What is the ruling on shaving the beard of an insane person?

If the shaving of a madman's beard is done by someone else, it is not permissible, because it goes against the command of the Messenger of Allah, peace and blessings be upon him, unless the beard's continued presence causes him harm. However, if the madman shaves it himself while he is insane, there is no sin upon him, due to the Prophet, peace and blessings be upon him, saying: "The pen has been lifted from three: from the sleeper until he awakens, from the child until he reaches puberty, and from the insane person until he regains his sanity."