How distinguishing among types of trauma is essential to the healing process
When we talk about trauma, we often make the mistake of generalizing. We use terms such as “trauma-informed” or “traumatized self” without providing more specific information about what these terms refer to. In fact, trauma is a complex psychological phenomenon that is deeply interwoven with interpersonal relationships and social structures and that has a long history as a point of study for doctors, psychologists, and sociologists.
As therapists, counselors, coaches, and other healthcare professionals, it is worth taking the time to understand exactly what defines trauma, its history in research and treatment, and the different forms it can take in the lives of individuals and groups.
What Is Trauma?
The most commonly used definition of trauma comes from the work of John Briere and Catherine Scott, who assert that if an event is upsetting enough to temporarily overwhelm the internal resources of a person, it is traumatic.  That is to say that there are many ways in which an individual can be traumatized and therefore many reasons for which a person may hold trauma.
This view helps professionals working with trauma draw parallels among vastly different types of harm – physical, psychological, threats to integrity, etc. – to provide cohesive and effective treatment. However, this conceptual approach to trauma is relatively new in the field. For a significant portion of history, trauma was relegated to the primarily white, primarily male field of military conflict.
History of Trauma Research
Trauma as a condition was first addressed, or noticed, in soldiers and civilians who lived through periods of war, battle, or other mass violence. Early names for trauma from the American Civil War were “soldier’s heart” and “nostalgia.” By the Second World War, the phenomenon known as “shell shock” was being commonly discussed, marking the first instance of descriptive language being applied to the particular feeling of shock or stress that comes from exposure to traumatizing events.
It was not until after the Vietnam War that the term trauma – as a part of the diagnosis of Post-Traumatic Stress Disorder (PTSD) – came into routine use in a medical and psychological context in the United States.  Thereafter, the study of trauma developed outwardly to encompass more than just military conflict: physical trauma, family trauma, sexual trauma, and generational trauma are now all recognized categories of trauma research.
There now exists an internationally recognized measure of trauma known as the Trauma Symptom Inventory (TSI). This clinical tool assesses certain symptoms associated with or related to trauma, including depression, anger, dissociation, and intrusive experiences, among others. 
Types of Trauma
There are many ways to distinguish types of trauma, and many of these are specific to the type of trauma research or trauma work being done. For the purposes of trauma as it relates to family therapy and Substance Abuse Disorder treatment, it is crucial to recognize the following four major categories of trauma when dealing with traumatized individuals and those who are connected to them:
“I am the victim of trauma, and something is done to me. I have been mugged. I have been raped. I am beaten. The trauma that is happening is flowing towards me.”
Inflow trauma has been inflicted on the individual seeking treatment. The subject of trauma has had it done to them by an actor separate from themselves. This is perhaps the type of trauma that most of us envision when we think of the word, but it is by no means the only type.
“I am the one responsible for trauma. I am the victimizer. I have done something to someone else. The trauma is flowing from my past or present actions.”
Outflow trauma is the situation in which the actor of the trauma is the subject of the situation. Whereas inflow trauma sees the trauma flowing towards the individual in question from another person, outflow trauma originates from the individual in question and flows outwardly. This category of trauma is particularly useful when doing family therapy, as the trauma experienced by one member of the system is often enacted by another, yet both will still need treatment in order to heal together.
“I have witnessed something that has been traumatic to me. I have seen my family member being abused or I have witnessed violence in my home. I have seen video of abuse or violence online or on the television, or from a friend at school.”
Crossflow or vicarious trauma occurs when an individual witnesses traumatizing events in their lives. Children are very often subject to this type of trauma, as are soldiers, and medical or emergency workers.
“I have been traumatized by something I have done to myself. I cut myself, or I starved myself. I have self-mutilated. I am responsible for the trauma that has been done to myself through my actions.”
Reflexive trauma is a complex form of trauma that places the individual in question as both the traumatizer and the traumatized: they have done the trauma to themselves through harmful actions. This type of trauma is particularly important when working with teenagers or young people who have difficulty expressing their feelings and can turn to dangerous or harmful acts in order to alleviate the tension they feel.
The benefits of being able to distinguish among these types of trauma in treatment and recovery are myriad. For a start, individuals who have experienced trauma are seldom alone in these experiences: families, friend groups, and other communities like schools or workplaces are all intimately linked to the ways in which trauma manifests both inwardly and outwardly. Knowing who is holding what type of trauma, rather than treating everyone involved as generically traumatized, is the first step in being able to identify how to work through it as a social system.
 Briere, J., Scott, C. (2006). Principles of Trauma Therapy: A Guide to Symptoms, Evaluation, and Treatment. India: SAGE Publications.
 Center for Substance Abuse Treatment (2014). Trauma-Informed Care in Behavioral Health Services. Rockville (MD): Substance Abuse and Mental Health Services Administration (US); 2014. (Treatment Improvement Protocol (TIP) Series, No. 57.) Appendix C, Historical Account of Trauma. Available from: https://www.ncbi.nlm.nih.gov/books/NBK207202/
 Orsillo, Susan M. (2001). Measures for acute stress disorder and posttraumatic stress disorder. In M.M. Antony & S.M. Orsillo (Eds.), Practitioner’s guide to empirically based measures of anxiety (pp. 255-307). New York: KluwerAcademic/Plenum. PTSDpubs ID 24368.