One in four people have mental health problems (Mind, 2023). This 25% of the population present with a vast array of conditions; the most prevalent presentations include depression and post-traumatic stress disorder (PTSD) (Mind, 2023). The Mental Health Foundation (2022) says that mixed anxiety and depression is the most common mental health condition in the UK, with up to 10% of adults experiencing at least one episode of depression in their lifetime.
The concept of psychological trauma has been evident for centuries; however, PTSD did not become an officially recognised diagnosis until the publication of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III) in 1980 (Frueh, 2012); before this, terms such as ‘shell-shock’, ‘battered woman syndrome’ and ‘war-related disorders’ were used. PTSD is unusual in that it is one of very few mental health conditions to have an aetiological explanation (Frueh, 2012).
It is estimated that any member of the general public in the UK will experience a traumatic event on average once or twice during their lifetime; such traumatic experiences include witnessing or being involved in natural disasters, major road traffic collisions or traumatic deaths (Mildenhall, 2019; Mind, 2023). Mind's Blue Light Together (2021) initiative suggests that people who work in the emergency services are more likely to experience some form of trauma than the general public because they have a much higher exposure to traumatic events, in both frequency and severity; this vicarious trauma can increase the prevalence of depression and PTSD among members of the emergency services (Mildenhall, 2019; Blue Light Together, 2021).
Beldon and Garside (2022) noted the cause of attrition in the ambulance service was multifactorial, including poor management, increased demand on services and a poor work-life balance; 91% of staff reported low mood, poor mental health and burnout. Much of the research available argues that it is not always the major trauma that triggers poor mental health but small, everyday stressors such as shift patterns and fatigue (Beldon and Garside, 2022).
Between 2005 and 2019, there were 75 registered deaths by suicide for paramedics in the UK (Office for National Statistics, 2016; 2019).
However, this number includes paramedics only; there is no known figure for other ambulance staff such as ambulance technicians, dispatchers or emergency care assistants.
Aims
Despite the increased risk of developing mental health problems, a paucity in research on how vicarious trauma affects the prevalence of depression and PTSD in the ambulance service remains; further research into the prevention and treatment of PTSD is also needed (Mildenhall, 2019; Bagai, 2020; Beldon and Garside, 2022).
This systematic literature review will critique the literature with an examination of the underpinning evidence, present a thematic synthesis and critically examine the potential for further study into the subject area.
Research design
A systematic review was the method selected to collate and synthesise research related to the prevalence of depression and PTSD in paramedics.
Methodology
Conducting a literature search using broad terms such as ‘PTSD’ or ‘depression’ may return an unmanageable yield; the results have to be optimised to return relevant literature (Aveyard and Sharp, 2017; Aveyard, 2019; Jolley, 2020). Inclusion and exclusion criteria were used to prevent an unmanageable yield. Only articles from the years 2005 to present were included and any articles nwot printed in the English language or without an abstract available were excluded.
MEDLINE, CINAHL, the Cochrane Library and PubMed were searched; these databases were chosen as they can return a wide range of relevant academic articles.
The Critical Appraisal Skills Programme (CASP) checklists enable the researcher to systematically assess the reliability and relevance of a paper as well as identify themes (CASP, 2023); this method of appraisal was used because it is trustworthy and straightforward to use.
This research is a review of existing literature, so no ethical declaration or ethical approval were required.
Results
The literature searches of the four databases yielded 1028 articles; the use of inclusion and exclusion criteria narrowed the results to 274. From this, four key articles were chosen for review: Lateef (2005); Simpson (2013); Petrie et al (2018); and Wild et al (2018). These four studies were chosen as they provided a wide range of information, included a randomised control trial and literature review methodologies and ranged over a 13-year period from 2005 (Lateef, 2005) to 2018 (Petrie et al, 2018; Wild et al, 2018).
These articles comprised an international collection, with studies from Singapore (Lateef, 2005), Australia (Petrie et al, 2018) and two from the UK (Simpson, 2013; Wild et al, 2018). The location of publication needs to be considered. As Lateef (2005) is the only study conducted in Asia, it can give a rare insight into the prevalence of PTSD in a non-westernised service. However, with occupational demands such as long and irregular work hours, exposure to human death and tragedy, and dealing with life-and-death situations cited as causes for PTSD among paramedics in Singapore, a similarity is evident that indicates transferability to the rest of the world (Leung, 2015).
To determine the validity of the chosen literature, the methodologies of the four studies were critically appraised, and their strengths and limitations examined against the CASP (2023) checklists.
To answer the question, ‘What are the real causes behind the raised prevalence of depression and PTSD in ambulance service staff and how can this be lowered?’, several key themes have been drawn from the articles chosen; these themes are organised into seven sections for discussion.
