Description
More than half of the population will experience a traumatic event in their lifetime, yet only a small percentage of them will go on to develop Posttraumatic Stress Disorder (PTSD). Cognitive models of PTSD suggest that individuals who have endured trauma experience a tendency to interpret neutral situations as threatening, thereby showing a negative interpretation bias. Interpretation biases may contribute to the development and maintenance of PTSD. Thus, determining the most efficient and predictive method of assessing these biases may lead to better delineation of the underlying mechanisms of the disorder. In this archival study, I compared a new self-report method of assessing interpretation bias in PTSD (LDQ) with an already published self-report measure (IBIP). Participants (N = 134) were undergraduate students from San Diego State University. Participants completed a 30-minute questionnaire designed to assess their interpretation biases. Participants were presented with sentences about future negative events and were asked to rate the likelihood and distress associated with the event (Likelihood and Distress Questionnaire; LDQ). Participants also rated the relatedness between ambiguous sentences and negative words (Interpretation Bias Index for PTSD; IBIP). Participants also completed a demographic questionnaire, questions about depression, anxiety and stress (Depression, Anxiety and Stress Scale; DASS-21) and self-report of PTSD symptoms (PTSD Checklist Civilian Version; PCL-C). Linear regression was used to predict PCL-C scores using the likelihood and distress as predictor variables while controlling for IBIP, and DASS symptoms. Multiple linear regression revealed that the LDQ accounted for a significant proportion of variance in PCL-C scores. Moreover, the LDQ accounted for more variance in PTSD symptoms than the IBIP alone. However, when controlling for depression, anxiety and stress, likelihood was the only significant predictor of PCL-C scores while distress was not. My results suggest that likelihood overestimation may play a key role in understanding the mechanisms of PTSD. Even when we controlled for depression, anxiety and stress, likelihood provided additional information about an individual’s PTSD symptoms. Thus, these findings suggest that the new LDQ measure, specifically the likelihood subscale, may help clinicians and researchers to understand an individual’s interpretation biases in PTSD.
