Facing the dilemma of trauma-focused therapy

Ganslmeier, Maximilian Georg (2025): Facing the dilemma of trauma-focused therapy: effects of imagery-based interventions on voluntary memory. Dissertation, LMU München: Fakultät für Psychologie und Pädagogik

Abstract

Trauma survivors often face a challenging dilemma: While clinical guidelines recommend early trauma-focused treatment to prevent chronic symptoms, legal actors frequently express concerns that such interventions – particularly imagery-based techniques like imagery rescripting (ImRs) and imaginal exposure (ImE) – could compromise the reliability of memory in legal contexts. This fear has led to widespread delays in clinical treatments until after judicial processes conclude, although empirical evidence from psychotherapy research supporting this cautious approach is lacking. The current dissertation systematically investigates whether and under which conditions imagery-based trauma-focused interventions impact voluntary, legally relevant memory of aversive events. To address this, three progressively building studies were conducted: two experimental analogue studies and one preregistered systematic review. Together, these studies aim to clarify potential memory effects of ImRs and ImE, compare their impact on memory accuracy, and integrate the findings into the broader memory distortion literature. This research offers essential insights for aligning clinical needs and forensic expectations in the treatment of trauma survivors. Study I examined whether ImRs influences memory accuracy following real-life stress exposure. A total of 100 students were exposed to the Trier Social Stress Test (TSST), which reliably induces a personally experienced, psychosocially aversive event. Two days later, participants were randomly assigned to either a single ImRs session or a no-intervention control condition. Voluntary memory was assessed through free recall (before the intervention and one week later) and cued recall (one week later and after three months). The findings revealed that participants in the ImRs condition recalled significantly more correct details in free recall one week after the intervention compared to the control condition, without an increase in incorrect details. No differences between conditions emerged in cued recall after one week and after three months, however, voluntary memory tended to deteriorate over time. Contrary to expectations, this effect was not associated with ImRs. Study II tested the effects of ImRs and ImE on memory accuracy following analogue trauma exposure. In a controlled laboratory setting, 120 highly anxious female participants watched a distressing scene involving sexual violence as part of the trauma-film paradigm. Twenty-four hours later, participants were randomly allocated to one of three conditions: ImRs, ImE, or a no-intervention control. Voluntary memory was measured through free recall (pre-intervention and six days post-intervention), cued recall, and recognition tasks (six days and two weeks post-intervention). The results showed that ImE significantly increased the number of correctly recalled details in free recall compared to both ImRs and control conditions, without increasing memory distortions. ImRs did not affect memory performance relative to the control condition. Across all condition, incorrect details decreased over time, and no evidence of false memory inflation was observed. Study III presents a preregistered systematic review synthesizing evidence from 95 studies examining the effects of imagery tasks and imagery-based interventions on voluntary memory. This review included basic memory studies and experimental analogue applications of ImRs, ImE, and hypnosis. Isolated eye movement tasks, often used as components of EMDR but not full EMDR protocols, were also analyzed in non-clinical contexts. The analysis revealed that experimental imagery tasks and hypnosis were frequently associated with belief inflation, source confusion, and memory distortion. In contrast, structured clinical interventions, particularly ImRs and ImE, showed no evidence of memory impairment and, in some cases, even improved recall accuracy or narrative coherence. Effects of isolated eye movement tasks in non-clinical settings were mixed. Across studies, the risk of memory distortion appeared to be more strongly linked to suggestive procedures and a lack of autobiographical grounding than to the use of imagery per se. Overall, the findings suggest that imagery-based intervention, when applied in structured clinical contexts, do not compromise memory accuracy. Collectively, the three studies provide converging evidence that manualized, structured imagery interventions such as ImRs and ImE do not compromise the factual accuracy of voluntary memory. They may facilitate access to correct details under certain conditions and with appropriate safeguards. Crucial protective factors include a clear session structure, sufficient time for memory consolidation, strong patient authorship, and transparent separation between original and rescripted memory elements. In contrast, suggestive, externally controlled, or hypnotic interventions remain problematic and can indeed pose a risk to memory credibility. The findings challenge the common practice of delaying trauma-focused therapy during legal proceedings out of fear of contaminating memory evidence. Instead, legal and clinical professionals should collaborate to ensure that psychological treatments is conducted under scientifically validated conditions that protect both the well-being of survivors and the integrity of their testimony. Ultimately, this dissertation offers a valuable framework for balancing therapeutic urgency with forensic reliability.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Themengebiete: 100 Philosophie und Psychologie ; 100 Philosophie und Psychologie > 150 Psychologie
• Fakultäten: Fakultät für Psychologie und Pädagogik
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 13. Oktober 2025
• 1. Bericht­erstatter:in: Wolkenstein, Larissa