If you get in a pattern of sleeping around the same time your body tends to automatically get "sleepy" during that time. It's all about staying on somewhat of a schedule.

Problem is, not sleeping will have negative effects on ANYONE past the first day of sleep deprivation. The first day you usually feel find but after that the mind generally deteriorates. Since it's said that there is an anti-depressant effect after the first day of sleep deprivation, I have a feeling enough of x neurotransmitter is released that exacerbates the manic symptoms. (As many people with BP are triggered by anti-depressants alone)