Discussion
PTSD
PTSD is not a new concept. Over time, it has become increasingly acknowledged and its impact on an individual's mental and physical health has become more apparent (Simpson, 2013). In comparison with the findings of historical studies, the prevalence of PTSD in ambulance service personnel is lower (Petrie et al, 2018; Wild et al, 2018); nonethless, it is still of serious concern. All four studies (Lateef, 2005; Simpson, 2013; Petrie et al, 2018; Wild et al, 2018) cite PTSD as a major problem within the ambulance service in both the UK and worldwide.
Up to 14% of people in the UK report symptoms of PTSD following a traumatic event (Simpson, 2013). Wild et al (2018) suggest the rate of PTSD in the ambulance service is three times higher than in the general public. A cross-national sample spanning 27 countries indicated a prevalence rate of one in 100 (1.1%) in the general population and one in 10 (10%) in emergency service personnel (Petrie et al, 2018). A meta-analysis has demonstrated a pooled estimated prevalence of PTSD in ambulance personnel of 11% (95% CI (0.07–0.14)) (Petrie et al, 2018).
Furthermore, ambulance service personnel have a higher prevalence of PTSD than those working in other emergency services such as the police and fire services (Simpson, 2013; Petrie et al, 2018; Wild et al, 2018). Studies on the prevalence of PTSD in ambulance service personnel show rates are similar to those in the military (Simpson, 2013; Wild et al, 2018). This correlation has been attributed to the high number of ambulance service personnel who are military veterans (Simpson, 2013); however, more research in the area is needed to support this theory.
The heterogeneity remains largely unexplained; variation in sampling studies across geographical locations resulting in differing levels of exposure to trauma and social support could be a major factor in the variation in the PTSD prevalence worldwide (Petrie et al, 2018). The difficulty in interpreting the available literature has also been attributed to the wide range in statistics, with figures ranging from 5% to 29% of the workforce reporting symptoms of PTSD (Petrie et al, 2018). A number of potential reasons for this variation have been speculated, including sample size, diagnostic classification, international differences in occupational roles and the use of mixed samples (Simpson, 2013; Petrie et al, 2018). Some studies, for example, involved members of different services, pooling ambulance, police and fire services together (Petrie et al, 2018).
Depression and other mental health disorders
While Petrie et al (2018) give the prevalence of PTSD as 11% in the ambulance service, it is not the most common condition among this population (Petrie et al, 2018). The estimated pooled prevalence of other mental health conditions is slightly higher: depression: 15% (95% CI (0.10–0.20)); anxiety: 15% (95% CI (0.08–0.22)); and general psychological distress: 27% (95% CI (0.14–0.40)).
A study conducted by the World Health Organization (2017), as cited by Petrie et al (2018), reports the prevalence of psychological distress in the general public is estimated to be 29.6%; therefore, unlike PTSD, the prevalence rates of depression and other mental health disorders are not significantly higher within ambulance services than in the general population (Petrie et al, 2018). However, there is a paucity of research in this area.
Therefore, the true burden of mental health disorders within the profession is unknown and more study is required.
External factors
A wide range of causes behind the prevalence of PTSD in paramedics and other ambulance service personnel have been attributed to job-specific issues, such as exposure to suffering and trauma, shift work and fatigue (Simpson, 2013; Petrie et al, 2018; Wild et al, 2018). Additionally, there are some person-specific problems, such as low social support and personality traits (Simpson, 2013; Wild et al, 2018). A further possibility is the increased exposure to natural disasters, such as the 1966 Aberfan disaster, acts of terrorism such as the 2005 London bombings or major incidents such as the 2015 Shoreham airshow crash (Petrie et al, 2018).
There is a strong correlation between the prevalence of PTSD and other mental health disorders and length of service (Simpson, 2013; Petrie et al, 2018). Long-term or repeated exposure to trauma increases the prevalence of PTSD and depression symptoms (Simpson, 2013), so ambulance service personnel who have been employed for a longer period of time have a higher prevalence of PTSD. This prolonged exposure is evident not in the immediate response of PTSD symptoms but the domino effect on psychological and physical symptoms; this effect, often referred to as burnout, leads to the compounding and prolonging of PTSD symptoms (Lateef, 2005; Simpson, 2013). There is a link between this prolonged complex PTSD (C-PTSD) and other complications such as self-harm, substance misuse and suicide (Simpson, 2013; Royal College of Psychiatrists, 2021).
Further external factors are the environment and workplace culture of ambulance services (Simpson, 2013). A common consensus among ambulance service personnel is that management are perceived to show little or no concern around employee welfare (Lateef, 2005; Simpson, 2013); however, there is limited research in this area to support this.
