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Prehospital Emergency Care
ISSN: 1090-3127 (Print) 1545-0066 (Online) Journal homepage: www.tandfonline.com/journals/ipec20
The Psychological Impact of Attending Out- of-Hospital Cardiac Arrest in Volunteer Lay Responders: A Mixed-Methods Systematic Review
Paul du Toit, Karan Botsford & Joe Copson
To cite this article: Paul du Toit, Karan Botsford & Joe Copson (06 Mar 2026): The Psychological Impact of Attending Out-of-Hospital Cardiac Arrest in Volunteer Lay Responders: A Mixed-Methods Systematic Review, Prehospital Emergency Care, DOI: 10.1080/10903127.2026.2640607
To link to this article: https://doi.org/10.1080/10903127.2026.2640607
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TITLE PAGE
The Psychological Impact of Attending Out-of-Hospital Cardiac Arrest in Volunteer Lay Responders: A Mixed-Methods Systematic Review
Authors: Paul du Toit;1 Karan Botsford;2 Joe Copson;3
Author Affiliations:
1School of Health Sciences, University of East Anglia, Edith Cavell Building, Norwich, NR4
7TJ, United Kingdom; p.dutoit@uea.ac.uk ORCiD ID 0009-0003-6417-6603
2School of Health Sciences, University of East Anglia, Edith Cavell Building, Norwich, NR4 7TJ, United Kingdom; k.botsford@uea.ac.uk ORCiD ID 0009-0005-3902-3116
3School of Health Sciences, University of East Anglia, Edith Cavell Building, Norwich, NR4 7TJ, United Kingdom; j.copson@uea.ac.uk ORCiD ID 0000-0003-1650-0950
Corresponding Author: Paul du Toit, 1School of Health Sciences, University of East Anglia, Edith Cavell Building, Norwich, NR4 7TJ, United Kingdom; p.dutoit@uea.ac.uk , +44 (0)1603 597001
ABSTRACT
The Psychological Impact of Attending Out-of-Hospital Cardiac Arrest in Volunteer Lay Responders: A Mixed-Methods Systematic Review
OBJECTIVES: To explore and describe the incidence of psychological impact, including post-traumatic stress-type symptoms, in volunteer lay responders following involvement with out-of-hospital cardiac arrest, and to identify factors influencing these outcomes.
METHODS: A convergent integrated mixed-methods systematic review was conducted (PROSPERO registration: CRD42023467307). APA PsycInfo, CINAHL (EBSCO), PubMed (Medline), and Web of Science were searched for studies published between January 2003 and October 2025. The Joanna Briggs Institute methodological approach guided study selection, quality appraisal, data extraction, and synthesis.
RESULTS: Twelve studies involving 80,742 participants from seven countries were included.
Five key areas were identified: risk and prevalence of psychological impact; lay responder characteristics; situational dynamics; social connectedness and a sense of community; and
emotions experienced while awaiting activation. Most studies reported low levels of severe psychological impact and individual characteristics, situational factors, and community support influenced psychological outcomes.
CONCLUSIONS: Severe psychological effects following out-of-hospital cardiac arrest were uncommon, but lay responders may experience mild-to-moderate distress influenced by demographics, situational exposure, and social support. This review highlights modifiable factors - targeted training, clear role expectations, and structured post-event support - that can mitigate psychological burden. Strengthening these areas is critical for protecting lay responders, enhancing the resilience of volunteer programs, and sustaining the Chain of Survival.
Word Count: 206
Keywords: Cardiopulmonary Resuscitation, Heart Arrest, Helping Behavior, Psychological Trauma, Volunteers
MAIN DOCUMENT
The Psychological Impact of Attending Out-of-Hospital Cardiac Arrest in Volunteer
Lay Responders: A Mixed-Methods Systematic Review
INTRODUCTION
Out-of-hospital cardiac arrest (OHCA) is a major cause of worldwide mortality and survival to hospital discharge is low (1–3). However, when bystander cardiopulmonary resuscitation (CPR) is performed during cardiac-origin arrest, and the cardiac rhythm is shockable by defibrillation, the likelihood of achieving a return of spontaneous circulation rises significantly to 54% (1). The critical role of immediate intervention from bystanders in improving OHCA outcomes is highlighted by the Chain of Survival, a concept outlining a series of steps to optimize cardiac arrest survival (4).

A lay responder (LR) is a trained volunteer within the community, who responds to medical emergencies prior to emergency medical service (EMS) arrival (5). Lay responders support the Chain of Survival by enabling earlier basic life support and automated external defibrillator (AED). Globally, initiatives focusing on intervention ahead of EMS arrival have increased due to health care system changes and the availability of resources (6). The number of volunteer responder schemes using LRs in OHCA has increased across the United Kingdom, Europe, and North America (7–9) with participation in programs largely
driven by intrinsic motivation and a strong sense of social responsibility (10).
However, attending out-of-hospital emergencies can be psychologically challenging, with reported rates of post-traumatic stress disorder (PTSD) within EMS personnel up to ten
times higher than in the general population (11). Development of PTSD is associated with poor quality of life and is a risk factor for developing chronic health conditions. Anyone witnessing a traumatic event can develop PTSD and symptoms can occur immediately or, in some cases, have a delayed onset (12). In-hospital and OHCA resuscitations have been associated with psychological effects among medical (13) and nursing professionals (14), first aid providers (15), and witnesses to cardiac arrest (16).

Less is known about the psychological toll to volunteer LRs, who occupy a distinct space between the bystander and health care professional (HCP); they are dispatched with professional expectations but operate with varying resources, training, and support, placing them at unique risk of psychological impact. The American Heart Association highlight this threat and advise further research to address gaps in understanding (7). Lay responder psychological injury may decrease their motivation, willingness to continue, and weaken the early links in the Chain of Survival.

