Association of Occupation, Employment Contract, and Company Size with Mental Health in a National Representative Sample of Employees in Japan: Akiomi Inoue, et al. Japan Society for the Promotion of ScienceObjectives: The purpose of this study was to investigate the cross‐sectional association of employment contract, company size, and occupation with psychological distress using a nationally representative sample of the Japanese population.Methods: From June through July 2007, a total of 9,461 male and 7,717 female employees living in the community were randomly selected and surveyed using a self‐administered questionnaire and interview including questions about occupational class variables, psychological distress (K6 scale), treatment for mental disorders, and other covariates.Results: Among males, part‐time workers had a significantly higher prevalence of psychological distress than permanent workers. Among females, temporary/contract workers had a significantly higher prevalence of psychological distress than permanent workers. Among males, those who worked at companies with 300–999 employees had a significantly higher prevalence of psychological distress than those who worked at the smallest companies (with 1–29 employees). Company size was not significantly associated with psychological distress among females. Additionally, occupation was not significantly associated with psychological distress among males or females. Similar patterns were observed when the analyses were conducted for those who had psychological distress and/or received treatment for mental disorders.Conclusions: Working as part‐time workers, for males, and as temporary/ contract workers, for females, may be associated with poor mental health in Japan. No clear gradient in mental health along company size or occupation was observed in Japan.

This study was aimed to investigate the test-retest reliability and validity of a short version of the New Brief Job Stress Questionnaire (New BJSQ) whose scales have one item selected from a standard version. Based on the results from an anonymous web-based questionnaire of occupational health staffs and personnel/labor staffs, we selected higher-priority scales from the standard version. After selecting one item with highest item-total correlation coefficient from each scale, a 23-item questionnaire was developed. A nationally representative survey was administered to Japanese employees (n=1,633) to examine test-retest reliability and validity. Most scales (or items) showed modest but adequate levels of test-retest reliability (r>0.50). Furthermore, job demands and job resources scales (or items) were associated with mental and physical stress reactions while job resources scales (or items) were also associated with positive outcomes. These findings provided a piece of evidence that the short version of the New BJSQ is reliable and valid.

Reliability and Validity of the Japanese Version of the Organizational Justice Questionnaire: Akiomi Inoue, et al. Department of Mental Health, Graduate School of Medicine, The University of TokyoObjectives: Previous European studies reporting low procedural justice and low interactional justice were associated with increased health problems have used a modified version of the Moorman's Organizational Justice Questionnaire (OJQ, Elovainio et al., 2002) to assess organizational justice. We translated the modified OJQ into the Japanese language and examined the internal consistency reliability, and factor‐based and construct validity of this measure. A back‐translation procedure confirmed that the translation was appropriate, pending a minor revision.Methods: A total of 185 men and 58 women at a manufacturing factory in Japan were surveyed using a mailed questionnaire including the OJQ and other job stressors.Results: Cronbach alpha coefficients of the two OJQ subscales were high (0.85–0.94) for both sexes. The hypothesized two factors (i.e., procedural justice and interactional justice) were extracted by the factor analysis for men; for women, procedural justice was further split into two separate dimensions supporting a three‐ rather than two‐factor structure. Convergent validity was supported by expected correlations of the OJQ with job control, supervisor support, effort‐reward imbalance, and job future ambiguity in particular among the men.Conclusion: The present study shows that the Japanese version of the OJQ has acceptable levels of reliability and validity at least for male employees.

Background Research on the association between job strain or other job stressors and depressive disorders is still limited. The purpose of the present study was to investigate the prospective association of job strain, role stressors and job insecurity with long-term sick leave due to depressive disorders. Methods A prospective study was conducted of a total of 15 256 men aged 18–67 years with no previous history of mental disorders employed in six manufacturing factories located in several regions of Japan. At baseline, they were surveyed using a self-administered questionnaire, including self-reported measures of job strain, as well as its components (job overload and job control), role stressors (role ambiguity and role conflict), social support at work, job insecurity and other demographic and psychological covariates. During the follow-up, a long-term sick leave of 30 days or more due to depressive disorders was recorded. Results During 5.14 years of follow-up on average, 47 incident cases of sick leave of 30 days or more due to depressive disorders were observed. High job control at baseline was associated with a lower risk of long-term sick leave due to depressive disorders, after adjusting for demographic variables, depressive symptoms and neuroticism at baseline (hazard ratio 0.28, 95% CI 0.11 to 0.71); high role ambiguity was associated with the higher risk (hazard ratio 3.49, 95% CI 1.43 to 8.49). Conclusion Job control and role ambiguity may be important predictors of long-term sick leave due to depressive disorders among male employees, independent of depressive symptoms and neuroticism.