[Characteristics of compensated mental disorders caused by overwork among drivers and non-drivers in the Japanese trucking industry].

Objectives: This study examined the characteristics of occupational mental disorders among those involved in the transport and postal activities in the trucking industry.

Method: We examined 237 out of 3,517 cases of occupational mental disorders, compensated between the fiscal years 2010 and 2017. An assessment was made for sex, "life-or-death" status at compensation, age at the onset and suicide, the diagnosis according to the International Classification of Diseases, Tenth Revision, and other factors regarding occupational compensation. The participants were divided into two groups: truck drivers and non-truck drivers.

Results: Men accounted for approximately 90% of the cases. Depressive episode (F32) was the most common diagnosis in drivers and non-drivers, thus constituting 65 out of 149 and 48 out of 88 cases, respectively. The next most common type of mental disorder was adjustment disorders (F43.2), with 34 out of 149 drivers and 24 out of 88 non-drivers reporting them. Furthermore, the majority of drivers that had posttraumatic stress disorder (24 out of 27 cases) reported that they "suffered a serious illness or injury" and "experienced or witnessed a terrible accident or disaster." Occupational disasters due to long working hours were 52.4% for drivers and 73.9% for non-drivers. A total of 30.8% of the drivers reported working long hours since they joined the company.

Conclusion: Drivers' long working hours entail waiting at the origin and cargo destination site, handling cargo, and incidental tasks other than driving. Thus, the reduction in work hours regarding these tasks needs to be a fundamental goal, and measures that include mental health care for accidents and miserable experiences must be implemented. However, long working hours for non-drivers are likely linked to job expansion/increase and reassignment/relocation. These findings highlight that to prevent overwork-related mental disorders, appropriate actions should be taken considering different sources of exposure for drivers or non-drivers.