Workplace social capital and mental health: baseline results from a large scale panel study of Japanese workers

Introduction: Some European studies showed that low workplace social capital was associated with employees'' poor mental health, such as psychological distress and major depressive disorders.  In Japan, however, these kinds of studies are still limited.

Objectives: The purpose of the present study was to investigate the cross-sectional association of workplace social capital with psychological distress and major depressive episode (MDE) in the past 12 months in Japanese employees.

Methods: A total of 822 males and 236 females (response rate, 24.7%) from an information technology company in Japan completed a self-administered questionnaire, including a scale of workplace social capital, which was developed based on the theoretical notion and showed high internal consistency reliability (Cronbach''s alpha coefficient = 0.90 in the present sample), the Job Content Questionnaire (JCQ), the Eysenck Personality Questionnaire-Revised (EPQ-R), the K6 scale, and other demographic characteristics.  A web-based self-administered version of computerized Composite International Diagnostic Interview Version 3.0 (CIDI 3.0) was used to assess MDE in the past 12 months.  Multiple logistic regression analyses were conducted. Results: After adjusting for age, sex, education, the number of family members, life events in the past 12 months, chronic physical conditions, occupation, workplace social support, and neuroticism, low workplace social capital was significantly associated with psychological distress (i.e., five or more on the K6 scale score) (p for trend = 0.003).  However, non-significant association of workplace social capital with MDE in the past 12 months was observed (p for trend = 0.292).

Conclusions: Low workplace social capital may be associated with psychological distress independently of workplace social support and neurotic personality traits among Japanese employees.  Non-significant association of workplace social capital with MDE in the past 12 months may be due to small sample size.