Self-injury often derives from traumatic experiences. It differs from suicidal behavior because it is essentially an adaptive strategy, intended to allow the individual to endure and carry on. It therefore does not always call for the interventions described in Part II of this volume. Nonetheless, for those who work with patient emergencies, it is important to be able to distinguish those who injure themselves as an adaptation from those who injure themselves with intent to die; of course, emergency intervention may be required for the physical effects of self-injury. If an adaptation that is more constmctive than self-injury is to develop, however, long-term treatment, rather than emergency or crisis intervention, is typically required.The behavior of self-injury is an adaptive strategy to manage intense physiological arousal and emotional suffering. For many people, self-injury begins as a response to unbearable circumstances in which response choices are restricted. It is adaptive because it allows these overwhelming states and unbearable circumstances to be managed so the individual survives, and therefore has the opportunity to change and grow. There are physiological mechanisms through which self-injury may serve to adapt to trauma, including selfinjury's effect of quieting an oversensitized alarm system in the brain, and 211