Researchers in Southampton, America and Sweden have collaboratively found a link between two conditions that commonly affect children – attention deficit hyperactivity disorder (ADHD) and asthma.
A team led by Dr Samuele Cortese, an associate professor of psychology and medicine at the University of Southampton, combined and analysed the results recorded in 49 previous studies from around the world.
They also looked at a cohort of health records of around one million individuals from the Swedish national registry which helped to confirm that the common pattern between ADHD and asthma wasn’t due to other factors, such as gender or additional health conditions.
Their findings, published in The Lancet Psychiatry, found a significant link between ADHD and asthma. The occurrence of asthma was almost 17% in individuals with ADHD but only 11.5% in those without, and the occurrence of ADHD was almost 9% in individuals with asthma but only 5.6% in those without.
In the UK, surveys of children between the ages of five and 15 years found that 3.62% of boys and 0.85% of girls had ADHD. It is the most commonly diagnosed psychiatric condition in children and includes symptoms such as short attention span, hyperactivity and impulsiveness.
Asthma is the most common long-term medical lung condition in children in the UK, with around 1 in 11 children receiving treatment. When a child has asthma, their airways are inflamed and more sensitive than usual, with symptoms including coughing, wheezing and shortness of breath.
Putting patients first
“We hope the results from our study and confirming the link between ADHD and asthma will lead to positive changes around how children are diagnosed and treated for these common conditions – especially when they exist together,” explained Dr Cortese.
“It may prompt psychiatric and respiratory specialists referring patients with early forms of each condition to the corresponding specialist, helping to reduce delayed diagnoses in both conditions.”
The next step is to understand why the link exists, with researchers focussing on how inflammation – such as that seen in asthmatics – can affect psychiatric disorders.
“Inflammation is a characteristic feature of asthma which is made worse when the airways are irritated, usually by an allergic reaction. This reaction, or response, is carried around the body to the brain by an increased level of inflammatory proteins in the bloodstream.”
“It is this response that holds the most interest as we know that changes to the brain can lead to attention and concentration problems, which are common in people with ADHD.”
This potential link supports further investigation into the relationship between the two conditions and whether drugs used to treat asthma may also be beneficial for patients with ADHD.
Posted on Tuesday 6 November 2018