Background
Problems in learning that sights, sounds, or situations that were once associated with danger have become safe (extinction learning) may explain why some individuals suffer prolonged psychological distress following traumatic experiences. Although simple learning models have been unable to provide a convincing account of why this learning fails, it has recently been proposed that this may be explained by individual differences in beliefs about the causal structure of the environment.
Methods
Here, we tested two competing hypotheses as to how differences in causal inference might be related to trauma-related psychopathology, using extinction learning data collected from clinically well-characterised individuals with varying degrees of post-traumatic stress (N = 56). Model parameters describing individual differences in causal inference were related to multiple post-traumatic stress disorder (PTSD) and depression symptom dimensions via network analysis.
Results
Individuals with more severe PTSD were more likely to assign observations from conditioning and extinction stages to a single underlying cause. Specifically, greater re-experiencing symptom severity was associated with a lower likelihood of inferring that multiple causes were active in the environment.
Conclusions
We interpret these results as providing evidence of a primary deficit in discriminative learning in participants with more severe PTSD. Specifically, a tendency to attribute a greater diversity of stimulus configurations to the same underlying cause resulted in greater uncertainty about stimulus-outcome associations, impeding learning both that certain stimuli were safe, and that certain stimuli were no longer dangerous. In the future, better understanding of the role of causal inference in trauma-related psychopathology may help refine cognitive therapies for these disorders.
Problems in learning that sights, sounds, or situations that were once associated with danger have become safe (extinction learning) may explain why some individuals suffer prolonged psychological distress following traumatic experiences. Although simple associative learning models have been unable to provide a convincing account of how and why this learning fails, it has recently been proposed that this may be explained by individual differences in beliefs about the causal structure of the environment. Here, we tested two competing hypotheses as to how differences in causal inference might be related to trauma-related psychopathology, using extinction learning data collected from clinically well-characterized individuals with varying degrees of post-traumatic stress (N=56). Latent cause modelling revealed that individuals with more severe PTSD were more likely to assign observations from conditioning and extinction stages to a single underlying cause. Specifically, multivariate analysis incorporating multiple PTSD and depression symptom dimensions revealed a negative relationship between tendency to infer multiple causes were active in the environment and re-experiencing symptom severity. We interpret these results as providing evidence of a primary deficit in discriminative learning in participants with more severe PTSD re-experiencing symptoms. Specifically, in these individuals, a greater tendency to attribute all stimulus configurations to the same underlying cause resulted in greater uncertainty about stimulus-outcome associations, and impeded learning both that certain stimuli were safe, and that certain stimuli were no longer dangerous. Better understanding of the role of causal inference in trauma-related psychopathology may have relevance for the refinement of cognitive therapies for these disorders.
<p><strong>Background:</strong> Nearly two decades following the 9/11/2001 world trade center (WTC) attacks, a substantial proportion of WTC rescue and recovery workers (“responders”) and WTC survivors continue to experience WTC-related posttraumatic stress disorder (PTSD) symptoms. Internet-based cognitive behavioral therapies (I-CBT) are short-term, evidence-based, scalable treatments with the potential to reach large numbers of symptomatic WTC workers and survivors. However, no I-CBT studies have been conducted in the WTC cohort.</p><p><strong>Methods:</strong> This report describes the rationale and design of an ongoing randomized controlled trial comparing integrative testimonial therapy (ITT), an I-CBT, to an active comparison treatment, internet-based modified present-centered therapy. The primary aim is to evaluate the efficacy of ITT in mitigating WTC-related PTSD symptoms in WTC responders and survivors with full or subthreshold WTC-related PTSD. The efficacy of ITT in reducing comorbid depressive and anxiety symptoms, and improving functioning, quality of life, and post-traumatic growth will additionally be evaluated. Saliva samples are also collected to explore genetic and epigenetic biomarkers of treatment response.</p><p><strong>Conclusions: </strong>This is the first I-CBT trial to compare ITT to a credible and active treatment, controlling for critical third-variable explanations of superiority (e.g., non-specific therapy effects). This RCT bridges an important research gap in the rising field of I-CBT interventions and adds to the literature on the design of trials investigating evidence-based treatments for PTSD in WTC- and other trauma-affected populations. </p><p><strong>Trial registration: </strong>This trial was registered on clinicalTrials.gov on May 16, 2017 (NCT03154151).</p>
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