Restless leg syndrome, also known as Willis-Ekbom disease, is a common condition of the nervous system that causes an overwhelming and irresistible urge to move the legs. Estimates are that around 10% of people suffer from RLS at some stage in their lives. It often occurs during sleeping hours and can cause severe insomnia. In the majority of cases there's no obvious cause (i.e. it's termed idiopathic).

RLS can be triggered (or exacerbated) by other medical problems, pregnancy, or by medications, drugs, etc.

Further reading NHS, UK

Note: One of the prominent drugs used to treat RLS, Gabapentinplugin-autotooltip__plain plugin-autotooltip_bigGabapentin

Gabapentin, a medicinal drug sold under the brandnames Gralise, Gabarone, Fanatrex, Neurontin (and many others) was discovered in the 1970s, and was first used as a muscle relaxant and painkiller.

In the US alone, it currently has more than 40 million prescriptions per year. provides some relief in some patients - by an as yet unknown mechanism.

Also see Hypnic jerksplugin-autotooltip__plain plugin-autotooltip_bigHypnic jerks

Hypnic jerks (a.k.a. hypnagogic jerks, sleep starts, sleep twitches, myoclonic jerks, night starts etc) are brief and sudden involuntary muscle contractions (twitches) which happen as a person (or other mammal) is beginning to fall asleep. They can be severe enough to wake the sleeper. Approximately 70% of people have experienced them.