This review aims to explore the psychological impact on LRs following response to OHCA. The primary objective is to describe the incidence of these impacts, while a secondary objective is to identify contributory and protective factors influencing the LR’s psychological response. These findings have direct relevance for HCPs, policymakers, and volunteer program leaders seeking to optimize responder well-being, volunteer retention, and system resilience. Therefore, this systematic review sought to answer the following research
question: What is the incidence of psychological impact among volunteer LRs following

METHODS

Study Design

response to OHCA, and what factors influence these outcomes?
This systematic review was conducted in accordance with the Joanna Briggs Institute (JBI) mixed-methods systematic review guidance (17) and is reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (18) (Supplemental File Material 1). A prospective study protocol was published on PROSPERO systematic review registry (CRD42023467307).

Eligibility Criteria
Following JBI guidance for mixed-methods systematic reviews (17), the eligibility criteria were defined using the Population, Phenomenon of Interest, and Context (PICo) framework. The Population (P) comprised organized volunteer LRs who were not employed by health
care or emergency services. The Phenomenon of Interest (I) was the psychological impact of responding to OHCA, including distress, stress reactions, post-traumatic stress symptoms, and factors influencing these outcomes. The Context (Co) included OHCA events occurring in community, residential, or public settings.
Search Strategy
The APA PsycInfo, CINAHL (EBSCO), PubMed (Medline), and Web of Science were searched using a combination of keywords for “lay responder,” “cardiopulmonary resuscitation,” and “psychological impact.” These terms were combined with synonyms using Boolean operators and subject headings, while truncation expanded key phrases. An example full search matrix is provided in Supplemental File Material 2.
Peer-reviewed articles, using quantitative, qualitative, or mixed-methods, published in English between 01/01/2003 and 10/10/2023, were eligible. The date range reflects the global increase in LR schemes and related research over the last 20 years (6). We conducted a subsequent search of all databases, from 10/10/2023 up to the final search conclusion date of 17/10/2025, to capture studies published or indexed following the initial search end date. The reference list and citations of all eligible papers were screened for further potential studies.
Inclusion/ Exclusion Criteria
Studies were included if they examined the psychological impact or wellbeing of LRs following exposure to OHCA (Table 1). To ensure the population aligned with the review’s focus, studies were excluded if they examined professional responders (e.g., paramedics, British Association for Immediate Care members), who often have greater exposure to
cardiac arrest training and debriefing systems (19) or bystanders who were not part of an organized LR program. Attempts were made to verify participant status with study authors where necessary. Only studies reporting outcomes related to psychological experiences, prevalence, risk, or contributing/protective factors were included.
Study Selection
Two reviewers independently screened article title and abstract, retrieved full texts of potentially eligible papers, and conducted a full-text review. Discrepancies were resolved by
consensus discussion with a third reviewer. Twelve articles met the inclusion criteria (Figure
1).
Methodological Quality Assessment
Two reviewers independently appraised study quality using the JBI risk of bias tools appropriate for each study design (20). Given the heterogeneity of study designs and the review’s aim to synthesize evidence on the prevalence, nature, and contributing factors of psychological impact among LRs, no studies were excluded based on methodological quality. Quality assessments informed data synthesis and interpretation.

Two reviewers independently extracted data using a standardized JBI data extraction form for mixed-methods systematic reviews (17). Extracted data included the methodological approach, sample (including characteristics), aims and phenomena of interest, setting and contextual information, outcomes or findings, and conclusions. These reviewers, who compared the extracted data, discussed and resolved any discrepancies through consensus. Where agreement could not be reached, a third reviewer adjudicated.

Data Transformation, Synthesis, and Integration
To facilitate the synthesis of studies with varying methodologies, a convergent integrated approach, as recommended by the JBI, was undertaken (17). This approach was deemed appropriate as the review’s objectives could be addressed by either qualitative or quantitative data (21). Quantitative data were transformed into qualitative data, through
textual description of reported findings (22). This process is less error-prone than quantifying
qualitative data (21).
Narrative interpretation of quantitative data allowed for the integration of qualitative and quantitative data. Statements of findings that related to the research objectives were generated from each study (23,24) and were analyzed through an iterative process, to identify similarities in meaning between statements and to produce categories (17), which were subsequently organized into synthesis domains. Three researchers independently reviewed all extracted statements. We compared our interpretations, discussed differences, and reached consensus on the placement of statements within synthesis domains. This ensured that the classification of findings was consistent and accurately reflected the overall patterns in the data. Disagreements were resolved through discussion; no consultation with additional external researchers was required. An example of the quantitative-to-qualitative data transformation process is provided in Supplemental File Material 3. This structured process enabled integration of findings across studies, producing a unified synthesis that directly addresses the research objectives.
RESULTS
Description of Studies

Overall, 1020 studies were initially screened for eligibility. Of these, 38 reports were retrieved for full text review. Thirteen studies were excluded, primarily for failing to meet the population criteria by describing EMS or first-aider cohorts. Other reasons for exclusion included not meeting study type, exposure, and outcome. Twelve studies met the inclusion criteria (25– 36). A summary of the included studies outlining their characteristics and key findings is presented in Table 2. The included studies, completed between 2008 and 2023 were conducted across seven countries. Five studies were undertaken in Denmark (25,29,32,33,35), three in Sweden (27,31,34) and one study each in Ireland (26), Wales
(28), Australia and New Zealand (30), and the Netherlands (36).
Nine studies used quantitative methodology (25,27,29,30,32–36) and used various methods: four observational prospective cohort studies (25,27,30,36), two observational retrospective cohort studies (29,33) and three cross-sectional studies (32,34,35). The total quantitative sample population was 80,710. Three studies used qualitative methodologies (26,28,31): one used interpretative phenomenological analysis (28) and two used thematic analysis (26,31). All three collected data using semi-structured interviews. The total qualitative
sample population was 32.

