Causes of restless legs syndrome

In many cases, the exact cause of restless legs syndrome is unknown.

When no cause can be found, it'sknown as "idiopathic" or primary restless legs syndrome.

Research has identified specific genes related to restless legs syndrome, andit can run in families. In these cases, symptoms usually occur before the age of 40.


There's evidence to suggest restless legs syndrome is related to a problem with part of the brain called the basal ganglia. The basal ganglia uses a chemical (neurotransmitter) called dopamine to help control muscle activity andmovement.

Dopamine acts as a messenger between the brain and nervous system to help the brain regulate and co-ordinate movement. Ifnerve cells become damaged, the amount of dopamine in the brain is reduced, which causes muscle spasms andinvoluntary movements.

Dopamine levels naturally fall towards the end of the day, which may explain why the symptoms of restless legs syndrome are often worse in the evening and during the night.

Underlying health condition

Restless legs syndrome can sometimes occuras a complication of another health condition, or it can be the result of another health-related factor. This is known as secondaryrestless legs syndrome.

You candevelop secondaryrestless legs syndrome if you:

  • have Iron deficiency anaemia low levels of iron in the blood can lead to a fall in dopamine, triggeringrestless legs syndrome
  • have a long-term health condition such as chronic kidney disease , diabetes , Parkinson's disease , rheumatoid arthritis , an underactive thyroid gland , or fibromyalgia
  • are pregnant particularly from week 27until birth; in most cases the symptoms disappear within four weeks of giving birth


There are a number of triggers that don't causerestless legs syndrome, but can make symptoms worse. These include medications such as:

  • some antidepressants
  • antipsychotics
  • lithium used in the treatment of bipolar disorder
  • calcium channel blockers used in the treatment of high blood pressure
  • some antihistamines
  • metoclopramide used to relieve nausea

Other possible triggers include:

  • excessive smoking , caffeine or alcohol
  • being overweight or obese
  • stress
  • lack of exercise
Content supplied by the NHS Website

Medically Reviewed by a doctor on 29 Nov 2016