Joseph E. LeDoux Terrence Keane - Employees with post traumatic stress disorder

The global war on terrorism and the military actions in Iraq and Afghanistan (i.e., Operation Iraqi Freedom and Operation Enduring Freedom) represent significant risks to the mental health of the American forces assigned to these regions. Coupled with the impact of the terrorist attacks on the Pentagon and the World Trade Center (WTC), the diagnosis of post-traumatic stress disorder (PTSD) is currently receiving increased attention in both the scientific and popular literature. This chapter seeks to provide a current understanding of the nature of the diagnosis, its prevalence across a variety of different populations, and risk factors associated with developing it. In addition, we present an overview of an etiological model for PTSD previously proposed (). We, finally, summarize the literature on structural equation modeling in PTSD, a statistical approach that has contributed greatly to our understanding of the associations and predictive value of many of the key variables underlying the development of PTSD.

Our ultimate understanding of this condition, to include its biological and psychological substrates, is premised on the use of a common definitional framework across scientific and clinical venues. Great progress in the field was stimulated by the inclusion of the diagnosis of PTSD in the psychiatric nomenclature in 1980 and by several attempts to strengthen the operational criteria employed to define cases and noncases of people who have PTSD ().

In its current conception, the Diagnostic and Statistical Manual of Mental Disorders (DSM) defines PTSD as stemming from an event in which one is exposed to serious threat of injury or death and then experiences extreme fear, helplessness, or horror. Three symptom clusters define the disorder. In addition to recurrent and intrusive recollections and dreams of the event, the reexperiencing cluster includes the experience of flashback episodes in which an individual experiences a recurrence of at least a portion of the trauma. Hyperarousal symptoms are characterized by an enhanced startle reaction and difficulty sleeping, concentrating, and controlling anger as well as hypervigilance for danger and a sense of a foreshortened future. Extreme distress and avoidance of cues or reminders of the trauma, as well as an inability to remember aspects of the event, also can accompany this disorder. Additional avoidance symptoms include emotional numbing, described as an inability to feel any positive emotions, such as love, contentment, satisfaction, or happiness.

The interpersonal, psychosocial, physical health, and societal consequences of PTSD contribute to the overall costs of developing this condition. People with PTSD are more likely to divorce, report trouble raising their children, engage in intimate partner aggression, experience depression and other psychological problems, report poorer life satisfaction and physical health problems, become involved with the legal system, earn less, and change jobs frequently (). These findings suggest that PTSD constitutes a major public health challenge for this nation and the world and highlight the importance of our complete understanding of the biological, psychological, and social factors associated with this condition. This review outlines our achievements to date in understanding the characteristics of PTSD and its prevalence, course, and treatment. Further, we provide a heuristic model for understanding the development of PTSD while specifying future directions for scientific work.

Initially, PTSD was considered a relatively rare condition, and traumatic events were considered extreme life stressors that were outside the range of normal human experience (). Most important, though, are the consistent findings indicating that, although exposure to potentially traumatic events is common, development of PTSD is relatively rare. Elucidation of the factors responsible for some people developing PTSD while others exposed to similar threatening events do not may inform our understanding of key variables in the etiology of this condition.

Perhaps the most complete general U.S. population studies are those conducted by Kessler and colleagues. In the original National Comorbidity Survey (NCS) (), 5,692 individuals in a nationally representative sample were interviewed and had an overall lifetime PTSD prevalence rate of 6.8% detected.

Compared with the NCS and NCS-R, similar or slightly higher PTSD rates were obtained in selected, specialized samples. For instance, among 21- to 30-year-old members of a Detroit area health maintenance organization (HMO), 40% reported experiencing a trauma, and 9.5% met PTSD criteria (11.3% of women and 5.6% of men) ().

Other studies focused on sexual assault and criminal victimization of women. For example, in a nationally representative sample of 4,008 women, Kilpatrick, Edmunds, and Seymour () estimated that 36% of women had been criminally victimized, with 14.3% experiencing attempted rape or molestation and 12.7% experiencing a completed rape. They estimated lifetime and current PTSD rates to be 12% and 5%, respectively. Among those who were exposed to criminal victimization, rates of lifetime and current PTSD were 26% and 10%, respectively.

Clearly, the prevalence of exposure to traumatic events in the United States is far more common than anticipated in 1980 when the diagnosis of PTSD was incorporated into the diagnostic nomenclature. Even more surprising are findings indicating that the rate of current PTSD in the general population falls only behind major depression, attention deficit/hyperactivity disorder, specific phobia, and social anxiety disorder, making it the fifth most common psychiatric condition in the United States ().

Soldiers sent to fight wars and to keep peace are among those most at risk for trauma exposure and the development of PTSD. Despite the high frequency of military action and war worldwide, few countries have ever estimated the psychological toll of war. The major exception to this was the National Vietnam Veterans Readjustment Study (NVVRS) (), which included a representative sample of 1,632 Vietnam theater veterans (VTVs), a matched sample of 716 Vietnam era veterans (VEVs), and 668 civilian comparison subjects. Of VTVs, 64% were exposed to trauma in their lives, compared with 48% of VEVs and 45% of civilians. More than 15% of male VTVs and 9% of female VTVs met criteria for current PTSD, and 30% of male VTVs and 27% of female VTVs met criteria for lifetime PTSD. Notably, the direction of this gender difference is opposite that of the civilian samples reviewed here, likely attributable to the different roles women had in the military at that time, the different types of stressors to which they were exposed, and the higher educational level of women in the study. In all cases, PTSD prevalence rates for VTVs were five to ten times higher than those found for the VEVs and civilians.