Migrant workers worldwide commonly are susceptible to mental disorders. Since the 1980s, there has been a large-scale increase in the number of migrant workers in China; this development parallels the acceleration of socio-economic transformation. Studies addressing this population rarely focus on workers' mental health or psychological well-being, yet it is imperative to understand the mental health status of rural-to-urban migrant workers and study the relationship between migration and mental health.
A cross-sectional survey of 3286 participants (response rate 85.4%) was conducted among different work units in Shanghai. All of the variables of this survey were assessed by a self-administered questionnaire, with depression measured by the Patient Health Questionnaire-9 (PHQ-9) scale and poor mental health (PMH) measured by the World Health Organization 5-Item Well-Being Index (WHO-5) scale. Pearson's χ2 test and logistic regression were used to compare migrants with urbanites, and to identify factors related to mental health outcomes.
Migrant workers (15.3%) had a slightly higher prevalence of depression than non-migrant (12.0%) workers, with notable PMH (26.9%) among participants >45 y of age. In the logistic regression models, those who reported low job satisfaction, unhealthy organizations, poor physical health (self-rated) and long working hours were 2.86 (95% CI 2.14 to 3.84), 1.42 (95% CI 1.06 to 1.91), 1.89 (95% CI 1.41 to 2.55) and 1.48 (95% CI 1.08 to 2.03) times more likely to have depression, respectively. Similarly, workers >45 y of age were 2.92 (95% CI 1.65 to 5.16) and 1.80 (95% CI 1.01 to 3.21) times more likely to have PMH for low job satisfaction and unhealthy organizations, respectively.
There are numerous potential causes affecting the mental health of Chinese internal migrant workers. Strengthening the construction of healthy organizations and enhancing workers' job satisfaction may improve the mental health status or psychological well-being of this group.