They actually played a pretty important role in early civilizations. For one, building a major urban civilization takes a lot of work. Slaves could be used for building projects to enlarge the city and its defenses, for agricultural labor to ensure that the people of the city could eat, or as domestic assistants to kings, lords, and shop-owners.
He might be sent to a mental institution because he is afraid and scared. He might have a medical condition or he might try to hurt himself to avoid whatever he went to trial for. People could also just think that he was crazy.
