Read the in-game descriptions for the voodoo. What happened to me in the demo is that Doc used the voodoo and some of his stats (AG and PE, I think) went up by 1 or 2 BUT his luck went to 1!!!! So the effect was that in the character screen, some of his stats where afflicted by the voodoo and therefore his skills went down where luck was involved. Doc never returned to normal but I still could finish the mission with 4 of the characters (geez, the ppl at Black Isle took it serious when they balanced the damage made by some weapons like the hunting rifle, Bullseye took 2 shots and dropped dead...Ghost bit it because I pressed the right click in front of a raider and he promptly tossed a frag grenade in front of a wall )...correct me if I am wrong.