What is Attention Deficit Hyperactivity Disorder?

Attention Deficit Hyperactivity Disorder – or ADHD – is the term given to a common behavioural condition that is defined by problems with attention, hyperactivity or impulsiveness that are extreme for a given age. The illness is most common in children; however, up to 50 per cent of people affected will continue to have symptoms throughout their lives.

ADHD is the most common neurodevelopmental disorder affecting children and teenagers. As of 2013, it was estimated to affect 39 million people worldwide, three-quarters of whom are male. ADHD is not strictly considered a learning disorder. However, research shows that 20–25% of children with the condition have coexisting learning disabilities in reading, spelling or maths. 

Signs of ADHD

Young children or teenagers with ADHD typically are hyperactive and have trouble paying attention and controlling their impulses. Researchers believe the condition results from a mix of genetic, environmental and neurological factors. Studies using magnetic resonance imaging (MRI) have identified several brain regions that differ in people with ADHD. These include the frontal lobe, which is important for executive functions such as planning and controlling attention, as well as regions involved in motor activity.

Who gets ADHD?

ADHD appears to run in families, suggesting a genetic basis. Close, or first-degree, relatives of people with ADHD are far more likely to also have the disorder, with the risk for siblings being two-to-three times as great as those of siblings without ADHD. 

Diagnoses and treatment of ADHD

There remains significant debate and controversy over both the diagnosis and management of ADHD, complicating studies on its effect on learning. 

At this stage, researchers do not have a clear understanding of what causes children to develop ADHD. It is thought the brain region known as the prefrontal cortex and its connecting areas might be particularly important in allowing humans to control behaviour and attend with constancy – these brain areas may be inefficient in children with ADHD.

The condition is treated with either, or both, behavioural therapy or specific drugs.

ADHD research at QBI

In 2010, cognitive and behavioural neuroscientist Associate Professor Bruno van Swinderen discovered a way to measure the attention span of a fruit fly, which could lead to further advances in the understanding of ADHD and autism in humans.

Associate Professor van Swinderen fed the fruit flies methylphenidate, which is sold under the brand name Ritalin and used to treat children with ADHD. He found the drug had similar effects on fruit flies as it did on people – that is, it helped the distractible flies pay attention to visual stimuli.

“It suggests there may be similar pathways in the brains of fruit flies and humans, which means we now have a simple reductionist model, with all the genetic tools that go along with it,” Associate Professor van Swinderen explained.