What Causes Restless Legs Syndrome?

Possible causes of RLS range from genetics to diet.

Do your legs refuse to stay still at night — so much so that they interfere with your ability to fall and stay asleep? You may be one of the more than 12 million adults in the United States who have restless legs syndrome (RLS), a neurologic sensorimotor disorder that causes bothersome “creepy-crawly” sensations or a sudden urge to move your limbs.

In most cases, the cause of RLS is unknown (referred to as idiopathic). Research is mounting, however, that there may be a genetic component to the disorder. Experts estimate that about half of all people with restless legs syndrome have a family history of the condition. One study found that siblings of people with RLS are 3.6 times more likely than the general population to develop restless legs. They also tend to be younger when symptoms start and have a slower progression of the condition.

In other cases, RLS appears to be related to an underlying condition, although researchers don’t yet know for sure if the condition actually causes RLS or simply coexists. Below are some possible risk factors:

  • People with low iron levels or anemia may be prone to developing RLS. Once iron levels or anemia is corrected, patients may see a reduction in symptoms.
  • Chronic diseases such as kidney failure, diabetes, Parkinson’s disease, and peripheral neuropathy are associated with RLS. Treating the underlying condition often provides relief from RLS symptoms.
  • Some pregnant women experience RLS, especially in their last trimester. For most of these women, symptoms usually disappear within 4 weeks after delivery.
  • Certain medications-such as antinausea drugs (prochlorperazine or metoclopramide), antiseizure drugs (phenytoin or droperidol), antipsychotic drugs (haloperidol or phenothiazine derivatives), and some cold and allergy medications-may aggravate symptoms. Patients can talk with their physicians about the possibility of changing medications.

Researchers also have found that caffeine, alcohol, and tobacco may aggravate or trigger symptoms in patients who are predisposed to develop RLS. Some studies have shown that a reduction or complete elimination of such substances may relieve symptoms, although it remains unclear whether elimination of such substances can prevent RLS symptoms from occurring at all.

To find out what’s behind your RLS — and to figure out the best course of treatment — talk with your doctor about your symptoms. Be prepared to give a rundown of your medical history.