Evaluating the effectiveness of a group-based resilience intervention versus psychoeducation for emergency responders in England: A randomised controlled trial.

BACKGROUND: Emergency responders are routinely exposed to traumatic critical incidents and other occupational stressors that place them at higher risk of mental ill health compared to the general population. There is some evidence to suggest that resilience training may improve emergency responders' wellbeing and related health outcomes. The aim of this study was to evaluate the effectiveness of a tertiary service resilience intervention compared to psychoeducation for improving psychological outcomes among emergency workers.
METHODS: We conducted a multicentre, parallel-group, randomised controlled trial. Minim software was used to randomly allocate police, ambulance, fire, and search and rescue services personnel, who were not suffering from depression or post-traumatic stress disorder, to Mind's group intervention or to online psychoeducation on a 3:1 basis. The resilience intervention was group-based and included stress management and mindfulness tools for reducing stress. It was delivered by trained staff at nine centres across England in six sessions, one per week for six weeks. The comparison intervention was psychoeducation about stress and mental health delivered online, one module per week for six weeks. Primary outcomes were assessed by self-report and included wellbeing, resilience, self-efficacy, problem-solving, social capital, confidence in managing mental health, and number of days off work due to illness. Follow-up was conducted at three months. Blinding of participants, researchers and outcome assessment was not possible due to the type of interventions.
RESULTS: A total of 430 participants (resilience intervention N = 317; psychoeducation N = 113) were randomised and included in intent-to-treat analyses. Linear Mixed-Effects Models did not show a significant difference between the interventions, at either the post-intervention or follow-up time points, on any outcome measure.
CONCLUSIONS: The limited success of this intervention is consistent with the wider literature. Future refinements to the intervention may benefit from targeting predictors of resilience and mental ill health. TRIAL REGISTRATION: ISRCTN registry, ISRCTN79407277.

RCT Entities:   Population Interventions Outcomes

Introduction

Emergency responders are routinely exposed to highly stressful, often traumatic, critical incidents as well as organisational stressors, such as increased workload, staff reductions and reduced access to informal support, that place them at higher risk of mental ill health compared to the general population [1-3]. Whilst they dedicate their lives to improving health and public safety, they are more likely than the general population to suffer from trauma-related psychological disorders, such as posttraumatic stress disorder (PTSD) [4]. A survey conducted by the UK’s national mental health charity, Mind, found that 87% of UK-based emergency services staff and volunteers reported high levels of ongoing stress, low mood and poor mental health [5]. Interventions that could improve psychological resilience may improve emergency responder wellbeing and related health outcomes.

The last few decades have seen a surge in the development of interventions aimed to improve resilience in emergency worker populations, with resilience generally being defined as the capacity to maintain wellbeing in response to adversity or stress [6]. Despite widespread use, however, there is conflicting evidence for their efficacy with some resilience interventions demonstrating improvements in wellbeing, sleep or stress symptoms [7-11] whilst others show no significant effects on mental or physical health outcomes [12-17]. Evaluations have typically been hampered by heterogeneity in intervention design, content and outcome measurement, and low methodological quality among studies [18-21]. The majority of trials have evaluated interventions aimed at improving resilience against wait-list rather than an active comparator, making it impossible to determine if improvements in resilience or wellbeing are related to active components of the intervention or to non-specific factors, such as contact with a group. It is unclear whether or not a resilience intervention tailored for emergency workers would fare better than an active alternative and would lead to improvements in emergency responder wellbeing, resilience and related health outcomes.

In 2015, Mind introduced their Blue Light programme, the overall aim of which was to improve the mental health of emergency workers in England. Supported by LIBOR funding from the Cabinet Office, the programme included a number of initiatives, one of which focused on resilience. As part of their pilot phase in the development of this initiative, Mind tailored a group-based resilience intervention for delivery to police, ambulance, fire, and search and rescue workers, which had previously been used in military services and administered to high risk populations, such as new mothers and men at risk of social isolation [22]. The intervention was based on their model of resilience, which posits that improving wellbeing, social capital and use of psychological coping strategies will improve an individual’s resilience. The model incorporates the five ways to wellbeing, a set of evidence-based public health messages, identified by the New Economics Foundation, for improving the mental health and wellbeing of the population [23].

This study is a randomised controlled trial evaluating the effectiveness of Mind’s pilot phase resilience intervention for emergency workers compared to accessing psychoeducation about mental health. Overall, randomised controlled trials have found no effect of psychoeducation for reducing psychological symptoms [24] or distress in military personnel [25]. We therefore hypothesised that the resilience intervention would be more effective than psychoeducation in improving resilience, wellbeing, self-efficacy, and social capital, as well as in improving emergency workers’ confidence to manage their mental health and reduce days off work due to illness. We hypothesised that neuroticism would predict the degree of change participants would experience in wellbeing, resilience, self-efficacy and social capital.

Methods

Design

This study is a two-arm, parallel-group randomised controlled trial conducted in England. Participants were randomly allocated on a 3:1 basis to Mind’s group-based resilience intervention or to reading mental health information online. There were no changes to the trial design throughout the study. This paper was written in accordance with CONSORT guidelines [26]. Ethical approval was granted by the Medical Sciences Division Research Ethics Committee at the University of Oxford (1/4/15; ref MS-IDREC-C1-2015-059). The protocol was approved by the funder and the ethics committee prior to recruitment and no changes were made to the protocol at any point during the trial. The trial was registered retrospectively during participant follow-up. The reason for the delay in registering the trial was one of time constraints associated with the priority completion of a number of procedures at the outset to ensure the trial of N = 430 emergency responders, including their follow-up, could be completed within 12 months. The authors confirm that all ongoing and related trials for this intervention are registered, and have all been registered prospectively.

Participants and recruitment

Recruitment was conducted from May to November 2015 in collaboration with local Mind centres and local emergency services at nine selected sites across England: Andover, Brighton and Hove, Coastal West Sussex, Dudley, Southampton, Birmingham, Oxfordshire, Cambridgeshire, and Peterborough and Fenland. Recruitment methods involved giving talks at emergency service sites, circulating emails, posters, and leaflets, and using social media. Emergency workers were directed to Mind’s website where they could sign up for the trial via a link to the registration survey on Qualtrics, a secure online software platform. Participants could read and print a PDF copy of the Participant Information Sheet and pause the registration process to discuss questions with the research assistant over the telephone. If they decided to take part, they were emailed an individualised link where they could log-in, re-read the Participant Information Sheet, and complete a consent form and two short screening questionnaires. Participants were screened for depression and suicidal ideation using the Patient Health Questionnaire 9 (PHQ-9) [27], and for post-traumatic stress using the Post-Traumatic Stress Disorder Checklist for DSM-5 (PCL-5) [28]. They were considered eligible if they scored below 10 on the PHQ-9, below 33 on the PCL-5, and 0 on question nine of the PHQ-9, which assesses suicidal ideation. If participants scored above these cut-off points, they had a telephone call with the researchers to discuss whether their symptoms interfered with their lives and whether they wished treatment. They were re-included in the study if their symptoms had little impact on their lives and they did not want treatment, otherwise they were excluded and signposted for evidence-based psychological treatment within local Improving Access to Psychological Therapies services. To reduce the risk of participants dropping out, eligible participants were asked to confirm they could commit to a six-week programme before they were randomised.

Interventions

Resilience intervention

The resilience intervention was a six-week, group-based course developed for Mind by Shaun Goodwin, a psychotherapist with expertise in transpersonal counselling, and previously delivered in their work with new mothers and men at risk of social isolation [22]. The intervention included information about mental health and experiential exercises drawn from stress management and mindfulness, with the overarching aim to improve wellbeing and use of adaptive coping strategies, such as social support. Table 1 shows an overview of the weekly content. Homework exercises were set between each session to reinforce learning. Each group session lasted 2.5 hours. Mind facilitators attended a one-day workshop on how to deliver the intervention and then weekly supervision whilst it was ongoing.

Table 1

Overview of the weekly content of the resilience intervention.

