Horizontal Violence or Workplace Bullying Among Intensive Care Unit Nurses: A Mixed Systematic Review

ABSTRACT

Aims

To synthesise literature about horizontal violence or workplace bullying among Intensive Care Unit nurses, exploring its awareness, factors, impacts, and strategies.

Design

Following PRISMA standards, a mixed systematic review using a narrative synthesis approach and thematic analysis design of the Joanna Briggs Institute.

Data Sources

Four electronic databases from 2013 to 2023 studies published were searched.

Results

Eight studies were included: three qualitative and five quantitative. Four key themes emerged: (i) awareness and understanding of horizontal violence or workplace bullying, (ii) factors affecting horizontal violence or workplace bullying, (iii) impacts of horizontal violence or workplace bullying, and (iv) strategies to address horizontal violence or workplace bullying.

Conclusion

Addressing horizontal violence or workplace bullying requires hospitals should adopt conflict resolution policies, stress management programs, and supportive supervision to improve nurse retention. Nurse management should establish confidential reporting mechanisms, provide training on interpersonal respect, and implement supportive structures to promote psychological safety. Intensive care unit nurses are encouraged to take proactive steps to address workplace bullying, ensuring improved staff well‐being and care quality.

Impact

This paper addresses a significant gap in the literature regarding horizontal violence or workplace bullying among Intensive Care Unit nurses.

The findings will impact on healthcare administrators, policymakers, and educators. By understanding horizontal violence or workplace bullying, strategies can be implemented to improve workplace environment, support nurses' well‐being, increase nurse retention, and improve the quality of patient care.

Reporting Method

This systematic review adheres to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. The review methodology, including data selection, extraction, and synthesis, follows PRISMA standards to ensure clarity, transparency, and reproducibility.

Patient or Public Contribution

This study did not include patient or public involvement in its design, conduct, or reporting.

Trial Registration

There is a protocol that does not require registration, it made accessible at: https://doi.org/10.17605/OSF.IO/CFNEJ.

Summary.

• What does this paper contribute to the wider global clinical community?

  • ○
    It synthesises existing research to awareness of the behaviours, explore contributing factors, examine its impacts, and identify strategies for prevention and management.
• What already is known?

  • ○
    Horizontal violence or workplace bullying is particularly prevalent in intensive care unit settings, occurring between nurses or initiated by management. This affects nurses' well‐being, the workplace environment, and patient outcomes.
• What does this paper adds?

  • ○
    This mixed review examines existing evidence on Intensive Care Unit nurses' experiences with horizontal violence or workplace bullying. This study synthesized the awareness, factors, impacts, and strategies about horizontal violence or workplace bullying among Intensive Care Unit nurses. Victim Intensive Care Unit nurses experienced both verbal and non‐verbal abuse. Key findings include the identification of factors contributing to the prevalence of these behaviours, such as high workload, the stress and emotional labour, power dynamics and leadership styles, the hierarchical and professional socialisation create a toxic cycle. And highlights evidence‐based strategies to mitigate these issues.
• Study implications for practice/policy

  • ○
    This review highlights the impact of horizontal violence or workplace bullying on nurses' well‐being, job satisfaction, patient safety, and high turnover rates in Intensive Care Unit setting. It provides vital evidence to actionable insights for healthcare policymakers and managers to create a safer and more supportive ICU work environment.

1. Introduction

Horizontal violence or workplace bullying (HVWB) is a significant global issue in the nursing profession, adversely impacting both nurses and patient outcomes (Varghese et al. 2022; Mohamed et al. 2024). The prevalence of HVWB is particularly high in high‐pressure environments such as intensive care units (ICUs) and other critical care settings, with reported rates of 75% in Iran, 42.7% in Cyprus, and 57.1% in Australia and New Zealand (Aristidou, Mpouzika, and Karanikola 2020; Ruíz‐González et al. 2020; Amini et al. 2023; Parke et al. 2023). Research has showed that ICU nurses face unique challenges, including high workloads, emotional exhaustion, and complex team dynamics, making them particularly vulnerable to bullying behaviours (Ganz et al. 2015; Ruíz‐González et al. 2020; Bry and Wigert 2022). These high‐pressure settings are characterised by intensive human interactions, closely teamwork, rapid decision‐making under stress, exacerbating the likelihood of interpersonal conflicts and bullying incidents (Smith et al. 2020; Shorey and Wong 2021). Unfortunately, these issues are often denied or normalised, perpetuating a culture of silence (Karatuna et al. 2020). Furthermore, World Health Organisation (2024) projected that the global nursing shortage to exceed 9 million by 2030 which further intensifies retention challenges. More and more researchers concerned these issues and to develop effective strategies for ICU nurse retention and well‐being around the world.

1.1. Background

Horizontal violence (HV) in nursing includes behaviours from emotional neglect to physical assault, encompassing incivility, group bullying, and direct violence (Houck and Colbert 2017; Xie et al. 2024). Workplace bullying (WB) defined as frequent exposure to repeated negative behaviours, leaves individuals feeling powerless (Luca et al. 2024). This phenomenon, often described by the phrase “nurses eat their young” (Meissner 1986; Yun et al. 2014). It has become a global concern, affecting caregivers in various healthcare settings (Galanis et al. 2024; Xie et al. 2024).

HVWB can occur in vertical forms, involving interactions between employees at different levels of the organisational hierarchy, such as nurse managers and nurses, or in horizontal forms, involving conflicts or aggressive behaviours among nurses at the same hierarchical level (Mohamed et al. 2024). However, identifying HVWB is challenging due to inconsistent definitions (Bunce et al. 2024). The prevalence of HVHB rates vary widely, with some studies reporting up to 90.4% (Goh et al. 2022) and others estimating 26.3% (Galanis et al. 2024). In 2023, the National Nurses United (NNU) reported 81.6% of its members experienced HVWB (NNU, 2024). In contrast, studies showed that non‐healthcare settings estimate a global prevalence of 15% (Goh et al. 2022), attributed to differing perceptions of workplace violence (Shorey and Wong 2021; Xie et al. 2024).

