This study examines how psychological distress (measured by the K10 screening test) and presenteeism (measured by the quality and quantity method) change in the six months after returning to work from having taken a sick leave because of a mental illness. In a manufacturing company with approximately 2,600 employees, 23 employees returned to work after experiencing mental illness between April 2015 and March 2016, and all 23 agreed to participate in the study. We analyzed 18 cases for which we had sufficient data. Two of the employees were absent from work in the sixth month. We performed multilevel analysis for K10 and presenteeism over time on the 16 without recurrence. A significant decreasing trend was observed for both K10 and presenteeism. Eleven of the 16 employees were consistently below the K10 cutoff value of 10 for six months, and 5 had zero presenteeism in the sixth month, whereas 6 employees showed improvement in presenteeism that stopped midway through the study. An occupational physician judged that the employees could work normally with presenteeism of zero. After returning to work, it is important to monitor not only psychiatric symptoms but also presenteeism.
