Summary The ability of firms to introduce product innovations is generally acknowledged to be a key determinant of firm performance, and much more generally, improved societal welfare. The literature on open innovation suggests that firms rely heavily on knowledge exchange with external parties to successfully innovate. Yet, downsides of open innovation are still relatively unexplored. In this project, we aim at examining the relationship between changes in firms' degree of openness to the use of firm-external knowledge and the stress of their employees, as measured by drug prescriptions. The unique Danish mental health data are of great value to address this relationship thoroughly. We intend to build and extend existing infrastructure in terms of a research dataset at Statistics Denmark.