The studies’ methodological quality scores varied. On assessment of the three qualitative studies, the lowest scored 7/10 (28), while the other two scored 10/10 (26,31).
Methodological quality scores for cohort studies were 7/11 (33), 8/11 (25,30), 9/11 (36), and 10/11 (27,29). Notably, participants being free of the outcome at the outset of the study was unclear in all cohort studies. All cross-sectional studies scored 8/8 (32,34,35). Supplemental File Material 4 presents methodological quality results.

Integrated Synthesis Findings
Following convergent integrated synthesis of the included studies (25–36), five domains were identified, representing recurrent patterns across the integrated qualitative and quantitative findings.
Risk and Prevalence of Psychological Impact
Psychological impact to LRs from OHCA activity was a potential risk acknowledged by all studies (25–36). Quantitative studies used a variety of validated, adapted, and unvalidated self-reported rating scales (25,27,29,30,32–36). Acute psychological impact measures were collected post-incident at 90 minutes (25,27,29,32,33), three days (36) and between two and
six-weeks (27,30,35,36). Qualitative studies used in-depth interviews to explore impact
(26,28,31).
Increased post-event emotional responses were observed (25,27,29,32,33) but diminished during follow-up intervals (27). Studies using both self-perceived numerical scales (25,29,32,33) and validated clinical scales (36) recorded severe impact. Incidence of severe impact (at 90 minutes) were 2% or lower (range 1.1-2%) (25,29,32,33), though a rate of 13% (3-days post-incident) was observed using a validated measurement tool (36).
The prevalence of post-traumatic stress symptoms was low at 24-72 hours (32), 2 weeks (30), and 4-6 weeks (30,36); with no observable differences to symptomology between exposed and unexposed groups at 4-6 weeks (27). A sense of burden (34) and feelings of guilt immediately after LR activation (31,34) were described by LRs. Emotional reactions, such as increased alertness (27) and hyperarousal were reported (26), as were decreased pleasantness (27) and symptoms such as existential thinking and nightmares (31). Changes to LR relationships outside of the volunteer program and social avoidance were recorded (26). LR schemes observed minimal rates of volunteer attrition (25,27,32–36).

Lay Responder Characteristics Across the studies, similar ratios of LRs identifying as male and female (25–27,29,32,34) or higher rates of male responders (30,31,35,36) were reported. One study examining sex as a variable noted LRs who identified as female were significantly more likely to report severe impact (32). However, two further studies did not find sex to be significantly associated with increased impact (35,36). Lay responder age was reported in most studies (27–32,34,35). Younger LR age was significantly associated with severe impact (32) but did not reach significance with psychological impact by others (35,36). Experienced LRs outlined the importance of supporting peers with relatively lower experience levels, and a perception that individuals with life experience (related to illness or OHCA) were better able to manage
psychologically (26).
High scores in agreeableness and general self-efficacy (GSE) personality traits were statistically associated with lower psychological impact, while high scores in openness and neuroticism were statistically associated with higher psychological impact (35). Positivity, confidence, focus, emotional detachment when responding, and realistic appraisal of self and situation were recurring factors described for protection against post-traumatic stress

symptom development (28).

The LR's professional background was reported in most studies (25–28,30–32,34–36).
Lower rates of psychological impact in LRs were associated with an EMS or HCP background when compared to those without (31,32,35) but not by all (36). Lay responders with HCP or EMS professional background scored lower self-blame (35), lower burden after alert and higher competence (34) compared to other professions.
Situational Dynamics

Several studies identified that the dynamics of the situation can positively and negatively influence the psychological experience of an LR (26,31,32,36). A primary source of impact was the unpredictable and often unsupported nature of the OHCA scene. This included being first on scene, being alone, and time to EMS arrival. The LR’s perception of the event, for example whether it was perceived as challenging or as a positive event, influenced the psychological experience. Limitations to equipment could cause feelings of helplessness and negativity (36) and a philosophical understanding of the LR role, its scope of practice and
limitations, was viewed as a protective factor by experienced LRs (26).
The level of LR involvement in the OHCA was an important factor. Not connecting an AED (29) and not being actively involved in the resuscitation led to a greater impact (34). Lay responders had a higher psychological impact when attending a true cardiac arrest (32) and reported experiences of negotiating complex moral and ethical dilemmas, such as commencement of CPR, within their practice (26). During the COVID-19 lockdown, when compression-only CPR was advocated, incidence of reported LR stress reduced (29).
The characteristics of the patient influenced psychological impact. Zijlstra et al. (36) observed an increase in mild stress experienced between 4-6 weeks post-OHCA when LRs attended to a patient below the age of 40. Barry et al. (26) reported that LRs being subjected to the heightened emotional responses of bystanders on scene can impact the psychological response experienced, especially if the volatility of the scene made the LR feel unsafe. This was further compounded when arriving before the EMS, with feelings perpetuated by the length of time awaiting support.
Social Connectedness and a Sense of Community

A sense of community, both within the LR group and the local population, was a factor in maintaining their psychological well-being. In three studies, LRs reported that feeling your role is of utility within your local community was a protective factor against psychological distress. It was also a motivating factor for performing the role (28,31,34). A feeling of community within the LR group was important for managing the psychological impacts of the role, with LRs reporting a sense of increased psychological safety and an ability to reach out to scheme members for support (28,31). Conversely, a negative working environment, or evaluating the LR experience as negative, may contribute to psychological distress (26,36).

