A team of scientists scanned gene maps of more than 1,400 children for the study. After comparing the abnormal samples to the DNA of children without ADHD, the researchers discovered those with ADHD were more likely to have small pieces of their DNA missing or duplicated.
The DNA irregularities among ADHD children were prevalent in the same region where schizophrenia and autism is believed to develop; solidifying the belief ADHD is a neurodevelopmental condition.
ADHD is commonly diagnosed in childhood and causes impulsiveness, restlessness and difficultly focusing. In the U.S., ADHD affects roughly two million children and three to five percent of the global child population. Medication and behavioral therapy are common forms of ADHD treatment.
The results from the study are expected to help researchers develop better methods for ADHD treatment. However, it is doubtful the findings will lead to an ADHD genetic test, as many experts consider environment part of the cause as well.
Speaking of environmental factors, another recent study suggests children with high levels of the pesticide malathion in their urine have a greater risk of developing ADHD.
The new study is the first to base its findings on a general U.S. population sample rather than on children from farm-working families or those living in locations where high chemical exposure is prevalent. Researchers estimate the majority of participants in the study were exposed to the malathion through food consumption.
The study compared data from National Health and Nutrition Examination Surveys conducted during 2000 to 2004. The findings concluded children with malathion metabolite levels 10 times above the normal rate are 55 percent more likely to have ADHD.