the ball is the circle of her soul… She misses it and it goes down into the pond… this is depression, this is loss of energy and joy in life; something essential has slipped out.
Campbell identifies the golden ball explicitly as the soul in its perfect circular form, and interprets its descent into the underworld spring as the mythic structure of depression and the loss of vital selfhood.
, Pathways to Bliss: Mythology and Personal Transformation, 2004thesis