PTSD, as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), is "the development of characteristic symptoms following exposure to an extreme traumatic stressor involving direct personal experience of an event that involves actual or threatened death or serious injury" (American Psychiatric Association, 1994, p. 424). PTSD can also develop from "experiencing threats to one s physical integrity; witnessing another person s serious injury, death, or threatened physical integrity; and learning about death or serious injury to family members or friends" (Brannon & Feist, 1997, p. 99).

The development of the diagnosis of PTSD originated from military veterans who came back from war with shell shock or battle/combat fatigue (colloquial names for PTSD). Many of these veterans, particularly after the Vietnam War, all exhibited similar clusters of problems. These characteristic symptoms eventually were grouped together and a link was established to traumatic events (particularly those that involve a threat to life). Repeated research and studies found support for traumatic stressors causing these symptoms and led to the development of posttraumatic stress as a disorder.

PTSD affects hundreds of thousands of people, of all ages and gender, who have been subjected to violent events, such as war, rape, child and domestic abuse, and natural disasters. The prevalence in the population for clinically diagnosable PTSD is estimated to be approximately one to three percent, while still higher numbers of the population (approximately fifteen percent) exhibit some of the characteristic symptoms of the disorder. Studies of at-risk individuals (victims of criminal violence, combat veterans) have yielded prevalence rates ranging from three to fifty-eight percent (American Psychiatric Association Online, 1998).

The symptoms of PTSD include recurrent and intrusive flashbacks of the traumatic event in the form of vivid daydreams or nightmares, and intense emotional disturbances and reactions to people and situations (sometimes without cause or provocation). Events that resemble the original experience, conversations, and anniversaries of the event can trigger these symptoms. For example, a young woman who was raped and subsequently diagnosed with PTSD exhibited terrifying flashbacks of the attack, especially around the anniversary date of the rape.