• suicide
• organisation of work
• stress

Approximately 800 000 people die due to suicide every year and the number of suicide attempts is more than 20 times higher.1 This leads to millions of people to be affected or experience suicide bereavement every year. In young people aged 15–29 years, suicide is the second leading cause of death.1 Suicide occurs throughout the lifespan; suicide accounted for 1.4% of all deaths worldwide, making it the 17th leading cause of death in 2015.1 Suicide accounts for the largest share of the intentional injury burden in developed countries and it is projected to become an even greater contributor to the global burden of disease.2

Preventable risk factors of suicide include mental disorders, such as mood, impulse control and substance use disorders, as well as psychological factors such as feelings of hopelessness, anhedonia and impulsiveness.2 Stressful events, such as family and romantic conflicts, legal problems and job loss often precede suicidal behaviour, and persistent stress among some occupations, for example, physicians, military personnel and police officers, has been suggested to contribute to increased risk of suicide in those occupations.2 A recent study from the USA reported increased risk of suicidal ideation among lawyers, judges, and legal support workers, social scientists and related workers, and media and communication workers.3 In Japan, suicide caused by overwork and work stress (Karojisatsu) has been suggested to be common, partly because showing weakness, such as depression in work spheres, means betraying one’s coworkers.4

A comprehensive analysis of work-related suicide has been lacking, and addressing this gap in the present number of Occupational and Environmental Medicine, Milner and colleagues carried out the first systematic review and meta-analysis on the association between job stressors and suicidality.5 They used psychosocial factors at work as a broad concept to describe work-related stress exposures. These have usually been operationalised by the three leading theoretical models: the demand-control model (‘job strain’)6 and the effort-reward imbalance model.7 The third established model is organisational justice model, referring to the quality of leadership and supervisor behaviour.8 9 Job strain is a situation in which employees simultaneously have high job demands and low control over work. Job control (or decision latitude) refers to control over task performance (eg, pace, quantity of work, policies and procedures) and skill discretion (ie, possibility to use of skills and develop in one’s job).6 According to the effort-reward imbalance model, work stress is defined as experienced imbalance between high effort and low rewards at work.7 This imbalance violates core expectations about reciprocity and adequate exchange at work. Low rewards refer to insufficient financial compensation from work, low esteem (eg, low support from supervisors and colleagues) and poor career opportunities (no promotion prospects, high job insecurity and status inconsistency). Organisational justice has been conceptualised as distributive justice (eg, salary), procedural justice (whether organisation’s decision-making procedures include input from affected parties, are consistently applied, suppress bias, are accurate, are correctable and are ethical) and relational justice (whether supervisors treat workers with fairness, politeness and consideration).8 9

Although there is considerable evidence on the association between work-related psychosocial factors and depression,6 10 the association with suicidal behaviours as an outcome has not been extensively investigated. Recently, one study with individual-participant data from six cross-sectional studies found support to the cross-sectional association between the three work stress models and suicidal ideation by showing an increased risk for the association of job strain, effort-reward imbalance and organisational injustice.11 Other psychosocial factors, such as precarious employment, might also contribute to suicidal behaviour.12 However, the evidence on this topic has not previously been summarised into a systematic review and meta-analysis.

In the meta-analysis published by Milner et al in the present number,5 a total of 22 studies were included after the systematic literature searches. They were located in Germany, Norway, South Korea, the USA, France, China (Hong Kong Special Administrative Region), Australia, Canada, Italy, South Korea and Sweden. Exposure to job stressors included supervisor support, low job control, high psychological job demands, job strain, effort-reward imbalance, job insecurity, role conflict, long working hours and shift work. Suicidal ideation was examined in 14 studies and the association was found for high job demands, low control, low supervisor and colleague support, job insecurity, effort-reward imbalance, role conflict and job strain. For completed suicide (six studies), low job control and low supervisor and collegial support were associated with an increased risk. Two studies that examined suicide attempt were found, both of which suggested an adverse effect of job stressors. After their comprehensive analyses on the material, the authors concluded that their meta-analysis gives some evidence that psychosocial job stressors may be related to suicidal outcomes, but due to the cross-sectional nature of most of the studies, there is a need for more longitudinal research to assess the robustness of observed associations. Observational data also set some limitations to conclusions about causality. However, six longitudinal studies suggested an association between psychosocial job stressors and suicide death, particularly for low job control, although high heterogeneity between studies suggested that subgroup analyses with larger data are needed. It would also be important to have more research on exposures that have been rarely addressed or ignored, such as long working hours13 and workplace bullying,14 for which there is evidence of adverse effects on mental health. However, this first excellent meta-analysis can be considered an opening of a discussion on the potential high importance of work-related psychosocial factors in the prevention of suicidal behaviour.