Restless legs syndrome and sleep-related disorders

History “Wherefore to some, when being at bed they betake themselves to sleep, presently in the arms and legs leapings and contractions to the tendons, and so great restlessness and tossing of their members ensue, that the diseased are no more able to sleep than if they were in a place of the greatest torture” [1]. Thomas Willis provided in 1672 what is thought to be the first clinical description of restless legs syndrome (RLS), which would be considered as a distinct clinical entity only centuries later, when Ekbom commented: “The syndrome is so common and causes such suffering, that it should be known to every physician” [2]. Following this seminal paper, RLS has also been known as Ekbom syndrome. This peculiar symptomatology has since attracted the interest of physicians but it has remained an elusive entity because of diagnostic uncertainties. The link between iron and RLS was formally made in 1953 when Nordlander put forward the theory that iron insufficiency caused RLS, and used large doses of intravenous iron to treat it [3]. More recently, evidence of the involvement of the dopaminergic system (in particular the deficiency of dopamine D2 receptors) suggested the use of dopaminergic agonists in the treatment of RLS, which proved to be highly effective [4]. In 2006, the US Food and Drug Administration (FDA) approved the use of pramipexole for the treatment of moderate to severe RLS. In 1995, the International Restless Legs Syndrome Study Group (IRLSSG) established consensus diagnostic criteria [5], which were further revised in 2003 [6]