Restless legs syndrome (RLS) is generally a long term disorder that causes a strong urge to move one's legs. There is often an unpleasant feeling in the legs that improves somewhat with moving them. This is often described as aching, tingling, or crawling in nature. Occasionally the arms may also be affected. The feelings generally happen when at rest and therefore can make it hard to sleep. Due to the disturbance in sleep, people with RLS may have daytime sleepiness, low energy, irritability, and a depressed mood. Additionally, many have limb twitching during sleep.Wherefore to some, when being abed they betake themselves to sleep, presently in the arms and legs, leapings and contractions on the tendons, and so great a restlessness and tossings of other members ensue, that the diseased are no more able to sleep, than if they were in a place of the greatest torture.The name Willis–Ekbom disease: Restless legs syndrome (RLS) is generally a long term disorder that causes a strong urge to move one's legs. There is often an unpleasant feeling in the legs that improves somewhat with moving them. This is often described as aching, tingling, or crawling in nature. Occasionally the arms may also be affected. The feelings generally happen when at rest and therefore can make it hard to sleep. Due to the disturbance in sleep, people with RLS may have daytime sleepiness, low energy, irritability, and a depressed mood. Additionally, many have limb twitching during sleep. Risk factors for RLS include low iron levels, kidney failure, Parkinson's disease, diabetes mellitus, rheumatoid arthritis, and pregnancy. A number of medications may also trigger the disorder including antidepressants, antipsychotics, antihistamines, and calcium channel blockers. There are two main types. One is early onset RLS which starts before age 45, runs in families and worsens over time. The other is late onset RLS which begins after age 45, starts suddenly, and does not worsen. Diagnosis is generally based on a person's symptoms after ruling out other potential causes. Restless leg syndrome may resolve if the underlying problem is addressed. Otherwise treatment includes lifestyle changes and medication. Lifestyle changes that may help include stopping alcohol and tobacco use, and sleep hygiene. Medications used include levodopa or a dopamine agonist such as pramipexole. RLS affects an estimated 2.5–15% of the American population. Females are more commonly affected than males and it becomes more common with age. RLS sensations range from pain or an aching in the muscles, to 'an itch you can't scratch', a 'buzzing sensation', an unpleasant 'tickle that won't stop', a 'crawling' feeling, or limbs jerking while awake. The sensations typically begin or intensify during quiet wakefulness, such as when relaxing, reading, studying, or trying to sleep. It is a 'spectrum' disease with some people experiencing only a minor annoyance and others having major disruption of sleep and impairments in quality of life. The sensations—and the need to move—may return immediately after ceasing movement or at a later time. RLS may start at any age, including childhood, and is a progressive disease for some, while the symptoms may remit in others. In a survey among members of the Restless Legs Syndrome Foundation, it was found that up to 45% of patients had their first symptoms before the age of 20 years. Individuals with RLS have higher rates of depression and anxiety disorders.