To clarify - the flight did not fly 80 minutes past KMSP. It flew 80 minutes or so without radio contact from the time it was handed off by Denver Center (i.e. over central Nebraska) until 150 miles (or 14 minutes) past KMSP (Eau Claire, Wisconsin or thereabouts).
MSNBC reports tonight that blood tests ruled out alcohol, and repeated the brief front-door interview with one of the pilots as reported above - also that CVR caught only last 30 minutes, and that the looping return was due to ATC, whi wanted to be sure the hands at the controls were fully awake and/or not also holding boxcutters.
Hearings coming up Monday.