What is the origin of the idiom 'to have rocks in your head'?

Answer 1

This phrase originated during the Middle Ages, where city street vendors would commonly perform pseudo-surgery on street corners. Troubled persons displaying symptoms associated with mental illness would often frequent these vendors for relief. The vendors, in turn, would make a minor incision on the skull, while an accomplice would surreptitiously pass to the surgeon a few small stones. The surgeon would then pretend to have taken the stones from the patient's head. The stones were then claimed to be the cause of the person's problems, and that the person was now cured. A similar variant on this theme is quite popular with modern magicians and some faith healers who purport to painlessly remove diseased organs from the bodies their subjects. The procedure involves an elaborate ritual involving chicken or beef blood and associated meat parts from the animal. The magic rests in the illusion of the magician's arm-twisting while as he or she turns toward and into the blood-covered exposed belly of the subject, combined with the slow removal of what appears to be a body part.