A relationship with or knowledge of the patient was associated with mild stress (36).
Furthermore, performing their role inside a community member’s home was seen as a potential stressor (31) and that being an LR can have a profound, negative impact on their
social life (26). Some LRs experienced changes in relationships with community members
outside of their role and reported social avoidance.
The working dynamics with EMS staff was a contributing factor to psychological
experiences. Haskins et al. (30) observed that LRs reported benefit from positive interactions (such as debriefing) with EMS personnel. Barry et al. (26) also reported similar feelings and added that negative interactions had the opposite effect.

Emotions Experienced While Awaiting an Activation
A powerful feeling of duty and responsibility profoundly shaped the psychological experience of LRs, with the act of not responding often proving more impactful than actual OHCA participation. Studies observed that when LRs were unable to respond they experienced guilt (26,31,34). Conversely, the importance of a sense of obligation and the pride in
completing an activation felt by LRs was reported by Källestedt et al. (31). The LR’s selfimage and identity are intertwined with their role, and they enjoy being able to execute their duties and satisfy a profound willingness to help. Barry et al. (26) further supported the impact that a feeling of duty has on LR psychological well-being as participants felt a strong community responsibility.
Awaiting activation to respond was reported as psychologically challenging, with individuals potentially suffering from anticipatory stress while maintaining a state of hyperarousal. A subsequent sympathetic arousal following activation to a potential OHCA was reported as a stressful experience for LRs (26). The ability to manage emotions when awaiting a call was a
protective factor, lowering negative impact, and helped maintain task focus and control of the flight or fight response when an activation is received (28).
The findings across all synthesis domains signal that the psychological impact to LRs exposed to OHCA is a complex phenomenon influenced by a multifaceted interplay of
personal characteristics, situational factors, and the social environment.

DISCUSSION
To our knowledge, this represents the first mixed-methods systematic review to synthesize quantitative and qualitative evidence on the psychological impact of OHCA among volunteer LRs. While recent qualitative syntheses have described the phenomenology of LR experiences during CPR (37), and a systematic review has examined psychological and behavioral factors influencing CPR initiation among laypeople (38), integrating prevalence data with experiential accounts provides a more comprehensive understanding of LR wellbeing than has previously been available. Importantly, these findings have direct implications
for the sustainability and effectiveness of volunteer LR systems and, therefore, early CPR and defibrillation.
The complex nature of the OHCA is well recognized (39) with psychological impacts observed in survivors (40), relatives (41), and bystanders (42). The results of this review suggest that, while most LRs demonstrate psychological resilience, a distinct subset is vulnerable to acute distress and post-traumatic stress symptoms following OHCA. A positive finding for both LR and the Chain of Survival was the low incidence of severe psychological impact. Furthermore, LR volunteer schemes observed minimal rates of attrition (25,27,32– 36) suggesting a stable workforce. However, organized LRs occupy a unique experiential space between bystander and HCP; they are dispatched with professional expectations but operate with varying resources, training, and support, which places the LR at a risk of psychological impact unique to them.
Self-Efficacy and Experience Mediators
The psychological impact on LRs is not solely a consequence of OHCA exposure but is mediated by differences in experiential readiness. Younger LR age (32) and limited prior exposure to cardiac arrest (26) were factors associated with greater psychological impact. We conceptualize this as an experience gap in which limited exposure and developmental readiness constrain an LR’s ability to process the complexity of OHCA cognitively and emotionally. The observation that LRs with HCP or EMS experience report comparatively lower psychological impact (31,32,34,35) suggests that resuscitation competence (developed through training and clinical exposure) may provide a protective psychological effect. Prytz et al. (34) specifically observed significantly higher reported rates of competence in LRs with an emergency services background; and supporting this, Ganter et al. (43), in their study of medical professional volunteer responders, report that CPR training
(and therefore resuscitation competence) correlates with reduced psychological distress rates.
General self-efficacy is fundamental to this mediation. As a reflection of an individual’s belief in their ability to perform under pressure (44), GSE plays a pivotal role in regulating emotional states and enhancing resilience (45,46). This was evidenced by the significant correlation between high GSE scores and lower perceived LR stress (35). These findings imply that confidence is vital, as is competence, in reducing the psychological burden. Confidence in one's ability to respond, alongside an understanding of the LR’s specific sphere of influence was seen as protective against stress (28). This requires a shift from outcome-based success (patient survival) to process-based success (quality of LR intervention) and was described as the first responder mindset by Davies et al. (28).
While personality traits such as neuroticism and openness to experience were associated with increased LR stress (35) and have been linked to increased susceptibility to psychopathology in populations (47,48), self-efficacy remains an actionable target for intervention. A lack of confidence has been identified as a key reason why bystanders may not initiate CPR (38) and hands-on training (and time elapsed since training) significantly influence first-aider readiness to undertake resuscitation (49). Lay responder training programs should prioritize confidence-building through repeated, hands-on exposure and realistic scenario-based learning, enabling LRs to develop both technical competence and psychological readiness. Emphasizing process-based success rather than patient survival outcomes may further protect LRs from psychological harm. By strengthening self-efficacy and experiential readiness, LR systems can proactively mitigate distress at an individual level.
Scope of Practice and Operational Distress

Building on individual competence and confidence, system-level clarity around LR scope of practice and resource availability further protects LRs from operational distress. The increased psychological impact reported when LRs were first on scene - facing equipment challenges, such as difficulties connecting an AED (36), and negotiating complex decisions, such as whether to initiate CPR (26) - reveals an operational dilemma. Lay responders have been shown to feel professional responsibility due to their mobilized status yet are hindered as they may operate with limited equipment (50), a basic scope of practice, and training (51).

