The following elements are considered necessary for an event to be traumatizing: (1) the event must be experienced as extremely negative, uncontrollable, and sudden; and (2) initial core responses to trauma include re-experiencing and avoidance symptoms that occur across different modes of experience. Explanations of how each response is theoretically linked to traumatic events are offered to clarify how the responses reflect the natural human response to uncontrollable, negative, and sudden events. The conceptual framework delineates behavioral learning and cognitive processes that elucidate the persistence of the initial response to trauma. Factors are proposed that influence the response to trauma, including biological factors, developmental level at the time of trauma, stressor severity, social context, and prior and subsequent life events. Finally, secondary and associated responses to trauma are discussed that are common across many types of traumatic experiences. These include depression, aggression, substance abuse, physical illnesses, low self-esteem, identity confusion, difficulties in interpersonal relationships, and guilt and shame. 73 references