I've never noted lots of episodes; but the abruptness of the shifts when they happen is just really scary to me. Even more so now that I know what it is. I mean seriously, last summer, I'd been crashing around the outside of the house, dead in the middle of painting the exterior, high up on a ladder, and my energy just crashed. I went inside, barely wiped off with a towel; crashed on the floor, and that was it... for I guess 4 months or so. One day 2-3 hours sleep... 10-14+ from then on.