Prolonged ambulance waiting times, which are a challenging feature for modern EMS systems (52,53), may further exacerbate the LR’s psychological impact while they wait for clinical support. A feeling of helplessness was noted due to practice limitations (36) and implies a failure of expectation management. Lay responders highlighted the importance of being comfortable within their role and understanding the positive impact they have despite a defined scope of practice and limitations (26). To address this, LR training should focus on role realism. This means aligning expectations with their actual scope of practice and resources. Success should be measured by the timely initiation of CPR and defibrillation, rather than the final patient outcome.

Social Context and Community Connectedness
The psychological experience of LRs is strongly shaped by the social and emotional context of the scene; specifically, when responding to younger patients (36), known individuals within the community (26,36) or when faced with heightened bystander reactions (26). These high- emotion incidents could lead to event and post-event questioning as responding to known individuals introduces complexities, such as feelings of embarrassment, heightened grief, or a sense of personal responsibility (54). Phung et al. (55) reported that community first responders questioned whether they could have done more following patient contact with
known individuals. Furthermore, the reception from the community may not always be positive, with some community members feeling uncomfortable about LRs entering their homes (54).
The finding that LRs’ experiences are shaped by their social and relational context aligns with sociological literature linking volunteering, well-being, and social connectedness (56). Social connectedness influences volunteer motivation (57) and studies investigating UK LR experiences have reported similar benefits from scheme participation (55).
The EMS Professional and Lay Responder Relationship
A pivotal finding of this review is that the relationship between LRs and professional EMS personnel contributes to psychological well-being. While many LRs report supportive interactions, the presence of professional hostility or isolation serves as a significant psychological stressor (58). In the wider volunteer literature, such negative interactions are a leading cause of withdrawal from volunteer schemes (59). This suggests that the Chain of Survival is not just a clinical sequence, but a social one.
For the LR to remain resilient, they must be perceived and treated as a legitimate component of the health care team. We recommend that EMS workforce education includes specific training on volunteer integration, ensuring that paramedics understand how their onscene behavior directly impacts the long-term retention and mental health of the volunteer responder (55,60). While informal peer support was beneficial (28), the relationship between LRs and professional EMS personnel is an important determinant of well-being.
Social Connectedness as a Resilience Framework
Finally, our results highlight that social support is an effective shield against psychological harm. We found a clear distinction between informal support (peers and family) and formal support (organizational debriefing). The value of peer support from within the LR group is
crucial (61), as it provides a shared language environment where the unique OHCA experience can be processed without the need for extensive clinical explanation.
We argue that EMS agencies must not leave support to chance. Instead, they should foster collegiate networks between local ambulance crews and LR schemes. Formalizing these structures, moving to a mandated debrief for all, aligns with established best practices in professional EMS well-being (62,63). By helping LRs build an experiential perspective through integrated feedback, organizations can turn a potentially traumatic event into a
manageable professional experience, ensuring the sustainability of the volunteer response

LIMITATIONS

model and the Chain of Survival.
While adhering to established methodological guidelines (17), and integrating qualitative and quantitative data, this review has several limitations. Restricting to English-language studies and not consulting a subject-expert librarian may have led to missed studies. The overall quality and heterogeneity of included studies - across methodology, cohorts, time points, outcome measures, and reporting - limit the direct applicability of the findings. Many studies included mixed cohorts of LRs with and without HCP/EMS backgrounds, making it challenging to isolate the psychological impact for non-professional responders. Selfreported, often unvalidated measures and the lack of baseline data on pre-exposure mental health introduce potential measurement bias. Despite these limitations, this review provides a foundational synthesis highlighting the need for standardized research in this area.
RECOMMENDATIONS

While findings should be interpreted cautiously, this review provides a foundation for further research into the psychological experiences of LRs. Longitudinal mixed-methods research could explore the effects of time, exposure, and experience, while qualitative research may clarify the complexity of LRs’ lived experiences, particularly in their interactions with EMS staff, peers, and communities. Future quantitative studies should adopt uniform outcome measures, and research on specific psychological conditions must align with established diagnostic guidelines (64). Studies aligned to a particular psychological condition, such as
PTSD, should foreground methodological alignment with established guidelines and diagnostic criteria. Results from the HeartRunner Trial (NCT03835403) (65), an ongoing
randomized controlled trial into volunteer responder physical and psychological impact
following OHCA response, may provide further insight.
To minimize psychological impact, organizations should view the Chain of Survival as a socio-technical system reliant on responder readiness. LRs’ success depends not only on clinical skills (early cardiac arrest recognition, CPR, and defibrillation) but also on confidence, support, and social integration.
Training should prioritize psychological well-being, confidence, and competence through resilience priming and role realism. Volunteer monitoring should identify at-risk individuals based on age, experience, and situational factors – such as activations involving younger patients or community members. Occupational health support and psychological assessment must be accessible. Fostering self-efficacy, peer networks, and strong relationships with EMS personnel enhances resilience.
Structured debriefing sessions, as recommended by the American Heart Association (66) and the Resuscitation Council UK (67), is essential. Our recommendations align with calls to develop standardized first responder support structures (68). A collective effort to support
LR’s well-being will not only protect individual safety but ensure their continued and valuable contribution to responder programs.
CONCLUSIONS
Severe psychological impact and post-traumatic stress symptoms are uncommon among LRs to OHCA, though exposure can result in mild-to-moderate stress, anxiety, and feelings of guilt. Psychological well-being is influenced by individual factors, situational dynamics, social connectedness, and available resources. Supporting LRs through hands-on training, realistic role expectations, and strong peer and EMS relationships is essential – not only for their well-being but for sustaining an effective Chain of Survival. Ensuring responders feel competent, confident, and socially integrated strengthens the earliest links of the survival chain and protects both LRs and patient outcomes. This review indicates the need for longitudinal, standardized research, and provides a foundation for optimizing LR program design and support structures.
ACKNOWLEDGEMENTS: None.
FUNDING SOURCES: None.
DECLARATION OF INTEREST STATEMENT: The authors report there are no competing interests to declare.
DECLARATION OF GENERATIVE AI IN SCIENTIFIC WRITING: The authors did not use a generative artificial intelligence (AI) tool or service to assist with preparation or editing of this work. The authors take full responsibility for the content of this publication.

