Mechanisms of change in posttraumatic stress disorder

Schumm, Hannah (2024): Mechanisms of change in posttraumatic stress disorder: the roles of posttraumatic cognitions, rumination, and sleep. Dissertation, LMU München: Fakultät für Psychologie und Pädagogik

Abstract

There are several effective psychological treatments for Posttraumatic Stress Disorder (PTSD). However, not all patients appear to benefit from the available treatment options to a satisfying extent. A possible pathway to increasing efficacy and efficiency of existing treatments could be to focus on mechanisms of change, i.e. processes that are responsible for the desired change in symptoms. By establishing mechanisms of change, treatments could be further refined and distilled to their essential elements. For trauma-focused treatments, cognitive models of the disorder have long stressed the importance of cognitive factors and processes, such as posttraumatic cognitions and rumination. Additionally, the role of sleep has received considerable attention. The present thesis first gives a detailed overview of the current empirical evidence for each of these processes as possible mechanism of change. It is then the major aim of the thesis to further investigate the roles of posttraumatic cognitions, rumination, and sleep as possible mechanisms of change in trauma-focused treatment. Studies I and II were conducted with a clinical sample of patients with PTSD who received trauma-focused treatment in a naturalistic setting. Study I (N = 61) assessed posttraumatic stress symptoms and dysfunctional posttraumatic cognitions every five sessions. We investigated whether changes in posttraumatic cognitions would differentially predict changes in the different PTSD symptom clusters. We found that posttraumatic cognitions predicted subsequent total PTSD symptom severity, and that posttraumatic cognitions predicted three out of four symptom clusters as expected. However, all these effects were no longer statistically significant when the general effect for time was controlled for. Potential limitations might have influenced the results. Study II (N = 89) assessed posttraumatic stress symptoms and rumination at every session, and examined whether changes in rumination would precede and predict changes in symptoms. We found three main results: first, rumination decreased over the course of therapy. Second, rumination was a significant predictor of PTSD symptoms in the following week, although this effect was at least partly explained by the time factor. Third, we also found the reverse effect with changes in symptoms predicting changes in rumination. This study provided preliminary evidence for a possible role of rumination as mechanism of change, although further replication is warranted. Study III focused on the role of sleep in a sample of refugees with PTSD (N = 70). Participants filled out measures of PTSD severity, sleep problems, social impairment, and quality of life. We examined the prevalence of sleep disturbances in this population, their association with PTSD severity and their contribution to social functioning and quality of life over and above the effect of other PTSD symptoms. Results showed a very high prevalence of sleep problems, and significant associations to both self-reported and clinician-rated PTSD severity. Contrary to expectations, sleep problems did not add to the prediction of social impairment or quality of life beyond the effect of other symptoms of PTSD. Several reasons for these in partly unexpected findings are discussed. Using three studies with clinical samples of patients with PTSD, the present thesis aimed to further elucidate the roles of posttraumatic cognitions, rumination, and sleep, as possible mechanisms of change in trauma-focused treatment. Following different stages of previous research regarding the hypothesized processes, the three studies each tackled different research questions. Findings from these studies add to our knowledge on possible mechanisms in trauma-focused treatments, and hope to stipulate further research. Possible directions for future research into the three mechanisms are outlined. Moreover, potentials and implications for further research on mechanisms of change in general are discussed.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: Posttraumatic Stress Disorder, mechanism of change, rumination, cognitions, PTSD
• Fakultäten: Fakultät für Psychologie und Pädagogik
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 9. Februar 2024
• 1. Bericht­erstatter:in: Ehring, Thomas