|Back to October Ed Reporter|
|NUMBER 261||THE NEWSPAPER OF EDUCATION RIGHTS||OCTOBER 2007|
|Questionable Study Claims ADHD is Under-Diagnosed|
"There is a perception that ADHD is overdiagnosed and overtreated," said lead researcher Tanya E. Froehlich, M.D., of the Cincinnati Children's Medical Center. "But our study shows that for those who meet the criteria for ADHD, the opposite problem under-diagnosis and under-treatment seems to be occurring."
The research team used the fairly new standard for ADHD diagnosis found in the fourth and latest edition of the Diagnostic and Statistical Manual for Mental Disorders (DSM-IV). This is the first study to use this standard to calculate ADHD's prevalence in the population. According to the researchers' application of the standard, 2.4 million children between the ages of eight and 15 have ADHD 9% of all children in that age group. Only 48% of these have been diagnosed with ADHD, and only 32% receive drug treatment.
The news about ADHD's supposed under-diagnosis went out immediately over every major business wire. The study could greatly enrich the pharmaceutical companies responsible for drugs such as Ritalin and Adderall, on which Americans already spend $2.3 billion a year. In fact, the study was funded in part by the Robert Wood Johnson Foundation, which has close financial and policy ties with the pharmaceutical industry.
Many scientists and others, however, still question the usefulness of the ADHD diagnosis. "The behaviors exist, but the concept of ADHD is too simplistic to account for the complexity that exists in all the reasons that kids may have difficulty concentrating, being impulsive, or being distractible," says Thomas Armstrong, Ph.D., author of The Myth of the ADD Child. Armstrong also points out that the loose list of symptoms composing the "gold standard" for ADHD diagnosis is far from definitive.
Dr. Karen Effrem, a pediatrician and policy analyst, agrees. "Given that the authors of the DSM call their own criteria for mental disorders 'subjective'; that authors of major textbooks on ADHD and the National Institutes of Mental Health admit that there is no evidence to call ADHD a brain disorder; that the Surgeon General and the World Health Organization both say that it is extremely difficult to accurately diagnose children with any disorder due to rapid changes in development, I think it is foolish and very dangerous to put out these kinds of statistics."
The study concluding that 9% of children have ADHD shows, among other things, that the "gold standard" in the DSM-IV defines ADHD much more broadly broadly enough to diagnose twice as many children as having ADHD. In the past, scientists have seen the disorder's very definition as ruling out anything like a 9% population incidence.
Since ADHD does not have any strictly biological markers the way diseases like diabetes and cancer do, its definition is or was based on statistical rarity. By definition, ADHD is a disorder in which children act more hyperactive, less attentive, etc., than other children their age. "Given that the definition of ADHD is based on statistical rarity, only a limited number of children can qualify as having the disorder," explained a 2003 paper in the Scientific Review of Mental Health Practice. "The ADHD prevalence estimate was set at 3% to 5%. . . . Unless a biological marker is identified, an agreed-upon gold standard diagnostic procedure is established, or ADHD is redefined, a population-based ADHD rate exceeding 3% to 5% by definition represents a problem of ADHD over-diagnosis." The recent study may indicate that just such a redefinition of ADHD is occurring. Of course, as the standard for ADHD diagnosis is broadened, the more children will seem to have ADHD, and the more children will be treated with medications that have serious and sometimes fatal side effects.
The study's authors also treated it as a given that stimulant drugs are the most effective treatment for ADHD. Recent scientific evidence tells a different story. Ritalin, the most popular ADHD drug, improves children's behavior in the short term, but the advantage compared to behavioral intervention wears off within three years. A major study demonstrated this in August's Journal of the American Academy of Child and Adolescent Psychiatry. After three years, children who receive only behavioral intervention are as well-behaved as those who take drugs, and have several advantages: they have learned to control their symptoms on their own, and have avoided the side effects of Ritalin, which include stunted growth. This news, however, made less of a splash than the 9% study. Just days after the study's publication, various researchers and practitioners called out for more children to go on ADHD drugs.
American children are ten times more likely to take psychiatric drugs for ADHD than children in Europe. European children are also less likely to be diagnosed with ADHD, at least in part because European nations use a stricter set of criteria to diagnose the disorder. Nevertheless, Europe's prescription rates of behavior-altering drugs for children are also on the rise. In the U.K., doctors write ten times as many prescriptions for drugs in this class for children as they did just a decade ago.
Several other important studies have recently investigated ADHD, and have made some surprising discoveries about factors that accompany or may be responsible for ADHD symptoms in some children.
A study from New Zealand linked children's excessive TV watching with attention problems later in life. Children who watched more than two hours of TV a day between the ages of 5 and 11 were much more likely to have attention problems between the ages of 13 and 15. Each extra hour of TV children watched increased their likelihood of "high adolescent attention problems" serious difficulty concentrating as teenagers by 40%. "Children who watch a lot of television may become less tolerant of slower-paced and more mundane tasks, such as school work," hypothesized the researchers. The study appeared in Pediatrics' September issue.
Another study published in Pediatrics indicated that the sleep disorder obstructive sleep apnea (OSA) might result in an ADHD misdiagnosis for some children. Children who don't sleep well because of apnea may become inattentive and exhibit other symptoms associated with ADHD. Enlarged adenoids and tonsils usually cause OSA. In this study, half of the children who had been diagnosed with both OSA and ADHD no longer showed symptoms of ADHD a year after having their tonsils and adenoids removed.
British researchers found that a mixture of food additives made elementary-aged children significantly more hyperactive, and shortened their attention spans. The study, published in The Lancet, tested a mixture of artificial food colorings and preservatives, all common in the packaged foods that so many kids love. The findings supported years of anecdotal evidence from parents of children with ADHD, some of whom have found that a more natural diet with fewer additives helps their children's symptoms.