Depression is a commonly occurring mental disorder that usually have a chronic recurrent course throughout the life causing extensive sufferings to the patients. Previous studies suggest that depressed patients are prone to develop several other disorders, so called multimorbidities, most likely due to common biological and environmental risk factors. The aim of the TRAJECTOME project is to investigate how these multimorbidities emerge in time in order to identify disease trajectories. These disease trajectories will help to distinguish depressed patients with similar multimorbidity profiles and identify which specific biological, socioeconomic and lifestyle factors contribute to the development of their symptoms. By understanding these processes, the TRAJECTOME project will enable improved disease prediction and prevention in depression and also provide new insight for drug discovery to promote personalized medicine in depression related multimorbidities.