Part III begins with a chapter that delineates the background issues for the development of PTSD as a diagnostic category in DSM-III and DSM-IV.  Since the placement of psychiatric problems within diagnostic systems determines how clinicians and investigators conceptualize the inner structure of a disorder, this raises the very important question of whether PTSD is most appropriately classified as an anxiety disorder.  This chapter examines the rationale for establishing a separate axis for stress disorders in the DSM system of diagnostic classifications, which could include dissociative disorders, adjustment disorders, grief reactions, and a variety of characterological adaptations.

 

  The next two chapters of this section—Chapter 7, on the nature of the stressor, and Chapter 8, on vulnerability and resilience—examine the interactions between external events and subjective response.  In this regard, the meaning of the trauma, the physiological response, preexisting personality structures and experiences, and the degree of social support are all critical factors in a person’s ultimate response to trauma.  The stressor criterion defines who is and who is not included in the diagnosis, and hence this determines the prevalence of PTSD.  Chapter 8 summarizes the epidemiological studies conducted to date, which emphasize the importance of traumatic stress as a public health issue.  It further examines the relative importance of the traumatic event itself, in contrast to vulnerability or predisposing factors.  The conclusion is that issues of predisposition and vulnerability may be more relevant to understanding recovery from acute symptomatology and the individual’s long-term resilience than to understanding acute patterns of response to a stressor. Vulnerability factors may also define the patterns of comorbidity, which play an important role in chronic PTSD.  Critical in these considerations is the emergence of chronic patterns of adaptation, in which lack of involvement in current reality, rather than preoccupation with the past, are the most pathological features.

 

  Chapter 9, on the complex nature of adaptation to trauma, examines the intricate ways in which psychological and biological processes interact with development to produce a range of problems with self-regulation, attention, the ways people view themselves, and the ways they make their way in the world. Chronic trauma is associated with dissociative disorders, somatization, and a host of self-destructive behaviors (e.g., suicide attempts, self-mutilation, and eating disorders). In addition, trauma at different developmental levels has different effects on further personality development. This theme of complexxivity of adaptation continues in Chapter 10, which examines the biology of PTSD, including both hormonal and autonomic nervous system dimensions. Topics covered include the unusual patterns of cortisol, norepinephrine, and dopamine metabolite excretion; the role of the serotonergic and opioid systems; and receptor modification by processes such as kindling. This chapter also examines the involvement of central pathways involved in the integration of perception, memory, and arousal, as well as the impact of these central pathways on patterns of information processing in PTSD.

 

  Part III concludes with a chapter on research methodology, which discusses the currently available diagnostic and assessment tools that are helpful in both clinical and research settings. There is often conflict between clinical realities and research paradigms in PTSD. Because of forensic as well as research issues, the problem of a valid and reliable diagnosis is of paramount importance. This question is given further relevance by the fact that a number of studies demonstrate low rates of PTSD in exposed populations. Whereas strict standards of diagnosis for PTSD are essential for good research, broader definitions may be helpful in clinical settings to assess the full extent of disability. Over time some people’s PTSD may become subclinical, and yet it may continue to influence their level of functioning.