The link between involuntary non-regular employment and poor mental health: A cross-sectional study of Japanese workers

Involuntary non-regular employment is a severe inequity problem worldwide, and it may significantly affect the mental health of employees. The present study aimed to examine the relationship between employment type and mental health. Additionally, the characteristics of involuntary non-regularly employed workers were explored. An online-based cross-sectional study was conducted in Japan, and 1566 participants were included in the data analysis. The eligible participants were divided into four categories: regularly employed (n = 1092), voluntary (n = 134), average (n = 233) and involuntary (n = 107) non-regularly employed individuals, respectively. Involuntary non-regular employment was associated with greater lack of vigour, anger-irritability, fatigue, anxiety, and depression. It was higher among women, those who were single or had no childcare, and those who had lower personal income or shorter working hours, or who tended not to practice relaxation activities. Lower personal income was associated with a risk of anxiety and depressive symptoms. Those individuals experiencing involuntary non-regular employment had a higher risk of poor mental health; subgroup analysis showed that this was particularly true among men. Both encouragement of employment stability via policy reform and workplace mental health support for involuntary non-regularly employed individuals are urgent health concerns.