The Revised ACE Pyramid: A Contemporary Framework for Understanding Childhood Adversity and Advancing Toxic Stress Prevention and Healing

Background: The Adverse Childhood Experiences (ACE) Pyramid has been widely used for more than two decades to illustrate pathways linking childhood adversity to health outcomes across the lifespan. Since its development, substantial advances in the science of toxic stress have expanded understanding of the biological mechanisms through which adversity influences lifelong health. Objective: To describe the development and scientific rationale for a revised ACE Pyramid that reflects contemporary evidence on toxic stress, the biological pathways linking childhood adversity to health, and opportunities for prevention and healing. Methods: A multidisciplinary revision process was conducted in collaboration with subject matter experts from government, academia, healthcare, professional associations, and community-based organizations. Iterative review and refinement were used to align the framework with current scientific evidence and practice. Results: A revised ACE Pyramid was developed that preserves the familiar structure of the existing framework while incorporating advances in the science of toxic stress, prevention, and healing. Compared with the ACE Pyramid featured on the CDC website during development of the revised framework, the revised framework more explicitly emphasizes prolonged or excessive activation of the stress response as a central mechanistic pathway linking childhood adversity to lifelong health, expands the biological layer to encompass multiple interacting biological systems beyond neurodevelopment alone, and integrates prevention and healing opportunities throughout the framework. Conclusions: The revised ACE Pyramid synthesizes more than two decades of advances in the science of toxic stress into an accessible conceptual framework. It explains how childhood adversity becomes biologically embedded to shape lifelong health while emphasizing that prevention is possible and healing can occur throughout the life course. By providing a shared framework for understanding toxic stress biology, it may help inform trauma-informed clinical care, public health action, research, and policy aimed at advancing health equity and improve outcomes for children and families.