Session	Content
1	Hopes and Expectations. Looking at how stress affects thoughts, feelings, physical wellbeing and behaviour.
2	Understanding anxiety and learning why we react the way we do. Identifying distorted thoughts and moods.
3	How we can limit ourselves through habitual negative thoughts and moods. Challenging distorted negative thoughts and moods.
4	Managing worry. Managing stress. ‘Time for me’ and learning how to relax and the importance of doing so. Breathing techniques. Controlling panic.
5	Setting goals and challenges. Understanding passive anger and resistance. Learning about comfort zones and panic zones.
6	Reviewing learning. Planning for the future.
Throughout the course	A different relaxation technique is introduced in each session, including techniques based on mindfulness.

Psychoeducation

The comparison intervention included psychoeducation about six topics: sleep, stress, depression, anger, mindfulness, and post-traumatic stress disorder. These were selected from a range freely available online from Mind’s website https://www.mind.org.uk/information-support/types-of-mental-health-problems/, which the researchers then tailored for emergency workers. Each topic was delivered as an online module, one released each week for six weeks during the same six-week period that the resilience intervention took place. Participants completed the modules remotely at a time during the week that suited them. They could contact the research assistant by email if they had any questions about any part of the modules.

Primary outcome measures

We adopted a liberal approach to primary outcome, registering seven primary outcome measures. This was for the purpose of ensuring there would be no missed effects linked to the intervention. All primary and secondary outcome measures were administered three times during the study: at baseline, post-intervention, and at three-month follow-up. All outcome measures were self-reported assessments. There were no changes to outcome measures after the trial commenced. The Warwick Edinburgh Mental Wellbeing scale [29] assessed wellbeing. Internal reliability for the scale in the sample was excellent; Cronbach’s alpha = 0.94. The Connor-Davidson Resilience Scale [5] measured resilience. Internal reliability was excellent; Cronbach’s alpha = 0.93. The General Self-Efficacy Scale [30] is a 10-item scale that assessed optimistic self-beliefs for coping with a variety of difficult demands in life. Internal reliability was good; Cronbach’s alpha = 0.89. Two questionnaires were administered to assess social capital: the Social Participation scale [31] and the Social Support scale adapted from Sarason et al’s scale [32], which has two subscales, Social Support (Home) and Social Support (Work). Internal reliability for the Social Participation scale was excellent: Cronbach’s alpha = 0.92. The Social Support scales showed good internal reliability: Social Support (Home) Cronbach’s alpha = 0.77, and Social Support (Work) Cronbach’s alpha = 0.83. A one-item measure assessed the degree to which participants felt confident to manage their mental health on a scale from 1 = Totally disagree to 7 = Totally Agree. Higher scores reflect greater confidence in managing mental health. We also administered a two-item questionnaire to assess how many days off work due to illness an individual had taken in the past three months (when administered at baseline and follow-up) and past six weeks when administered at post-intervention.

Secondary outcome measures

The Depressive Attributions Questionnaire [33] assesses attributions of negative events. Internal reliability was excellent; Cronbach’s alpha = 0.93. We administered three subscales of the Brief Coping Behaviour Questionnaire [34] to assess adaptive coping (active coping, use of emotional support, and acceptance) and five subscales to assess dysfunctional coping (self-distraction, denial, substance use, self-blame, behavioural disengagement). To the dysfunctional coping subscale, we added wishful thinking, which had previously been shown to correlate with severe stress in paramedics [35]. Internal reliability for the adaptive coping scale was good (Cronbach’s alpha = 0.81) and excellent for the dysfunctional scale (Cronbach’s alpha = 0.93). The Responses to Intrusions Questionnaire [36] assessed suppression, rumination and intentional numbing in response to stressful events. Internal reliability for each scale was good; suppression, Cronbach’s alpha = 0.84; rumination, Cronbach’s alpha = 0.90; and intentional numbing, Cronbach’s alpha = 0.74. The Ruminative Responses Scale [36] measured the frequency of engaging in dwelling. Internal reliability was excellent; Cronbach’s alpha = 0.95. An unpublished trauma screener, adapted from the Clinician Administered PTSD Scale for DSM-5 (CAPS-5) to include events relevant to emergency personnel, was used to record exposure to traumatic events [37]. The PCL-5 was administered to assess symptoms of PTSD [28]. The PHQ-9 [27] assessed severity of depression symptoms. Internal reliability of the scale was good, Cronbach’s alpha = 0.86. The General Anxiety Disorder 7 (GAD-7) [38] assessed anxiety. Internal reliability was good, Cronbach’s alpha = 0.88. The Alcohol Use Disorders Identification Test [39] measured a person’s weekly intake of alcohol and substances and whether it has caused problems for them. Internal reliability was good, Cronbach’s alpha = 0.74. We administered an unpublished questionnaire to assess problem solving, which had been used in previous evaluations of Mind’s resilience intervention [22]. The questionnaire consisted of eight items to assess a person’s perception of how well they can solve problems and achieve goals. Internal reliability in the sample was excellent; Cronbach’s alpha = 0.90. The neuroticism subscale of the Short-Form Revised Eysenck Personality Questionnaire [40] assessed emotionality. Internal reliability of this scale was good, Cronbach’s alpha = 0.84.

Perceived helpfulness and adherence assessment

To measure perceived helpfulness of the interventions, participants completed a helpfulness rating, indicating on a scale of 0 to 100% how helpful they found their interventions to be. To assess facilitator adherence to the resilience protocol, we created a short questionnaire that related to the core elements for each of the six sessions. Each group session was recorded using SanDisk MP3 players and the researchers rated 10% of the sessions for adherence to protocol.

Sample size

Guidelines set by the Cabinet Office for this study suggested a target sample size of 430. We conducted a power analysis to confirm the sample would be large enough to detect an effect should one exist. We referred to a study by Kuehl et al. [8] who compared a group-based 12-week stress management intervention for police officers against standard practice. The intervention led to between-group improvements in wellbeing with small effect (d = 0.34). A sample size calculation was performed for a superiority trial with continuous outcome. Using an alpha of 0.05, 90% power, a standard deviation for the CD-RISC of 14, and a group difference of 5 points (which equates to d = 0.34 from the previous study), would require a total of 330 participants. Allowing for 20% attrition, a total sample size of N = 398 would be required, suggesting that the target sample size was large enough to detect an effect.

Randomisation

Participants self-enrolled online, were screened and gave consent. They completed their baseline measures before they were randomised on a 3:1 basis to the resilience intervention or to online psychoeducation. The researchers used Minim software to randomly allocate participants by method of minimisation, stratifying the allocation by site and gender. The research assistant entered eligible participants into Minim and then emailed the allocation result to each participant. This randomisation method allowed allocation concealment to be maintained and reduced the risk of selection bias. Blinding was not possible due to the type of interventions.

Procedure

The period from the online screening to the onset of the interventions ranged from a few days to 8 weeks, with the majority of participants beginning their intervention within two weeks. Participants (N = 33) who waited more than four weeks to start their interventions re-completed baseline questionnaires. Participants were contacted by email at post-intervention (6 weeks) and 3 months later with a link to complete follow-up questionnaires. The resilience and psychoeducation interventions were delivered 31 times in four phases from May to December 2015. The mean number of participants per group in the resilience intervention was N = 9. The supporting CONSORT checklist for this trial is available as supporting information. See S1 and S2 Files.

Statistical methods

Data on the number of sessions/modules completed and perceived helpfulness were analysed descriptively and using one-way ANOVA. Facilitators’ adherence to the resilience intervention was assessed through independent ratings of session audio recordings.

Linear Mixed-Effects Models were used for the analysis of the primary and secondary outcome variables. Such models have the advantage of using the available data from all participants who were randomized, as well case as accounting for nested data structures and data missing at random. Time (post-intervention, and three-month follow-up), treatment condition (resilience intervention or online psychoeducation [active control]), and the time-by-condition interaction were entered as categorical fixed factors along with the stratification variables of gender and site. Baseline score was included as a covariate, and a random effect of participant was specified to account for between-person variation. Scores on the primary or secondary outcome measure being evaluated were used as the dependent variable. When analysing secondary outcome measures, the baseline scores of the primary outcome measures were included as additional covariates. All models were estimated using restricted maximum likelihood estimation. Q-Q plots indicated that the normality of residuals assumption was met for all models.

