Pain and Depression: the Janus Factor of Human Suffering

The Cartesian dualism between res extensa (material substance) and res cogitans (the thinking thing) has governed biological research and medical science for centuries. Research on pain and in psychiatry has suffered more than any other field the consequences of this dichotomisation into body and soul (or mind). In this context, mood disorders represent a paradigm, but also a framework for an integrated view, which allows to improve the knowledge and management of pain. On the basis of the relevance of the body's perception and as a result of integrated efforts between neuroscientists and clinicians, a new concept of mind appears to be under construction. In this chapter we report the psychoanalytic point of view, which overcomes the concept of body and mind, defining pain as a psychical state expressed through localised sensations rather than as a concept in itself and offering a further interpretation of pain and its attributes. In addition, the chapter discusses research findings, both historical and recent, as well as clinical evidence that has contributed to disclosing the association between mood disorders and pain - with particular focus on depression, medically unexplained pain, brain changes in pain, and the role of antidepressants as "analgesic" in pain symptom management in neurological and psychiatric disorders.