Research master thesis | Psychology (research) (MSc)
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Avoidance is a hallmark symptom of Post-Traumatic Stress Disorder (PTSD), yet the link between avoidance learning and PTSD severity and treatment outcome has not yet been explored. For this purpose...Show moreAvoidance is a hallmark symptom of Post-Traumatic Stress Disorder (PTSD), yet the link between avoidance learning and PTSD severity and treatment outcome has not yet been explored. For this purpose, we administered a computer-based avoidance learning task to 144 treatment-seeking PTSD patients during the baseline assessment of a randomized clinical trial. The task consisted of a photo of blue or red colored lamps (conditional stimuli, CS+) followed by aversive photos (unconditional stimulus, US), while a photo of a yellow-colored lamp was followed by a black screen (safety stimulus, CS-). The US could be avoided by pressing a button during one CS+ (CS+ avoidable) but not the other (CS+ unavoidable). Participants were asked to fill in a threat expectancy rating after the CSs, and to report their relief after omission of the US. Participants were then given exposure therapy, and their PTSD symptoms were measured throughout 52 weeks. We predicted that higher rates of unnecessary or ineffective avoidance, higher expectancy ratings after omission of the US, and higher relief scores would relate to higher PTSD severity, and lower treatment gains. Results did not confirm any hypothesis; however, elevated threat expectancies (regardless of CStype) were related to PTSD symptom severity at baseline, and expectancies following CS- were related to PTSD severity across time points. Findings suggest general impairment in action-safety learning; however, it might be more relevant in light of PTSD severity to further explore the role of general threat expectancy. Furthermore, future studies should consider utilizing physiological measures, and adapting the task to include avoidance costs.Show less
