Abstract # 20:

Scheduled for Thursday, June 21, 2007 02:05 PM-02:30 PM: Session 4 (North Main Hall C/D) Symposium


Does One View of Self-injurious Behavior (SIB) Fit All?

M. A. Novak1,2, M. D. Davenport2, C. K. Lutz3 and J. S. Meyer1
1Department of Psychology, , University of Massachusetts, Amherst, MA 01003-9271, USA, 2New England Primate Research Center, Harvard Medical School, 1 Pine Hill Rd., Southborough MA 01772, 3Southwest National Primate Research Center, Southwest Foundation for Biomedical Research, P.O. Box 760549, San Antonio, TX 78245
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     We have developed an integrated developmental/neurochemical hypothesis to explain the onset and maintenance of SIB in rhesus monkeys in which adverse early experiences result in lasting alterations in neuropeptide and neuroendocrine systems associated with the regulation of stress and anxiety. Monkeys with SIB show a dysregulation of hypothalamic-pituitary adrenal axis and altered opioid concentrations both of which may heighten reactivity to subsequent stressful events. These events produce anxiety which leads to biting and occasional wounding. Biting, in turn, may serve to counteract anxiety by eliciting the euphoria associated with the release of endogenous opioids. Evidence for this hypothesis is presented. If anxiety is a key component of SIB, then treatment with an anxiolytic drug (diazepam) should reduce SIB in monkeys. However, SIB was reduced only in a subgroup of monkeys receiving the drug, namely those monkeys that were exposed to adverse stressful experiences. These findings suggest that multiple subtypes of SIB may exist in monkeys, as has recently been noted for humans. Monkeys with adverse early experience that develop SIB may fit the profile of “Reactive SIB” where early life stress is a hallmark characteristic. Whether there are other subtypes of SIB in the rhesus monkey population is currently unknown; however, a single hypothesis may not account for all occurrences of SIB in rhesus monkeys.