Research master thesis | Psychology (research) (MSc)
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In PTSD research, script-driven imagery procedures are used to induce fear expression in traumatized participants but no consensus on a standard script for research has been established yet. This...Show moreIn PTSD research, script-driven imagery procedures are used to induce fear expression in traumatized participants but no consensus on a standard script for research has been established yet. This study fills a research gap by being the first to directly compare two contemporary imagery script procedures to evaluate their feasibility. We hypothesized an audio-scripted imagery procedure to lead to higher fear expression (heart rate, skin conductance, subjective distress) than an imagery-only script. A moderating effect of the vividness of the stressful memory on fear expression was also hypothesized. In a between-subjects design, participants (N = 37) were sorted into two conditions and were interviewed regarding a stressful life experience. Fear expression was measured during baseline and imagery. Contrary to expectations, both procedures led to a similar increase in fear expression. Crucially, the audio-scripted imagery procedure might be especially effective for participants with a high baseline vividness of the stressful memory which has implications for future PTSD research. Upcoming studies should investigate changes to the script procedures to facilitate comparison between scripts and further explore the effect of script procedures on high-vividness participants.Show less
Background: Posttraumatic cognitions are part of posttraumatic stress disorder (PTSD), contributing to the development and maintenance of the disorder. To measure posttraumatic cognitions Foa et al...Show moreBackground: Posttraumatic cognitions are part of posttraumatic stress disorder (PTSD), contributing to the development and maintenance of the disorder. To measure posttraumatic cognitions Foa et al. (1999) developed the Posttraumatic Cognitions Inventory (PTCI). Later, Wells et al. (2019) shortened the PTCI to a 9-item version (PTCI-9), in an attempt to improve its psychometric properties. Objectives: A short version of the PTCI is highly warranted, as posttraumatic cognitions are directly linked to PTSD symptom severity. Therefore, the current study investigates the factor structure, reliability and validity of the PTCI-9 in a non-clinical trauma exposed sample. Methods: A sample of 149 participants were recruited in the Netherlands. Participants were not diagnosed with a mental disorder or were in treatment at the time of the study. Participants were asked to fill out a series of questionnaires, among which the PTCI. Results: Confirmatory Factor Analysis (CFA) showed that a three-factor model was not a good fit for the PTCI-9. Results showed that the PTCI-9 was reliable (Cronbach’s α = 0.80). Analyses indicated moderate criterion validity (r(147) = .61, p < .001) and moderate correlations to depressive symptom measures (r(147) = -.04, p = .327), as well as weak correlations to childhood trauma measures (r(147) = .46, p < .001). Conclusions: The current study does not support a three-factor structure for the PTCI-9, although shortening the inventory improved model fit significantly compared to the 36-item version. The PTCI-9 is reliable and has moderate criterion and convergent validity. Possible implications are discussed.Show less
Early intervention of the Ultra High Risk (UHR) population is fundamentally important in preventing a potential psychosis. The two crucial steps in psychosis detection are the screening procedure...Show moreEarly intervention of the Ultra High Risk (UHR) population is fundamentally important in preventing a potential psychosis. The two crucial steps in psychosis detection are the screening procedure for (subclinical) psychotic symptoms, via the Prodromal Questionnaire (PQ) as well as a clinical interview, the Comprehensive Assessment of At-Risk Mental States. The aim of this study is to replicate an earlier study, by analyzing the psychometric properties of the PQ-16. More specifically, the cut off score will be evaluated, as well as the sensitivity, specificity, and positive predictive value in a new and larger sample. An additional research question will be examined, specifically whether the level of distress that patients experience per symptom has added value in classifying someone as UHR on the CAARMS. 31,734 participants were included in the analyses. A ROC analysis was used to display the connection and trade-off between clinical sensitivity and specificity for every possible cut-off score. In this study, the most suitable cut off score was 6, with a sensitivity of 70%, a specificity of 60%, a positive predictive value of 30.7 and a negative predictive value of 88.6. Additional ROC curves were plotted to measure various levels of distress; the highest AUC value being 0.64. Therefore, the level of distress on the PQ-16 does not have additional value in predicting UHR on the CAARMS. To conclude, due to the sufficient psychometric properties and clinical benefits, the PQ-16 remains an accessible and feasible tool to screen for subclinical psychotic symptoms. Future research should consider further replication, including an equal range of PQ scores in order to generalize to a wider population.Show less
