We found that the main factor contributing to depression are mental and physical components of nurses, marital status (married compared to single), night work hours, overtime, and history of depression among nurses whose direct effect outruns their indirect effect (through physical and mental components).
Mental component plays an essential part in depression as better mental health gives rise to increase in trust and cohesion and prevent depression (
3,
4). However, compared to other jobs, nursing profession sets nurses up for numerous high-risk factors such as emotional issues related to the patient, arduous conditions of work, particularly in sections like CCU, ICU, and pediatric section, long working hours, night shifts, heavy workload which in turn increases stresses, depression, and emotion-related problems (
1,
20). According to epidemiological studies, psychological factors at work setting play a pivotal role in developing depression. Nurses are exposed to high level of stress which causes depression in them (
3,
5,
11).
Previous studies found a significant relationship between marriage and depression which is in accord with our findings (
3,
5). Depression is found more in single people as married couples have a purposeful joint life and hopefully attempt to improve it; therefore, married nurses as opposed to single ones experience less, risk factors contributing to depression (
21).
Long and irregular night shifts hours negatively affect nurses’ physical and psychological aspects, personal and social life, performance and efficiency. They are contributing factors to depression among nurses. Portela et al. found that there is a relationship between night shifts and nurses’ depression (
22). Shifts can cause physical and psychological after-effects resulting in a reduction in people’s efficiency and capability of doing work. Depression as an after-effect of night shifts can lead to nurses’ low efficiency. A lot of research have shown the correlation between depression and shifts, especially night shifts (
6,
22,
23). As shown by Ruggiero et al., night shifts can develop or even exacerbate sleep disorder, and on the other hand, there is a relationship between sleep disorder, affective disorder, and depression (
23), so a direct relation exists between increased working hours and depression, which is consistent with our findings (
24,
25).
As we found, there is a relationship between sex and nurse’s depression as depression has been revealed to be more common in women than men. According to research conducted in the U.S. and Europe, about 9% - 21% of women and 5% - 12% of men go through depression in their life span. Baba et al. found that there is a significant relationship between depression and nurses’ sex which is in accord with our findings (
3,
26). This difference is probably due to more emotionally engagement of female nurses as well as their hormonal differences (
26,
27). Rovner et al. found in their study that there is a significant relationship between nurses’ age and depression, which is similar with findings of the present study (
28).
Evaluating anxiety and depression among nurses, Teresi et al. argued that working hours, education, number of children, and their age are the main factors related to the nurses’ depression, but no relationship was found between the nurses’ gender and depression (
29). It seems that with increasing age, due to decreased energy and more engagement, people’s social interaction and communication accordingly decline and their physical problems increase which may explain the relationship between age and depression, as physical and psychological issues are intertwined (
23,
25,
29).
Mental component is a factor affecting depression as better mental health can give rise to increase in trust and cohesion and prevent depression, thus, it is essential to make plans for people’s psychological improvement and nurses, in particular. Promoting mental health is considered the index of social system efficiency which is, in practice, measured through the appraisal of people’s life in community. Policy makers and planners should promote nurses’ quality of life with the available resources. Given the psychological and physical after-effects of night shifts as a contributing factor to depression, careful plans are necessary for reducing night shifts hours. Nurses’ physical health is also an important factor in depression as the better a nurse’ physical health, the lower the incidence of depression. In this regard, focusing on physical health through a healthy life style could be helpful. Direct effects of quality of life (mental and physical components), marital status, night shifts, and overtime are important findings yielded from path analysis which makes it essential for policy makers and health care officials to closely concentrate on them. Further research can help scrutinize the relationship between depression and quality of life among nursing community.