Restless legs syndrome and pain disorders: what's in common?

Between 10 % and 30 % of the population report chronic pain. More than half of these also have sleep complaints. From considering these data, it can be inferred there is a significant overlapping between these conditions. Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED) is characterized by complaints of an "urge to move" frequently associated with dysesthesias. From that perspective, these sensations can also have painful characteristics. By the same token, the presence of comorbid diseases as predicted by a higher prevalence RLS/WED, have many of them with pain as an important complaint. Pain is a multidimensional response involving several levels of expression ranging from somatosensory to emotional. The potential shared mechanisms between RLS/WED and pain may involve sleep deprivation/fragmentation effect, inducing an increase in markers of inflammation and reduction in pain thresholds. These are modulated by several different settings of neurotransmitters with a huge participation of monoaminergic dysfunctional circuits. A thorough comprehension of these mechanisms is of utmost importance for the correct approach and treatment choices.