What Are Stress Systems and How Do They Change?

For decades scientists have studied stress system development in children experiencing low and high stress environments. There are two main stress systems that work together to promote survival, the NE-SAM system, and the HPA-axis.
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Stress systems change quickly across infancy and early childhood as they take in information about the world in which the child lives, their relationships, and their overall health. In these first few years of life, stress systems are calibrating their output and patterns to help the child survive in whatever world they live. Stress systems can continue to change in adulthood following very stressful events and as part of physical and psychological health concerns. For both children and adults, stress system biology will prioritize survival in the short term over long-term health and well-being should they detect a threat-level that exceeds available resources.