Major, C. A., Kelly, B. J., Novak, M. A. et al. 2009. Self-directed biting in male rhesus monkeys (Macaca mulatta) with self-injurious behavior (SIB) increases following acute treatment with the anxiogenic drug FG7142. American Journal of Primatology 71(S1), 89. (32nd Meeting of the American Society of Primatologists Scientific Program, Abstract #182)

A small percentage of captive macaques spontaneously exhibit self-injurious behavior (SIB), mostly in the form of self-directed biting. Several risk factors have been identified in the etiology of SIB in monkeys, including exposure to early life stressors. We hypothesize that SIB has developed as an anxiety-coping mechanism, and we therefore predict that biting frequency should increase when the animals are more anxious. This hypothesis was tested in the present study by determining whether exposure to the anxiogenic compound FG7142 would provoke self-directed biting in monkeys with SIB. Individually housed male rhesus monkeys [n=10 SIB, 6 control] received intramuscular injections of FG7142 (0.1, 0.3, and 1.0 mg/kg) or vehicle control and were videotaped for 60 minutes post-injection. Frequencies of self-biting and anxiety-related behaviors (e.g., scratching) were recorded. Blood samples were obtained 60 minutes post-injection for measurement of plasma cortisol and ACTH. Repeated-measures ANOVA revealed significant increases in scratching [F(3,42)=3.81, p< 0.05]. We conclude that self-biting is anxiety-related in some but not all monkeys with SIB, suggesting an important source of heterogeneity in this disorder. Supported by NCRR grants #RR011122 and #RR00168.