Feeblemind

If the target creature fails a saving throw vs. Spells, its Intelligence and Charisma scores each drop to 1. The affected creature is unable to cast spells, understand language, or communicate coherently. The victim does remember who its friends are and can follow and protect them from harm. The subject remains in this state until a heal spell is used to cancel the effect. A target creature that can cast Magic-User spells suffers a penalty of -4 on its saving throw against this spell.