MONDAY, March 4 (HealthDay News) -- Children with ADHD often grow up to be adults with ADHD, a new study suggests.

Researchers found that of the 232 young adults in the study who had childhood attention-deficit/hyperactivity disorder, 29 percent still had it at an average age of 27. What's more, 57 percent had at least one other mental health issue, such as alcohol abuse, depression or chronic anxiety.

"This shows us [ADHD] is a serious, chronic condition that's not being adequately addressed," said lead researcher Dr. William Barbaresi, who directs the Developmental Medicine Center at Boston Children's Hospital.

The findings, published online March 4 and in the April print issue of the journal Pediatrics, give a clearer picture of how often ADHD symptoms persist into adulthood, Barbaresi said.

Past studies have made a wide range of estimates -- partly because they often have focused on specific groups of kids, like boys referred to specialty treatment programs.

But the new study included 600 young adults from Rochester, Minn. -- about 40 percent of whom had ADHD as children. Barbaresi's team evaluated them for symptoms of adult ADHD and other psychiatric disorders.

"This is likely to be a more accurate description of what's happening in the real world," Barbaresi said.

His team found that persistent ADHD often went hand-in-hand with other issues. Of the study participants with adult ADHD, 81 percent had at least one additional mental health condition, compared with 47 percent of those whose ADHD symptoms had faded and 35 percent of those who had never had ADHD.

The study was funded by the U.S National Institutes of Health, but the original pilot work received funds from McNeil Consumer and Specialty Pharmaceuticals, which makes the ADHD drug Concerta.

J. Russell Ramsay, co-director of the Adult ADHD Treatment and Research Program at the University of Pennsylvania in Philadelphia, said the findings add to evidence that "ADHD has important ripple effects throughout and across one's life, particularly in adulthood."

Depression, anxiety and substance abuse are the most common accompanying mental health issues. "In some cases," Ramsay said, "adults with previously unrecognized ADHD may seek treatment for these other conditions and may make partial progress -- only to later recognize that undiagnosed ADHD was a primary source of their coping difficulties."

According to the U.S. Centers for Disease Control and Prevention, between 3 percent and 7 percent of school-aged kids nationwide have ADHD. A child with ADHD might be habitually unable to sit still, finish homework assignments or pay attention in class.

As kids get older, though, the signs generally become more subtle. Teenagers may no longer be disruptive in class, but instead be impulsive in their decisions -- such as taking risks when they're driving, Barbaresi said.

Likewise, an adult with ADHD may be impulsive and have trouble staying organized, being productive at work or sticking with one task at a time. Whatever the age, ADHD treatment involves medication, behavioral therapy or a combination of the two.

There is, however, a good deal of controversy surrounding ADHD, with critics charging that some children are being labeled as having a "disease" and treated with drugs they do not need. Ritalin and other so-called stimulant medications often are prescribed for ADHD, and some parents balk at the idea of having their child on such a powerful drug long-term.

"Of course, there are concerns about the accuracy of diagnosis and inappropriate treatment," Barbaresi said. But, he added, that's a concern in medicine in general.

Dr. Steve Balt, editor-in-chief of the Carlat Psychiatry Report, which bills itself as an alternative to journals with drug-industry funding, said the study "emphasizes the importance of accurately diagnosing and treating ADHD in childhood," but it has its limitations.

For one, Balt said, the researchers used a "questionnaire-based tool," rather than a full evaluation, to measure young adults' mental health. And the fact that most adults said to have ADHD also had other psychiatric conditions "may, in fact, speak to the overlap of psychiatric symptoms," he said.

Alcohol abuse and antisocial personality disorder were the two most common psychiatric diagnoses in the group. And they "have many features in common with ADHD," Balt said.

None of that, he said, negates the importance of recognizing and addressing children's behavioral issues or problems with attention. The problem, he said, is in diagnosing those kids with a single "clinical entity."

"We should use caution in describing this constellation of behaviors as a 'disease,'" he said.

The American Academy of Pediatrics says doctors should do an evaluation for ADHD for any child aged 4 to 18 who has behavioral problems or is falling behind at school. But that should also include a thorough assessment for learning disabilities, emotional issues or physical conditions that could be causing their symptoms -- such as sleep apnea.

Barbaresi's advice to parents: "Don't accept a cursory evaluation and a prescription."

And will getting ADHD treatment cut a child's risk of adulthood symptoms, or other mental health issues? No one knows for sure.

Barbaresi said, however, that other studies of this same group have found that kids treated with stimulant medication tended to fare better in certain regards up to age 19. They had fewer academic problems and better reading skills, for instance.

But the effects of childhood ADHD treatment on adults' outcomes were not analyzed in the current study, Balt said. "If treatment worked," he said, "one would expect their rates of other disorders to be the same as the non-ADHD [participants']."

More information

Learn more about ADHD from the U.S. National Institute of Mental Health.