Babies born in the summer could be more likely to suffer from depression by the time they reach GCSE age, a study suggests.
Researchers found the youngest children in the academic school year are 30% more likely to develop mental health problems, such as depression.
The study also revealed those born in the last quartile of the academic year were 36% more at risk of attention deficit hyperactivity disorder (ADHD) and 30% more likely to be diagnosed with an 'intellectual disability'.
The research, led by the London School of Hygiene and Tropical Medicine (LSHTM), and published in the journal JAMA Paediatrics, used electronic GP records for a sample of one million school-aged children in the UK.
The results revealed children born in the last quarter of the school year were 1.3 times more likely to be diagnosed with intellectual disability, 1.4 times more likely to be diagnosed with ADHD, and 1.3 times more likely to be diagnosed with depression compared with their older peers.
Researchers noted children in the same school year can be almost 12 months apart in age.
Younger children may find it harder to concentrate, grasp what they are being taught or maintain friendships with their older peers, they explained.
Study lead author, Jeremy Brown from LSHTM, said in a statement: “We’ve known for a while that children who are young in their school year are more likely to have hyperactivity disorders and tend to do less well academically than older children.
“However, we believe this is the first evidence of an association between younger relative age in the school year and increases in the diagnosis of depression.”
Should summer babies start school later?
The research team note there are a number of potential interventions to address the mental health link, but there is limited evidence of their effectiveness.
In some countries parents of summer-born children can defer school entry for a year, but parent choice has the potential to increase socioeconomic inequality.
Parents in England of children born between April and August are able to request a delayed school start so children would begin in reception at five years old, rather than at four years old.
The scientists believe that further research into interventions to help reduce associations of age with academic achievement and mental health is needed.
Professor Ian Douglas, senior author from LSHTM, said: “Just 1% of the youngest quartile in a school year will be diagnosed with depression by age 16, and fortunately there is an increasing awareness about mental health as a priority. However, we should focus on reducing the number of children affected.
“Better recognition of this as a problem might help. Support is now available through NHS Child and Adolescent Mental Health Services but further improving availability of support within the school and health systems could also tackle the issue.
“Further research into the specific causes and interventions is required, as well as seeing if the depression persists into young adulthood. A fairer and clearer process for parents to request deferring school entry if their child is young for their school year and shows signs of slower development may also help.”
Study authors acknowledge limitations of the study, including the possibility that children who had deferred school entry would have been included in the wrong age category, though statistics reveal this is uncommon.
Additionally, as with any observational study, the possibility that other differences between the children could explain some of the findings cannot be completely ruled out.
Summer-born children at a disadvantage?
According to a study by the London School of Economics and Political Sciences (LSE), the youngest students in school year groups are less likely to have friends than their peers.
Some 24% of children born in July and August start reception knowing no one, compared to 22% of those born in September and October, says the report.
Summer-born children are less likely to attend a school-run nursery compared to peers – so they are likely to move from a different nursery when starting reception year.
The report concluded ministers should increase access to school nurseries for summer-born children.
Summer-born children aren’t just thought to suffer socially.
Previous research has suggested that summer-born babies are at an academic disadvantage compared to their older peers.
There is also some evidence that autumn-born children, the oldest in their year, have a sporting advantage compared to the younger members of their class, according to a study by the Centre for Sports and Exercise Science at Essex University.
On the other hand, some parents might consider enrolling summer babies in school earlier an advantage, allowing them to avoid paying additional childcare.