Educational environments can pose serious risks for students; these risks include bullying, truancy, and even student suicide [1]. These conditions also undermine the mental health status of teachers engaged in solving such problems. Several studies conducted in different countries internationally have reported that teachers have a higher risk of mental disorders and work-related stress, compared with other workers [2, 3].
According to a survey [4] conducted by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT), teachers scored higher on fatigue and job stressors than workers from other industries (e.g., forestry, mining, construction, manufacturing, real estate and service). The main causes of stress reported were problems related to the amount of work (teachers: 60.8%; other workers: 32.3%) followed by problems with work quality (41.3, 30.4%, respectively) [4]. However, not only teaching itself but also spending long periods of time on pedagogical practices, student counseling, and miscellaneous administrative tasks associated with their work can be stressors and may undermine the mental health of teachers. Given the recent changes in Japanese educational settings, teaching has become more challenging. In the MEXT [4] summary mentioned previously, teachers were found to be facing not only issues with students who require various considerations but also with parents who demand the best for their children [4]. Due to these conditions, teachers’ overtime hours have increased, while their holidays have decreased [5].
According to a survey conducted by the Japan Trade Union Confederation, 72.9% of elementary school teachers, 86.9% of junior high school teachers, and 61.4% of high school teachers worked more than 80 h of overtime per month, which is recognized as passing the threshold of “karoshi” (literally translated as “death from overwork”) or occupational sudden mortality [6].
Teachers are exposed to various stressors under sometimes severe working conditions, resulting in deteriorating mental health status. The latest report by MEXT [7] indicated that among 920,760 teachers, sick leave was taken by 7796 public school teachers in 2018. Of these teachers, 5077 (65.1%) were diagnosed with at least one mental disorder, as formally diagnosed by a physician. Additionally, the turnover rate of public school teachers due to mental health disorders has remained high: 57.6% in elementary schools, 58.1% in junior high schools, and 58.8% in senior high schools [4]. In private schools, the turnover rate was 47.4% for elementary schools, 42.4% for junior high schools, and 37.9% for senior high schools [4].
Various factors cause the stress experienced by teachers, and poor physical and mental health can affect teachers’ ability to perform their duties [5]. Further, if teachers continue working while having impaired mental health or develop a mental illness requiring a leave of absence, the management of the school may be affected [5]. Thus, developing methods to maintain and improve high school teachers’ mental health is urgently needed. Occupational stressors are one factor having a negative impact on the mental health of teachers. According to existing research, some of the stressors that affect the mental health of teachers are job content stress [8], long working hours [9], job dissatisfaction [10,11,12], interpersonal conflict at work [13, 14], conflict with students and parents [13], and high job demands with low job management [15, 16]. However, most of these existing studies have focused on primary school and junior high school teachers, with few focusing on high school teachers [9, 11, 12, 14,15,16]. Moreover, the educational and career guidance needed by high school students is more specialized than that required for elementary and junior high school students [17]. Thus, differences in the stress structure between high school teachers and those working in elementary and junior high schools might exist. Previous research that investigated teacher stress by school type indicated that high school teachers had higher stress levels and received less social support than elementary school and junior high school teachers [18]. Therefore, this study aimed to examine private and public high school teachers.
Despite these sometimes severe working conditions, many teachers are able to manage their stress and even perform well, carrying out their duties without experiencing deterioration of their mental health. Another aspect affecting teachers’ mental health involves the factors that enable teachers to maintain positive mental wellbeing. We hypothesized that sense of coherence (SOC) [19], job satisfaction, and social support might positively affect teachers’ mental health status.
SOC is a key concept of stress-coping behavior. It comprises three components: “comprehensibility,” “manageability,” and “meaningfulness.” [19] As individuals cope with stress, SOC mobilizes psychosocial resources known as generalized resistance resources [19]. Previous studies have suggested that higher SOC levels may protect mental health, regardless of location, occupation, age group, and gender [20,21,22,23,24,25]. Additionally, job satisfaction contributes to mental health, regardless of occupation type [10,11,12, 26, 27]. Moreover, social support creates conditions that help individuals cope with stressful situations [28]. This is especially true among teachers, as social support has been found to help maintain mental health and avoid burnout [29], while also acting as a buffer for depression [15]. Additionally, job satisfaction contributes to mental health regardless of location (e.g., Iran, Japan, South East Nigeria, Thailand) [10,11,12] or occupation type (e.g., factory worker, school teachers, local civil servants) [10,11,12, 26, 27].
In this study, we examined how SOC, job satisfaction, and workplace social support contribute to mental health status when mental health status is undermined by occupational stressors. We considered four types of occupational stressors: workload stress generated by the work itself; high job demands due to time constraints and quantitative load; low participation in job decision-making, including low job control; and interpersonal environment stressors generated from the workplace atmosphere and interpersonal relationships.