Common HVWB forms include abuse, rejection, malicious gossip, hostility, silence, and oppression (Shorey and Wong 2021). Contributing factors such as power imbalances and cultural differences contribute to a toxic work environment (Xie et al. 2024).

The consequences of workplace bullying are profound. Victims often experience depression, anxiety, psychological distress, insomnia, and headaches (Nielsen and Einarsen 2012; Houck and Colbert 2017). Professional consequences include decreased well‐being, engagement, and motivation, leading to absenteeism, turnover, and burnout (Trépanier et al. 2015; Bambi et al. 2018). Unequal power dynamics often leave victims without adequate support (Ruíz‐González et al. 2020; Xie et al. 2024). Effective interventions are urgently needed to address these issues and improve patient care.

1.2. Rationale

Despite the high‐risk nature of ICUs, their unique challenges have been relatively understudied (Bailey et al. 2022). Systematic reviews on workplace bullying in nursing report mixed findings due to varied study designs and contexts (Castronovo et al. 2016). Most research focuses on general hospital settings, neglecting ICUs. Although reviews exist on aggressive behaviours by patients and families toward ICU staff (Sridharan et al. 2024) and horizontal violence among nurses (Shorey and Wong 2021), there is a gap in literature on HVWB among ICU nurses.

This study fills this gap by using a mixed‐methods approach. It examines four key themes: nurses' knowledge of HVWB, predisposing factors in ICUs, negative impacts on nurses and workplaces, and mitigation strategies. The study seeks to describe HVWB behaviours and factors in ICUs, analysing their impact on nurse well‐being, workplace dynamics, and patient care quality. By understanding these, the study aims to develop a theoretical framework for analysing workplace bullying in nursing, aiding in the creation of effective interventions.

2. The Review

2.1. Aim(s)

This mixed‐methods systematic review aimed to investigate horizontal violence or workplace bullying among ICU nurses and address the following four research questions:

1. What is the level of awareness and understanding of horizontal violence or workplace bullying among ICU nurses?

2. What factors contribute to the occurrence of horizontal violence or workplace bullying in ICU settings?

3. What are the impacts of horizontal violence or workplace bullying?

4. What strategies to address horizontal violence or workplace bullying?

2.2. Design

This mixed‐methods systematic review using a narrative synthesis approach and thematic analysis design of the Joanna Briggs Institute(JBI) Manual for Evidence Synthesis (Munn et al. 2018) and adheres to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines (Anna Bry and Wigert 2022).

2.3. Search Methods

The search adhered to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines (Page et al. 2021). It focused on papers published between 2013 and 2023, utilising databases like PubMed, CINAHL, PsycINFO, and Embase. The searches were conducted in CENTRAL, the Cochrane Database of Systematic Reviews, and MEDLINE (Ovid) to ensure the originality of the studies. PubMed and CINAHL were initially searched for index keywords and text phrases in titles and abstracts, followed by identifying keywords and index terms across all databases. Key terms such as “nurse,” “Intensive Care Units,” “workplace bullying,” and “horizontal violence” were combined using Boolean operators. The specific search approach was demonstrated using PubMed and CINAHL as examples in the Data S1. Additionally, backward citation tracking was performed, and reference lists of identified articles were reviewed for further studies, excluding grey literature. All articles were uploaded to Covidence to eliminate duplicates, and titles and abstracts were screened by two independent reviewers. Discrepancies were resolved through discussion or consultation with a third reviewer if needed.

2.4. Inclusion and Exclusion Criteria

The search was restricted to English‐language publications. Inclusion criteria were empirical peer‐reviewed literature of any design (qualitative or quantitative), published from 2013 to 2023. Exclusion criteria included systematic reviews, commentaries, editorials, letters, protocols, grey literature, and studies published in languages other than English or over 10 years old. Details of the PIC framework (participants, phenomena of interest, and context) are provided in the Data S2.

2.5. Search Outcomes

A total of 273 articles were retrieved through database searches and citation tracking. After removing duplicates, 193 articles were screened by abstract and title, of which 35 met the criteria for full‐text screening. No additional records were found when searching the reference lists of the selected secondary literature. Eight studies were included in the review, comprising five quantitative and three qualitative studies. The search results were fully recorded and depicted in a PRISMA flowchart (Page et al. 2021) (Figure 1).

FIGURE 1.

PRISMA 2021 flow diagram for horizontal violence or workplace bullying among Intensive Care Unit nurses: A mixed systematic review.

2.6. Quality Appraisal

The methodological quality of the included studies was rigorously appraised by two independent reviewers using the JBI Critical Appraisal Checklist (Munn et al. 2018). This checklist, selected for its comprehensive approach to both qualitative and quantitative studies, provided a systematic evaluation framework. Reviewers were trained in its application to ensure consistency, and any disagreements were resolved through discussion. The qualitative checklist comprised 10 items, while the quantitative checklist for cross‐sectional studies included 8 items. Each criterion was scored as ‘Yes,’ ‘No,’ ‘Unclear,’ or ‘Not applicable,’ with one point given for ‘Yes.’ Discrepancies were discussed and resolved. Regardless of their methodological quality, all studies proceeded to data extraction and synthesis. Cross‐sectional studies were classified as poor (≤ 2 points), moderate (3–5 points), or good (6–8 points), and qualitative studies were rated as poor (≤ 3 points), moderate (4–6 points), or good (7–10 points). Detailed assessment tables are available in the Data S3.

2.7. Data Extraction

Two reviewers independently extracted data from selected studies, utilising the JBI standardised data extraction tool to Microsoft Excel. Information extracted from each included article was categorised into two core categories: (1) general characteristics (i.e., author, country, aim, sample, gender, and character and design) seen in Table 1, (2) and findings seen in Table 2.

TABLE 1.

General characteristics of included papers.

