I was taught that Restless legs syndrome (RLS) is not related to Parkinson Disease (PD), even though they can be treated with similar medications. However, here is a study that shows a potential relationship between RLS and PD. Researchers studied almost 23,000 men with self-reported RLS and documented PD. The results showed that RLS symptoms were associated with higher risk of developing PD during the first 4 years of follow up. This relationship was only statistically significant in the men with severe RLS symptoms, occurring 15 or more times per month.
The researchers speculate that RLS may be an early feature of PD, and be a distinct entity from RLS that is not associated with PD.