4 Bible Verses about Lunatics

So David changed his behavior before them and acted like he was crazy in their presence. He scribbled on the doors of the gate, and let his saliva run down his beard. Achish told his officials, "Look, you see a person acting like a madman. Why'd you bring him to me? Am I lacking madmen that you bring me this one to act like a madman around me? Shall this one come into my house?"

As these words were being spoken by the king, a voice came out of heaven: "King Nebuchadnezzar, this is declared to you: "The kingdom has been taken from you! You're to be driven away from people. You're to live with the wild animals of the field. You are to be made to eat grass like cattle, and seven years will pass you by until you realize that the Most High is sovereign over human kingdoms and grants them to whomever he desires.'" The decree was fulfilled against Nebuchadnezzar immediately. He was driven away from people to eat grass like cattle, and his body was drenched with dew from the sky, until his hair grew like eagles' feathers and his nails like birds' claws.read more.
"When that period of time was over, I, Nebuchadnezzar, lifted my eyes to heaven and my sanity returned to me. I blessed the Most High, praising and honoring the one who lives forever: For his sovereignty is eternal, and his kingdom continues from generation to generation. All who live on the earth are nothing compared to him. He does what he wishes with the heavenly armies and with those who live on earth. No one can hold back his power or say to him, "What did you do?' At that moment I recovered my sanity, and my honor and majesty returned to me, for the sake of my kingdom. My advisors and officials sought me out, my throne was restored, and even more greatness than I had before was added to me.

Many of them were saying, "He has a demon and is insane. Why bother listening to him?"

As he continued his defense, Festus shouted, "You're out of your mind, Paul! Too much education is driving you crazy!"