antisocial behaviors.
"When you see signs of antisocial behavior you really have to step in," she told Reuters Health. "You have to keep treating these kids as long as they face problems."
It's estimated that between three and seven percent of school-aged children in the U.S. have ADHD, according to the Centers for Disease Control and Prevention.
Fewer than half will have lasting problems; for the rest, the outlook is better.
"The ones who had made it through adolescence were no different from ordinary kids," Klein said. "Most of them are married, most of them are employed. I think that is a silver lining."
J. Russell Ramsay, who studies ADHD at the University of Pennsylvania's Perelman School of Medicine, pointed out that although the kids fared worse than the comparison group, they still were within the normal range in many cases.
"We are not talking about awful outcomes necessarily," Ramsay, who was not involved in the research, told Reuters Health.
"There are different outcomes for different individuals with ADHD based on severity and complexity," he added. "This is sort of a reminder to pay attention to the unique needs of the child, the educational environment and the home environment."
Treatment options include both stimulant medications such as Ritalin or Adderall and behavioral coping strategies that can help address a child's specific difficulties.
"The going phrase is that pills don't teach skills," said Ramsay. "It is really an individualized treatment planning decision."