How messed up are they? I think it's OK if you go to sleep and wake up at roughly the same time. Even if you don't, after a week of getting up early, you will! I'm not sure how critical it is to have a strict sleep/wake cycle before you start CAT. The longer you do CAT and stick to the wake times, the more you must be training yourself to stick to the schedule, so maybe it doesn't matter too much if your sleep is a bit messed up before you start. It would probably just take longer to start working while your body adjusts.