"Trauma is a widespread, harmful and costly public health problem. It occurs as a result of violence, abuse, neglect, loss, disaster, war and other emotionally harmful experiences. Trauma has no boundaries with regard to age, gender, socioeconomic status, race, ethnicity, geography or sexual orientation. It is an almost universal experience of people with mental and substance use disorders … The purpose of this paper is to develop a working concept of trauma and a trauma-informed approach and to develop a shared understanding of these concepts that would be acceptable and appropriate across an array of service systems and stakeholder groups. SAMHSA puts forth a framework for the behavioral health specialty sectors, that can be adapted to other sectors such as child welfare, education, criminal and juvenile justice, primary health care, the military and other settings that have the potential to ease or exacerbate an individual’s capacity to cope with traumatic experiences … The desired goal is to build a framework that helps systems “talk” to each other, to understand better the connections between trauma and behavioral health issues, and to guide systems to become trauma-informed" (p. 2-3). Sections of this publication include: introduction; purpose and approach—developing a framework for trauma and a trauma-informed approach; background—trauma—where we are and how we got here; SMAHSA's concept of trauma; SAMHSA's trauma-informed approach—key assumptions and principles; guidance for implementing a trauma-informed approach; next steps—trauma in the context of community; and conclusion.