My psychiatrist says I live on Australia time. Because of trauma issues I don't go to bed till dawn and I sleep till around noon. As long as I keep a consistent sleep -wake cycle it hasn't been a problem for my bipolar 1 disorder. If I find myself not going to bed at dawn and scrubbing the bathroom with a toothbrush instead, that's a problem. I write for a living and live alone so it actually doesn't matter when I start my day. I can't sleep in the dark no matter how hard I try even heavily medicated with seroquel, so Australia time works for me.