One of the biggest debates among parents who have the choice is whether to send their newly-turned 5 year olds to school, or hold them back a year in order for them to gain more maturity before the rigors of kindergarten.
A newly-released study published in the New England Journal of Medicine adds yet another data point to a complicated decision. The researchers found that kindergarten students who had turned 5 in the month before starting kindergarten were more likely to be diagnosed with attention deficit hyperactivity disorder than children who started kindergarten in the month that they turned 6.
The study also has implications for the validity of ADHD diagnoses. Other research has lent credence to the idea that least some diagnoses of ADHD—a disorder linked to inattention, impulsive behavior and excessive activity—may be connected to immaturity. And other surveys have found that doctors often prescribe medication as a first-line treatment for young children with ADHD, even though behavioral therapy is considered the first option.
“Our findings suggest the possibility that large numbers of kids are being over-diagnosed and overtreated for ADHD because they happen to be relatively immature compared to their older classmates in the early years of elementary school,” said study author Timothy Layton, and assistant professor of health care policy at Harvard Medical School.
Differences Among Children Before and After a Kindergarten Cutoff Date
Most states have cutoff birth dates that determine when a child can start kindergarten. These researchers looked at the insurance records of more than 400,000 children who live in states with a Sept. 1 cutoff date. That means that children with birthdays in late August might be in the same kindergarten class as children who have birthdays in early September or later—almost a full year’s difference.
The study found that children born in August had a 30 percent greater chance of being diagnosed with ADHD than children born in September. That difference did not show up in states that don’t have a Sept. 1 enrollment cutoff.
The study found that 85 out of 100,000 students born in August were either diagnosed with or treated for ADHD, compared with 64 students per 100,000 born in September. Researchers also found differences when they looked solely at children who were given medication: 53 of 100,000 students born in August were medicated for ADHD, compared to 40 out of 100,000 for those born in September.
Another study author, Dr. Anupam Jena, noted that this research is not the only one that has tied outcomes to age of school start. Another study published in 2017 said that children who are older-for-grade receive a measurable edge compared to their younger classmates over the long term—they have higher test scores, are more likely to attend college, and are less likely to spend time in the juvenile justice system.
“The diagnosis of this condition is not just related to the symptoms, it’s related to the context,” said. “The relative age of the kids in class, laws and regulations, and other circumstances all come together.” All of the factors have to be considered before making a decision, he said.
What Does This Mean For Holding Children Back?
It is important to note that the children in these studies were not held back by their parents, however. The study exploited natural differences in age at school start, as opposed to measuring the benefits or drawback of actually holding a child back for a year. Other studies have shown a mixed bag for children based on their relative ages at school start: a 2013 paper, for example, found that “old for grade” children outperform their younger peers in reading and math, but they are also more likely to drop out or commit a felony by age 19.
“On average, it is the case that August-born children are going to do slightly worse than September-born children, but this has no implication that Mr. Smith should redshirt their perfectly fine kid to give them an extra edge,” said Krzysztof Karbownik, one of the authors of the 2017 study, in an interview with Education Week last year. “There are real costs to them.”
A version of this news article first appeared in the On Special Education blog.