Author (year)	Country/region	Research question/aim	Sample/gender	Method/research design
Ruíz‐González et al. (2020)	Mexico	To determine the perception of the intensive care unit (ICU)	12 ICU nurses/female	A qualitative approach using grounded theory
		Nursing staff on mobbing (workplace bullying)
Bry and Wigert (2022)	Sweden	To analyse the organisational climate and interpersonal interactions experienced by registered nurses at a level III neonatal intensive care unit (NICU)	13 NICU nurses/female/female	Qualitative study using semi‐structured interviews
McKenzie et al. (2021)	Australia	To investigate the clinical and professional learning experiences that recently qualified registered graduate nurses had in the first 6 months following their registration in a NICU	8 newly qualified registered graduate nurses/unclear	Narrative inquiry with thematic analysis
Ganz et al. (2015)	Israel	To describe the prevalence of ICU nurse bullying and what strategies were taken to prevent bullying	156 ICU nurses/most female	Descriptive study
Yun et al. (2014)	South Korea	To examine the relationship between perceived work environment and workplace bullying among Korean intensive care unit (ICU) nurses	134 ICU nurses/most female	Quantitative research/cross‐sectional descriptive study
Cha and Sung (2020)	South Korea	To investigate potential factors that influence nursing performance in South Korean intensive care units (ICUs).	177 ICU nurses/most female	Cross‐sectional descriptive design
Aristidou, Mpouzika, Papathanassoglou, et al. (2020)	Cyprus	To explore the prevalence of bullying at work and associated factors among Greek‐Cypriot nurses working in emergency and critical care settings in both public and private settings	113 (ED, ICU, CCU) nurse/most female	Descriptive, cross‐sectional correlation study
Oja (2017)	United States	To examine the relationship between perceptions of nurse‐to‐nurse incivility and professional comportment among critical care nurses and the extent to which nurse characteristics influence their perceptions	301 ICU nurses/most female	Quantitative, cross‐ sectional, descriptive survey

TABLE 2.

Study findings of all studies.

