Reducing intrusive memories of past trauma using a brief mental imagery competing task intervention: A case series including trauma exposed women in Iceland (Preprint)
Authors: Thorarinsdottir Kristjana 
Published: February 2025

BACKGROUND

There is a need for scalable and simple interventions for trauma exposed people. In this case series, we built on our previous case study and case series findings and further explored the utility and potential effectiveness of a brief novel intervention to reduce the number of past intrusive memories of trauma. The imagery competing task intervention consists of a memory reminder, and the visuospatial task Tetris played with mental rotation, targeting one intrusive memory at a time. Here we test remote delivery of the intervention, including guidance from researchers without specialist mental health training, in a sample of women in Iceland with current intrusive memories from trauma occurring several years previously.

OBJECTIVE

In a case series of trauma exposed women, we aimed to explore whether this brief novel intervention reduces the number of established intrusive memories (primary outcome) and improves general functioning and symptom reduction in post-traumatic stress, depression and anxiety (secondary outcomes). Acceptability of the intervention along with adaptations i.e., delivery by psychology students without specialist mental health training and digital delivery, were explored.

METHODS

Participants (N=8) monitored the number of intrusive memories from an index trauma (occurring 3 – 16 years previously) in a daily diary at baseline, during the intervention phase (ranging from three to six weeks), and post intervention at 1-month and 3-month follow-ups. The intervention was delivered digitally with guidance from clinical psychologists/psychology students. A repeated AB design was used (“A”: pre-intervention baseline, “B”: intervention phase). Intrusions were targeted one-by-one, creating repetitions of an AB design (i.e., length of baseline ‘A’ and intervention ‘B’ varied for each memory).

RESULTS

The number of intrusive memories reduced for all participants from the baseline phase compared to the intervention phase, although the reduction was minimal for 2 participants (6.3% - 93%). The number of intrusive memories continued to reduce for 6 out of 8 participants (58% - 100% reduction at 1-month follow up; 72% - 100% reduction at 3-month follow up).
Symptoms of post-traumatic stress, depression and anxiety were reduced for most participants post intervention and continued to decrease during the follow-up periods. Functioning was improved for 7 of the 8 participants from baseline to post intervention and continued to improve at the follow-up assessments for three participants. The intervention delivered digitally and partly by students was perceived to be an acceptable way to reduce the frequency of intrusive memories by all participants (mean rating 9.5 out of 10).

CONCLUSIONS

Data from this case series of traumatized women provide preliminary evidence for the effectiveness of this novel brief intervention in reducing intrusive memories of trauma occurring several years ago and in improving functioning and reducing core symptom burden. This study will inform a randomized controlled trial of this novel intervention, which may have considerable implications for large scale clinical management of traumatized populations.

CLINICALTRIAL

The study was approved by the National Bioethics Committee in Iceland (No: VSNb2017110046/03.01).
The study was preregistered prior to study start on ClinicalTrials.gov (NCT04209283) on 2020-11-03.

INTERNATIONAL REGISTERED REPORT

RR2-10.2196/29873