The prevalence of CMD found (16.2%) was equivalent to the one observed among primary care health professionals of the Brazilian Northeast and South (16%) (Tomasi et al. 2008). However, a study in primary care units in Botucatu (São Paulo, Brazil) found higher prevalence (48% for nurses and 43.8% for nursing technicians/assistants) (Braga et al. 2010). This variation may be associated with the employment characteristics in the investigated contexts. In this study, temporary work predominated, as has been commonly reported, as the predominant health employment profile in the northeast region. Such precariousness of the nursing profession can influence the provided answers: instability in the employment bond can produce a positive response bias due to the constant fear of unemployment. It is also possible that continuous hiring and firing mechanisms are operating, in which only the healthiest workers maintain their jobs.
Brazilian studies with nursing professionals from the hospital network found distinct CMD prevalence: in the northeast, the prevalence ranged from 14.6 (Souza, Martins Júnior, et al. 2011) to 35% (Rodrigues et al. 2014.); in the south and southeast, prevalence rates from 18.7 (Kirchhof et al. 2009) to 44.6% (Baptista and Tito, 2014) were observed. The observed variations allow us to infer that regional iniquities imply differences in the environment and working conditions, specifically affecting the workers’ mental health conditions. It is worth mentioning that although all the aforementioned studies used the same research instrument (SRQ-20), cut-off points for suspected CMD were not presented. Thus, it is possible that this definition influenced the estimated prevalence, compromising the compatibility among the studies. Therefore, it is necessary to standardize the forms of analysis by means of a validation study of this instrument for this professional category, in order to obtain a better comparison.
The factors associated with CMD were professional category, longer working hours, personal insecurity at work, effort-reward imbalance, high domestic overload, dissatisfaction with oneself, poor quality of life, and negative self-assessment of health. This reveals an association between the working, domestic and professional, and sickness causing characteristics of these female professionals, as well as between satisfaction with life and work and health conditions of the individual.
Evidence of increased exposure to mental illness by female nurses diverges from the understanding that individuals with higher schooling are less exposed to illness (Abbas et al. 2013; Farias and Araújo, 2011; Pinho and Araújo, 2012). It seems that in nursing, this relationship is reversed: a cross-sectional study with workers from Botucatu’s primary health network (São Paulo, Brazil) showed a 9.5% increase in CMD among nurses (Braga et al. 2010); another investigation in two hospitals in Manaus (Amazonas, Brazil) found a 13% higher CMD prevalence among nurses (Arruda, 2014); in the hospital network of Bahia (Brazil), nurses had a CMD prevalence 23.7% higher when compared to the auxiliaries and 8% higher than the nursing technicians (Rodrigues et al. 2014). This reality is also identified in specialized hospital professionals (Feira de Santana, Bahia, Brazil), with 8% more CMD among nurses (Souza, Martins Júnior, et al. 2011). Only a study with female nursing professionals from a public hospital in Salvador (Bahia, Brazil) showed evidence of a higher prevalence of CMD among nursing technicians (36.4%, compared to 20% in nurses) (Araújo et al. 2003).
This higher evidence of exposure to mental illness among nurses can be attributed to their work process, in which multiple tasks are developed, including management and care. This entails an intense rhythm, activity accumulation, and work overload. These characteristics are not exclusive of hospital work as they can also be seen in primary care (Almeida, 2012). Due to this overload, the job invades the nurse’s “way of life,” extending the workday and often preventing the development of quality work.
We identified that the workload per day was associated with mental illness among the female nursing professionals, corroborating the findings in the literature that identify a 33% higher prevalence of CMD among female urban workers with longer working hours (Farias and Araújo, 2011); in primary health care workers, this difference was 92% (Oliveira, 2013). Long workdays are common among health professionals, as a result of multiple employment bonds, which in turn are a reflection of low wages and employment insecurity, due to the precariousness of health work in Brazil. The long hours dedicated to work produce two events that together can potentiate the negative effects of work: (a) prolonged alertness, which increases the production of the so-called stress hormones (Karasek and Theorell, 1990), requiring that the individuals should be prepared to meet the demands of work—in activities that involve risks for others, such as health activities, the pressure for attention, and vigilance increases even more; (b) reduction of the time for activities of resting, physical activity, and leisure constitute mechanisms of recovery and physical and mental balance. Thus, the greater the workload, the more vulnerable will the situation for mental health be.
