How does working time impact perceived mental disorders? New insights into the U-shaped relationship

Area of Science:

• Sociology
• Public Health
• Labor Economics

Background:

• Existing literature often assumes a linear relationship between working hours and mental health.
• Endogeneity issues in studying working time's impact on mental disorders require robust methods.

Purpose of the Study:

• To investigate the non-linear relationship between working hours and perceived mental disorders.
• To identify the optimal threshold for weekly working hours concerning mental health.
• To examine subgroup variations in the impact of working hours on mental health.

Main Methods:

• Utilized a large-scale, nationally representative survey from China.
• Employed automation's impact on working hours as an instrumental variable to address endogeneity.
• Analyzed the U-shaped relationship between working time and perceived mental disorders, controlling for complex nonlinearities.

Main Results:

• A U-shaped relationship was identified: mental disorders decrease with working hours up to 48.69 hours/week, then increase.
• The identified turning point aligns with the International Labor Organization's 48-hour standard.
• Significant subgroup heterogeneities observed: males, older workers, and the highly educated are more vulnerable to overwork's negative mental health effects.

Conclusions:

• Working time exhibits a U-shaped impact on perceived mental disorders, with a critical threshold around 48.69 hours/week.
• Specific demographic groups (males, older, highly educated) show increased vulnerability to overwork.
• Labor protections and social security can mitigate mental health issues associated with overtime, informing optimal work hour policies.