Surprisingly, a factor not discussed in any of the four studies (Lateef, 2005; Simpson 2013; Petrie et al, 2018; Wild et al, 2018) is workplace violence; health workers are three times more likely to experience work-related violence than the general population (Alshahrani et al, 2021). A recent study into the prevalence of violence against staff in emergency departments reported a high level of abuse, with 34.5% of staff experiencing physical assault, 71.6% verbal abuse and 44.4% bullying and harassment (Afshari Saleh et al, 2020). The perceived or actual threat of physical violence or verbal abuse is known to elicit a PTSD response in individuals, with prolonged or repetitive abuse causing C-PTSD (Michael et al, 2016; NHS, 2022); therefore, research is needed to investigate the correlation between violence and rates of PTSD within the ambulance service.
Biological factors
One study (Simpson, 2013) investigated the difference in prevalence between the sexes. In the general population, the prevalence of PTSD is higher in women than men; conversely, within the ambulance service, rates of PTSD in the two sexes are thought to be equal (Simpson, 2013).
There are a few possible reasons for this. First, it is thought that because of the selection process and often tough nature of the role, only women who are seen to be more resilient take employment within the ambulance service. Second it is suggested that women have better coping mechanisms; they are often open to social support and talk openly about emotional struggles, thus reducing the chances of developing PTSD symptoms compared to their male counterparts (Simpson, 2013). This article, however, is dated; the selection criteria and entry routes, such as graduate entrants, has changed the demographic of people joining the ambulance service.
The correlation between mental health and its comorbidities may be linked to immunological and endocrine markers (Wild et al, 2018). Brain imagery studies suggest systemic inflammation levels potentiate amygdala reactivity, which, in turn, increases negative valence or threat response; thus, inflammation is a pre-existing vulnerability marker for the development of PTSD in trauma-exposed individuals (Wild et al, 2018).
The stress hormone cortisol has also been linked to depression and PTSD (Wild et al, 2018). The cortisol awakening response, an endocrine marker indicating change in salivary cortisol concentration that occurs in the first hour of waking from sleep, has been assessed against individuals' diurnal cycle (Wild et al, 2018); an increased cortisol awakening response was strongly linked with stress, fatigue and burnout, leading to depression within 2.5 years. Li et al (2018) supported this, explaining that salivary cortisol levels in shift workers were higher than in non-shift workers, increasing chances of both physical and mental ill health (Wild et al, 2018).
Post-exposure interventions
Figures for PTSD and other mental health disorders in ambulance service personnel have unexpectedly fallen in the last few years (Petrie et al, 2018); the cause of this decline could be attributed to a number of factors, including under-reporting.
The under-reporting of symptoms may have increased in recent years because of the stigma surrounding mental health or fear of organisational consequences in reporting mental ill health (Petrie et al, 2018); this may not account for a reduction in cases of PTSD but merely a drop in reporting.
Another theory for this decline in rates is an awareness of PTSD and its associated effects, which has led to an increase in both pre-exposure interventions and post-exposure treatment plans (Simpson, 2013).
Post-exposure interventions to prevent or treat PTSD symptoms are used by ambulance services worldwide (Lateef, 2005; Simpson 2013; Petrie et al, 2018; Wild et al, 2018), the most common being debriefing or counselling services. Studies have shown the ability to ventilate, defuse and offload during a debrief following a traumatic experience enables individuals to better handle their emotional response (Lateef, 2005). Of the 166 paramedics who participated in the study by Lateef (2005), 100% responded positively, stating that the ability to debrief, not only for major incidents but also for minor or individual traumatic events, would be beneficial.
However, Simpson (2013) noted that a single debriefing session following a traumatic event was ineffective; a single session could deeper embed the event into an individual's memory, increasing the chance of developing PTSD symptoms. The National Institute for Health and Care Excellence (2018) supports this theory; it discourages the use of psychologically focused debriefing as research has shown no improvement in PTSD symptoms; studies into debriefing have found that, because it is likely to make people relive traumatic events, their symptoms could worsen if they are not closely monitored and followed up.
However, these studies were conducted on the general population; more research is needed into the effectiveness of debriefing in the ambulance service.
As symptoms of PTSD often occur weeks or months after the traumatic event, it is recommended that a debriefing session take place up to 1 month later, and follow-up services, such as talking therapies, should be readily available to staff (Simpson, 2013).
Stigmatic attitudes towards counselling services are still evident in ambulance services because of the perceived personality traits of staff; emergency service workers are presumed to be resilient and stoic and are therefore expected to be able to cope with their workload and its emotional and psychological toll (Lateef, 2005; Simpson, 2013). One theory behind this stigma is the limited knowledge or understanding of PTSD among ambulance service workers; breaking down this barrier through improving awareness and access to confidential counselling services could increase the use of these services and therefore reduce symptoms of PTSD (Simpson, 2013).
