Professor Matthew Smith, Vice-Dean of Research for the Faculty of Humanities and Social Sciences at Strathclyde University, said children can be diagnosed with ADHD for simply being naught or daydreaming in class.

Smith, author of "Hyperactive: The Controversial History of ADHD" said: "Rather than questioning why children are naughty or daydream in class, naughtiness and daydreaming are seen as symptoms of ADHD.

"It is much easier to blame the child and label them as different or abnormal than it is to adapt classroom environments in ways that are more accommodating for children who find it difficult to pay attention or to resist the urge to misbehave.

"Blaming a glitch in the brain is also easier than looking for other potential triggers for such behaviour, such as problems at home, lack of physical activity or time spent outdoors, too much screen time or even reactions to food chemicals.

"Research has also shown that the children who tend to be diagnosed with ADHD are usually the youngest in their class cohort, meaning that simply may be less mature than their older classmates.

"We need to be think of these things first before diagnosing a child with ADHD and prescribing stimulant drugs."