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Reducing intrusive trauma memories using a brief mental imagery competing task intervention: A case series of trauma exposed women in Iceland (Preprint)

Reducing intrusive trauma memories using a brief mental imagery competing task intervention: A case series of trauma exposed women in Iceland (Preprint)
Reducing intrusive trauma memories using a brief mental imagery competing task intervention: A case series of trauma exposed women in Iceland (Preprint)
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. Clinical Trial: 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.
Thorarinsdottir, Kristjana
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Holmes, Emily
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Hardarsson, Johann
dcf10ee2-4645-4194-b358-ed1fe9de12d6
Agustsdottir, Freyja
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Kanstrup, Marie
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Singh, Laura
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hauksdottir, Arna
dc5aadcc-f333-4a74-9af1-7384271203af
Halldorsdottir, Thorhildur
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Gudmundsdottir, Berglind
bba161b1-2cba-48a5-8db6-55fa212f8855
Thordardottir, Edda Bjork
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Valdimarsdottir, Unnur
bb80ee18-aa00-4bc4-a978-1b0387a23fcd
Bjornsson, Andri S.
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Thorarinsdottir, Kristjana
7fb06e0e-d68c-455d-be3f-a7bcc2d77a74
Holmes, Emily
a6379ab3-b182-45f8-87c9-3e07e90fe469
Hardarsson, Johann
dcf10ee2-4645-4194-b358-ed1fe9de12d6
Agustsdottir, Freyja
d9fe6689-3650-42c7-8d47-5108fe676f0e
Kanstrup, Marie
5ca5fe0c-402a-425c-bf8e-40d3b79b900d
Singh, Laura
1d79dded-61a6-4874-a333-470e169a6100
hauksdottir, Arna
dc5aadcc-f333-4a74-9af1-7384271203af
Halldorsdottir, Thorhildur
f29a5eee-250a-4600-8093-4f3a52cec4dd
Gudmundsdottir, Berglind
bba161b1-2cba-48a5-8db6-55fa212f8855
Thordardottir, Edda Bjork
f444d28e-c6b7-472e-983b-48bc49458f74
Valdimarsdottir, Unnur
bb80ee18-aa00-4bc4-a978-1b0387a23fcd
Bjornsson, Andri S.
911fd777-437a-4bc6-938c-5821bdd9daac

Thorarinsdottir, Kristjana, Holmes, Emily, Hardarsson, Johann, Agustsdottir, Freyja, Kanstrup, Marie, Singh, Laura, hauksdottir, Arna, Halldorsdottir, Thorhildur, Gudmundsdottir, Berglind, Thordardottir, Edda Bjork, Valdimarsdottir, Unnur and Bjornsson, Andri S. (2025) Reducing intrusive trauma memories using a brief mental imagery competing task intervention: A case series of trauma exposed women in Iceland (Preprint). JMIR Formative Research. (doi:10.2196/72748). (In Press)

Record type: Article

Abstract

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. Clinical Trial: 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.

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Submitted date: 17 February 2025
Accepted/In Press date: 3 October 2025

Identifiers

Local EPrints ID: 507817
URI: http://eprints.soton.ac.uk/id/eprint/507817
PURE UUID: 2957ee6c-18f5-4d74-8a7d-0a185ca5d387
ORCID for Emily Holmes: ORCID iD orcid.org/0000-0001-7319-3112

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Date deposited: 06 Jan 2026 17:54
Last modified: 10 Jan 2026 05:07

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Contributors

Author: Kristjana Thorarinsdottir
Author: Emily Holmes ORCID iD
Author: Johann Hardarsson
Author: Freyja Agustsdottir
Author: Marie Kanstrup
Author: Laura Singh
Author: Arna hauksdottir
Author: Thorhildur Halldorsdottir
Author: Berglind Gudmundsdottir
Author: Edda Bjork Thordardottir
Author: Unnur Valdimarsdottir
Author: Andri S. Bjornsson

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