Yes, it works. I'm currently playing a lot lvl 1 to 4, to test what class I'm going to play at release. In one of the lvl 3 fights I had Crown of Madness on Gale, as replacement for Shatter (a stupid choice), and cast it on a Gnoll with success. He/It attacked one of the comrades one time, then the spell was gone, presumably by a saving throw.
I usually stay away from any cc or similar spell (like Fog Cloud) in BG3, they suck in comparison to damage spells. I use Sleep once at the ruins, then throw it out, the only cc I keep on my chars is Grease on Gale. Maybe in later levels, when the enemies have higher damage, cc spells are an absolute necessity (I'm not a DnD player, don't know)? Currently for my playstyle at least it's almost always better to do damage than to try to prolong the fight with cc.
