Psychophysiological Assessment of PTSD.

Studies of the psychophysiology of PTSD can be traced to the observations of Kardiner (1941), who viewed the psychological sequelae of combat as a “physioneurosis. ” He characterized patients with this condition as having obvious elevations in muscle tension, tachycardia, startle response, and a hyperresponsivity to external stimulation. These observations led to empirical studies by Wenger (1948) and then Dobbs and Wilson (1960), which found that physiological and psychophysiological measures distinguished veterans with combat stress disorders from a variety of comparison groups of veterans. The clinical observations of Kardiner and the empirical studies of a variety of scientists, in­ cluding Grinker and Spiegel (1945), established the foundation for contemporary studies of the psychophysiology of PTSD among Vietnam veterans. The purpose of this report is to update the field on the status of a multi-site clinical trial that examined the ability of psychophysiological responses to pre­ dict PTSD diagnosis in a large sample of male Vietnam veterans. Data were collected from 1990 to 1992 at 15 clinical research laboratories in VA Medi­ cal Centers in the United States. The scientific premise of the study came from a series of publica­ tions, reflecting work of three independent research groups, that demonstrate how combat veterans with PTSD can be distinguished from combat veterans without PTSD on the basis of psychophysiological information. A large-scale study was needed to determine the generalizability of the accumulated findings to a broader sample of help-seeking veter­ ans. Such an effort would strengthen the scientific foundation for this type of assessment and help clarify its diagnostic implications for a larger seg­ ment of the VA population. Three studies conducted in the 1980s served as the contemporary foundation for the multi-site project. The first of these, by Blanchard et al. (1982), found that psychophysiological responses to stan­ dardized sounds of combat discriminated Vietnam veterans with PTSD from an age and gender matched comparison group. At about the same time, Malloy et al. (1983) employed standardized audiovisual cues of neutral and combat situations while measur­ ing heart rate, skin resistance, and subjective dis­ tress. Male Vietnam veterans with PTSD were found to be more physiologically responsive to the combat cues compared to veterans with psychiatric impair­ ment (but without PTSD) and veterans with no psychiatric impairment. The third influential study was conducted by Pitman et al. (1987). These inves­ tigators adapted Peter Lang’s (1985, 1995) imagerybased methods for studying the psychophysiology of emotion and set about comparing Vietnam veter­ ans with and without PTSD on heart rate, skin conductance, and facial electromyographic re­ sponses. The study used a set of 30-second imagery scripts that were constructed in a systematic fashion so that each contained stimulus, response, and mean­ ing elements. Scripts depicted individually-tailored traumatic and non-traumatic (e.g., neutral) experi­ ences that were compared to one another in terms of the physiological and subjective reactions they pro­ duced. Results based on this procedure demon­ strated again that veterans with PTSD react to indi­ vidually-relevant combat cues with greater arousal and distress than do veterans without PTSD. These and other studies from a number of labora­ tories provided impressive preliminary evidence that individuals who qualify for a PTSD diagnosis can be discriminated from those who do not meet PTSD criteria when the groups are compared on their psychophysiological response to challenge tasks that involve presentation of trauma-relevant cues (see Orr & Kaloupek, 1997; Prins et al., 1995). Despite the impressive consistency of findings, there are methodological limitations that raise questions about the individual estimates of diagnostic accu­ racy obtained by any particular study in the set. These limitations include: (a) problems of inflated base rates due to the fact that PTSD patients typi­ cally comprised 1/3 to 1/2 of the study sample, a higher rate than is likely to occur in the population at large; (b) several of the comparison groups con­ sisted of veterans who were not seeking help for their problems (e.g., VA health services) while par­ ticipants in the PTSD group were; (c) only two studies (Blanchard et al., 1991; Orr et. al., 1993) attempted to cross-validate findings within the con­ text of a single study; and (d) most of the studies did not employ contemporary multivariate data ana­ lytic strategies to investigate classification accuracy. Many of the studies conducted during the 1980s