Data collected on 378,881 children between the ages of 4 to 17 showed that children born in August were more likely to be diagnosed with ADHD or receive ADHD medication than those born in September, according to a study published in the Journal of Pediatrics.
The researchers used the annual school cutoff date of Aug 31 to see if the youngest students in a grade were more at risk for ADHD diagnosis compared to the oldest students in the grade.
The researchers found that 1.8 percent of children born in September had diagnosis or medication for ADHD compared to 2.9 percent of children born in August. The findings build on previous studies that have found younger children in a grade are at increased risk of an ADHD diagnosis.
"Our findings emphasize the importance of considering the age of a child within a grade when diagnosing ADHD and prescribing medication to treat ADHD," said Dr. Mu-Hong Chen, lead author of the study.
Dr. Max Wiznitzer, a pediatric neurologist at University Hospitals Rainbow Babies and Children's Hospital, said the study shows that it is vital that doctors look at multiple factors when making an ADHD diagnosis and that they take a student's age into account.
Wiznitzer, who was not involved in the study, pointed out that two children, who are both 5 years old, can be at vastly different temperamental levels depending on whether they are 5 years and 1 month old versus 5 months and 11 months old.
"The 11 months apart is a 20 percent difference in ages and has to do with temperament and attention," Wiznitzer said.
Wiznitzer said finding actual cases of ADHD versus just developmental differences can be challenging, especially in extremely young children.
"It’s very important that when the diagnosis is made, you need to get data from multiple reporters than just one," said Wiznitzer, explaining he will want to hear from family members, baby sitters, school officials and even sports coaches when making a diagnosis.
If children do in fact have ADHD, they will not grow out of it as they get older, he said.
"If it’s a real diagnosis, it should not disappear after a year," he explained.