[Depression, yesterday, today and tomorrow: historical evolution of concepts].

Depressive thoughts have been apparent since the origins of humanity. References to depressive thoughts can be found in philosophical writings and other literature since antiquity. They were always approached in a religious or medical way, with arguments for a mix of psychological and mystical origins. With the advent of psychiatry as a medical discipline, depressive syndromes were integrated into classifications of mental disorders. The definition of depression is multifactorial, integrating psychosocial, social and biological factors. In this article we use an historical perspective to describe the sociological, psychopathological and biological concepts relating to depressive illness. Over one century, the sociology of mental illness has evolved from the Durkheimian position to psychosocial models which incorporate environmental stressors, social support and coping mechanisms. Psychology encompasses psychoanalytical, cognitive-behavioural and phenomenological theories. Finally, biological psychiatry suggests various approaches--genetic, biochemical, neurophysiological, neuroanatomical.... The therapeutic directions are central to these concepts, just like public health, which seeks to promote the concept of mental health rather than to limit itself to the definition of the various psychiatric disorders.