Interesting thoughts alex - I seem to remember (it is documented somewhere) the deep sleep cycle is particularly affected. It was borne out in my case when raising low Gabapentin given for pain relief I was allowed to raise to full levels indicated. It resulted in a period (? two - three weeks) of very deep sleeps rising only to go to the bathroom or eat lightly. Winding it down I just felt so much better afterwards - does this restoration (not just light sleeping) hold some key in healing processes one has to wonder.