Between-group effect sizes (dCohen) were calculated by dividing the adjusted group difference by the baseline standard deviation of the full study sample. Within-group effect sizes were calculated from separate models that incorporated the baseline score as a timepoint rather than as a covariate, to permit calculation of within-group changes from baseline. These models used an unstructured covariance matrix. 95% confidence intervals for dCohen were calculated by dividing the upper and lower limits of the adjusted group difference by the baseline standard deviation of the full study sample.

A series of linear regressions was performed to examine if baseline neuroticism scores predicted the extent of Baseline-Post change in Wellbeing, Resilience, Self-efficacy, and Social Capital within the treatment group. Residualised gain scores (which represent participants’ observed change in relation to that predicted from the overall Baseline-Post relationship) were used as the dependent variable in each analysis, and Gender, Site, and Baseline score were included as covariates.

All analyses used the intention to treat sample and a significance level of 0.05. Analyses were conducted in R version 3.5.1 (R Core Team, 2017) [41]. The packages ‘tidyverse’ (Wickham, 2017) [42], ‘nlme’ (Pinheiro, Bates, DebRoy, Sarkar, & R Core Team, 2018) [43], ‘jmv’ [44] and ‘psych’ [45] were used. The Confidence in Managing Mental Health variable was log transformed prior to analysis given non-normality of the raw data. The total score for days off work due to illness was non-normal and could not be corrected with transformations. We analysed this variable at post-intervention and follow-up with Mann-Whitney U Tests.

Results

Four hundred and thirty participants (N = 317 resilience intervention, N = 113 online psychoeducation) took part in the trial from May 2015 to March 2016. Fig 1 shows an overview of the number of participants from enrolment to analysis. Follow-up began in July 2015 and continued until March 2016. The trial ended with the end of Mind’s pilot year of the Blue Light programme. The majority of participants were female (58.1%), White British (89.7%), police officers (52.3%), and were on average 41 years old (SD = 9.78). Table 2 describes the study sample by intervention arm. Table 3 shows the means and standard deviations of primary outcome measures at baseline, post-intervention and three-month follow-up.

Fig 1

Consort flow diagram.

Table 2

Demographic description of participants at randomisation.

		Resilience Intervention (N = 317)	Psychoeducation (N = 113)	Total (N = 430)
Age	Mean (SD)	41.09 (9.98)	42.32 (9.20)	41.41 (9.78)
Gender	Female	186 (58.68%)	64 (56.64%)	250 (58.14%)
	Male	131 (41.32%)	49 (43.36%)	180 (41.86%)
Marital Status	Single	57 (17.98%)	19 (16.81%)	76 (17.67%)
	Married	164 (51.74%)	51 (45.13%)	215 (50.00%)
	Divorced/Separated	30 (9.46%)	14 (12.39%)	44 (10.23%)
	Widowed	3 (0.95%)	0 (0%)	3 (0.70%)
	Civil partnership	3 (0.95%)	2 (1.78%)	5 (1.16%)
	Long-term partner	60 (18.93%)	27 (23.89%)	87 (20.23%)
Highest Qualification	GCSE	56 (17.67%)	13 (11.50%)	69 (16.05%)
	A-Levels	82 (25.87%)	35 (30.97%)	117 (27.21%)
	Degree/College	140 (44.16%)	50 (44.25%)	190 (44.19%)
	Masters	33 (10.41%)	10 (8.85%)	43 (10.00%)
	PhD or Other qualification	6 (1.89%)	5 (4.42%)	11 (2.56%)
Ethnicity	White British/European	299 (94.32%)	107 (94.69%)	406 (94.42%)
	Black/Indian/Asian/Arab	18 (5.68%)	6 (5.31%)	24 (5.58%)
Service	Police	170 (53.63%)	55 (48.67%)	225 (52.33%)
	Ambulance	89 (28.08%)	31 (27.43)	120 (27.91%)
	Fire	47 (14.83%)	21 (18.58)	68 (15.81%)
	Search and rescue	11 (3.47%)	6 (5.31%)	17 (3.95%)

Table 3

Primary outcome measures at baseline, post-intervention and follow-up.

	Resilience Intervention			Psychoeducation
	Baseline (N = 314)	Post (N = 256)	Follow-up (N = 281)	Baseline (N = 113)	Post (N = 92)	Follow-up (N = 100)
	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)
Resilience (CD-RISC)	66.49 (14.72)	67.94 (17.01)	68.52 (16.18)	67.48 (14.62)	68.48 (15.26)	69.43 (15.25)
Wellbeing (WEMWBS)	48.57 (8.90)	50.69 (9.36)	50.29 (9.10)	48.49 (9.17)	51.28 (9.93)	50.76 (9.51)
Self-Efficacy (GSE)	30.94 (4.22)	31.75 (4.48)	31.82 (4.58)	31.69 (4.22)	31.91 (4.73)	32.33 (4.54)
Social Participation	59.06 (15.84)	62.38 (17.82)	61.38 (16.89)	56.84 (17.37)	60.63 (17.90)	59.94 (18.94)
Social Support (Home)	33.04 (6.08)	33.64 (6.43)	34.14 (6.71)	32.58 (6.86)	32.83 (7.09)	33.09 (7.93)
Social Support (Work)	27.20 (6.64)	27.17 (6.58)	27.42 (6.80)	26.51 (6.64)	27.14 (7.16)	26.71 (7.13)
Days off work/week	0.25 (0.93)	0.25 (0.94)	0.38 (1.42)	0.28 (1.00)	0.24 (0.80)	0.44 (1.29)
Confidence to manage mental health	5.04 (1.32)	5.42 (1.18)	5.41 (1.31)	4.98 (1.43)	5.42 (1.21)	5.49 (1.31)

Notes. Data completeness in the Resilience Intervention group was 99% at baseline, 81% at Post-intervention, and 89% at Three-month Follow-up. In the Psychoeducation group the figures were 100%, 81%, and 88%, respectively. CD-RISC = Connor-Davidson Resilience Scale; WEMWBS = Warwick Edinburgh Mental Wellbeing scale; GSE = General Self-Efficacy.

Sessions/modules completed, perceived helpfulness and adherence assessments

Participants receiving the resilience intervention completed a mean number of 4.11 group sessions (SD = 2.02) whilst those receiving the psychoeducation intervention completed a mean number of 4.71 (SD = 2.01) modules. Participants receiving psychoeducation completed more modules than sessions attended by participants in the resilience intervention (F(1,429) = 7.21, p = 0.008). Participants rated the resilience intervention (84%, SD = 19.49) as significantly more helpful than the psychoeducation intervention (77%, SD = 22.79), (F(1,278) = 9.4, p = 0.002). Thirty audio-recordings from the group sessions (15%) were randomly selected to measure the facilitators’ adherence to protocol whilst delivering the resilience intervention. Two research assistants independently rated the recordings for inter-rater reliability, which yielded a correlation coefficient of r = 0.985, suggesting excellent inter-rater reliability. Adherence to protocol ratings ranged from 60% to 100%, with a mean rating of 85.65% (SD = 13.07), suggesting that the facilitators demonstrated good adherence to protocol.

The results of the Linear Mixed-Effects Models are given in Table 4. There were no significant differences between the intervention groups on any of the primary outcome measures at either the post-intervention or three-month follow-up timepoints. The between- and within-group effect sizes suggested there was little to no change on these measures resulting from either intervention. The groups did not differ in the number of days off work due to illness they had taken at post (Mann-Whitney U = 11,684.00, p = 0.892) or at follow-up (Mann-Whitney U = 13,715.00, p = 0.754).

Table 4

Adjusted group differences and effect sizes of the primary outcome measures for the intention to treat sample.

