There is a common misconception about the tradition of Holy Fools in the Orthodox Church. The term fool in this context is meant to convey the meaning of somebody who acts in an irrational manner. In other words, they act like an insane person would act. They are in fact considered insane by many. This is true. Where people's understanding goes wrong is when they think that the person is actually insane, and happens to chance upon holiness somehow - perhaps by virtue of his mental illness. This couldn't be further from the truth. In actual fact, when a person takes on the podvig of foolishness-for-Christ, they are doing it voluntarily. They could, if they so wished, revert to acting like a normal person in full possession of their reasoning faculty. The reason they act foolishly is because they want to hide their holiness and also invite upon themselves ridicule in order to further acquire more holiness through the humility that comes along with being scorned by society. This is one of the most difficult spiritual feats that can be accomplished, and it presupposes a high level of perfection and spiritual achievement. Often these saints were found to spend whole nights in prayer. A person who is insane cannot be expected to reach a high spiritual state, and their illness necessarily obviates the ability to perform this spiritual feat. It is enough for them to bear their infirmity with patience, and they will be saved.