Depression and immunity

Townsend Letter for Doctors and Patients,  June, 2005  by Robert A. Anderson

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The role of cytokines in depression was first elucidated when the cytokine interferon resulted in "sickness behavior," symptoms of which are similar to those of major depression. Depression is associated with an increase in pro-inflammatory cytokines IL-1, IL-6 and tumor necrosis factor-alpha (TNF-[alpha]) which are potent modulators of corticotropin releasing hormone which produces heightened hypothalamic-pituitary-adrenal axis activity characterized by increases in ACTH and cortisol, both of which are elevated in major depression. Antidepressant treatment has immunomodulatory effects which increase the production of the anti-inflammatory IL-10.

O'Brien SM, Scott LV, Dinan TG. Cytokines: abnormalities in major depression and implications for pharmacological treatment. Hum Psychopharmacol 2004 Aug; 19(6): 397-403

COMMENT: This review of 1980-2003 depression/cytokine literature focuses on the evidence for cytokine changes in acute stress, chronic stress and major depression. There are a number of implied or demonstrated feedback-loops in this aspect of body chemistry, making it difficult to determine which element is at the beginning of everything. It does appear, however, that when an environmental or internal event is perceived to be threatening and therefore stressful, that a cascade of biochemical events is triggered, including release of a number of proinflammatory cytokines as well as changes in the hypothalamic-pituitaryadrenal axis balance which leads to risk of depression. To emphasize what I said above, dealing with the initial stressor and the degree to which it is perceived to be threatening may be the most important therapeutic intervention. Everything else is "downstream." The degree to which a given stressor is thought to be threatening is highly related to our attitudes and beliefs. Rarely does medical care "go there" or intrude in this aspect of the human psyche. But perhaps it is important for us to now recognize and teach that this is a quintessential aspect of whole person care.

COPYRIGHT 2005 The Townsend Letter Group
COPYRIGHT 2005 Gale Group