A guided single session intervention to reduce intrusive memories of work-related trauma: a randomised controlled trial with healthcare workers in the COVID-19 pandemic

Abstract

Background: Intrusive memories of psychologically traumatic events bring distress both sub-clinically and clinically. This parallel-group, two-arm randomised controlled trial evaluated the effect of a brief behavioural intervention on reducing intrusive memories in frontline healthcare workers exposed to traumatic events during the COVID-19 pandemic.

Methods: Participants with at least two intrusive memories of work-related trauma in the week before recruitment were randomised 1:1 to an imagery-competing task intervention (n = 73) or attention-based control task (n = 71). The number of intrusive memories was assessed at baseline and 5 weeks after the guided session (primary endpoint).

Results: The intervention significantly reduced intrusive memory frequency compared with control [intervention Mdn = 1.0 (IQR = 0-3), control Mdn = 5.0 (IQR = 1-17); p < 0.0001, IRR = 0.30; 95% CI = 0.17-0.53] and led to fewer post-traumatic stress-related symptoms at 1, 3 and 6 month follow-ups (secondary endpoints). Participants and statisticians were blinded to allocation. Adverse events data were acquired throughout the trial, demonstrating safety. There was high adherence and low attrition.

Conclusions: This brief, single-symptom, repeatable digital intervention for subclinical-to-clinical samples after trauma allows scalability, taking a preventing-to-treating approach after trauma.

Trial registration: 2020-07-06, ClinicalTrials.gov identifier: NCT04460014.

Keywords: Digital intervention; Healthcare workers; Intrusive memory; Mental health; Pandemic; Post-traumatic stress disorder; Prevention-to-treating; Psychological trauma.

Fig. 1

Procedure timeline and participant flow diagram. a, Procedure timeline. After enrolment, participants completed a baseline diary recording number of intrusive memories (week 0) then completed baseline questionnaires. They were randomised to condition prior to the researcher-guided session (control or intervention) on day 1. During the following 7 days, participants completed a second diary (week 1), and completed week 1 follow-up questionnaires on day 8. During the study, participants could use the intervention self-guided (orange horizontal line). After completing the 1-month follow-up questionnaires, participants again completed the 7-day diary (week 5, primary outcome). Follow-up questionnaires were administered at 3 and 6 months. Total study duration was 176 days. AEs, adverse events. b, Participant flow (CONSORT diagram) indicating participant numbers throughout the course of the trial. Missing data refers to instances when a participant had no reported entries for that timepoint. IMs, intrusive memories. Lost-to-follow-up refers to participants who did not complete follow-up questionnaires up to 6 months

Fig. 2

Number of intrusive memories of work-related traumatic events per condition at each of three time points: week 0 (pre-intervention baseline), week 1 (immediately post-intervention) and over week 5 (primary outcome) Boxplots show number of intrusive memories of traumatic events, whereby the midline is the median value. Upper and lower box limits are the third and first quartile (75th and 25th percentile), with the whiskers covering 1.5 times the interquartile range (IQR). All outliers are included in this figure and shown as dots (each dot represents one participant that departed by more than 1.5 times the IQR above the third quartile and below the first quartile). Number of intrusive memories of traumatic events are recorded by participants in a brief daily online intrusive memory diary for 7 days (daily diary) The figure is based on diary data available in the ITT sample, including incomplete diary data, for week 0: n = 144, week 1: n = 136, and week 5: n = 130 The imagery-competing task intervention consisted of a cognitive task involving a brief memory cue plus Tetris® computer gameplay with mental rotation instructions, with a first guided session with the researcher The active control (attention-based placebo comparator) consisted of a cognitive task that also involved a digital activity and, for the same amount of time, listening to a podcast on philosophy, with a first guided session with the researcher Week 0: Baseline measure. Number of intrusive memories in the daily diary during the baseline week for both arms (black = control arm, n = 71: attention-based placebo control; red = intervention arm, n = 73: remotely-delivered, imagery-competing task intervention) showing that the two arms did not differ at baseline (i.e., before the intervention was provided to either arm) Week 1: Secondary outcome measure. Number of intrusive memories in the daily diary during week 1 for each arm (black = control arm, n = 67: attention-based placebo control; red = intervention arm, n = 69: remotely-delivered, imagery-competing task intervention). The intervention arm had fewer intrusive memories at week 1 compared to the control arm Week 5: Primary outcome measure. Number of intrusive memories of traumatic events recorded by participants in a brief daily online intrusive memory diary for 7 days during week 5 for both arms (black = control arm, n = 66: attention-based placebo control; red = intervention arm, n = 64: remotely-delivered, imagery-competing task intervention). The intervention arm had fewer intrusive memories at week 5 compared to the control arm