Abstract # 19:

Scheduled for Thursday, August 18, 2005 11:30 AM-11:45 AM: Session 2 (Mayfair Room) Oral Presentation


C. Shively1, T. C. Register1, D. P. Friedman3, T. Morgan2, J. Thompson1,4 and T. Lanier1
1Department of Pathology (Comparative Medicine), Dept. of Comparative Med., Wake Forest Univ. School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1040, USA, 2Public Health Sciences, 3Physiology & Pharmacology, 4Post-bacculaureate Research Education Program
     Case reports of depression-like behavior in adult monkeys suggest that monkeys may exhibit a depressive response to stress similar to that observed in humans; however, this has not been systematically studied. We recorded time spent depressed (i.e., slumped/collapsed body posture, lack of responsiveness to environmental stimuli to which other monkeys are attending, and open eyes) in 36 adult female cynomolgus monkeys, housed in small social groups of 4 females each, for approximately 36 months. Activity, autonomic, hypothalamic-pituitary-adrenal, and reproductive system function were also evaluated. Three patterns of depression seemed apparent: one group of monkeys rarely/never displayed depression, one group displayed depression intermittently, and one group displayed depression nearly all the time. The number of months a monkey displayed the depressed posture was correlated with the average time spent in the depressed posture throughout the experiment (r = 0.84, P < 0.001). The average time spent depressed predicted mortality (r = -0.41, P < 0.02 between days lived and % time depressed). Monkeys above the mean in percent time depressed (n = 15) had less body fat, lower activity levels, lower social status (determined by the outcomes of agonistic interactions), higher heart rate, and impaired ovarian function and cortisol secretion relative to those below the mean (n = 21) (all P values < 0.05). These data suggest that monkeys may exhibit behavioral and physiological characteristics that are similar to those of human beings with major depressive disorder, and that depression may be an adaptive response to adverse social environmental circumstances. Supported by MH56881, GM64249, and the MacArthur Foundation.