A further possible intervention is the promotion of social support networks often found among emergency services workers (Simpson, 2013). Increasing morale in the workplace through various means, such as online forums, space for religious or spiritual support, peer support networks and team-building events may create a positive platform to promote staff welfare and an openness to conversations, thus reducing susceptibility to PTSD and other mental health disorders (Lateef, 2005; Simpson, 2013). However, this is not always possible because of constraints such as winter pressures or, more recently, increased demand due to the COVID-19 pandemic (Mildenhall, 2019; Bagai, 2020).
Pre-exposure interventions
Studies indicate that post-exposure interventions may be ineffective as they fail to identify predictors of mental health disorders as they are offered after rather than before exposure to traumatic events (Wild et al, 2018).
Several pre-exposure interventions have been recognised in the prevention of PTSD and other mental health disorder symptoms; these include personality testing, job rotation and internet-delivered cognitive training for resilience (iCT-R) (Simpson, 2013; Wild, et al, 2018).
Aptitude testing is used in a wide variety of job roles, such as military or probation services (Barrett, 2008). This could be used to select employees whose personality traits make them less susceptible to PTSD (Simpson, 2013). Through this, ambulance services could benefit through having fewer staff sickness days, increased productivity and higher morale. However, the process, which may be perceived as ruthless by some, could deter individuals who are otherwise altruistic and empathetic towards patients from applying for the role; furthermore, there are legal, moral and ethical complications to consider (Simpson, 2013).
Given the link between long service in the ambulance service and the likelihood of PTSD, it has been suggested that job rotation may be of benefit (Simpson, 2013). Regular breaks in frontline work through rest periods, study breaks and secondments allow ambulance service personnel a sufficient break in trauma exposure; this return to a normal state could reduce or prevent PTSD symptoms. However, this could present both logistical and economical problems to ambulance services; they would need to recruit a higher number of staff so absent shifts during rotation could be covered (Simpson, 2013). Nonetheless, this cost may be offset by lower levels of absenteeism and increased staff retention, with reductions in the cost of recruiting new staff (Simpson, 2013).
Cognitive strategies used in pre-exposure interventions have been successful in lowering the prevalence of PTSD in police officers (Wild et al, 2018). The study on the iCT-R by Wild et al (2018) demonstrated that exposure to traumatic images while in a safe environment during training significantly reduced PTSD and depressive symptoms after exposure in practice. This method is delivered in a six-session online presentation and aims to move individuals away from rumination and towards resilience. Participants were encouraged to take a more concrete style of thinking when faced with traumatic experiences; by directing their focus on objectives and the sequence of events, rather than emotional triggers, rates of PTSD symptoms were lowered (Wild et al, 2018). This style of cognitive training has proven to be successful in other services such as the military and police (Wild et al, 2018); however, more research is needed in its applicability to the ambulance service.
Conclusion
This systematic literature review on the prevalence of PTSD in paramedics provides a synthesis of four studies.
With rates of PTSD in ambulance service personnel up to 10 times greater than the general public and equal to those in the military, research is needed into the causes and potential prevention.
The four studies included in this review have poor generalisability to the ambulance service in the UK and each have limitations regarding their evidence.
Up to 29% of ambulance service personnel have self-reported PTSD symptoms—a figure thought to be inaccurately low. Statistics vary for numerous reasons, such as stigma surrounding mental health conditions deterring some individuals from reporting, or the classification of PTSD differing between studies. Therefore, the true burden of mental health disorders within the UK ambulance service is unknown and more research is required.
There are two main themes in this review: cause and prevention.
The first finding of the review concerns the causes of PTSD and depression in ambulance service personnel in the UK. The rates of PTSD in the ambulance service are commonly attributed to vicarious trauma because of greatly increased exposure to traumatic events; however, the studies indicate other causes are as influential. Shift work interrupting an individual's circadian rhythm has been proven to affect salivary cortisol levels, thus increasing chances of developing PTSD in as little as 2.5 years. Furthermore, a link has been established between systemic inflammation levels and amygdala reactivity; thus, inflammation is a pre-existing vulnerability marker for the development of PTSD in individuals exposed to trauma.
The second finding of this review concerns the prevention of PTSD in ambulance service personnel through pre- and post-exposure interventions. Post-exposure debriefing has been found to be unhelpful as it can embed memories more deeply; re-living a traumatic event without sufficient follow-up is thought to worsen PTSD symptoms. These studies, however, were not conducted within the ambulance service so transferability is not clear and further research is needed.
Studies have been conducted on resilience training, similar to that used in the military and in police services; exposure to traumatic images while in a safe environment has proven to significantly reduce levels of PTSD. Therefore, studies on its application to the ambulance service are greatly needed.