Trauma- and stressor-related disorders are a new grouping of disorders introduced in the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition whose etiology pairs the onset of the mental disorder with the presence of an external event. These events range from extreme high magnitude stressors such as torture, terror attacks, rape, childhood sexual abuse, natural disasters, or war to more commonly experienced stressors such as the loss of a romantic relationship, persistent physical illness, or business difficulties. Traumatic-stressor exposure is common and, for the majority of individuals exposed to stressors, normal psychological reactions that occur in the immediate aftermath will abate within days or months of the event. Posttraumatic stress disorder and acute stress disorder share the same traumatic stressor criteria involving “exposure to a threatened death, serious injury, or sexual violation” and include direct experiencing, witnessing, or learning about a stressor.