A highly publicized study in Taiwan has renewed interest in the idea that a child’s immaturity, relative to peers’, may be driving some diagnoses of attention-deficit hyperactivity disorder.
The study, published this month in the Journal of Pediatrics, looked at more than 378,000 children ages 4 to 17, between 1997 and 2011. Researchers found that 4.5 percent of boys born in August—just before the Aug. 31 birthdate cutoff for school entry—were diagnosed with ADHD, a disorder linked to inattention, impulsive behavior, and excessive activity, and 3.3 percent were taking medication for it. In contrast, among boys born in September—the children who would be the oldest of their grade-level peers—2.8 percent were diagnosed with ADHD, and 1.9 percent were taking medication.
Among girls, the same pattern held, but the overall rates of diagnosis were much lower. The study found that 1.2 percent of August-born girls were diagnosed with ADHD versus 0.7 percent of September-born girls. As the researchers examined births through the year, they found the closer that children were to the school enrollment cutoff age, the more likely they were to be diagnosed with ADHD.