DATA SHARING STATEMENT: The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
AUTHORSHIP STATEMENT: Conceptualization, data curation, formal analysis, investigation, methodology project administration, supervision, validation, visualization, and writing (original draft/ review and editing) was undertaken by all authors.
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TABLE CAPTIONS & FIGURE CAPTIONS
Figure 1: PRISMA 2020 Flow Diagram
Table 1: Inclusion / Exclusion Criteria
Table 2: Summary of Included Studies
Figure 1: PRISMA 2020 Flow Diagram

Table 1: Inclusion / Exclusion Criteria
Inclusion Criteria	Exclusion Criteria	
Reports primary research	Secondary research such as literature reviews
Discussion or opinion articles	
Published in the English language	Non-English language	
Published since 2003	Published prior to 2003	
Peer reviewed publication	Gray/ non-peer reviewed literature	
Participants – LR who were not HCP or emergency services personnel	Studies which only included LRs who are
HCPs, EMS or who respond in a professional capacity (i.e. paramedics working for third- sector organizations)
Bystanders, family members who were not operating on behalf of a responder scheme
Individuals specifically trained to provide first aid within one area, location, or institution	
Assesses, explores, or explains psychological impact following OHCA exposure	Does not assess, explore, or explain psychological impact in LRs
Not related to OHCA response exposure	

Table 2. Summary of Included Studies
Auth or, Year	Country	Aim	Methodolog y and Methods	Sample (n=)	Participan t
Characteri stics	Lay respon der HCP experie nce	Main Findings
(including measurement instruments)	
Andel ius et al.
2020 (25)	Denmar k	Seconda ry aim - investiga te psycholo gical impact among citizen responde rs attendin g OHCA	Quantitative
Prospective observational cohort	6,836
Complet ed psychol ogical question naire - n=1,621	Specific study population characteris tics not stated.
Regional scheme demograph ics reported as:
Age -18 yrs. or over (median 34 yrs.)
Sex - male (50.7%)	Region al citizen respond er occupat ion reporte d as 26% HCP
Specifi c study populat ion not stated	Psychological impact:
•		Selfperceived 5-point scale at 90 minutes
•		Severely affected - n=22 (1.4%) of 1,621
Required professional follow-up - n=3
(0.2%) of 1,621
Wish to continue responding - n= 1,602 (99.0%) of 1,618	

Barry	Ireland	Explore	Qualitative	12	Age -	HCP -	LR activities may	
et al.		reasons			varying	n=2	cause	
2019		for LR	Semi		ages	(16.67	psychological	
(26)		participa	structured		(specific	%)	distress and have	
		tion in	interviews		mean,		a psychosocial	
		OHCA			median, or		impact	
		response	Thematic		range not			
		and the reality of voluntee	analysis		stated)
Sex –		Psychosocial
impact of mpac o
pCaormticmipuantiitnygFiinrst	
		r			equal male			
		participa tion			female
distributio dnistributio		Responder Schemes - subthemes:	
					Self-		• Burden of being	
					selected		on call	
					population		• Difficult	
					– LRs		and	
					experience		distressin	
					d in		g	
					OHCA,		situations	
					working		•	Changed	
					across		relations	
					Ireland’s		hips with	
					rural/		communi	
					urban LR		ty	

					network		•	Volunteer wellbeing and support	
Bergl	Sweden	Investiga	Quantitative	2,386	Age – 18	Non-	Multiple	
und et		te post-			yrs. or	HCP/	psychological	
al.		traumati	Prospective	Exposed	over (mean	Emerge	self-perceived	
2022		c stress	observational	0	41.62 yrs.,	ncy	scales measured	
(27)		reactions	cohort	(Unexpo	SD12.16)	Service	at 90 minutes and	
		and		sed) -		s -	4-6 weeks	
		wellbein		n = 915	Sex - male	n=1,32		
		g after			n= 1,129	7	After confounder	
		LR		Exposed	(47.3%)	(56.9%)	adjustment:	
		attend or		1 (tried			• Increased	
		respond		to reach			Alertness	
		to		victim) -			in	
		OHCA		n= 850			exposed	
							groups (1	
				Exposed			& 2)	
				2			(p<0.001	
				(reached			)	
				victim) -			•	Decrease	
				n=621			d	
							Pleasant	
							ness in	
							exposed	
							group 2	