Author/year	Findings
Ruíz‐González et al. (2020)	The Awareness and Understanding of HVWB Mobbing, often referred to as workplace bullying, is a type of ongoing psychological and emotional abuse where victims are intimidated, isolated, or subjected to emotional exhaustion by peers or superiors Factors affecting HVWB Work environment stress: Overwork, high stress, lack of support, and insufficient leadership Power dynamics: When those in positions of power put pressure on their subordinates, it can result in an unequal division of labour and the denial of rights at work Jealousy among colleagues: Behaviours such as being innovative, hard‐working, and not being intimidated by peers can cause jealousy, which can result in mobbing Impacts of HVWB Workplace stress and burnout: Higher stress levels, less motivation, decreased job contentment, and eventually, burnout among colleagues on a professional level Mental health issues: Mobbing can lead to mental health problems such as depression and anxiety, which lead to work performance and interpersonal relationships
	3 Decreased productivity: Mobbing victims frequently show lower productivity as well as a lack of initiative and decision‐making skills at work Strategies of HVWB Leadership training: Enhancing leadership and management skills to reduce pressure and unfair treatment from superiors toward subordinates Support systems: Establishing support systems to provide psychological support and counselling services to help victims cope with mobbing Organisational culture improvement: Improving organisational culture at the workplace to encourage a positive and supportive work atmosphere
Bry and Wigert (2022)	The awareness and understanding of HVWB New nurses often experience incivilities, such as being belittled or socially excluded by more experienced nurses Factors affecting HVWB Lack of group cohesion: The NICU presents a challenge to establishing mutual trust and efficient communication due to high turnover and the presence many unfamiliar professionals Subgroup formation: Nurses tend to form subgroups within the larger group to seek camaraderie and support. While this can provide a sense of belonging, it may also lead to divisions and hinder group cohesion Unrealistic expectations: The nature of work at a new‐born intensive care unit (NICU) is often beyond the realistic expectations of newly hired nurses, which can lead to dissatisfaction and higher turnover Unrealistic expectations: The nature of work at a new‐born intensive care unit (NICU) is often beyond the realistic expectations of newly hired nurses, which can lead to dissatisfaction and higher turnover Stress and unease: High turnover and a preponderance of inexperienced nurses contribute to a stressful environment. Experienced nurses often feel burdened by the additional responsibility of training new hires, leading to psychological stress Impacts of HVWB Lack of group cohesion: The high turnover and presence of many unfamiliar colleagues make it challenging to establish mutual trust and effective communication, which are essential for teamwork in the NICU Subgroup formation: Nurses tend to form subgroups within the larger group to seek camaraderie and support. While this can provide a sense of belonging, it may also lead to divisions and hinder group cohesion Unrealistic expectations: The nature of work at a NICU is often beyond the realistic expectations of newly hired nurses, which can lead to dissatisfaction and higher turnover Stress and unease: High turnover and a preponderance of inexperienced nurses contribute to a stressful environment. Experienced nurses often feel burdened by the additional responsibility of training new hires, leading to psychological stress Strategies of HVWB Improving communication: Implementing communication training to enhance nurses' skills and emotional intelligence, fostering a culture of respect and support Strengthening team building: Organising regular team‐building activities to enhance group cohesion and reduce the formation of cliques Providing psychological support: Offering counselling and support for nurses who experience bullying to help them cope and recover Role of management: Management should recognise bullying behaviours, take action to stop them, and set an example with their behaviour
McKenzie et al. (2021)	The Awareness and Understanding of HVWB Horizontal violence is viewed as an act of aggression that harms teamwork, creates a hostile work atmosphere, and affects patient care among nurses Factors affecting HVWB Horizontal violence: Interactions with other Neonatal Intensive Care Unit (NICU) nurses often resulted in stress due to perceived unavailability, disinterest, and direct victimisation from senior staff, including rudeness and incivility Supportive structural environment: Limited support for (Newly Registered Graduate Nurse) NRGNs was caused by staffing issues, such as a dearth of senior professionals with experience and erratic clinical educators Seeking feedback: NRGNs expressed a need for constructive feedback, which was often absent or delivered in an unhelpful manner Keep silent: NRGN did not want to ask for feedback for fear of upsetting colleagues or attracting horizontal violence Impacts of HVWB Stress and anxiety: NRGNs felt unprepared and unsupported, which led to high levels of stress, worry, and feelings of inadequacy Negative work environment: Horizontal aggression and lack of helpful criticism created an aggressive work environment that made employees feel like victims and unable Job satisfaction and retention: The negative experiences and lack of support may have contributed to NRGN's job satisfaction and could potentially lead to early career burnout and departure from the profession Patient safety: The stress and inadequate preparation of NRGNs posed risks to patient safety Strategies of HVWB Regular and constructive feedback: Establish mechanisms for regular and constructive feedback to help NRGNs improve their clinical practice Addressing horizontal violence: fostering a positive work environment and promoting respectful communication among staff Manageable workloads: Adjust workloads to ensure they are manageable for NRGNs, considering their experience and skill levels. Avoid placing NRGNs in high‐stress situations without adequate support and preparation Support systems: Creating a supportive work environment, including mentors and supervisors for new nurses, to ensure they receive adequate support during their transition Educational programs: Hospitals should strongly consider investing in more comprehensive educational programs to support the clinical and professional
Ganz et al. (2015)	The Awareness and Understanding of HVWB Bullying refers to repeated, offensive, abusive, intimidating, or insulting behaviours, abuse of power, or unfair sanctions that make recipients feel humiliated, vulnerable, or threatened Factors affecting HVWB. High‐intensity and stressful environments The prevalence of bullying might also be affected by the local culture, the work environment, and the ethical environment Impacts of HVWB Physical and psychological consequences include headaches, changes in eating habits, sleep disturbances, anxiety, and depression Hostile work environment: It may also have an impact on patient care by decreasing job satisfaction, increasing burnout, and leading to higher absenteeism and turnover rates
	Strategies of HVWB Awareness: Increasing individual and managerial awareness about the presence of bullying Policies: Develop institutional policies that enforce zero tolerance for bullying and documentation of incidents with disciplinary action Education: Nurses should be educated to accept only zero tolerance for bullying and to report incidents. This can be included in primary nursing education, orientation programs, and continuing education
Yun et al. (2014)	The awareness and understanding of HVWB Workplace bullying is defined as repeated negative verbal, psychological, and physical behaviours and is also called horizontal violence, horizontal hostility, lateral violence, or nurses eat they're young. Nursing bullying refers to the frequent negative behaviours or unfair treatment experienced by nurses in the workplace. These negative behaviours include verbal abuse, threats, exclusion, insults, severe criticism, making fun of, disturbing work, withholding vital information, and breaching privacy Factors affecting HVWB Oppression and social learning theories: Nurses tended to display harmful. Behaviour toward their colleague nurses to decrease the frustration from work‐related stress in the hospital environment with a significant hierarchy Vicious cycle: Some new nurses perceived bullying from their seniors as being a process of adjusting to the nursing job, or that it was an organisational culture, and through time, they repeated similar disruptive behaviours when they became seniors, creating a vicious cycle Keep silent: bullying might be neglected because of a fear of revenge The work environment and the organisational culture are unstable, or the organisation is overly authoritative or has permissive leadership Impacts of HVWB Personal impact: Nurses subjected to workplace bullying may experience emotional issues such as sadness, anxiety, depression, and low self‐esteem. Insomnia, headaches, abuse of drugs, chronic exhaustion, chronic fatigue, and decreased appetite can all be linked to long‐term bullying Work environment: Workplace bullying leads to a deteriorating work environment, decreased job satisfaction among nurses, and higher turnover rates Patient safety: Poor work environments and high‐stress levels among nurses can lead to the quality of care, increasing the risk of patient falls and medication errors Strategies of HVWB Leadership support: Increase the focus of administrators and nurse managers on the problem of bullying and make sure that staff members can resolve conflicts peacefully Education and intervention: Organise education and awareness campaigns to provide nurses with a better understanding of workplace bullying and coping mechanisms Writing group journals could lead to a reduction in hostile acts within the work environment. This might be because when nurses read and write together about an important issue, their relationships become more solid and supportive
Cha and Sung (2020)	The Awareness and Understanding of HVWB Bullying in nursing, also known as workplace incivility, is defined as behaviours that breach norms of the workplace and demonstrate a disregard for others. These behaviours are frequently underrecognized due to their subtle intent and relatively lower intensity, distinguishing them from more overt forms of workplace violence Factors affecting HVWB Organisational culture: Hierarchical culture emphasising rank and inflexibility. Hospitals in Korea tend to value the group over the individual, impacting nurses performance due to rigid structures Societal influences: Korean societal norms rooted in Confucianism stress collectivism and hierarchy, which can allow mistreatment of subordinates by seniors or superiors Impacts of HVWB Nursing performance: Nurses' intrinsic motivation and collaboration are diminished by authoritarian and rude behaviour from supervisors and rudeness from patients and families. This lowers performance and productivity and has a negative impact on patient outcomes Workplace environment: An unfriendly workplace with rudeness impedes effective teamwork and lowers productivity Strategies of HVWB Reducing workplace incivility: Hospital management should focus on reducing workplace incivility through education and training, raising awareness of respectful behaviours among all staff, and establishing clear behavioural norms Promoting positive organisational culture: Hospitals should assess and promote relation‐oriented and task‐ oriented cultures that encourage trust, respect, and teamwork, thereby improving nursing performance Providing professional support and development opportunities: Offering professional support and development opportunities to nurses Establishing a healthy work environment: Developing standards and guidelines for evaluating the health of the work environment is essential
Aristidou, Mpouzika, and Karanikola (2020)	The Awareness and Understanding of HVWB Nurse bullying is defined as unethical behaviour (verbal, physical, interpersonal) systematically employed to humiliate and disempower the target victim Factors affecting HVWB Psychological impact: This leads to anxiety, depression, and emotional distress among victims Physical impact: Can cause health issues such as hypertension and chronic pain Decreased job satisfaction: Victims have significantly lower job satisfaction, which can result in reduced work efficiency Team collaboration breakdown: Bullying disrupts team collaboration, affecting overall work performance Impacts of HVWB Mental and physical health issues: leading to psychological distress and burnout for the victims Work environment: Bullying is more common in high‐stress environments such as EDs and ICUs, especially in public hospitals Employee satisfaction: Victims of bullying are often dissatisfied with how incidents are handled by administrators, as there is frequently a lack of effective response from management Work efficiency and care quality: The presence of bullying affects the mental and physical health of nursing staff, which in turn impacts the safety and quality of patient care Strategies of HVWB Policy implementation: Development and strict enforcement of anti‐bullying policies Education: Training programs on assertive communication and team building to empower nurses Support systems: Establishing support mechanisms, including counselling and incident reporting systems to assist victims Management action: Encouraging proactive involvement of hospital administration in addressing and mitigating bullying incidents
Oja (2017)	The Awareness and Understanding of HVWB Incivility is defined as rude or disrespectful behaviour that violates social norms and expectations. It can include actions such as belittling, insulting, or ignoring others, as well as engaging in gossip, spreading rumours, or making inappropriate jokes. In the context of nursing, incivility refers to disrespectful behaviour between nurses. Involves rude, discourteous, and antagonistic behaviours among nursing staff Factors affecting HVWB High‐stress environment: High‐stress settings like intensive care units (ICUs) make nurses more prone to incivility Lack of professional comportment education: Insufficient education on professional comportment and civil behaviour contributes to the occurrence of incivility Organisational culture and leadership: Tolerates uncivil behaviour and lacks supportive leadership, which permits the behaviour to continue and proliferate Impacts of HVWB Health issues: Exposure to workplace incivility can lead to multiple physical and emotional health issues, including cardiovascular problems, headaches, fatigue, and depression Patient care: Increased errors in patient care and decreased quality of patient care are associated with incivility Staff retention: A culture of rudeness negatively affects staff nurse retention and the departure of nurses and leadership who work to provide high‐quality patient care Organisational outcomes: Uncivil behaviours negatively affect organisational outcomes, impacting overall hospital performance and patient satisfaction Strategies of HVWB Education on professional comportment: Nurses' perceptions of their professional behaviour can rise when they receive education on professional comportment, while their perceptions of other nurses' incivility can be reduced Development of courses: Nurse educators and leaders are responsible for creating curricula that support appropriate behaviour and foster a safe workplace Conflict management training: Training on effective conflict management, communication, shared processes, coordination, and professionalism can help reduce incidences of incivility Supportive leadership: Supportive nursing leadership that fosters collaboration and mentorship is crucial in reducing uncivil behaviour

