engleski

Basal psychophysiology and startle response in croatian combat veterans with PTSD

According to the DSM-IV (APA, 1994), posttraumatic stress disorder (PTSD) is characterized by three major symptom clusters following an event that elicited fear, helplessness, or horror. The first category covers symptoms of re-experiencing the event, such as intrusive thoughts, nightmares, and flashbacks induced by reminders of the event. The second cluster includes avoidance of stimuli associated with the trauma, while the final category incorporates symptoms of increased arousal. As described above, one of the central problems in PTSD is the inability to suppress fear under safe conditions. Responses to fearful stimuli can be so powerful that the cortical inputs are not able to inhibit amygdala activity, as indicated by evidence of decreased prefrontal cortex activity (Bremner et al., 1999) and increased amygdala activity (Liberzon et al., 1999) during presentations of traumatic imagery. Outputs from the amygdala affect the autonomic nervous system which provides good peripheral targets to measure exaggerated fear or arousal (Lang, Davis, & Ohman, 2000). Aim: Including psychophysiological assessment methods in diagnostic procedures can contribute to a more objective assessment of posttraumatic stress disorder. The aim of the current study was to compare basal psychophysiology and startle reflexes in a sample of Croatian war veterans with PTSD and healthy non-veteran controls. Methods: We measured heart-rate, respiratory sinus arrhythmia, skin conductance, and eyeblink muscle contraction during an acclimation period and during the presentation of startle stimuli in 27 PTSD patients and 19 healthy controls. Results: We found elevated basal heart-rate and decreased respiratory sinus arrhythmia in the PTSD subjects, as well as slowed habituation of the skin conductance response to the startle probes. However, the PTSD patients did not exhibit exaggerated startle. Conclusion: Resting heart-rate and skin conductance habituation appear to offer the most reliable psychophysiological indexes of PTSD.

psychophysiology; combat veterans; PTSD; posttraumatic stress disorder

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