							(p<0.001 )
•		At 4 –6 weeks - Alertness remained unchange d (all groups) and Pleasant ness increased (all groups)
Secondary outcomes (after confounder adjustment):
•		No significa nt PTSD symptom ology differenc e between	

							all
groups
Continue as LR:
•		Exposed
0 - 98.8%
•		Exposed
1 - 99.5%
•		Exposed
2 - 97.6%	
Davie	Wales	Investiga	Qualitative	6	Age - 23-	Not	Central themes	
s et al.		te			55 yrs.	stated	included:	
2008		protectiv	Semi			(individ	• Motivatin	
(28)		e factors	structured		Sex - not	uals	g Factors	
		for LR	interviews		reported	belongi	• Reward	
		adverse
psycholo	Interpretative		Same local	ng
concurr	Factors
• Essential	
		gical	Phenomenolo		responder	ently in	Requirem	
		reaction develop	gical
Analysis		scheme – specificall	other
volunte	ents for a
First	
		ment			y not	er	Responde	
					members	scheme	r	
					of	s (e.g.	• First	
					additional	St. John	Responde	
					schemes	Ambula	r Mindset	
						nce)	(protectiv	
					Participant	were	e factors	
					s had	exclude	and	

					attended at	d)	emergenc	
					least 25		y state of	
					emergency		mind)’	
					OHCA		• Post-	
					responses		Event	
							Functioni	
					No PTSD		ng	
					symptomol		(coping	
					ogy at		afterward	
					interview		s)	
					stage			
Grege	Denmar	Seconda	Quantitative	6,120	Wider	Not	Psychological	
rs et	k	ry aim -			scheme	stated	impact (self-	
al.		to	Retrospective	Complet	demograph		perceived scale)	
2022		understa	observational	ed			at 90 minutes:	
(29)		nd	cohort	question			No lockdown:	
		increase		naire -	Age -		•	Severely	
		in		n=1,152	median 35		- n=16	
		psycholo			yrs. (IQR		(2%)	
		gical		Complet	19)		• Moderate	
		distress		ed			ly - n=52	
		for LR		psychol	Sex -		(7%)	
		attendan		ogical	During		•	Mildly -	
		ce of		impact	COVID		n=267	
		OHCA		element	lockdown:		(35%)	
		during		of	male -		• Not	
		the		survey -	n=1016		affected -	

		COVID-		n=1,133	(53%); not		n=435	
		19			during		(56%)	
		lockdow			COVID		During COVID	
		n			lockdown:		lockdown:	
					male - n=		•	Severely	
					2140		- n=7	
					(52%)		(2%)	
							• Moderate	
					Characteri		ly - n=16	
					stics of		(4%)	
					participant		•	Mildly -	
					s		n=94	
					completing		(26%)	
					psychologi		• Not	
					cal impact		affected -	
					survey:		n=246	
					Arrived		(68%)	
					before			
					EMS -		Decrease in	
					n=375		affected (56%) vs	
					(33%)		not affected	
					Performed		(68%)	
					CPR -		(p=<0.0001) and	
					n=249		mildly affected	
					(21.9%)		(p=0.0033)	
							during lockdown	

							Change to resuscitation practice – chest compression only CPR – lockdown 79% vs nonlockdown 59% (P=0.0029)	
Haski	Australi	To	Quantitative	1,985	Age -	Non-	PTSD screening	
ns et	a	assess			median 39	HCP or	tool - Beyond	
al.		LR	Prospective		yrs., (IQR	Emerge	Blue - answering	
2021		availabil	observational		29-50)	ncy	the call	
(30)		ity,	cohort			Service		
		intervent			Sex - male	s -	2-week survey	
		ions			- n= 1,177	n=203	(n=1985):	
		provided			(59.3%)	(.	)	•	Positive	
		, and					for PTSD	
		frequenc			Most had		- n=12	
		y of			provided		(0.6%)	
		probable			CPR to a		(*not	
		PTSD			patient		linked to	
		experien			previously		smartpho	
		ced by					ne alert	
		responde					app/	
		rs					respondi	
		receivin					ng work)	
		g a						

		smartph one alert.					6-week survey (n=1443):
•	Positive for PTSD
- n=9
(0.6%)
(one linked to
smartpho ne alert
app/
respondi ng)
High rates of positive EMS interactions reported	
Källes tedt et al.
2022 (31)	Sweden	Describe how LRs perceive OHCA and cope with distressi ng incidents	Qualitative
Interview stu dy
Data driven inductive approach	14	Age - range 3069 yrs.
30-39yrs. - n=3 40-49yrs. - n=5
50-59yrs. - n=4
60-69yrs. -	Non-
HCP/
Emerge ncy Service s - n=8
(57.1%)	Perception of
OHCA identified themes of:
•		Profound Wish to Help
•		Facing the Situation
•		Potential	

					n=2		for	
							Improve	
					Sex - male		ment	
					- n=10			
					(71.4%)			
					OHCA			
					alerts			
					received in			
					total - n=			
					31			
Kragh	Denmar	Evaluate	Quantitative	7,102	Age -	Non-	Psychological	
et al.	k	perceive			median 38	HCP/	impact at 90	
2021		d	Cross-	Complet	yrs.	Emerge	minutes:	
(32)		psycholo	sectional stud	ed		ncy	• No	
		gical	y	psychol	Sex -	Service	impact -	
		impact		ogical	female -	s -	n=3,700	
		to LRs		impact	n= 2,619	n=3,21	(68.6%)	
		followin		survey -	(48.5%)	0	•	Low	
		g OHCA		n=5,395		(59.5%)	impact -	
		response					n=1,334	
							(24.7%)	
							• Moderate	
							impact -	
							n=294	
							(5.5%)	
							•	Severe	

						impact - n=67	
							(1.2%)	
							Reporting severe	
							psychological	
							Impact (n=67):	
							•	HCP - n=16
(23.9%)	
							•	Police/	
							ambulanc	
							e/ firefighte
r - n=1 (1.5%)	
							•	Students	
							- n=19	
							(28.4%)	
							•	Other -	
							n=31	
							(46.3%)	
							This distribution	
							differs from those	
							reporting	
							no impact	

							where:
•		HCP - n=1,274 (34.4%)
•		Police /ambulan
ce /firefight
ers - n=462
(12.5%)
•		Students
- n=426 (11.5%)
Increases severe impact:
•		Respondi ng to true OHCA (vs presumed OHCA) (1.4% vs 1.0%, p=0.001)	