	Adjusted group difference (SE)		Effect size dCohen [95%CI]
	[95%CI], p value
	Post	FU	Between-group at Post	Between-group at FU		Within-group pre-posta	Within-group pre-FUa
WEMWBS
Resilience Intervention vs Psychoeducation	-0.27 (0.85)	-0.52 (0.83)	0.03	0.06	Resilience	0.03	0.06
	[-1.94, 1.40], .755	[-2.15, 1.11], .532	[-0.16, 0.22]	[-0.12, 0.24]		[-0.16, 0.23]	[-0.13, 0.25]
					Psychoeducation	0.25	0.24
						[0.09, 0.42]	[0.08, 0.40]
CDRISC
Resilience Intervention vs Psychoeducation	0.52 (1.41)	-0.44 (1.36)	0.04	0.03	Resilience	0.06	<0.01
	[-2.25, 3.29], .712	[-3.11, 2.23], .749	[-0.15, 0.22]	[-0.15, 0.21]		[-0.13, 0.26]	[-0.19, 0.19]
					Psychoeducation	0.03	0.13
						[-0.13, 0.20]	[-0.03, 0.30]
GSES
Resilience Intervention vs Psychoeducation	0.55 (0.43)	0.05 (0.42)	0.13	0.01	Resilience	0.19	0.08
	[-0.30, 1.40], .209	[-0.78, 0.88], .902	[-0.07, 0.33]	[-0.18, 0.21]		[-0.02, 0.40]	[-0.13, 0.28]
					Psychoeducation	0.01	0.14
						[-0.18, 0.18]	[-0.04, 0.31]
Problem Solving
Resilience Intervention vs Psychoeducation	-0.15 (0.47)	0.04 (0.46)	0.03	0.01	Resilience	0.01	0.05
	[-1.07, 0.77], .751	[-0.86, 0.94], .929	[-0.16, 0.22]	[-0.18, 0.20]		[-0.20, 0.22]	[-0.16, 0.25]
					Psychoeducation	0.19	0.19
						[0.02, 0.36]	[0.03, 0.36]
SPS
Resilience Intervention vs Psychoeducation	0.67 (1.55)	-0.33 (1.51)	0.04	0.02	Resilience	0.01	0.05
	[-2.38, 3.72], .667	[-3.30, 2.64], .828	[-0.15, 0.23]	[-0.16, 0.20]		[-0.18, 0.21]	[-0.14, 0.24]
					Psychoeducation	0.20	0.17
						[0.05, 0.35]	[0.03, 0.32]
SS(Home)
Resilience Intervention vs Psychoeducation	0.72 (0.62)	0.60 (0.60)	0.11	0.10	Resilience	0.09	0.08
	[-0.50, 1.94], .246	[-0.58, 1.78], .321	[-0.08, 0.31]	[-0.09, 0.28]		[-0.12, 0.30]	[-0.12, 0.28]
					Psychoeducation	0.03	0.09
						[-0.13, 0.18]	[-0.07, 0.24]
SS(Work)
Resilience Intervention vs Psychoeducation	-0.41 (0.57)	0.01 (0.55)	0.06	<0.01	Resilience	0.08	0.03
	[-1.53, 0.71], .478	[-1.07, 1.09], .985	[-0.11, 0.23]	[-0.16, 0.16]		[-0.10, 0.25]	[-0.14, 0.20]
					Psychoeducation	0.07	0.05
						[-0.08, 0.22]	[-0.10, 0.20]
CMH
Resilience Intervention vs Psychoeducation	<0.01 (0.01)	-0.01 (0.01)	<0.01	0.07	Resilience	0.04	0.09
	[-0.02, 0.02], .876	[-0.03, 0.01], .522	[-0.14, 0.14]	[-0.07, 0.21]		[-0.21, 0.29]	[-0.14, 0.29]
					Psychoeducation	0.29	0.30
						[0.07, 0.47]	[0.13, 0.47]

Note. In the Intervention group, 306 participants provided data at baseline, 256 at posttreatment, and 282 at follow-up. In the Psychoeducation group, 108 participants provided data at baseline, 92 at posttreatment, and 100 at three-month follow-up. All Linear Mixed-Effects Models included the baseline score, gender, and site as covariates, and a random effect of participant. WEMWBS = Warwick Edinburgh Mental Wellbeing Scale; CDRISC = Connor-Davidson Resilience Scale; GSES = General Self-Efficacy Scale; SPS = Social Participation Scale; SS = Social Support; CMH = Confidence in Managing Mental Health and Resilience Scale.

a Within-group effect sizes obtained from separate Linear Mixed-Effects Models including baseline score as a timepoint (see Method).

Analysis of the secondary outcome measures showed the same pattern of results, indicating that the resilience intervention was not superior to psychoeducation and did not lead to significant improvements in depressive attributions, coping strategies, responses to intrusions, rumination, or symptoms of PTSD, depression, anxiety, or problematic alcohol use.

Looking at within-subjects effects, participants receiving psychoeducation demonstrated small improvements in wellbeing, social participation, confidence to manage mental health, depressive attributions, dysfunctional coping, rumination and suppression in response to stressful memories at follow-up compared to when they came into the trial. Participants who received the resilience intervention demonstrated small improvements in suppression in response to intrusive memories at post-intervention and at follow-up compared to their baseline assessment. Model results and descriptive statistics for the secondary outcomes are provided in the supplementary material.

To examine the hypothesis that baseline levels of neuroticism may predict the extent of individual pre-post change in the resilience intervention, a series of linear regressions was conducted using residualised gain scores of the primary outcome measures as the dependent variables. The results (see Table 6 in S3 File) showed that none of the overall models were significant, with low R2 values, indicating there was no evidence within this sample that neuroticism predicted the extent of change in wellbeing, resilience, self-efficacy, or social capital associated with the intervention.

Discussion

This randomised controlled trial evaluated the effectiveness of a tertiary service resilience intervention for improving psychological outcomes among emergency workers compared to a psychoeducation-only intervention. There were no significant differences between the interventions on any of the primary or secondary outcome measures at the post-intervention or follow-up timepoints although participants receiving the resilience intervention rated it as more helpful than those receiving psychoeducation.

The results of this trial are consistent with findings that resilience interventions may have limited effects on mental health outcomes in emergency workers [12-17] and the growing concern in the field that although some interventions may improve wellbeing [7-11], it remains to be seen whether or not this translates to better mental health outcomes. Interestingly, modest improvements were observed for participants receiving psychoeducation on some outcomes at follow-up compared to their baseline assessments. However, these are likely to be due to non-specific factors, such as contact with a research assistant, since the differences were not found between the groups on the same outcomes. This would be in keeping with the wider literature, which suggests psychoeducation is generally ineffective in terms of building resilience to stress. For example, a cluster randomised controlled trial attempted to directly measure the impact of psychoeducation among new firefighter recruits and evidenced no long-term benefits of psychoeducation in terms of help seeking or symptom levels [46]. Similarly, Sharpley et al. [25] compared Naval and Marine personnel who had and had not received psychoeducation about stress and stress reactions in a briefing session prior to being deployed to the 2003 Iraq war. There was no evidence that pre-deployment psychoeducation reduced subsequent psychological distress after deployment. What is emerging is evidence that it is the type of education that matters: training about the job rather than training in stress management [i.e., 46–51].

The resilience intervention evaluated in this trial included tools to promote mindfulness and manage stress with the aim of fostering wellbeing, psychological coping, and social capital in an attempt to improve overall resilience. Perhaps a more theory-driven approach to resilience-building is needed, such as identifying and then targeting predictors of resilience and also mental ill health. A recent systematic review of interventions aimed to improve wellbeing and resilience to stress among emergency responders found that those most likely to demonstrate intervention-specific improvements targeted modifiable risk factors of trauma-related psychological disorders, such as PTSD and depression [18]. This approach is echoed in medicine where interventions for building resilience to ill health target modifiable risk factors, such as targeting hypertension to reduce the risk of cardiovascular disease and mortality [52]. Targeting modifiable risk factors for psychological disorders has also been shown to be effective in preventing the development of depression [53]. A similar approach may be effective for populations, such as emergency responders, at risk of developing severe stress reactions like PTSD. To date, there is little prospective research identifying these risk factors, although a study conducted by Wild et al. [4] identified two predictors of poor mental health that could serve as targets for future interventions.