2.8. Synthesis

Since this review included both quantitative and qualitative studies, a narrative synthesis approach combined with thematic synthesis was adopted. Quantitative data were extracted using the standardised JBI data extraction form (Voils et al. 2009), and then processed narratively, converting quantitative reports into textual descriptions (Voils et al. 2009; Pearson et al. 2015). Qualitative data were synthesised thematically (Thomas and Harden 2008) by grouping similar findings to generate key themes (Stern et al. 2014).

The review re‐analysed the studies by comparing commonalities, differences, and variations across results. Data were categorised based on similarities, with variations sorted separately for re‐evaluation to identify emerging patterns. Two reviewers independently assigned data points to topics, and similar content was labelled with representative concepts. After reviewing the results, the reviewers reached consensus on the final themes, with a third researcher involved in cases of disagreement. The final themes were systematically compiled line by line (Thomas and Harden 2008).

3. Results

Seven countries across four continents participated in these mixed‐method studies: North America (USA, Mexico), Europe (Sweden, Greece), Asia (South Korea, Israel), and Australia. All included studies were of good quality. Sample sizes varied from 8 to 301 respondents. The findings revealed four themes: awareness and understanding of HVWB, contributing environmental and organisational factors, severe negative impacts on nurses, the workplace environment, and patient care, and potential strategies for resolution. The analysis of the included studies revealed four key themes: (i) The awareness and understanding of horizontal violence or workplace bullying (ii) factors affecting horizontal violence or workplace bullying (iii) impacts of horizontal violence or workplace bullying, (iv) strategies of horizontal violence or workplace bullying. Further details are presented in Table 2.

3.1. Question 1—What Is the Level of Awareness and Understanding of HVWB Among ICU Nurses?

There is a general lack of awareness and understanding of HVWB among ICU nurses, as evidenced by numerous studies (Yun et al. 2014; Ganz et al. 2015; Ruíz‐González et al. 2020; McKenzie et al. 2021; Bry and Wigert 2022). HVWB lacks a standardised definition in the literature; it is described as workplace bullying, mobbing (Ruíz‐González et al. 2020), or incivility (Oja 2017; Cha and Sung 2020; Bry and Wigert 2022) in the literature.

Victim ICU nurses experienced both verbal and non‐verbal abuse, including repeated insults, humiliation, ignoring, intimidation, gossiping, isolation, offensive actions, and abuse of power (Yun et al. 2014; Ganz et al. 2015; Oja 2017; Aristidou, Mpouzika, and Karanikola 2020; Ruíz‐González et al. 2020). Such behaviours are typically characterised by persistent psychological and emotional harm inflicted by superiors and colleagues. New nurses often face disregard and harsh criticism from senior nurses or nurse management (Oja 2017; Bry and Wigert 2022; Xie et al. 2024). These behaviours are frequently underestimated because they are less severe than more serious kinds of HVWB and have unclear intentions (Cha and Sung 2020).

3.2. Question 2—What Factors Contribute to the Occurrence of Horizontal Violence or Workplace in ICU Settings?

3.2.1. Workplace Environment Stress

Various factors in the ICU workplace, such as high workload, excessive fatigue, and stressful environments, are associated with HVWB. The special needs of the newly graduate nurse require a high level of competence and resilience (Bry and Wigert 2022). Nurses often work with individuals experiencing a range of emotional states, including seriously ill patients and vulnerable family members (Ruíz‐González et al. 2020). Additionally, ICU nurses frequently face ongoing stress due to a lack of autonomy and decision‐making authority (Ruíz‐González et al. 2020). This stress fosters misconduct and increases susceptibility to hostility and HVWB among ICU nurses (Ganz et al. 2015; Oja 2017; McKenzie et al. 2021; Bry and Wigert 2022).

