Are curse, feeblemind, etc., completely useless?

[Bones_xa]

Whenever I cast spells like curse and feeblemind on enemies they never seem to do anything. Do they do anything?
As an example, I've tried many times casting feeblemind and curse on creatures such as druids, harpies, fire archers, etc. and they continue to throw spells at me not seeming to be effected at all.
I read somewhere that this is their primary attack or something so its not considered a spell, same with many other creatures. So if this is simply the case, what creatures would these spells actually work on?

Maybe I actually know the answer and answered my own question, but maybe not, and I still would like to know what other people think about these spells.

[Arret]

Yes feeblemind is trash. Think apprentice mage and goblin king for the type of monster that it should work on. The "attack" is a melee swing. but they can cast spells.

Mass curse isn't terrible because curses are also supposed to affect melee attacks as well, but honestly just mash damage spells (sparks/poison spray/shrapmetal).