A friend from yrs ago had it, she'd drop off unexpectedly at any moment & then be right back as good as new, a short nap would be just the right thing for her. Her sister would say leave her alone she be fit as a fiddle in just a few. Don't know if she took meds for it or if it continued (lost track of her over the yrs) but I think she had the condition since childhood.
Sorry that doesn't help much does it.

Barry