Depression: A psychological state characterised by a lack of energy.

Energy not available to consciousness does not simply vanish. It regresses and stirs up unconscious contents (fantasies, memories, wishes etc.) that for the sake of psychological health need to brought to light and examined.. Depression is not necessarily pathological. It often foreshadows a renewal of personality or a burst of creative activity.’

Daryl Sharp.C.G. Jung Lexicon: A Primer of Terms and Concepts. Inner City Books. Canada. 1991.