One key conditioning abnormality in posttraumatic stress disorder (PTSD) is heightened generalization of fear from a conditioned danger-cue (CS+) to similarly appearing safe stimuli. The present work represents the first effort to track the time-course of heightened generalization in PTSD with the prediction of heightened PTSD-related over-generalization in earlier but not later trials. This prediction derives from past discriminative fear-conditioning studies providing incidental evidence that over-generalization in PTSD may be reduced with sufficient learning trials. In the current study, we re-analyzed previously published conditioned fear-generalization data (Kaczkurkin et al., 2017) including combat veterans with PTSD (n = 15) or subthreshold PTSD (SubPTSD: n = 18), and trauma controls (TC: n = 19). This re-analysis aimed to identify the trial-by-trial course of group differences in generalized perceived risk across three classes of safe generalization stimuli (GSs) parametrically varying in similarity to a CS+ paired with shock. Those with PTSD and SubPTSD, relative to TC, displayed significantly elevated generalization to all GSs combined in early but not late generalization trials. Additionally, over-generalization in PTSD and SubPTSD persisted across trials to a greater extent for classes of GSs bearing higher resemblance to CS+. Such results suggest that PTSD-related over-generalization of conditioned threat expectancies can be reduced with sufficient exposure to unreinforced GSs and accentuate the importance of analyzing trial-by-trial changes when assessing over-generalization in clinical populations.
Bibliographical noteFunding Information:
This project was supported by the National Institutes of Health [grant number # R00MH080130 , 2010] to Dr. Lissek and the Congressionally Directed Medical Research Program and the Department of Defense [grant number # PT074550 , 2009] to Dr. Sponheim.
© 2019 Elsevier Ltd
- Exposure therapy
- Nonparametric regression
- Posttraumatic stress disorder
- Threat expectancy