Trauma occurs as an emotional response to an experience that is or was extremely distressing or disturbing. People process traumatic events differently because all events are faced through the lens of prior life experience. Trauma can be described as "Big T" or "Little T" based off of their intensity.
"Big T" traumas are the type usually associated with Post-Traumatic Stress Disorder (PTSD) including serious injury, sexual violence, or life-threatening experiences. Threats of serious physical injury, death, or sexual violence can cause intense trauma even if the person is never physically harmed. Witnesses to these types of events or people living and working in close proximity to trauma survivors are also vulnerable to PTSD, especially those who encounter emotional shock on a regular basis like paramedics, therapists, and police officers.
"Little T" traumas are are highly distressing events that affect individuals on a personal level, but don’t fall into the "Big T" category. This category include non-life-threatening injuries, emotional abuse, death of a pet, bullying or harassment, and loss of significant relationships.