On the whole, the majority of evaluations of resilience interventions are hampered by trials of low methodological quality and comparison to wait-list rather than active comparison conditions, making it difficult to conclude whether or not any improvements are intervention-specific. The current trial overcame these shortfalls by implementing a robust design with a large sample of emergency workers. However, despite the rigorous approach employed in this trial, there are limitations worth considering. First, all outcome measures were self-report, which are subjective and open to bias. Second, there was no wait-list condition. In addition to an active comparison condition, a wait-list condition allows conclusions to be drawn about intervention-specific effects rather than natural fluctuations in outcomes over time. Third, the interventions differed in their mode of delivery, which may have advantaged one over the other. However, since no effects were found, this is unlikely. Fourth, the follow-up period was fairly short. Fifth, consistent with the model of resilience used to design the intervention, resilience was assessed as a combination of thoughts and behaviours reflective of resilient functioning. Perhaps an operationalised definition of resilience is needed that allows an assessment of better than expected outcomes following stress exposure. Future research could overcome these limitations by including objective assessment measures, such as clinical interviews, including a wait-list arm, and a longer follow-up period that measures exposure to stressful events and subsequent trajectories of outcome.

Notwithstanding the limitations mentioned above, this trial is an important step forward in the development of resilience interventions for emergency workers. It is the first randomised controlled trial to rigorously evaluate a resilience-building programme delivered to a combined sample of emergency responders (i.e., police, paramedics, firefighters and search and rescue personnel) rather than responders from a single service (i.e., police-only). The results are thought to have good generalisability since the intervention was implemented to male and female emergency workers from varied emergency services covering city and rural locations. Our trial demonstrated that a resilience intervention is acceptable to emergency workers and despite their demanding schedules, many were able to commit to a six-week group course. Future resilience interventions may benefit from being tailored to target predictors of resilience and mental ill health in this population.

Conclusion

We evaluated a tertiary service resilience intervention for emergency workers in a large-scale randomised controlled trial. Although the intervention was acceptable to emergency workers, the results demonstrated that it could not be linked to any intervention-specific improvements in health and wellbeing outcomes. Equally, the comparison condition, psychoeducation, could not be linked to intervention-specific improvements, although participants did fare better on some outcomes at the end of the follow-up period compared to their baseline assessments. Overall, the resilience intervention performed similarly to psychoeducation, suggesting that it fails to be cost-effective in its current form. The limited success of this intervention is consistent with the wider literature. A more promising approach to developing interventions to improve resilience to stress may be to identify then target modifiable risk factors of stress-related psychopathology.

CONSORT checklist.

(DOC)

Click here for additional data file.

Trial protocol.

(PDF)

Click here for additional data file.

Secondary outcome.

(DOCX)

Click here for additional data file.

9 Jun 2020

PONE-D-20-05224

Evaluating the effectiveness of a group-based resilience intervention versus psychoeducation for emergency responders in England: A randomised controlled trial

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Reviewer #1: The manuscript entitled ‘Evaluating the effectiveness of a group-based resilience intervention versus psychoeducation for emergency responders in England: A randomised controlled trial’ with the aim to evaluate the effectiveness of a tertiary service resilience intervention compared to psychoeducation for improving psychological outcomes among emergency workers.

The manuscript can be further improved based on the following comments.

Comments

Abstract, the sentence ‘ to the interventions on a 3:1 ratio’ incomplete.

Methods

The mode of administration of all the questionnaires/inventories to be clearly stated. E.g. self-administered or filled up by interviewer/assessor.

Page 11 Line 234 the sentence ‘effect size f=0.17) between two groups (three measurement points: pre-intervention, post-intervention, and follow-up) not clear and more information to be added.

Line 167, for the ‘baseline, Intervention and 3 months’ the period for the intervention to be stated. In some part, post intervention was used. This needs to be standardized. Also could explore the use of symbol T0, T1, T2 to denote the period.

Statistical analyses

Page 12 Line 259, Linear mixed effect models to be written as Linear Mixed-Effects Models.

All statistical tests highlighted in the results section to be stated in the statistical analyses section in the methodology.

Page 12 Line 271, 272, 276, what group differences to be stated.

The level of accepted significance to be stated.

Results

Table 2, for ethnicity White British/European, percentage figures were missing. The highest qualification for resilience intervention has a total percentage 100.2 (if can't be avoided is fine). Total marital status does not tally 100% (the percentage for 87 is incorrect (should be 20.2%). Decimal point to be standardized for all percentage figures. Likewise for the percentage figures in the text.

Table 3, 5 N to be stated on the table.

Information on the dropout rates in % at various point of assessment to be provided.

Table 4, for the data under adjusted difference, denote clearly what data in the Post and FU refers to.

Table 5, some of the SDs are larger than mean. Please check if median ± IQR to be used.

Table 6, figures or parameter indicator to be centralized. R square to be added into discussion to support Page 21 Line 363.

The analysis was based on intent to treat. Were the results any different to per protocol analysis?

Figure 1, baseline to be incorporated in. Post intervention period to be stated.

References did not conform to the journal format.

Reviewer #2: Paper description:

Authors performed a methodologically well balanced study in which they compared effects of two resilience intervention types, aimed for emergency workers: resilience Intervention and psychoeducation. Study is performed on 430 participants, and several primary and secondary outcome measures. Results did not reveal any significant difference between the two intervention types. Also, both interventions showed weak or no effects on primary and secondary outcome measures. Study is well designed and data analysis are well performed.

General comments:

Main shortcoming of this paper is not enough elaborated hypothesis that resilience intervention would be more effective than psychoeducation. Especially having in mind that study did not reveal any significant differences authors must explain in more details why is important to look for such differences. This paper is confirming null hypothesis, and therefore we must have really good argumentation for doing this research.

Another shortcoming is due to sample and analysis. Authors should explain why they used 3:1 ratio for compared groups. In the analysis part, it seems like it is not explicitly mentioned what is used as a dependent variable in mixed models. It seems like authors performed series of analysis in which each score on follow up was predicted by the same score on the baseline (covariate) and other factors. If my assumption is true, then it is hard to expect to get any other significant effects besides the effect of a covariate – since one measure predicts itself best, and does not leave room for other predictors. I would suggest to authors to use differences of baseline-post measures (gains) as dependent variables instead, and to test the effects of factors on those gains. If not instead, then authors should add it as another approach to data analyzing.

Detailed comments:

Abstract: on a 3:1 ratio – please add that it refers to group-based resilience intervention and psychoeducation

“We hypothesised that the resilience intervention would be more effective than psychoeducation in improving resilience, wellbeing” – on what bases is this assumed? Why should we expect this? This must be explained and argumented in more details, especially having in mind that result confirmed null hypothesis.

“...risk of social isolation (Robinson et al., 2014)” – why is this reference in a different formatting?

Did the whole group 314 people attend the session at the same time? Is it too big?

Is it checked if homework exercises were done regularly and how long?

“Psychoeducation about stress and mental health delivered online” – why is one intervention performed online? This leaves room for confounding variable, live versus online training. I understand that it is not too important since no effects are found, but it must be elaborated and argumented.

Is it checked and how, if participants really attended online psychoeducation?

“A one-item 180 questionnaire” – I would suggest to call it one-item measure, since questionnaire usually assumes more items

Why 3:1 ratio for intervention groups? Why not 1:1? This must be explained and argumented

“Residualised gain scores were used as the dependent variable in each analysis...” – what are they residualised from? What where the variables used to separate residuals? Why residuals? Why not just gains?

“Time (post-intervention, and three-month follow-up), treatment condition (resilience intervention or online psychoeducation [active control]), and the time by-condition interaction were entered as categorical fixed factors along” – but it does not seem so form the results, a separate analyses are shown for two time points, it does not seem it was added as a factor

“The resilience and 296 psychoeducation interventions were delivered 31 times in four phases from May to December 297 2015. Follow-up began in July 2015 and continued until March 2016.” –Why is this in the results section, why not in procedure part?

Table 2, for White British/European percentage numbers are missing in brackets. Also in some places a sign % is written on others is missing

“Significantly greater than the number of sessions attended...” – do authors by “sessions” refer to group-based resilience intervention? If yes, please write so, since both interventions types can be referred to as sessions.

“...although participants receiving the resilience 373 intervention rated it as more helpful” – please add statistics on this in the results part

Why is not emergency workers group included as a variable in the analysis? Can authors check are there maybe some effects in some of the groups (police, ambulance, fire, and search and rescue services personnel)

It should be explicitly mentioned what is used as a dependent variable in mixed models. It seems to me that authors performed series of analysis in which each score on follow up was predicted by the same score on the baseline (covariate) and other factors. This should be mentioned explicitly.

