Don't Throw Out the Baby with the Bathwater (PTSD is Not Overdiagnosed)

Abstract

Alain Brunet, PhD1, Vivian Akerib, MA2, Philippe Birmes, MD, PhD3 (Can J Psychiatry 2007;52:501-502) In the aftermath of the terrorist attacks on the World Trade Center, some media experts predicted that up to 1 out of 5 New Yorkers would suffer from full-blown posttraumatic stress disorder (PTSD). In fact, 2 months after the attacks, among a random sample of 1008 adults living in Manhattan, only 7.5% reported symptoms consistent with a diagnosis of acute PTSD.1 It is relatively easy these days to find instances among the media and the general public where the concept of psychological trauma is overapplied or misrepresented, giving the impression that PTSD must be rampant and therefore overdiagnosed. Despite the popular use of this term, actual prevalence rates demonstrate that PTSD is not overdiagnosed by those whose job it is to diagnose: the epidemiologists and the mental health professionals. If we consider the evolution in the field of trauma research, there are at least 2 major tendencies: on the one hand, the criteria for diagnosing PTSD have become stricter, while, on the other hand, our ability to detect and correctly assess trauma exposure and PTSD has improved, thereby leading to the identification of new, previously undiagnosed cases. The net result of these 2 tendencies is a remarkably stable rate of PTSD in the epidemiologic surveys of the last decade. Changes in the Diagnostic Criteria of PTSD The diagnostic criteria of PTSD have undergone many minor changes since they were introduced in the DSM-III (1980). With the publication of DSM-IV (1994), however, a major change was introduced: the definition of what constitutes a traumatic event shifted from a nomothetic to an idiographic one. From that point on, trauma was no longer defined as an objective event but rather as a life-threatening experience that must, in addition, be appraised by the exposed individual with fear, helplessness, or horror. In the absence of such distress, the event was no longer considered traumatic. In many instances, this change dramatically reduced the number of individuals typically considered as having been exposed to a traumatic event.2 In addition, the emergence of the social impairment criterion in the DSM-IV (for all mental disorders) decreased the prevalence rate of PTSD up to 24%, according to a recent study.3 Changes in Epidemiologic Survey Methodology Although the criteria for diagnosing PTSD have evolved toward being more restrictive, our ability to detect and assess trauma has also improved. For instance, in epidemiologic surveys, lists of potentially qualifying events (and the use of explicit definitions, as in the case of sexual abuse) to prime the memory of the participants are now routinely used, something which was not done in the earlier surveys. As a result of this and other methodological improvements, the rates of PTSD did go up. For instance, in 1987 Helzer et al4 found in the Epidemiological Catchment Area study a lifetime rate of PTSD of only 1%. Since then, however, large surveys conducted in the United States have found higher but remarkably similar rates of lifetime PTSD: 7.5% and 6.6% in 2 representative samples of the US population5'6 and a conditional risk of 9.1% among the exposed in a sample of young urban US adults.7 This stabilization of the PTSD rate in carefully designed epidemiologic surveys argues strongly against the idea that PTSD is overdiagnosed. Another example of the crucial role played by the survey methodology comes from Thompson et al.8 In a reexamination of the National Vietnam Veterans Readjustment Study (NVVRS) and the Vietnam Experience Study (VES), Thompson et al managed to reconcile the 2 studies' quite different prevalence rates (15.2% and 2.2%, respectively) by applying each study's definitions related to diagnosis. Since the NVVRS made use of multiple standardized and well-validated diagnostic instruments and used many more PTSD symptom probes than the VES, the former's statistical results were deemed more reliable. …