Factors affecting mental health of seafarers on board merchant ships: a systematic review

Search strategy

This review is based on the analysis of scientific literature published between January 2006 and December 2021. Papers were identified through the search engines PubMed, Web of Science (WoS) and Cumulative Index to Nursing and Allied Health Literature (CINAHL).

The keywords used were: “mental health”, “behavioural disorder”, “seafarers’ stress”, “physical training on board”, and “seafarers’ mental status”, or a combination of these definitions. In the latter case, we used the “AND” Boolean operator and reported the following search strings in PubMed, Wos, and CINAHL: “mental health and seafarers on board commercial ships”, “behavioural disorders and physical training onboard”, “mental health and stress onboard”.

The authors operated the preliminary assessment independently by reading the abstracts and drafting a list of the articles considered eligible. The lists derived from the independent work of each author were compared for possible inconsistencies. If an inconsistency was identified, the different ideas were discussed to reach a unanimous consensus. Once the authors decided which articles were worth including in the review, they read all of them to gather useful data for the research. The information evaluation was conducted independently, and opinions were compared to get to a general consensus.

This review includes research articles published in 16 years (2006–2021) and in all sectors where the mental health of seafarers working on board commercial ships is most active. Since 2006, when the Maritime Labour Convention (a rule of international law establishing minimum safety requirements to ensure the health of seafarers) was enacted, a growing interest in the subject was witnessed … This review was made to evaluate whether the problem actually got the right scientific interest or it continues to be still not correctly identified, as it happened in the older literature.

The inclusion criteria for considering published literature were the following: availability of full-text English publication, original study, and research interest. The research initially provided 856 results, characterized by publications potentially relevant to the objectives of this study. Specifically, 429 works were found in PubMed, 43 in WoS and 384 in CINAHL. The types of articles analyzed were the following: research articles, case studies, surveys, and literature reviews. The inclusion criteria that guided the selection of the works were (1) type of study: analytical studies, original articles, and literature reviews published in the last 16 years (2006–2021), publications in English with full text available; and (2) articles dealing with seafarers on board merchant ships, where causes directly attributable to the mental problems of this category of workers are identified. The exclusion criteria were (1) studies with different characteristics other than those mentioned in the inclusion criteria and (2) studies that did not take into account factors directly related to the mental health of seafarers. We eliminated 333 duplicate articles.

From the analysis of the abstracts of selected articles, another 461 articles that were not pertinent to the objectives of this work were excluded for the following reasons: 318 articles related to the assessment of seafarers’s mental pathological conditions, 46 articles assessed the quality of pre-boarding visits for the preliminary identification of mental health, and 97 articles did analyze the degree of satisfaction of seafarers about working conditions on board. The remaining 62 articles met the inclusion criteria and were considered for a further analysis.

Quality evaluation

Quality evaluation of papers selected in the first phase of the study was made using the Newcastle-Ottawa Scale (NOS) [11]. NOS scores are used to assess the quality of non-randomized studies in meta-analyses, based on factors like structure, convenience, overall quality and suitability for review studies. Quality assessment was evaluated based on final NOS scores of each study: poor (if score 0–3), modest (4–6), and excellent (7–9). Studies that passed the quality test with NOS ≥7 were considered suitable for this review. Finally, 25 studies were chosen to carry out insight reviews. A complete description of study selection is summarized in Figure 1.

Figure 1:

Diagram showing the article selection process.

It should be emphasized that a selection process implemented by means of a particularly rigorous instrument such as the Newcastle-Ottawa Scale inevitably leads to the exclusion of a large number of papers resulting from an initial search. This also occurred in the research we carried out. This approach has the disadvantage of being very selective, thus excluding studies that may be of interest from the results, but has the advantage of allowing the authors to base their conclusions on more reliable data.

Summary of article pool

As mentioned above, literature search identified 25 articles centered on seafarers’s mental health.

Table 1 lists the studies about fatigue, stress, loneliness, boredom and social isolation factors on board ships that were selected for the present work. These articles are listed by the year of publication.

Fatigue

The International Maritime Organisation (IMO) guidelines define fatigue as: “A reduction of physical and/or mental condition, resulting from physical stress. It may impair almost all psycho-physical abilities including power, speed, reaction time, coordination, decision making, and/or emotional balance” [37]. The International Transport Federation (ITF) study “Seafarer fatigue: Wake up to the dangers” associates fatigue with any accidents that all crew members may incur [38].

