彼は乱心して、何をするかわからない。
He has lost his mind, and there is no telling what he will do.
殿がご乱心なされたと、城中は大騒ぎになった。
The whole castle was in an uproar at word that the lord had gone mad.
乱心した家臣が城内で刀を抜いた。
A retainer who had gone out of his mind drew his sword inside the castle.