The typical signs of RLS are prickling and uncomfortable sensations in the legs accompanied by an urge to move (1, 2). This urge to move arises when one is at rest and is relieved partly or wholly with movement. The urge to move also varies distinctly in the course of the day, with symptoms in the evening and at night, and not early in the day (2). Because of the association with evening and night, RLS is regarded as a sleep-related movement disorder (2, 3). However, the condition is also classified as a neurological disorder, which often arises in adulthood and is a lifelong condition (1, 2).
Surveys in several Western countries indicate the prevalence of the diagnosis restless legs syndrome to be 5–10 % (1, 3, 4). In a 2005 Norwegian population survey, 14.3 % of adults met the criteria for RLS, and about half of them described their distress as moderate or severe (5). The majority of those reporting the problem are women, and prevalence increases with age (3). Although the condition is common, it often remains undiagnosed and untreated (3, 4, 6).
There is a higher prevalence of RLS in patients with kidney failure or anaemia or who are pregnant or use certain medications (3, 7, 8). The mechanisms underlying RLS are unknown, but impaired functioning of the dopaminergic system has been found (1). Impaired iron metabolism also appears to play a part (1, 8). Genetic factors are involved, and 40–50 % of the patients with this diagnosis know other family members with similar complaints (3, 8).
The treatment of RLS depends on the severity of the symptoms. In cases of slight or rare discomfort, non-pharmacological treatment is recommended. The symptoms are alleviated by movement, and massage of the leg musculature can also help. Good sleep hygiene is important (3, 9). The circadian rhythm should be as stable as possible. Caffeine-containing drinks should be avoided in the evening. Alcohol and nicotine can trigger or exacerbate RLS in predisposed patients. The disorder may also arise as an adverse reaction to some medications (such as antidepressants and antipsychotics), and a change of medication or the time of taking it may be advisable.
Pharmacological treatment is normally recommended for frequent and more severe distress. Iron supplement may be effective (9) and is recommended when ferritin levels fall below 50 µg/L (10). For many years, the first-line therapy for RLS has been drugs that stimulate the dopamine receptors in the brain (dopamine agonists) (3, 9, 11). These often prove very effective, and if they have no effect, the diagnosis should be reassessed. There are often few initial side effects, but one problem with dopamine agonists is waning efficacy and a risk of symptom augmentation over time. There are alternatives to dopamine agonists, the most relevant being alpha-2-delta ligands (gabapentin and pregabalin), and these drugs have also been proposed as first-line therapy for RLS (1).
Little is known of the prevalence of RLS in Norwegian general practice. A Norwegian study revealed that the prevalence of other sleep-related disorders, such as insomnia, is more than twice as high among patients at the general practitioner's (GP's) office compared with that in population surveys, because insomnia is more widespread among persons with other illnesses and disorders for which patients consult their GP (12). It is uncertain whether this also applies to RLS. It is also unclear whether this disorder is associated with other common complaints seen in general practice.
The aim of this study was therefore to investigate the prevalence of RLS amongst patients who consult their GP. We also wanted to study the severity, and whether patients used medications for their symptoms. In addition we wanted to study whether the prevalence of RLS was associated with other common conditions about which patients consult their GP, such as irritable bowel syndrome (IBS), chronic fatigue (CF) and chronic muscle and back pain (CMBP).