Chapter 2 presents the types of evidence the committee reviewed, how the committee assessed the strength of the evidence, and the categories of evidence the committee used to summarize its findings. Chapter 3 discusses the many types of stressors to which veterans might be exposed in a war zone. Chapter 4 discusses the biology of the stress response and Chapter 5 the diagnosis, course, prevalence, risk factors, and neurobiology of PTSD. Chapter 6 compiles and summarizes the available data on health effects that might be associated with deployment-related stressors. Psychosocial effects associated with deployment-related stress are discussed in Chapter 7. Finally, Chapter 8 summarizes the committee’s conclusions and recommendations.