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Body and mind

People with ADHD have restless legs syndrome more often

Restless legs syndrome is a neglected and very common condition that has not garnered much attention from doctors so far. However, it should, because it is associated with poorer quality of life and an increased risk of many diseases. Researchers have now found that restless legs syndrome is also associated with the risk of having attention-deficit hyperactivity disorder (ADHD).

You may be one of the people who tosses and turns for hours at night with your legs continually and involuntarily moving.

About 5% of Danes have restless legs syndrome, and getting out of bed and standing up every single night to make their legs calm down can be a torment and a real hassle. It can ruin their sleep, and disturbed sleep is associated with increased risk of many diseases, including cardiovascular disease, obesity and mental disorders such as depression. So restless legs syndrome should be taken seriously.

New Danish research now shows another reason to take it seriously, because it is associated with ADHD.

“Restless legs syndrome can lower the quality of life of people who are severely affected, and unfortunately it more often afflicts people who already have a hard life. Now we have found that restless legs syndrome is associated with ADHD, and this is important when doctors encounter symptoms of either condition. Perhaps it would make sense for doctors to investigate whether people with ADHD also have restless legs syndrome and disturbed sleep at night and whether people with restless legs syndrome also have ADHD,” explains the researcher behind the new study, Henrik Ullum, Clinical Professor and Chief Physician, Department of Clinical Immunology, Rigshospitalet, Copenhagen.

The new study has been published in Sleep Medicine.

Restless legs syndrome is a neglected condition with major effects

Restless legs syndrome is insufficiently studied and affects many people, but doctors currently do not know what to do about it.

Several known factors are associated with an increased risk of having restless legs syndrome: iron deficiency, smoking, overweight, low educational level and a generally unhealthy lifestyle.

People who have restless legs syndrome often experience involuntary movements and abnormal unpleasant feelings in their legs just before sleeping, but the syndrome may sometimes continue during sleep, and the involuntary movement can wake people up at night.

Although many people have restless legs syndrome and its various negative effects, treatment is not very effective or consistent. No medicine is effective, and many people try various self-care measures to ease the condition, such as adopting a healthier lifestyle or taking mineral supplements with iron.

Henrik Ullum hopes to change this.

“Our research has two distinct focus points. We focus on restless legs syndrome, because it is associated with iron deficiency, and in our blood bank we often find that blood donors get restless legs syndrome, because giving blood often leads to iron deficiency. We want to help them by providing iron to the ones who need it. Second, we focus on ADHD because it is becoming much more common,” he explains.

25,336 Danes participating

In the study, the researchers searched for associations between ADHD and restless legs syndrome.

They used data from the Danish Blood Donor Study, which included people who donated blood in Denmark from 1 May 2015 to 1 February 2017. The 25,336 participants completed two questionnaires: one on symptoms of restless legs syndrome and one on symptoms of ADHD.

The participants also provided information on sex, age, body mass index, smoking status, alcohol consumption, whole-blood donation history and self-appraised quality of sleep.

Of the 25,336 participants, 1322 (5.2%) were classified as having restless legs syndrome, and 653 (2.6%) experienced ADHD symptoms.

The researchers examined whether ADHD is associated with restless legs syndrome and found that people with ADHD had a 3.5-fold greater risk of having restless legs syndrome than the rest of the study group.

“These participants were not necessarily clinically diagnosed with ADHD, but their ADHD score indicated that they could be diagnosed with ADHD if examined,” says Henrik Ullum.

Doctors should offer guidance to people with restless legs syndrome

According to Henrik Ullum, the results should be used to focus more intensely on restless legs syndrome and its association with ADHD.

Specifically, he recommends that doctors ask about restless legs if a person has ADHD and pay extra attention to signs of ADHD if a person has restless legs.

For patients who have ADHD and restless legs syndrome, doctors should enquire further about lifestyle and at least ensure that the patients get plenty of iron. Treatment for restless legs syndrome may start by getting the patient to stop smoking, lose weight or eat more healthily.

“These are the options we have right now. More research and better treatment are needed before we can do more, but we hope this will be possible because having restless legs syndrome can be serious if it disturbs people’s sleep,” says Henrik Ullum.

Self-reported restless legs syndrome and involuntary leg movements during sleep are associated with symptoms of attention deficit hyperactivity disorder” has been published in Sleep Medicine. A researcher from the Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen contributed to the study and is a co-author.

Henrik Ullum
Clinical Professor
Department of Clinical Medicine participates in teaching, research and dissemination of knowledge within the clinical field. The department undertakes undergraduate as well as postgraduate training of especially medical students in Eastern Denmark. The department employs 200 clinical professors, app. 500 clinical associate professors, a number of clinical lecturers and tutors and around 700 PhD students.