Jane Garland, a child and adolescent psychiatrist at the University of British Columbia in Vancouver and colleagues.

CNN: Youngest kids in class more likely to be diagnosed with ADHD

The problem could be a result of poor parenting, said Dr. Elizabeth Roberts, a child and adolescent psychiatrist.

CNN: STORY HIGHLIGHTS

But Dr Clare Lamb, consultant child and adolescent psychiatrist at North Wales adolescent service, Conwy and Denbighshire NHS Trust, said if patients are swiftly diagnosed their outlook is brighter.

BBC: NEWS | Health | Call for mental disorder checks