I was on olanzapine for about 10 months from 2.5-15mg. The max recommended dose is 20mg, but they do use off license doses up to 60mg that I've read in studies!

The sedation never went away for me. I did get used to it a little, but then increasing the dose increased the sedation. 10-15mg was unbearable for me, but even on 5mg I was still sleeping 12-16 hours a day, and that was taking it at 6pm at night.

However, lots of people do adjust to the sedation, or don't seem to get it, so YMMV

*Willow*