08/03/2012 10:13 GMT | Updated 22/05/2015 10:12 BST

ADHD Diagnosis Is Higher In December Babies, Study Claims

Children in a classroom PA

A Canadian study has found that December babies are significantly more likely to be diagnosed with attention deficit hyperactivity disorder than the rest of their classmates.

The researchers looked at nearly a million children, and concluded that some youngsters were being put on medication for ADHD when they were really just not as mature as the older pupils in the class.

The findings are published this week in the Canadian Medical Association Journal and reveal that the surveyed girls born in December were 70 per cent more likely to have an ADHD diagnosis than girls born in January, while boys born in December were 30 per cent more likely to have a diagnosis of ADHD than boys born in January.

In terms of being given drugs, girls were 77 per cent more likely and boys were 41 per cent more likely to be medicated for ADHD if they were born in December than if were born in January.

The study's lead author Richard Morrow from the University of British Colombia said: "Our study suggests younger, less mature children are inappropriately being labelled and treated. It is important not to expose children to potential harms from unnecessary diagnosis and use of medications."

In the study's geographical area (British Colombia), children within the same grade (or year group) can be almost one year apart in age, yet there have been very few studies (none outside of the US) that have examined the "relative-age" effect on the diagnosis of ADHD.

The researchers included 937,943 children in the study, aged from six to 12. In British Colombia, the cut-off for entry into each year's class is a December 31 birthday.

What do you think about this? Putting it into context in the UK, do you have a child with an August birthday who is in a class with children almost a year older? Does this have an impact on behaviour?