With a high dose of xanax you kinda nod off and wake up having no memory of what happened or what you were doing. Its certainly not an opiate nod though. I've "nodded off" many times watching a movie. Just starting a movie and then opening my eyes and the movie being over, having no idea what happened. Its weird you lose hours of your life without knowing where they went, kinda scary. At least xanax alone is safe, even if you "nod off" more like blackout nothing bad healthwise happens. Unless your driving a car or something like that. Taking larger amounts of xanax I always wanna be sitting down in a safe position, because you never know when one of these blackouts will happen. Sometimes its just 1 minute, sometimes its 5 hours.