Is chronic pain a variant of depressive illness? A critical review.

A critical review of the literature on the association of chronic pain of obscure origin and depression suggests the following: the nosological confusion in defining these two commonly occurring symptom complexes; poor sampling methods and widely ranging selection criteria; occasional lack of appropriate controls and use of unreliable instruments to measure pain and depression; and the frequently erroneous assumption that response of the pain to "antidepressant" medications implies that pain is masquerading some form of depression. All of the above observations lead to incomparable and sometimes opposing conclusions regarding the nature of the association between these two common symptom complexes. Some widespread recurring clinical features of the various studies include; a premorbid history of perfectionistic traits, an apparently minor precipitating event; and pain involving the head, face and musculoskeletal system. Otherwise, chronic pain of obscure origin appears to be a multifactorial and multifaceted problem, with each patient requiring a complete physical and psychosocial evaluation. Further understanding of this group of disorders requires studies of specific chronic pain syndromes using proper controls.