This interdisciplinary project combines the expertise of computer science and clinical psychology. The goal of this study is to develop the core function of an app that recognizes compulsive hand washing using wearable technology. By applying machine learning to inertial wrist motion we aim for detection with high recall (> 80%) and maximum precision – using consumer off-the-shelf hardware. This novelty has the potential to considerably advance the field of personalized medicine, in particular computer-aided assessment and therapy of mental disorders such as obsessive-compulsive disorders. The project is supported by Eucor – The European Campus in the “Research and Innovation” category of the Seed Money scheme.