Of the 25 articles chosen, 12 papers consider fatigue as the main cause of mental problems in marine workers. Many authors identify fatigue as a precursor to stress and mental disorders [14, 16, 21, 39, 40]. Fatigue seems to be inevitable due to activity of seafarers working on merchant ships. In general it becomes a problem as soon as the seafarer realizes that there is a problem to be addressed [16]. Papers examined have analyzed risks, acute effects, chronic health effects, and prevention of fatigue at sea. These elements are present in all the 25 articles considered. Fatigue can lead to mental health problems which are risk factors for chronic disease and early death (e.g. suicide) [14, 16, 18, 21, 39, 41]. Carotenuto et al. analyzed three different types of fatigue causes: demanding job, subjective stress and health problems [3]. Several studies have investigated in depth all aspects of fatigue such as irregular work shifts and sleep, physical risk factors, individual risk factors. All of these can cause short- and long-term health problems for seafarers [8, 13, 15–17, 22, 23, 40, 42].

Countermeasures and attempts to reduce fatigue at sea are also considered in different publications [3, 23] primarily from a regulatory point of view [3, 16, 17] rather than from a socio-health point of view. Regulatory perspective considers standard approaches such as the promotion of specific laws, international regulations, audits, supervision management, scheduling of work rest and sleep, in order to decrease the risk caused by fatigue [8]. The socio-health aspect analyzes corrective approaches concerning daily fatigue, quality, and quantity of sleep, work shifts, and nutrition [3, 11, 13, 15, 16, 25].

Stress

Seafarers are subject to numerous stress factors, most common are: adverse weather conditions, extreme variations in temperature, being tied up at sea for long periods of time, noise and vibrations, conflicts between crew members, separation from family, long working hours and shift work, irregular and poor-quality sleep, often poor-quality food, frequent crew changes, poor job and contract security [27].

Stress on board may also be secondary to experiencing a particularly tense atmosphere due to the fear of piracy attacks [33].

Stress and fatigue are closely related [3, 15, 16]. Stress can be due to fatigue [21, 39, 40], and could be associated with alcohol and drug abuse, and other mental problems [14, 18, 23–25, 39].

Some authors have also proposed measurement and prevention measures for stress [22, 23].

The cause of stress in mariners is mainly related to environmental situations, which can lead to serious problems and, in the worst cases, to substance abuse and suicide. The stress of mariners affects their partners too, though to a lesser extent [20]. Eight articles have analyzed the problem of suicides on board, from different perspectives, namely the analysis of the number of cases over the years [3, 22, 35] the evolution of mental illness up to suicide [3, 14, 24, 41], the association with alcohol and drugs abuse [3, 14, 18, 21].

Szymańska et al. define suicidal tendencies at sea as consequences of extreme stress, which outweigh adaptive abilities [14]. This situation represents a real danger to personal integrity and leads to the disappearance of the instinct for self-preservation instinct. Remedies and measures that can mitigate psychic problems about the working environment are also analyzed [13]. Some of these may consist in the promotion of on-board exercise programs [18], prevention and control of alcohol abuse, sleep and diet improvement [16, 20, 25, 41]. Another aid to mental health may come through telemedicine [43, 44]. Through telemedicine we may provide professional advice to solve the psychological difficulties of seafarers on board ships giving remote advice and support [3, 45].

Loneliness, boredom and social isolation

The problem of loneliness at sea is investigated in 11 articles of those selected for this analysis. This is related to stress, especially for long periods of navigation (8–10 months) [21] and is associated with the distance from the family for long periods [3, 26]. There are family-level repercussions, with the involvement of the partners, with possible intimate and relational consequences [26, 41]. Loneliness has been reported as a possible cause of suicide in vulnerable subjects, especially those working/living in particular environments like the open sea. Seafarers can compensate for the loneliness with excessive consumption of smoke and/or alcohol [18, 23–25, 35]. Loneliness can result from the lack of social contacts on board, often caused by existing language barriers between colleagues [21].

