Fri, 18 May 2001

      Cytokine Secretion Linked to Emotional and Cognitive Disturbances
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      WESTPORT, CT (Reuters Health) May 14 - Study results published this
week provide more evidence that the level of circulating cytokines may
influence not only emotional state but cognitive function as well.

      In a double-blind, crossover study, Dr. Raz Yirmiya, from the Hebrew
University of Jerusalem, Israel, and colleagues had 20 healthy volunteers
complete a battery of psychological and neuropsychological tests 1, 3, and 9
hours after injection of a low dose of Salmonella abortus equi endotoxin or
saline.

      They report, in the Archives of General Psychiatry for May, that
endotoxin caused a mild increase in rectal temperature but did not lead to a
subjective feeling of illness in the subjects.

      The endotoxin did, however, increase plasma levels of tumor necrosis
factor (TNF) alpha, soluble TNF receptors, interleukin (IL)-6 and IL-1
receptor antagonist, and cortisol. Moreover, "significant positive
correlations" emerged between cytokine secretion and endotoxin-induced
anxiety, depressed mood and decreased verbal and nonverbal memory.

      Increased cytokine secretion is associated not only with infectious
diseases, but also with autoimmune and neurodegenerative diseases as well as
brain trauma, Dr. Yirmiya and colleagues point out. The results of the
current investigation suggest that "at least some of the illness-induced
behavioral pathology may be directly caused by cytokine secretion," Dr.
Yirmiya and colleagues write."

      "This hypothesis," they conclude, "has important implications for the
development of new psychopharmacological approaches that should target the
negative psychological effects of cytokines in various medical conditions."

      Arch Gen Psychiatry 2001;58:445-452.