The workload per day of the studied professionals is incorporated into the domestic work, exposing them to the two working environments which entails physical and psychic overload (Araújo et al. 2005). A study with workers from the urban area of Feira de Santana (Bahia, Brazil) showed a CMD prevalence 5.23 times higher among domestic service workers when compared to the reference category (transportation sector) (Farias and Araújo, 2011). Therefore, when analyzing the workload, especially in occupations predominantly composed of women, such as health and education, one must also include the analysis of the contribution of the domestic workload (Araújo et al. 2005; Farias and Araújo, 2011). In this way, the necessary visibility of health of the women exposed to this double working day will be attained.
Female workers with high domestic overload had almost twice as many CMD compared to women with a low/medium overload. In addition to the overload attributed to double working hours, women are still subject to the devaluation of women’s work, considered an important triggering factor for physical and mental exhaustion (Araújo et al. 2005).
The imbalance between the efforts made at work and the received reward was also identified as a factor associated with mental illness. Similar results have been observed in other studies in the health sector, with primary care health workers (Oliveira, 2013) and hospital nursing professionals (Arruda, 2014), and in other sectors, such as high-voltage network electricians (Souza, Carvalho, et al. 2011). In these studies, robust and consistent associations between situations of imbalance between efforts and rewards at work and mental illness were observed. Thus, aspects related to the perception of justice, of balance between what is given and what is received at work also plays, as observed, a relevant role in the psychic balance. The perception that what is being given does not match what is being achieved seems to produce feelings of devaluation and non-recognition, generating suffering. The continuity of this imbalance is an open door to mental illness.
Hence, the hypothesis that the non-balancing of effort and rewards at work can be harmful to mental health (Siegrist, 1996) was strengthened. The characteristics of the working process in nursing evidence this situation as the work involves high effort and low rewards, attributed to lagged salaries and lack of recognition by co-workers and users.
In primary care, recognition comes from the community, and it is necessary to build a bond for the continuity and integrality of this care. In the Brazilian context, for many of the actions, the workers do not have total governability and depend on the support of the Municipal Health Secretaries and subsequent levels of attention belonging to the Health Care Networks.
This support is often precarious, compromising the quality of the provided assistance and the users’ satisfaction. These situations, that compromise the recognition of the effort given by nursing professionals, end up contributing with feelings of inadequacy and uselessness which, in turn, produce psychic suffering (Almeida, 2012). A research in nursing primary health care workers in a municipality of Bahia identified high prevalence of moderate/high emotional exhaustion (61.6%), high depersonalization (48.3%) and low job satisfaction (56.6%) (Merces et al. 2017), which, in turn, produce physical illness and mental.
Job insecurity was another factor associated with CMD. Several studies have shown that direct contact with communities, especially suburban ones, may represent exposure to violence, establishing a relationship between the latter and mental illness (Assunção and Silva, 2013; Oliveira, 2013; Yang, Wong, and Coid, 2013).
In primary care, work activities are performed in the health units and in their coverage areas, which are often high-risk areas. In addition, these professionals, especially the nursing team, remain longer and in greater interaction with patients and their companions, being constantly exposed to violent acts. This can cause permanent worrying, favoring the development of emotional symptoms, such as frustration, stress, sadness, anger, discouragement, and low self-esteem (Gasparini, Barreto, and Assunção, 2006). The relationship between lack of safety in the work environment and mental illness of the worker is thus established.