3.2.2. Organisational Culture and Leadership

Several studies highlighted how an inadequate organisational culture and leaders' inability to cultivate trust, respect, and a cooperative environment significantly contribute to the prevalence of HVWB (Cha and Sung 2020; Bry and Wigert 2022). Leadership deficiencies, such as a lack of management experience and tolerance for uncivil behaviour, allow negative behaviours to persist (Yun et al. 2014; Oja 2017). Inefficient managerial responses to bullying and incivility episodes further demoralise victims, leading to general dissatisfaction and a climate where uncivil behaviour is tolerated (Aristidou, Mpouzika, and Karanikola 2020). Insufficient leadership support exacerbates these issues, reinforcing the need for competent and supportive leadership (Ruíz‐González et al. 2020).

3.2.3. Power Dynamics and Vicious Cycle

In Confucian‐influenced societies like Korea, cultural norms emphasising collectivism and respect for hierarchy were found to contribute to the mistreatment of juniors by seniors (Cha and Sung 2020). Senior nurses felt threatened by new nurses and engage in HVWB to assert authority, creating a hostile work environment (McKenzie et al. 2021). New nurses were frequently excluded or subjected to harsh criticism by experienced colleagues.

Ruíz‐González et al. (2020) showed how superiors exert undue pressure on subordinates, leading to unfair work distribution and deprivation of work rights. Some studies reported that new nurses tended to view HVWB from senior nurses as a “rite of passage” or an inherent part of the organisational culture. Over time, individuals exposed to such behaviours often replicated them upon assuming senior roles, perpetuating a recurring cycle of bullying (Yun et al. 2014; Bry and Wigert 2022).

3.2.4. Interpersonal Relationships and Subgroup Formation

The findings indicated that the formation of subgroups among nurses within larger teams negatively impacts overall group cohesion (Bry and Wigert 2022). Jealousy among colleagues, especially toward those perceived as innovative and diligent, was observed to exacerbate team tensions. These emotions led to mobbing and other negative behaviours, creating a stressful environment and undermining the self‐confidence and professional efficacy of targeted individuals (Ganz et al. 2015; Ruíz‐González et al. 2020).

3.3. Question 3—What Are the Impacts of Horizontal Violence or Workplace?

3.3.1. Nurses' Health and Job Satisfaction

This findings noted that HVWB has affected on ICU nurses with both physical and psychological consequences. Reported symptoms include headaches, changes in eating habits, sleep disturbances, depression, anxiety, and self‐doubt, impacting work performance and relationships (Yun et al. 2014; Ganz et al. 2015; Aristidou, Mpouzika, and Karanikola 2020; Ruíz‐González et al. 2020; McKenzie et al. 2021). Chronic stress from prolonged bullying may lead to severe psychological issues such as post‐traumatic stress disorder and substance abuse (McKenzie et al. 2021). Nurses reported struggling to concentrate, feeling distracted, stressed, and in a bad mood (Ruíz‐González et al. 2020). New nurses were particularly affected, expressing fear of making mistakes, hesitation in asking questions, and anxiety about attending work (Bry and Wigert 2022).

HVWB was also found to reduce job satisfaction, increases burnout, and elevates the intention to leave (Ganz et al. 2015; Aristidou, Mpouzika, and Karanikola 2020; Cha and Sung 2020; Bry and Wigert 2022). Some nurses reported underperforming due to fear, which impacted their ability to provide effective patient care (Ruíz‐González et al. 2020). Victims often feel dissatisfied with management's handling of these incidents was commonly reported (Aristidou, Mpouzika, and Karanikola 2020). In some cases, nurses did not receive positive feedback and left their jobs before fully adapting to their roles (Bry and Wigert 2022).

3.3.2. Workplace Environment

The findings indicated the HVWB impact on the undermine teamwork, reduce communication efficiency, and create a hostile atmosphere, ultimately decreasing productivity due to absenteeism and attrition (Yun et al. 2014; Ganz et al. 2015; Cha and Sung 2020; McKenzie et al. 2021). HVWB was also associated with elevated stress levels among nursing staff, which extended beyond the direct victims. Nurses who witnessed these behaviours reported a loss of interest in their job and profession (Ruíz‐González et al. 2020). Additionally, staff turnover resulting from HVWB was identified as a major factor complicating mutual trust and increasing the challenges of effective communication (Anna Bry and Wigert 2022). Frustration and stress arise when colleagues leave after a brief tenure, despite efforts to train and support them. This created a vicious cycle where high turnover negatively affects the group climate, leading to more nurses leaving and further compromising team stability and efficiency (Ganz et al. 2015; Cha and Sung 2020; Bry and Wigert 2022).

3.3.3. Patient's Safety

Some studies indicated that stress and fear induced by HVWB impair nurses' teamwork, productivity, judgement and decision‐making abilities, affecting patient care quality and safety (Yun et al. 2014; McKenzie et al. 2021). Yun et al. (2014) found that medication distribution errors and patient monitoring mistakes significantly increased among nurses experiencing workplace bullying. Patients inevitably suffered as HVWB's collateral victims.

In some cases, new nurses often hesitate to communicate due to fear of negative reactions, leading to nursing errors and suboptimal patient care (Bry and Wigert 2022). Some newly graduate nurses revealed that they frequently face questions about their competence in neonatal care due to high stress and inadequate preparation, directly endangering patient safety (McKenzie et al. 2021).

3.4. What Strategies to Address Horizontal Violence or Workplace Bullying?

3.4.1. Improving Work Environment and Psychological Support

Nurses reported a strong preference for a respectful and supportive work environment, with team‐building retreats and regular open communication meetings being identified as effective means of promoting these values (Cha and Sung 2020). Managing workloads to ensure they are manageable, especially avoiding placing newly graduate nurse in high‐stress situations without adequate support is recommended (McKenzie et al. 2021). Establishing specific nurse‐to‐patient ratios and defining maximum shift lengths can alleviate burnout and improve patient care outcomes (Yun et al. 2014).

Additionally, awareness programs aimed at increasing nurses' understanding of workplace bullying and provide coping strategies (Yun et al. 2014). Providing accessible and confidential counselling and support services helps nurses cope with stress and emotional issues (Yun et al. 2014; McKenzie et al. 2021). The introduction of group journals was also suggested as a way to foster a supportive community among nursing staff. Writing collaboratively about shared experiences and challenges was identified as a stress‐relief tool, as well as a means to strengthen relationships and reduce negative behaviours in the workplace (Yun et al. 2014).