							• Arriving before EMS (2.8% vs 0.7%;
p=<0.001 );	
							(9O5%R:2C.I6,	
							1.54-	
							4.60)	
							•	Performi	
							ng CPR	
							compare	
							d to those	
							who did	
							not	
							(1.0% vs	
							2.7%,	
							p=0.001);	
							(OR:2.6,	
							95% CI	
							1.54-	
							4.60)	
Increased severe

Kragh	Denmar	Follow	Quantitative	62,711	Age - all	Not	Psychological	
et al.	k	up on	Retrospective	(accepte	18 yrs. or	stated –	Impact at 90	
2023 (		LRs who	observational	d alarm)	over	respond	minutes	
		have	cohort	of		er	•	Severe	
		been		177,866		scheme	impact -	
		alerted				open to	n=725	
		to				the	(1.2%) of	
		OHCA				public	which
• Nurs e follo	
							w up	
							-n=53
5
(73.8	
							%)	
							•	Self- referr	
							ed -	
							n=12	
							2	
							(22.8	
							%)	
							•	Furth	
							er	
referr

					al	
							enco	
							urage	
							d -	
							n=3	
							(0.5	
							%)	
							Cancelled	
							registration (to respond) –	
							n=7,317 of	
							177,866 (4.1%)	
Prytz	Sweden	Explore	Quantitative	5,347	Age - all	Not	Community, Self-	
et al.		LR	Cross		1o8veyrrs. or	EMS -	Image, and	
2023		motivati	sectional	Complet		n=	Competence were	
(34)		ons		ed		1,816	strongest	
			Survey	psychol	Age -	(.	)	predictors to	
			analysis	ogical	mean 47.4		continue	
				survey -	yrs.		responding, while	
				n=5,169	(SD=13.1)		Alarm Fatigue	
							and Negative	
							Experience were	
					Sex/		the strongest	
					Gender -		negative	
					male -		predictors	
					n=2,789			
					(54%)		Less Burden	

					Female - n=2,367 (45.8%)
Other gender identity - n=4 (0.08%)
Did not declare gender - n=9 (0.18%)		After Alert and higher
Competence rates in LRs with HCP/ EMS background
Motivation to continue (on a scale of 1 (low motivation) to 7 (high motivation)) - mean score of 6.41 (SD=1.049)	
Ries et al.
2021 (	Denmar k	Investiga te the level of psycholo gical distress (and associate d factors) in LRs followin g	Quantitative
Cross sectional study	290
Complet ed psychol ogical survey - n=102	Age - all 18 yrs. or over Median age - 42 yrs., (3248)
Sex - male - n=68
(66.6%)
Average	Non-
HCP - n=47 (.	)	Psychological impact measured approximately 3 weeks
Mean PSS was 7.61 (SD, 4.81;
scale 0-40)
•	Severe stress (scores
27-40) - n=0 (0%)	

		resuscita
tion			time
between		• Moderate stress (sc	
		attempts			OHCA and		ores 14-	
					survey - 26		26) -	
					days		n=14	
							(13.7%)	
							•	Low	
							stress (sc
ores 0
13) -
n=88	
							(86.3%)	
							No reports of	
							severe stress at 4 weeks following	
							resuscitation	
							attempt	
							Mean PTSD	
							score (Impact of	
							Event – Revised	
							(IES-R)) 0.65 of	
							12
HCP/ EMS	
							background	

							significantly associated with
lower IES-R score and lower self-blame
scores
High general self-efficacy and agreeableness scores were significantly related to low
PSS
High neuroticism scores were associated with high scores on PSS and IES-R
Received professional help following OHCA response - n= 1
(1.0%)	
Zijlstr	Netherla	Investiga	Quantitative	6,572	Age - all	LR -	Perceived short-	

a et	nds	te			18yrs. or	n=109	term	
al.		perceive	Prospective	Complet	over	(58%)	psychological	
2015 (		d short	observational	ed		Off	impact at < 19	
		term	cohort study	Impact	Age –	duty	hours:	
		psycholo		of Event	mean 46	professi	•	Severe	
		gical	Telephone	(IES)	yrs. (SD	onal	impact -	
		impact,	interview	Scale -	12)	rescuer	n=24	
		associate	used to obtain	n=189		- n=80	(12.7%)	
		d	variable/dem		Sex - male	(42%)	•	Bearable	
		factors,	ographic and		- n=124		impact -	
		and	eligibility		(65.6%)		n=87	
		PTSD in	information				(46.0%)	
		LRs					• No/ mild	
		performi					impact -	
		ng CPR					n=78	
		in					(41.3%)	
		OHCA					IES at 28days:	
							•	Mild	
							stress (9-	
							25) -	
							n=36	
							(19.0%)	
							• No stress	
							(0-8) -	
							n=153	
							(81.0%)	

							•		No moderate or severe stress recorded by participa nts
Would resuscitate again - n=186
(98.4%)
Associated with mild stress levels:
•		Relations hip with patient (OR 2.1, 95% CI 1.0–4.3, p = 0.05)
•		Patient age (<40 years) (OR 4.4,	

							95% CI 1.2–16.4, p =
0.03).
•		LR not connectin
g an AED
(9O5%R 3C.8I , 1.3–11.3,
p = 0.02)
•		LR not performi ng CPR previousl y (OR 2.5, 95% CI 1.2– 5.3, p = 0.02)
Independently associated with mild stress:
•		No AED connecte	

							d by LR (OR 4.4, 95% CI 1.4–13.6, p = 0.01)
•		LR who perceived severe shortterm psycholo gical impact (OR 5.8, 95%CI 1.8–18.8, p < 0.01)
•		LR rating their experienc e as not (very) positive (OR 4.7, 95% CI 1.4–15.1, p =	

0.01)