If my assumption is true, then it is hard to expect to get any other significant effects besides the effect of a covariate – since one measure predicts itself best, and does not leave room for other predictors. I would suggest to authors to use differences of baseline-post measures (gains) as dependent variables instead, and to test the effects of factors on those gains. If not instead, then authors should add it as another approach to data analyzing.

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Reviewer #2: Yes: Oliver Toskovic

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18 Sep 2020

Dear Professor Matsuoka

Re: Evaluating the effectiveness of a group-based resilience intervention versus psychoeducation for emergency responders in England: A randomised controlled trial

Thank you for reviewing the above paper. We are grateful for your careful readings of the paper, and pleased that you and the reviewers found the paper of interest. Your suggestions were extremely helpful. We believe the presentation of the manuscript has been further strengthened and trust that it is now acceptable for publication.

For clarity, each of the revisions is outlined below. Changes to the manuscript are shown in quotations below.

Journal Requirements:

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>> Thank you for bringing this to our attention. We have now ensured all parts of the manuscript meet PLOS ONE’s style requirements, including those for file naming.

2. We note that you have stated that you will provide repository information for your data at acceptance. Should your manuscript be accepted for publication, we will hold it until you provide the relevant accession numbers or DOIs necessary to access your data. If you wish to make changes to your Data Availability statement, please describe these changes in your cover letter and we will update your Data Availability statement to reflect the information you provide.

>> We have readied our database for sharing and are awaiting the accession numbers.

3. Thank you for submitting your clinical trial to PLOS ONE and for providing the name of the registry and the registration number. The information in the registry entry suggests that your trial was registered after patient recruitment began. PLOS ONE strongly encourages authors to register all trials before recruiting the first participant in a study.

As per the journal’s editorial policy, please include in the Methods section of your paper:

1) your reasons for your delay in registering this study (after enrolment of participants started);

>>The reason for the delay in registering the trial was one of time constraints and has not been repeated with subsequent and related trials. The practicalities of conducting the trial of N=430 emergency responders, including their follow-up, within 12 months necessitated priority completion of a number of procedures at the outset. This meant that the MSD ethics application, the development of the standard operating procedures for nine sites and steps to initiate recruitment and screen participants took priority in the early phase of the study. The authors confirm that the design of the study was approved by both the funder and the MSD ethics committee and was fixed prior to commencing recruitment and no changes were made to the protocol at any point during the trial. The authors confirm that the trial was registered before follow-up was completed and data analysed. The authors confirm that all ongoing and related trials for this intervention are registered, and have all been registered prospectively.

We have added to lines 124 to 132 on page 6:

“The protocol was approved by the funder and the ethics committee prior to recruitment and no changes were made to the protocol at any point during the trial. The trial was registered retrospectively during participant follow-up. The reason for the delay in registering the trial was one of time constraints associated with the priority completion of a number of procedures at the outset to ensure the trial of N=430 emergency responders, including their follow-up, could be completed within 12 months. The authors confirm that all ongoing and related trials for this intervention are registered, and have all been registered prospectively.”

2) confirmation that all related trials are registered by stating: “The authors confirm that all ongoing and related trials for this drug/intervention are registered”.

>>Thank you for this suggestion. We have added it to line 132.

Please also ensure you report the date at which the ethics committee approved the study as well as the complete date range for patient recruitment and follow-up in the Methods section of your manuscript.

>>The Medical Sciences Division ethics committee approved the study on 1 April, 2015. This has been added to line 121. An amendment was made to revise the Participant Information Sheet to provide more detail and add two new contacts, which was approved on 15 May, 2015.

Additional Editor Comments (if provided):

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The manuscript entitled ‘Evaluating the effectiveness of a group-based resilience intervention versus psychoeducation for emergency responders in England: A randomised controlled trial’ with the aim to evaluate the effectiveness of a tertiary service resilience intervention compared to psychoeducation for improving psychological outcomes among emergency workers.

The manuscript can be further improved based on the following comments.

Comments

Abstract, the sentence ‘ to the interventions on a 3:1 ratio’ incomplete.

>>Thank you for highlighting this. We have updated the sentence on lines 34 to 35 as follows:

“We conducted a multicentre, parallel-group, randomised controlled trial. Minim software was used to randomly allocate police, ambulance, fire, and search and rescue services personnel, who were not suffering from depression or post-traumatic stress disorder, to Mind’s group intervention or to online psychoeducation on a 3:1 basis.”

Methods

The mode of administration of all the questionnaires/inventories to be clearly stated. E.g. self-administered or filled up by interviewer/assessor.

>>Thank you for raising this. We have added to lines 193:

“All outcome measures were self-reported assessments.”

Page 11 Line 234 the sentence ‘effect size f=0.17) between two groups (three measurement points: pre-intervention, post-intervention, and follow-up) not clear and more information to be added.

>>Thank you for raising the need for further clarification on this. We have amended this section to provide a simpler and clearer description of the sample size calculation. Line 275 to 279 now reads:

“A sample size calculation was performed for a superiority trial with continuous outcome. Using an alpha of 0.05, 90% power, a standard deviation for the CD-RISC of 14, and a group difference of 5 points (which equates to d = 0.34 from the previous study), would require a total of 330 participants. Allowing for 20% attrition, a total sample size of N = 398 would be required, suggesting that the target sample size was large enough to detect an effect.”

Line 167, for the ‘baseline, Intervention and 3 months’ the period for the intervention to be stated. In some part, post intervention was used. This needs to be standardized. Also could explore the use of symbol T0, T1, T2 to denote the period.

>>We have reviewed the manuscript and made changes to ensure the timepoints are referred to consistently throughout (baseline, post-intervention, and follow-up).

Statistical analyses

Page 12 Line 259, Linear mixed effect models to be written as Linear Mixed-Effects Models.

>>We have updated the text accordingly.

All statistical tests highlighted in the results section to be stated in the statistical analyses section in the methodology.

>>Thank you for highlighting this. We have now added details of the analysis of sessions/modules completed, ratings of perceived helpfulness, and facilitators’ adherence to protocol, into the ‘Statistical Methods’ section on page 12 lines 314 to 316.

Page 12 Line 271, 272, 276, what group differences to be stated.

>>Line 276 (now Line 333) refers to between-group effect sizes, estimating the size of any differences between the two intervention groups. Line 271/272 (now Line 326 to 327) just confirms that the models allowed for variation between individual participants – it does not refer to group differences.

The level of accepted significance to be stated.

>>This is now included in line 346:

“All analyses used the intention to treat sample and a significance level of 0.05.”

Results

Table 2, for ethnicity White British/European, percentage figures were missing. The highest qualification for resilience intervention has a total percentage 100.2 (if can't be avoided is fine). Total marital status does not tally 100% (the percentage for 87 is incorrect (should be 20.2%). Decimal point to be standardized for all percentage figures. Likewise for the percentage figures in the text.

>>Thank you for bringing this to our attention. We have now corrected the figures for ethnicity, qualifications and marital status. We have also standardised the percentage figures to two decimal points for the figure, all tables and throughout the text.

Information on the dropout rates in % at various point of assessment to be provided.

>> We have added information on the percentage of data completion at each timepoint to the notes section of Table 3. In addition, the study flowchart has also been updated to clarify rates of dropout/retention.

Table 4, for the data under adjusted difference, denote clearly what data in the Post and FU refers to.

>>The heading has been changed to ‘Adjusted group difference’ to highlight that these columns represent the difference between the two groups.

Table 5, some of the SDs are larger than mean. Please check if median ± IQR to be used.

>>It is correct that some of the SD values in this table (for the PCL-5, PHQ-9, and GAD-7) are greater than the mean. Following your suggestion, we have added the median and IQR values in these cases.

Table 6, figures or parameter indicator to be centralized. R square to be added into discussion to support Page 21 Line 363.

>>We have amended the formatting as suggested. The R square values are now highlighted within the discussion section on line 472.

