ADHD is the most common psychiatric diagnosis among children and adolescents. People with ADHD have difficulty concentrating, organizing, planning and carrying out activities. However, children who do not suffer from ADHD can also struggle with all these things—perhaps especially if they are among the youngest and most immature students in the class.
And because the diagnosis is based on a scale score, the line between children with and without ADHD can be difficult to draw. In a new research project, two economics students from the University of Copenhagen have investigated the question: Do age differences within the same grade affect ADHD prescription rates for children in Danish schools? "The purpose of our study is to get an indication of the degree of misdiagnosis of children due to relative age differences in the classes," says Konrad Juel Thide. The work is published in the journal Economics Letters .
Significant difference for girls To find the answer, the researchers have utilized the variation in school starting age, which comes from the fact that all Danish children must start school in the calendar year in which they turn 6. "Children born on 31 December typically have to start school a whole year earlier than children born the day after. The first child then becomes the youngest in the class, while the second child becomes the oldest in the year below," explains Felix Johannes Pettersson Bøgh.
In the study, he and fellow student Thide used administrative data .