What causes Ophelia to go insane?

think Ophelia is really being used here. Her father Polonius has told her to stay away from the man she loves yet uses her to set a trap for the man she loves. Hamlet uses Ophelia to further his own goals to expose the king. Laertres wants to control her sexual and romantic life. Ophelia should stir a lot of pathos in the audience. She is innocent of wrongdoing yet, as a young woman, must serve as a pawn under the men in her life.