Chapter 5 - Self-injurious Behavior: Nonhuman Primate Models for the Human Condition

Abstract

Self-injurious behavior (SIB) is a serious disorder defined as potential or actual physical damage directed towards one's own body without suicidal intent. SIB is often impulsive and is also diverse with respect to the forms of the behavior as well as the physical and environmental factors involved. Self-injurious behavior has been associated with a wide range of disorders that include mental retardation or learning disabilities, personality disorders, schizophrenia, autism, Tourette syndrome, and certain rare genetic disorders. Self-injury may be initiated or maintained through genetic abnormalities, neurochemical abnormalities, anxiety reduction/mood regulation, self-stimulation, redirected aggression, positive and/or negative reinforcement, or social reinforcement or through a group epidemic. Research on nonhuman primates demonstrates that maternal separation, isolation, and/or neglect can have devastating effects on the animal's later behavior. Both the human and nonhuman primate literature provide evidence that SIB can be ameliorated, at least partially, by administration of serotonergic agents. There is also a complex relationship between SIB and HPA axis activity in nonhuman primates. There are some important parallels between SIB in monkeys and SIB in humans who suffer either from developmental disabilities or other disorders with which SIB has been associated. Similarities between monkey and human SIB can be seen with respect to the form of the behavior, the physiological correlates of the behavior, the role of early experience in SIB development, and the beneficial effects of certain pharmacotherapeutic agents. In monkeys, SIB typically establishes itself as self-biting, which also occurs in some humans with SIB.