Over-reporting bias and the modified Stroop effect in Operation Enduring and Iraqi Freedom veterans with and without PTSD.

Abstract

The current study investigated in a sample of Operation Enduring and Iraqi Freedom (OEF/OIF) veterans how a symptom overreporting response style might influence the association between PTSD diagnostic status and color-naming response latency for trauma-related stimuli during the Modified Stroop Task (i.e., the Modified Stroop Task effect, MST effect). It was hypothesized that, if an overreporting response style reflected feigning or exaggerating PTSD symptoms, an attenuated MST effect would be expected in overreporters with PTSD as compared with PTSD-diagnosed veterans without an overreporting style. If, however, overreporting stemmed from high levels of distress, the MST effect might be greater in overreporters compared with those with a neutral response style. The results showed that veterans with PTSD and an overreporting response style demonstrated an augmented MST effect in comparison with those with a more neutral style of response. Overreporters also reported greater levels of psychopathology, including markedly elevated reports of dissociative experiences. We suggest that dissociation-prone overreporters may misattribute emotional distress to combat experiences leading to the enhanced MST effect. Other possible explanations for these results are also discussed.