PLMD and RLS can occur In isolation During drug withdrawal With use of stimulants, certain antidepressants, or dopamine antagonists During pregnancy In patients with chronic renal or hepatic failure, iron deficiency, anemia, diabetes mellitus, a neurologic disorder (eg, multiple sclerosis, Parkinson disease), or other disorders In primary RLS, heredity may be involved; more than one third of patients with primary RLS have a family history of it.