The association between satisfaction and mental health situation is consistently observed (Haddad, 2000), showing that mental health is favored when the individual is in harmony with himself and his environment. The findings showed that personal dissatisfaction was associated with CMD. Satisfaction stems from an assessment that the duty has been fulfilled and that a given social utility was attained (the desires at work have been achieved) which cannot always be done in real working conditions. It is also noteworthy that satisfaction is an important indicator of resilience that can contribute to reduction of the impacts generated by the working conditions and environment in mental illness.
The negative evaluation of quality of life was also associated with CMD, corroborating a study of Jansen et al. (2011): higher prevalence rates of CMD related to the worst levels of quality of life. Poor quality of life can influence both the onset and permanence of mental disorders (Jansen et al. 2011), and may have coincidental factors, that is, working conditions and environments have direct impacts on quality of life and mental health (Alvarenga and Marchiori, 2014). Therefore, the findings confirm that quality of life and CMD are correlated in different ways.
Therefore, health is reaffirmed as a biopsychosocial well-being, in which physical and mental health are interdependent, as already pointed out in other studies (Abbas et al. 2013; Assunção and Silva, 2013; Jansen et al. 2011; Merces et al. 2016). The nursing professionals who negatively assessed their health status had a 77% higher prevalence of CMD than those who positively assessed their health status, which is similar to results from other studies (Arruda, 2014; Assunção and Silva, 2013). It is worth remembering that health self-assessment encompasses various aspects, involving a multidimensional structure which includes the mental health conditions, to the extent that this indicator considers the signs and symptoms of diseases and their impact on the physical, mental, and social well-being (Griep, Rotenberg, Landsbergis, and Vasconcellos-Silva, 2011).
The results found in this study indicated the importance of several factors in the mental illness of the individuals, with emphasis on working conditions. This reinforces the need for studies deepening the investigation of each of these specific factors in the occurrence of mental disorders in the nursing work activities as well as the real impacts of this illness on their life and work.
There is a clear need for investments to promote the mental health of health professionals, especially through the implementation of policies to promote and protect the workers’ health, aiming at raising the quality of life and satisfaction of this category, as well as the quality of care provided to the users of the Unified Health System (Gärtner et al. 2010).
There are some aspects that should be considered in the evaluation of the results of this study. Since it is a cross-sectional study, it is not possible to define the chronological order of the events, which makes it impossible to establish causal relationships. It is neither possible to rule out reverse causality, since worse health levels can lead to the overestimation of risk situations. Another important limitation of this study design is the survival bias and the effect of the healthy worker, as we only analyzed only employed individuals that present the effect of interest at the time of the research and remained working, which can underestimate the actual prevalence of the disease (prevalence bias).
Therefore, the need for future investigations, through longitudinal studies to diagnose the actual prevalence and/or incidence of CMD and the causal pathway of the associations identified with them, needs to be highlighted. The planning and programming of health actions based on Health Surveillance requires a detailed knowledge of the occurrence and understanding of the factors that determine the distribution of diseases related to health, in order to propose measures to address the health necessities of the workers.
Intervention studies and/or extension projects in partnership with the Reference Centers in Occupational Health (Centro de Referência em Saúde do Trabalhador-CEREST in Portuguese) are also relevant, as they would allow to recognize locally the risk factors (physical, chemical, biological, ergonomic, of accidents, and psychosocial) in the nursing work processes and environments. These actions may favor the shared planning coping strategies to increase the resilience of these workers—understood by Sousa and Araujo (2015) as a set of social and intrapsychic processes that enable a healthy life in an unfavorable environment. In addition, permanent educational actions should be developed to understand psychological diseases and ways to overcome stigmas of them. In case of sickening, the workers should be taken to the Network of Psychosocial Attention (Rede de Atenção Psicossocial-RAPS in Portuguese) of reference. This will allow the delineation of lines of care for the integral and equitable attention of the workers in psychological suffering, including therapeutic measures integrated with cultural aspects.