For every girl diagnosed with ADHD, up to seven boys are diagnosed. Researchers looked at risk factors, the role of genetics, and mental health for clues.
Assessment scales for ADHD have been developed using mostly male research samples. As a result, the behaviours indicating ADHD in girls may not be what you expect.
This week, the prestigious journal The Lancet published a large study identifying objective differences in the brains of people diagnosed with attention-deficit hyperactivity disorder.
It's not necessarily the case children who are young for their year are being inappropriately diagnosed with ADHD. This is a simplistic analysis.