New research may help explain the dramatic increase in attention-deficit hyperactivity disorder cases. The answer, according to Oregon Health & Science University researchers, is that ADHD is more than one disorder.
Investigators believe ADHD symptoms may actually represent an entire family of disorders, similar to the classification of various subtypes of cancer.
The research, which highlights various versions of the disease, each with differing impacts, demonstrates that there is likely not going to be a “one-size-fits-all” approach to treating patients.
Experts believe that new methods will be required to improve the diagnosis, prognosis and treatment of the disease.
Researchers believe scientists will need to shift their thinking when it comes to conducting research. New objectives should be directed at understanding the cause and impacts of ADHD. Moreover, experts believe that child behaviors should be examined in a more comprehensive format including non-affected children as well.
The research, led by OHSU scientists Damien Fair, Ph.D., and Joel Nigg, Ph.D., will be published online this week in the Proceedings of the National Academy of Sciences.
“Traditionally, physicians and psychologists have diagnosed patients through the use of the Diagnostic and Statistical Manual of Mental Disorders, commonly known as the DSM,” explained Fair. “The problem with this approach is that it often relies on secondary observations of parents or teachers, where even if the descriptions are accurate, any given child may be behaving similarly, but for different reasons. Just as if there might be many reasons why someone might have chest pain, there might be many reasons why a child presents with ADHD.
“However, unlike diagnosing countless other well-understood diseases, there is no one test that can differentiate individuals when it comes to psychiatric and developmental conditions like ADHD.
“The data here highlights ways to recognize such individual variability and shows promise that we might be able to identify why any given child presents with ADHD, thus allowing for future examinations of more personalized treatments.”
In the study, Fair, Nigg and colleagues used an approach to isolate ADHD’s variations to allow a better understanding of the various disorder permutations. Their methodology compared test results for several cognitive skills among a large sampling of ADHD patients and a control group. The testing focused on memory, inhibition, attention, comprehension, and several other categories.
“We have known for some time that there is wide performance variation in both the ADHD group and the control group,” explained Nigg, “but this has never been formally described.”
Although, overall, the ADHD group did more poorly than the control group on all the measures, they noted that in some areas, certain control group patients outperformed the ADHD patients.
However, in those same areas, other ADHD patients outperformed the control group. Simply put, not all study participants – ADHD and control – consistently showed the same strengths and weakness.
Furthermore, researchers found that ADHD patients can be subcategorized depending on their deficits and relative strengths, showing unique subgroups among all children with ADHD.
Researchers believe some of the testing methods may lead to a more precise way in which to sub-categorize and perhaps diagnose children with ADHD. Psychologists and physicians could provide patients with a series of cognitive tests, determine their strengths and weaknesses, and subcategorize them based on these traits.
Source: Oregon State University