Boredom is analyzed in 3 studies [16, 18, 25]. It could deteriorate mental health with detrimental consequences for the quality of the work done [25]. It can also cause fatigue in the seafarer [16], and be the trigger of a serious problem such as social isolation. Social isolation has been analyzed in 11 of the selected works [3, 14, 15, 18, 21, 23–25, 28, 35, 41].

Swift has analyzed the difference between loneliness and social isolation. Loneliness is a person’s subjective emotional state, while social isolation is the state of deprivation of social contact. It is a form of the psychological state of alienation and can cause feelings of boredom, marginality, exclusion, anger, despair, sadness, frustration and above all loneliness [18]. Social isolation is one of the major causes of psychological problems on board and has caused a decrease in the number of seafarers in western countries [8]. Isolation can lead to despair and depression [3].

Isolation is also defined as a great challenge for seafarer’s mental health [21]. The same author has hypothesized a solution that may remedy social isolation: the possibility of including their partners in travel and in the working activity, where possible [18].

There are many proposals of a “communicative” kind to prevent loneliness and the sense of isolation on board, through the provision of instruments and stations for communications (for example Skype or other video calling software) and Internet access, as well as access to video recordings major sporting events, and receiving news from around the world [3, 18, 21, 35].

Also of interest is the amplifying effect of perceived social isolation attributable to social media use [30]. Continuous and frequent exposure to idealized representations of people leading lives full of sociality and success can lead to feelings of envy, which can promote the onset of depression.

The COVID-19 pandemic that erupted in late 2019 has contributed to even more extreme isolation conditions for many sailors [29, 31, 32, 46, 47].

In many cases, borders were closed, and travel restrictions led to changes in crew changes, further prolonging many seafarers’ time at sea.

Restrictions related to the health emergency imposed severe limitations on shore leave, which was even banned in many ports.

This was compounded by additional stressors such as fear of contagion, job insecurity, concern for the welfare of family members and more difficult access to medical care.

Abuse

Physical and/or verbal abuse on board can occur both between colleagues and between employer and employees. Prolonged, cruel and oppressive abuse is among the causes of depression, anxiety and suicidal thoughts among seafarers [24]. The main types of abuse found on board are: are: physical and/or verbal offenses, humiliation, personal insults, ridiculing a person, or his/her abilities, either in private or in front of others; Sudden rages or displays of temper against an individual or group, persistent criticism; making unreasonable demands of staff or colleagues, etc [48].

Competent authorities must take into consideration the problems of abuse on board since they can have serious consequences on the seafarer’s mental and working status. Wrong behaviors should be reported promptly, and reporting handled anonymously to avoid repercussions on the alerter [48]. Investigations on this phenomenon must be carried out objectively and independently, analyzing any circumstance that may have led to the phenomenon of abuse [48]. Marine authorities and shipping companies shall monitor these behaviors by establishing severe penalties especially for repeated physical abuse phenomena, as well as for other work environments.

Regulations

The lack of specific international regulations relating to the activity of seafarers in the world contributes to the irresolution of the problem of stress on board [3, 16, 17, 49]. Marine industry regulations are apparently focused more on seafarer’s individual problems rather than harmonizing the norms of each individual country [50].

In the articles examined, the norms are analyzed in reference to specific situations. Allen et al. addresses in depth the problem of fatigue and the regulations of seafarers’ shifts and working hours. They address a complex issue – the chance to verity the actual working time during navigation. They call for an approach that allows better management of working times, for example through registers or logbooks [16].

Another essential requirement is to apply existing guidelines with mandatory provisions and take serious measures to overcome the problem of false record-keeping. Working hours are likely to be under-recorded by managers or individual workers on board commercial ships who are afraid of losing their current or future occupation by subjecting their company to legislative control.

The International Labor Organization (ILO) Convention regarding the maximum of working hours on board, and ILO Conventions 92, 133, 140, 141, and 147, introduce higher living standards on board ships such as noise control and air conditioning [17]. The limits of working hours and hours off work reported in the Maritime Labor Convention 2006 are similar to those in ILO 180 [51].

The International Safety Management (ISM) Code states that if fatigue, excessive hours of work, or lack of adequate rest are or should be apparent, the master and the company should intervene as soon as possible to solve this problem [17]. What emerges is the need for greater legislative support in matters of close interest to mariners, also through the help of national and international shipping companies and agencies [40].