Lack of sleep is the single greatest, perhaps the only, cause of bipolar illness for me, just one night without sleep I can go manic.

For me the best thing is a little zyprexa/olanzapine every night and more if not sleeping due to excitement or stress.

It's slightly unsual for it to be used for sleep but is proven to be effective according to my Doctor, it works like a tranquilizer but is not addictive (as far as I recall), it's possible your Doc has not considered it.

Good luck