Understanding causative mechanisms in co- and multimorbidities combining mental and non-mental disorders Proposals should identify and validate causative mechanisms (e.g. molecular, genetic, correlative, drug-drug interaction) of co- and multimorbidities combining mental[[For the classification of mental disorders please refer to “Mental and behavioural disorders (FOO-F99) of WHO's International Statistical Classification of Diseases and Related Health Problems 10th Revision (lCD-10)”: http://apps.who.int/classifications/icd10/browse/2016/en#/V .]] and any non-mental disorders through the integration of basic, pre-clinical and/or clinical research[[Clinical trials are excluded]]. Applicants should prove the relevance of the identified mechanisms for co-morbid development. Where pertinent, development of biomarkers and other technologies for diagnosis and monitoring of comorbid conditions in patients is encouraged. A purposeful exploitation of existing data, biobanks, registries and cohorts is expected[[Including any national, EU or international resource or infrastructure if appropriate.]], but does not e The increasing number of individuals with co-and multimorbidities poses an urgent need to improve management of patients with multiple co-existing diseases. A better understanding of their causative mechanisms is needed to develop early diagnosis, efficient prevention and monitoring, and better treatments adapted to co- and multimorbid patients throughout their life course. Furthermore, there are many different etiological models of comorbid conditions (e.g. direct causation model or a consequence of treatment). In this context, capturing and measuring patient's complexity in the context of co- and multimorbidities is crucial for adequate management of these conditions and requires innovative approaches. New directions for clinical research to improve prevention, diagnosis, prognosis, therapy development, and management of co- and multimorbidities.Whenever relevant identified biomarkers for more accurate and earlier diagnosis, prognosis as well as monitoring of patients' condition.