Assessing Psychological Inflexibility Pertaining to Self in Patients With Posttraumatic Stress Disorder Using an Indirect Measure of (Nonassociative) Propositions

Relational frame theory (RFT) is a modern behavioral account of human language and cognition, which focuses on relations or propositions, rather than associations, as core explanatory constructs. In an attempt to measure such propositions, RFT researchers have developed the implicit relational assessment procedure (IRAP). It has been argued that the size of an IRAP effect may provide a metric for psychological inflexibility. The current study aimed to determine whether psychological inflexibility, as measured by the self-focused Natural Language-IRAP (NL-IRAP), would be higher in a clinical sample of individuals with a diagnosis of PTSD (N = 29) when compared to a nonclinical sample. Subsequently, the study investigated whether the self-focused NL-IRAP could be used to predict the presence of a clinical diagnosis, using a ROC analysis. As predicted, higher levels of psychological inflexibility were observed for the clinical group. The self-focused NL-IRAP also correctly classified the presence of PTSD (AUC = 76%) with a sensitivity level of 79.3% and a specificity level of 59.2%. Overall, the use of the IRAP as a nonassociative clinical measure appears promising.