3.4.2. Leadership Training and Management Actions

Studies showed that improving leadership and management skills can reduce pressure and unfair treatment from superiors toward subordinates (Bry and Wigert 2022). A culture that balances task completion with interpersonal support was found to improve nursing performance and may help alleviate HVWB (Cha and Sung 2020). For example, nurse managers and administrators should undergo specialised training in conflict management and receive certification to handle interpersonal disputes constructively (Yun et al. 2014; Ruíz‐González et al. 2020).

Additonally, research from public hospitals has revealed a higher frequency of HVWB and incivility incidents, indicating that the effects of organisational culture and leadership can vary significantly across different institutional settings (Oja 2017; Aristidou, Mpouzika, and Karanikola 2020). Management's role in identifying and intervening in HVWB behaviours was emphasised as a crucial step toward fostering a positive work environment (Ganz et al. 2015; Aristidou, Mpouzika, and Karanikola 2020; Bry and Wigert 2022).

Furthermore, developing and enforcing clear anti‐bullying policies ensures all employees understand acceptable behaviours and the consequences of bullying aslo reported (Aristidou, Mpouzika, and Karanikola 2020; McKenzie et al. 2021).

3.4.3. Education and Training

Training programs focused on assertive communication and team building are essential to empower nurses in conflict management and effective communication. For instance, establishing mechanisms for regular and constructive feedback can help newly graduate nurses improve their clinical practice and enhance their confidence and competence (McKenzie et al. 2021).

Studies by Oja (2017) and Aristidou, Mpouzika, and Karanikola (2020), and McKenzie et al. (2021) supported integrating these programs with education on professional demeanour and civil behaviour to enhance professionalism, collaboration, and communication skills. Additionally, training should cover emotional intelligence, including empathy, self‐regulation, and interpersonal relationship management (Bry and Wigert 2022).

4. Discussion

4.1. Why Stress and Emotional Labour in ICU Settings Contribute to Horizontal Violence or Workplace Bullying?

Stressful conditions inherent to ICU settings, including high workload, excessive fatigue, and fast‐paced nature of providing continuous care for critically ill patients, demand significant emotional labour from nurses. Emotional labour involves managing and sometimes suppressing natural emotional responses to align with professional expectations (Hochschild 1979; Xie et al. 2024). Hochschild (1979) defined the effort to align one's internal feelings with external social expectations as adherence to ‘feeling rules’. This is particularly evident in ICU setting, where nurses must manage their own emotions and their patients and families while maintaining professionalism.

Such emotion work also mirrors the strategies employed by family caregivers, as highlighted in the study by Halevi Hochwald et al. (2022). This research revealed that caregivers of individuals with end‐stage dementia navigate complex emotional landscapes, balancing authentic feelings of grief and frustration with socially expected emotions such as patience and compassion. Similarly, ICU nurses face ongoing dissonance as they suppress genuine feelings and control frustration to conform to perceived appropriate behaviours. This dissonance not only adds to emotional exhaustion but also impacts their ability to maintain genuine connections with patients and colleagues (Herron et al. 2019; Halevi Hochwald et al. 2022).

The ICU nursing staff often operates within a framework where care procedures are not carried out independently, leading to continuous stress from reduced autonomy and decision‐making authority (Ruíz‐González et al. 2020). High workloads escalate this stress, fostering an unsupportive culture without proper management. This ongoing stress strains relationships among staff, contributing to heightened irritability and conflict among colleagues (Ruíz‐González et al. 2020). For example, senior nursing staff often wield undue influence over junior nurses, cultivating a bullying culture as a distorted form of control or stress relief (Shorey and Wong 2021). These findings improved that high‐stress environments, such as ICUs, are fertile grounds for horizontal violence and other hostile behaviours (Ganz et al. 2015; Chatziioannidis et al. 2018).

The specialised nature of newly graduate nurse nursing further amplifies these pressures, requiring exceptional competence and resilience to endure intensive care stressors (Bry and Wigert 2022). These findings align with previous research indicating that young age is associated with burnout among ICU nurses, possibly due to increased perceived stress from inexperience or lack of self‐confidence (Kerlin et al. 2020). Prevention strategies for HVWB in ICUs should target improving the overall workplace climate by assessing stressors, redesigning workflows to mitigate stress, and training management to effectively regulate workplace conduct (Shorey and Wong 2021). For instance, adjusting workload distributions and shift patterns can prevent nurse fatigue and potential conflicts.

4.2. How Can Power Dynamics and Leadership Styles Mitigate or Exacerbate Horizontal Violence or Workplace Bullying in ICU Nursing?

Power dynamics and lack of leadership play crucial roles in fostering or mitigating HVWB. According to Emerson's Power‐Dependence Relations (Emerson 1962), power misuse arises when there is a critical need for quick decision‐making and high competence. Power misuse in the ICU, where quick decision‐making and high competence are crucial, can lead to harsh treatment of less experienced staff (Shorey and Wong 2021; Xie et al. 2024).

Authoritarianism manifests as a concentration of political power. In the context of authoritarian leadership, the leader exhibits behaviours that exert total authority and control over subordinates, requiring their absolute and unquestioned compliance (Ballou and Landreneau 2010; Peng et al. 2024). Authoritarian leadership can decrease morale and increase job dissatisfaction, conditions conducive to bullying behaviours (Pizzolitto et al. 2023). Such environments lack psychological safety, causing nurses to fear of repercussions suppresses communication. Nurses may hesitate to voice concerns or suggest improvements if they anticipate negative reactions or retaliation from colleagues or superiors, diminishing self‐confidence and increasing stress, burnout, and mental exhaustion. Thus, HVWB negatively impacts both nurse and patient outcomes, leading to increased costs and medical errors (Bae 2023). Despite the drawbacks of authoritarian leadership, the authority of senior nursing staff is crucial for maintaining discipline and ensuring patient safety (Zaitoun et al. 2023). Personal authority is based on knowledge, expertise and trust, and through these qualities voluntary influence and obedience are established (Bass 1990). Simply put, authority is earned through competence and trust, while authoritarianism manifests itself more in coercion and domination of obedience.