“The results (see Table 6, Supplementary Material) showed that none of the overall models were significant, with low R2 values, indicating there was no evidence within this sample that neuroticism predicted the extent of change in wellbeing, resilience, self-efficacy, or social capital associated with the intervention.”

The analysis was based on intent to treat. Were the results any different to per protocol analysis?

>>The results were not any different for the per protocol analysis. The ITT analyses are presented as they are more conservative.

References did not conform to the journal format.

>>Thank you for bringing this to our attention. We had formatted the References in Vancouver style and have made corrections to individual references which did not quite conform to this style.

Reviewer #2: Paper description:

Authors performed a methodologically well balanced study in which they compared effects of two resilience intervention types, aimed for emergency workers: resilience Intervention and psychoeducation. Study is performed on 430 participants, and several primary and secondary outcome measures. Results did not reveal any significant difference between the two intervention types. Also, both interventions showed weak or no effects on primary and secondary outcome measures. Study is well designed and data analysis are well performed.

General comments:

Main shortcoming of this paper is not enough elaborated hypothesis that resilience intervention would be more effective than psychoeducation. Especially having in mind that study did not reveal any significant differences authors must explain in more details why is important to look for such differences. This paper is confirming null hypothesis, and therefore we must have really good argumentation for doing this research. – don’t need good argumentation once results are null; why it is important to look at resilience

>>Thank you for raising this point. We review the literature on resilience interventions on p4 and their potential promise for improving resilience to stress. We have now added the following on lines 105 to 108 on p5 and refer to 2 studies, including 1 RCT, which found no effect for psychoeducation in terms of reducing psychological symptoms or distress or in improving help-seeking behaviour among emergency workers and military personnel. This research forms the rationale for the hypothesis.

“Overall, randomised controlled trials have found no effect of psychoeducation for reducing psychological symptoms [24] or distress in military personnel [25]. We therefore hypothesised that the resilience intervention would be more effective than psychoeducation in improving resilience, wellbeing, self-efficacy, and social capital, as well as in improving emergency workers’ confidence to manage their mental health and reduce days off work due to illness. We hypothesised that neuroticism would predict the degree of change participants would experience in wellbeing, resilience, self-efficacy and social capital. Another shortcoming is due to sample and analysis. Authors should explain why they used 3:1 ratio for compared groups.”

>>Thank you for raising this point. It is common for studies in this field to use weighted randomisation. We chose weighted randomisation so as to provide a greater incentive for emergency responders to take part. Since the study was adequately powered, we expected to see an effect should there be one.

In the analysis part, it seems like it is not explicitly mentioned what is used as a dependent variable in mixed models. It seems like authors performed series of analysis in which each score on follow up was predicted by the same score on the baseline (covariate) and other factors. If my assumption is true, then it is hard to expect to get any other significant effects besides the effect of a covariate – since one measure predicts itself best, and does not leave room for other predictors. I would suggest to authors to use differences of baseline-post measures (gains) as dependent variables instead, and to test the effects of factors on those gains. If not instead, then authors should add it as another approach to data analyzing.

>>Thank you, we have added a sentence in the Statistical Methods section to clarify the specification of the dependent variable (Line 327):

“Scores on the primary or secondary outcome measure being evaluated were used as the dependent variable.”

You raise an interesting point about the different options that might be considered for the dependent variable. The choice made here was based on guidance from a trial statistician, who advised that using follow-up scores and adjusting for baseline scores is preferable to using a change score as the dependent variable when analysing RCTs. This is largely because this method is better at accounting for chance baseline imbalances between the arms of the trial. We would note that this method does seem to be the current prevailing approach for the analysis of RCT data, and that the results of these suggest it remains possible to observe significant group differences even in the presence of baseline score as a covariate.

Detailed comments:

Abstract: on a 3:1 ratio – please add that it refers to group-based resilience intervention and psychoeducation

>> Thank you, this has been corrected.

“We hypothesised that the resilience intervention would be more effective than psychoeducation in improving resilience, wellbeing” – on what bases is this assumed? Why should we expect this? This must be explained and argumented in more details, especially having in mind that result confirmed null hypothesis.

>> Thank you, we have included the following rationale on page 5 lines 100-106.

“Overall, randomised controlled trials have found no effect of psychoeducation for reducing psychological symptoms [24] or distress in military personnel [25]. We therefore hypothesised that the resilience intervention would be more effective than psychoeducation in improving resilience, wellbeing, self-efficacy, and social capital, as well as in improving emergency workers’ confidence to manage their mental health and reduce days off work due to illness. We hypothesised that neuroticism would predict the degree of change participants would experience in wellbeing, resilience, self-efficacy and social capital. Another shortcoming is due to sample and analysis. Authors should explain why they used 3:1 ratio for compared groups.”

“...risk of social isolation (Robinson et al., 2014)” – why is this reference in a different formatting?

>> Thank you for spotting this error. We have now corrected this.

Did the whole group 314 people attend the session at the same time? Is it too big?

Is it checked if homework exercises were done regularly and how long?

>> The resilience intervention was delivered 31 times in four phases from May to December 2015. The mean number of participants per group in the resilience intervention was N=9. We have added this to p12 lines 306-309.

“Psychoeducation about stress and mental health delivered online” – why is one intervention performed online? This leaves room for confounding variable, live versus online training. I understand that it is not too important since no effects are found, but it must be elaborated and argumented.

>>The resilience intervention was designed by Mind as a group intervention and had previously been delivered as such to new mothers and men at risk of social isolation. Online psychoeducation offered a feasible comparison to the resilience intervention, which was attractive to emergency responders since it avoided the scheduling constraints of in-person group sessions. We were also keen to evaluate any potential effects of online psychoeducation, which can be delivered and accessed more easily than group sessions.

We appreciate that live training might be considered more engaging and that the modes of intervention delivery differ. We have discussed this as a limitation in the Discussion on p23, lines 530 to 531:

Third, the interventions differed in their mode of delivery, which may have advantaged one over the other. However, since no effects were found, this is unlikely.

Is it checked and how, if participants really attended online psychoeducation?

>> We checked completion rates for each module. The software with which the online psychoeducation was delivered records when a participant has completed the module. We report this on page 16, line 410:

Participants receiving psychoeducation completed a mean number of 4.71 (SD=2.01) topics.

“A one-item 180 questionnaire” – I would suggest to call it one-item measure, since questionnaire usually assumes more items

>> Thank you for bringing this to our attention. We have now corrected this. Please see line 208.

Why 3:1 ratio for intervention groups? Why not 1:1? This must be explained and argumented

>>Thank you for raising this point. It is standard in this field to use weighted randomisation. We chose weighted randomisation so as to provide a greater incentive for emergency responders to take part. Since the study was adequately powered, should there be an effect, we would have been able to detect one.

“Residualised gain scores were used as the dependent variable in each analysis...” – what are they residualised from? What where the variables used to separate residuals? Why residuals? Why not just gains?

>>The Residualised gain scores are the residuals of a linear regression to predict Post-intervention scores from baseline scores. They represent the difference between a participant’s Observed score at Post, and the score predicted by the overall Baseline-Post relationship. These values therefore capture the participant’s extent of change over time, scaled in relation to the ‘average’ change. The main advantage of this approach is that it avoids using the raw baseline scores in the final variable – these can introduce bias in that participants with more severe baseline scores are more likely to show greater gains due to regression to the mean.

We have added a definition in the Statistical Methods section (page 13, lines 341 to 343) to clarify this:

“Residualised gain scores (which represent participants’ observed change in relation to that predicted from the overall Baseline-Post relationship) were used as the dependent variable in each analysis…”

“Time (post-intervention, and three-month follow-up), treatment condition (resilience intervention or online psychoeducation [active control]), and the time by-condition interaction were entered as categorical fixed factors along” – but it does not seem so form the results, a separate analyses are shown for two time points, it does not seem it was added as a factor

>>As Time is treated categorically in these models, estimates are generated for the group difference at each time point separately. The Time*Condition interaction is therefore not estimated explicitly (as in ANCOVA), but we can confirm that it was included within the models, and that the estimates for the two time points come from a single model (i.e. they are not separate analyses).

“The resilience and 296 psychoeducation interventions were delivered 31 times in four phases from May to December 297 2015. Follow-up began in July 2015 and continued until March 2016.” –Why is this in the results section, why not in procedure part?

