Immunologic influences on emotion regulation

Recent data document meaningful interactions between the immune system and the brain that provide the foundation for considering the potential influence of immunologic processes on emotion regulation. Studies from both laboratory animals and humans demonstrate that cytokine signals can access the brain and in turn lead to profound changes in neurochemistry, neuroendocrinology and behavior. Interestingly, data suggest that the behavioral and physiological consequences of stressful life experiences may also derive in part from the effects of stress on the immune response. The extant literature on brain-immune interactions is reviewed herein with special emphasis on data derived from patients undergoing treatment with the cytokine, interferon alpha. Consideration is also given to the mechanisms by which cytokines induce behavioral change, including an examination of the differential mechanisms that may be involved in cytokine effects on mood and cognition versus cytokine effects on neurovegetative function. Finally, implications of these findings are examined both from an evolutionary perspective and in terms of their relevance for treatment of patients with neuropsychiatric disorders. (C) 2005 Association for Research in Nervous and Mental Disease. Published by Elsevier B.V. All rights reserved.