As I understand Jungian theory, he based his concept of depression on his theory of the libido. In Jung’s approach to analytical psychology he viewed the libido as a psychological component of life energy or what is called the Chi in Eastern religions. This is not to be confused with the Freudian theory of the libido as sexual energy.
In Jung’s view the libido drives the organism to grow and develop. It moves toward balance – the balance between the conscious and the unconscious to include the Shadow, between the male and female parts of the psyche and between the introverted and extroverted sides of the ego. The purpose of this balancing is to achieve what Dr. Jung called individuation or the wholeness of self realization.
When the ego is in a state of imbalance between its extroverted and introverted aspects, with the extroverted holding sway, introversion brings forward unconscious material in an attempt to balance ego’s attitude. Jung believed that introversion exhausts the ego. Depression then becomes the manifestation of the exhausted ego.
The libido while balancing opposition contains opposition. Thus, Jung thought that it held both the drive to live and the drive to die.
As a hereditary and lifelong Pagan I do not believe that life is the beginning or death the end. As a devout follower of the Goddess, Her mysteries and mysticism, I believe that we select a life that contains a path. Goddess gives us each our own light with which to follow that path. All we can do is follow our light as far and as long as we can – leaning as we go. For in reality it is the lessons and not the life we have chosen.