Good to know. The correlation seemed very strong, so I'm glad to know it's not all just a result of this drug. She came to the conclusion after she noticed every single customer that came in for RLS medicine was taking this other Merck medication. Not proof, but it was there.
It doesn't mean Merck doesn't have a drug that lowers the threshold, but it also doesn't mean that all cases are due to this Merck drug.
Anecdotally, RLS has been around for quite a long time, but again, I don't know the timeframe of the drug you refer to.