Compared to authoritarian leadership, transformational leadership emphasises inspiring and motivating subordinates, which leads to higher job satisfaction and lower turnover intentions (Cummings et al. 2010). Transformational leaders in ICU settings can effectively balance the need for discipline and patient safety with a nurturing approach that values feedback and personal growth. To prevent the misuse of power and reduce the incidence of HVWB in ICU settings, it is vital that nurse leaders foster a culture of transparency and open dialogue. This includes: regular training programs, establishing clear policies and reporting mechanisms and create feedback and Continuous Improvement (Shorey and Wong 2021). Additionally, fostering psychological safety through support systems can alleviate fear, enhance team cohesion, and reduce bullying's prevalence and impact.

4.3. What Cause Hierarchical and Professional Socialisation of Horizontal Violence or Workplace Bullying in ICU Nursing?

It was found that hierarchical horizontal violence and bullying (HVWB) are often viewed by some nurses as an inevitable part of professional initiation. This perception is rooted in norms within professional socialisation, where behaviours modelled by senior nurses set expectations for newcomers. According to Bandura's Social Learning Theory (Bandura 1977), observation and modelling lead junior nurses to adopt negative practices exhibited by seniors.

Furthermore, nursing was identified as a traditionally female‐dominated profession, is often perceived as a lower‐status profession compared to doctors or administrators, which may exacerbate hierarchical tensions (Embree and White 2010). Tajfel and Turner's Social Identity Theory (Turner et al. 1979) suggested that individuals enhance their self‐image by elevating their group's status. In the ICU, experienced nurses may form exclusive groups, and newcomers are targeted to reinforce boundaries and assert group identity, perpetuating HVWB. This aligns with Vessey et al. (2009), who noted the normalisation of HVWB during professional socialisation, continuing as victims ascend to senior roles (Yun et al. 2014; Bry and Wigert 2022). HVWB often results in nurse resignations, particularly affecting new nurses. A recent review showed annual turnover rates of newly licensed nurses ranging from 12% to 25% (Bae 2023). Responses to HVWB include resignation, retaliation, avoidance, and turnover intention (Small, Lindo, Aiken, and Chin 2017). However, newer generations of nurses show reduced tolerance for bullying, indicating a potential cultural shift (Hartin et al. 2020).

Efforts to foster anti‐bullying environments are crucial. Training programs emphasising psychological safety, peer support groups, and mentorship programs are implemented to enhance professional development and job satisfaction, particularly for new ICU nurses. These initiatives are vital for nurse retention and improving patient care by creating healthier work environments (Sarwar et al. 2020; Shorey and Wong 2021; Xie et al. 2024).

4.4. Limitation

This study has several limitations. First, the reliance on English‐language publications introduces language bias, potentially excluding relevant research. Second, despite thorough searches of four electronic databases, the selection of databases may have influenced the thematic analysis due to potential reporting bias. The small sample size and narrow setting limit the generalizability of the findings and may introduce selection bias. Additionally, the predominance of female interviewees limits the universality of the results. However, this study is the first mixed synthesis review exploring HVWB among nurses in ICU settings. Future research should include a larger, more diverse sample and consider publications in multiple languages to enhance the generalizability and comprehensiveness of the findings.

4.5. Implications for Practice and Research

To effectively address and reduce HVWB, future research should the identification and classification of HVWB characteristics in ICU settings. For instance, are there significant gender differences, such as male‐to‐female or female‐to‐female bullying? Do HVWB between different professional levels show consistency or variability? Additionally, attention should be given to the characteristics of covert bullying (e.g., silent treatment) versus overt bullying (e.g., verbal attacks) and their impact on team collaboration. These research directions will provide crucial guidance for creating a more inclusive and supportive work environment. Furthermore, the psychosocial impacts of bullying warrant deeper investigation, particularly how different power levels within the work environment influence interaction patterns.

Leadership development programs that promote transformational and empathetic skills are essential to create a work environment that encourages psychological safety and open communication. Introducing anti‐bullying measures during nurse orientation and assessing adherence to ethical norms during performance evaluations are crucial steps. Establishing mentorship and peer support programs can provide new ICU nurses with the necessary support. For example, managers should facilitate communication between newly graduate nurses and supervisions, ensuring preceptors are well‐prepared and have reduced clinical workloads to focus on teaching. Incorporating bullying and conflict management into nursing curricula can prepare young nurses for potential challenges. Regularly reviewing and enforcing clear, actionable anti‐bullying policies will ensure a healthy and respectful work environment, improving nurse job satisfaction and retention, and enhancing patient care outcomes by creating a safer, more supportive workplace.

5. Conclusion

This mixed systematic review examined existing evidence on nurses' experiences with HVWB in ICUs. This findings provided several critical issues, including the HVWB behaviours, the stress and emotional labour in ICU settings, the impact of power dynamics and leadership styles. The victim ICU nurse experienced exclusion, isolation, verbal and nonverbal abuse, hostility, silencing, oppression, and job‐related threats. Research has showed that ICU nurses also face unique challenges, including high workloads, emotional exhaustion, and complex team dynamics, making them particularly vulnerable to bullying behaviours. The hierarchical and professional socialisation create a toxic cycle, leaving many nurses were not recognised or understood in ICU settings, some nurses to tolerate the situation while others choose to leave. The high turnover rates highlighting the urgent need for improved awareness and intervention strategies.

A key policy priority that hospitals should implement programs focusing on conflict resolution, stress management, and supportive supervisory practices. Moreover, nurse management should establishing private ways to report HVWB and offering routine staff training on interpersonal respect are essential. Another important practice implication is that ICU nurses to adopt proactive and adaptive approaches to fight against HVWB. These efforts are critical not only for retaining skilled nurses but also for ensuring high‐quality patient care. Future research should focus on evaluating the long‐term effectiveness of interventions aimed at reducing HVWB and improving workplace cultures.

Disclosure

Acquired in accordance with The Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from Their Utilisation to the Convention on Biological Diversity.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Data S1.

Data S2.

Data S3.

Data Availability Statement

All data associated with this review have been provided in Supporting Information. Any further information can be requested from the corresponding author via email upon considerable request.