AUDITORY EVENT-RELATED POTENTIALS TO TONE STIMULI IN COMBAT-RELATED POSTTRAUMATIC-STRESS-DISORDER

This study attempted to replicate findings of abnormal auditory event- related potentials (ERPs) in posttraumatic stress disorder (PTSD) in a sample of Vietnam combat veterans, Veterans with combat-related PTSD, divided into unmedicated (unmed-PTSD, n = 12) and medicated (med-PTSD , n = 22) groups, and veterans without PTSD (non-PTSD, n = 10) complet ed a three-tone ''oddball'' target detection task while ERPs were meas ured. Individuals with comorbid panic disorder (PD) were excluded from the primary analyses. Parietal P3 amplitude to the target tone was si gnificantly smaller in unmed-PTSD compared to med-PTSD and non-PTSD gr oups. These differences did not remain significant when an adjustment was made for level of depression. Parietal P3 amplitude was also negat ively correlated with state anxiety. Secondary analyses within the unm ed-PTSD group indicated that participants with comorbid PD (n = 3) had the largest parietal P3 amplitudes to target tones. Results are consi stent with attentional or concentration deficits in PTSD and highlight the importance of considering comorbid diagnoses, The absence of ERP differences between med-PTSD and non-PTSD participants suggests that p sychotropic medication may normalize these deficits. (C) 1997 Society of Biological Psychiatry.