>> Thank you for spotting this. We have now moved this to the Procedure on p12 lines 306-309.

Table 2, for White British/European percentage numbers are missing in brackets. Also in some places a sign % is written on others is missing

>> Thank you for spotting this. We have now corrected this table.

“Significantly greater than the number of sessions attended...” – do authors by “sessions” refer to group-based resilience intervention? If yes, please write so, since both interventions types can be referred to as sessions.

>> Thank you for spotting this. We have now corrected this in the manuscript on p16, line 410.

“...although participants receiving the resilience 373 intervention rated it as more helpful” –

>> Thank you- the results of these ratings are presented on p16. We have also added the following to the Methods on page 12, lines 313 to 315.

Data on the number of sessions/modules completed and perceived helpfulness were analysed descriptively and using one-way ANOVA. Facilitators’ adherence to the resilience intervention was assessed through independent ratings of session audio recordings.

Why is not emergency workers group included as a variable in the analysis? Can authors check are there maybe some effects in some of the groups (police, ambulance, fire, and search and rescue services personnel)

>>There are no theory-driven hypotheses to suggest that certain subgroups of emergency responders would respond differently to a resilience intervention compared to others. In line with this, sub-group analyses of this type were not planned or registered as part of this study. We therefore did not run subgroup analyses and we would not expect to see differences among them.

It should be explicitly mentioned what is used as a dependent variable in mixed models. It seems to me that authors performed series of analysis in which each score on follow up was predicted by the same score on the baseline (covariate) and other factors. This should be mentioned explicitly.

If my assumption is true, then it is hard to expect to get any other significant effects besides the effect of a covariate – since one measure predicts itself best, and does not leave room for other predictors. I would suggest to authors to use differences of baseline-post measures (gains) as dependent variables instead, and to test the effects of factors on those gains. If not instead, then authors should add it as another approach to data analyzing.

>>Please see our response to this comment in the ‘General Points’ section of your review.

Thank you again for your time and attention. We look forward to hearing from you.

Yours sincerely,

Dr Jennifer Wild & Dr Graham Thew

Submitted filename: Response to Reviewers.docx

Click here for additional data file.

9 Oct 2020

PONE-D-20-05224R1

Evaluating the effectiveness of a group-based resilience intervention versus psychoeducation for emergency responders in England: A randomised controlled trial

PLOS ONE

Dear Dr. Wild,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

I kindly ask the authors to address the points by reviewer. I am waiting for your revision.

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Reviewer #1: (No Response)

Reviewer #2: I would point out that authors made significant improvements in the paper. Now it is much clearer what are analyses referring too and how they can be interpreted, at least to me. However I still have few minor concerns:

1. “The Time*Condition interaction is therefore not estimated explicitly (as in ANCOVA)...” – I would suggest that authors mention this somewhere in the text or so. Maybe I was not reading carefully but since it confused me, I believe it will confuse many readers of the paper.

2. I think it would be useful to mention somewhere in analysis part or maybe in the results part, that effect size measures in some sense represent the other approach to group difference testing. The first one is by Linear Mixed-Effects Models, and the other one (more similar to classical ones) is effect sizes approach (targeting mean differences instead of residuals). I strongly believe that this would help in clarity of the text for many readers.

3. I would suggest showing results for the secondary measures, too, at least in the appendix. It would be easier to see, track and so on. For instance, primary measures effect sizes are shown in table, but vaguely commented, while secondary measures differences are commented in more details, and no table is shown in the text. I think that adding it at least in appendix would make it a bit clearer, since readers might see the data text is referring too.

4. Authors write “...receiving psychoeducation completed a mean number of 328 4.71 (SD=2.01) modules, which was significantly greater than the number of sessions 329 attended (F(1,429)=7.21, p=0.008)”, but it confuse me, since I do not understand how can a number of completed be greater than the number of attended sessions? Maybe I misunderstood it, but I believe that other readers can misunderstand it too, so at least it requires come kind of explanation.

I would like to thank to authors for considering my reviews and changing their their text in accordance to comments.

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14 Oct 2020

Dear Professor Matsuoka

Re: Evaluating the effectiveness of a group-based resilience intervention versus psychoeducation for emergency responders in England: A randomised controlled trial

Thank you for reviewing the above paper. We are grateful for you and the reviewers’ careful readings of the paper. We have now incorporated the helpful suggestions of Reviewer 2. We believe the presentation of the manuscript has been further strengthened and trust that it is now acceptable for publication.

For clarity, each of the revisions is outlined below. Changes to the manuscript are shown in quotations below.

Review Comments to the Author

Reviewer #2: I would point out that authors made significant improvements in the paper. Now it is much clearer what are analyses referring too and how they can be interpreted, at least to me. However I still have few minor concerns:

1. “The Time*Condition interaction is therefore not estimated explicitly (as in ANCOVA)...” – I would suggest that authors mention this somewhere in the text or so. Maybe I was not reading carefully but since it confused me, I believe it will confuse many readers of the paper.

Thank you for this suggestion. We have added the below sentence into the Method in order to clarify that the Time*Condition interaction enables the calculation of the treatment effect at each timepoint. We hope that this makes it clearer for readers that the treatment effect at each timepoint is therefore the main outcome of interest.

“The time-by-condition interaction was also entered as a fixed effect in order to allow the estimation of the treatment effect at each timepoint.”

2. I think it would be useful to mention somewhere in analysis part or maybe in the results part, that effect size measures in some sense represent the other approach to group difference testing. The first one is by Linear Mixed-Effects Models, and the other one (more similar to classical ones) is effect sizes approach (targeting mean differences instead of residuals). I strongly believe that this would help in clarity of the text for many readers.

We have amended the below sentence from the Method to incorporate your suggestion, and provide a clearer rationale for the additional use of Effect sizes.

“Between-group effect sizes (dCohen), based on a mean differences approach, were then calculated from the results of these models in order to assist with interpretation of the findings.”

3. I would suggest showing results for the secondary measures, too, at least in the appendix. It would be easier to see, track and so on. For instance, primary measures effect sizes are shown in table, but vaguely commented, while secondary measures differences are commented in more details, and no table is shown in the text. I think that adding it at least in appendix would make it a bit clearer, since readers might see the data text is referring too.

>>Thank you for this suggestion. All secondary outcomes are shown in Tables 5 and 6 in the Supporting Information files. These were submitted in the previous revision and can be found on the page of the submission that says “Click here to download Supporting Information S2 Secondary Outcome Table 5” and “Click here to download Supporting Information S2 Secondary Outcome Table 6.”

4. Authors write “...receiving psychoeducation completed a mean number of 328 4.71 (SD=2.01) modules, which was significantly greater than the number of sessions 329 attended (F(1,429)=7.21, p=0.008)”, but it confuse me, since I do not understand how can a number of completed be greater than the number of attended sessions? Maybe I misunderstood it, but I believe that other readers can misunderstand it too, so at least it requires come kind of explanation.

>>We agree it would be helpful to clarify this further in the text. The modules formed the psychoeducation condition and group sessions formed the resilience intervention. We have clarified this point on lines 326 to 329:

Participants receiving the resilience intervention completed a mean number of 4.11 group sessions (SD=2.02) whilst those receiving the psychoeducation intervention completed a mean number of 4.71 (SD=2.01) modules. Participants receiving psychoeducation completed more modules than sessions attended by participants in the resilience intervention (F(1,429)=7.21, p=0.008).

Thank you again for your time and attention. We look forward to hearing from you.

Yours sincerely,

Dr Jennifer Wild & Dr Graham Thew

Submitted filename: Response to Reviewers.docx

Click here for additional data file.

20 Oct 2020

Evaluating the effectiveness of a group-based resilience intervention versus psychoeducation for emergency responders in England: A randomised controlled trial

PONE-D-20-05224R2

Dear Dr. Wild,

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Yutaka J. Matsuoka, MD, PhD

Academic Editor

PLOS ONE

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26 Oct 2020

PONE-D-20-05224R2

Evaluating the effectiveness of a group-based resilience intervention versus psychoeducation for emergency responders in England: A randomised controlled trial

Dear Dr. Wild:

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