I was replaying Avernum 3 and found a couple of Bitter Loss scrolls. I usually preemptively ditch these things after identifying them because they are cursed items, but for some reason I looked at the item description. It says "Changes Experience when used, Makes user very ill, adds 10 skill points"
The 'Adds 10 skill points' caught my attention, so I used the scroll. Lo and behold, I gained ten skill points. Unfortunately I lost 3000 XP, and became severely poisoned and acidified, but late in the game this wouldn't really matter.