SUBLIMINAL PROCESSING OF THREAT CUES IN POSTTRAUMATIC-STRESS-DISORDER

Vietnam combat veterans with and without posttraumatic stress disorder (PTSD) performed a computerized Stroop color-naming task involving su praliminal and subliminal (masked 57 ms presentations) of trauma words (e.g., medevac), positive words (e.g., celebrate), neutral household- item words (e.g., microwave), and color words (e.g., red in blue lette rs). Immediately thereafter, subjects performed a card Stroop involvin g similar word types. Although healthy combat veterans exhibited a sta ndard Stroop interference effect for subliminal as well as for suprali minal color words, there was no persuasive evidence of enhanced interf erence for subliminal trauma words in the PTSD group. PTSD subjects ex hibited enhanced interference for supraliminal trauma words early in t he experiment, but this effect waned, thus suggesting habituation to t he semantic content of threat cues. Interference for trauma material i n the PTSD group appeared much more robust in the card version than in the single-item computerized version. Although trauma-specific interf erence effects in PTSD may be automatic in the sense of being involunt ary, they do not appear automatic in the sense of occurring outside of awareness.