Can I cancel buffs like lycanthropy or invisibility after casting them? My high level sorceress has quite a long duration on those by now and it can be annoying having to wait for them to end.

no idea if you'll still read this, but i remember reading that you can cast Forgetfulness on yourself. it gets rid of Invisibility, but no clue on what other buffs it works.. just try it out, i suppose!
i really wish i knew it earlier myself, because it was always such a drag when i wanted to talk to NPCs but had to wait for invisibility to run out..