ADHD often lasts well into adulthood, increases mental illness risk Sometimes it's easy for people to simply dismiss attention deficit-hyperactivity disorder (ADHD) as just an irritating childhood learning disorder, which eventually disappears when people reach adulthood. However, ADHD can actually have a more lasting impact than previously thought. In the first ever population-based to study to follow children with ADHD into adulthood, researchers discovered that nearly a third of children diagnosed with the disorder continued to have ADHD well into their adult years. Along with this revelatory finding came a whole host of other surprising discoveries regarding the future of those with ADHD. Not only did their symptoms often persist, but children with ADHD were often diagnosed with another psychiatric disorder as adults. More disturbingly, those with ADHD were more likely to be incarcerated and a few small cases revealed that they were slightly more likely to commit suicide than control subjects. The researchers hope these shocking statistics will ultimately help reshape the future of the disorder's treatment. "ADHD is by far the most common neurodevelopmental disorder in childhood," lead author Dr. William Barbaresi, from Boston Children's Hospital, told FoxNews.com. ..." Knowing it's the most common one, and there are so many unanswered questions - that's why it was the focus of this nearly 20 year project." According to the Centers for Disease Control and Prevention (CDC), up to 9.5 percent of children between the ages of 4 and 17 have been reported as having ADHD. Classified as a psychiatric disorder by the American Psychiatric Association, ADHD is characterized by either trouble with inattentiveness, hyperactive behavior, or impulsiveness - or sometimes a combination of all three. We need to recognize ADHD for what it is: A serious health problem... Dr. William Barbaresi of Boston Children's Hospital The 20-year-long Mayo Clinic study followed a birth cohort of 5,718 children born in Rochester, Minn., between 1976 and 1982. Of the study's participants, 367 had been diagnosed with ADHD, three-quarters of whom had received treatment for the disorder as children. After analyzing the participants" medical records, as well as performing follow-up interviews and diagnostic tests, Barbaresi and his team gathered some very valuable - and unexpected - facts about ADHD. Of the children with ADHD, 29.3 percent still undoubtedly had the disorder as adults, and of that percentage, 81 percent had at least one other psychiatric disorder. The most common disorders included substance abuse, antisocial personality disorder, hypomanic episodes, generalized anxiety and major depression. Having another psychiatric illness was fairly common in general as 57 percent of all children with ADHD had another psychiatric disorder as adults, in contrast with 35 percent of control subjects. Of the 367 children with ADHD, seven had died at the time of the study's recruitment - three from suicide. Compared to the 4,956 children without ADHD, 37 of them had died - five from suicide. While the numbers were small, these statistics suggested a rate of suicide among ADHD children five times higher than those without the disorder. And finally, 10 children with ADHD (2.7 percent) were in jail when recruitment for the study began. While very disturbing, Barbaresi hopes that these revelations will inspire a paradigm shift in the way people perceive and treat ADHD. There's a continued tendency to trivialize ADHD and to conceptualize it as an annoying childhood behavior problem. We need to recognize ADHD for what it is: A serious health problem that requires the attention of our health care system, educational system, and health insurance industry. Another take home message Barbaresi hopes people gather from this research is that ADHD is a chronic disease - not a temporary disorder - and that children with ADHD need to be evaluated for learning and psychiatric conditions that have been shown to be strongly associated with the disorder. "We typically cannot get approval to do in-depth psychological assessment at the time of diagnosis for ADHD," Barbaresi said. So even though we know such a high percentage of these kids will have one or both of these problems, the system makes it so we cannot evaluate these issues until they're apparent and have caused significant adverse impact. While the findings of the Mayo Clinic study are hopefully enough to sway the minds of many researchers, Barbaresi said these aren't the only findings from their study. Over the next six to 12 months, Barbaresi and his team will release more information they found regarding how children with ADHD transition into adulthood - including statistics on their relationships, education, employment, and a whole spectrum of psycho-social outcomes. "There's a lot more to come," Barbaresi said, "and much of it equally concerning." The study is published in the April 2013 issue of Pediatrics and online March 4.