The environMENTAL project will investigate how some of the greatest global environmental challenges, climate change, urbanisation, and psychosocial stress caused by the COVID-19-pandemic affect mental health over the lifespan. It will identify their underlying molecular mechanisms and develop preventions and early interventions. Leveraging cohort data of over 1.5 million European citizens and patients enriched with deep phenotyping data from large scale behavioural neuroimaging cohorts, we will identify brain mechanisms related to environmental adversity underlying symptoms of depression, anxiety, stress and substance abuse. By linking population and patient data via geo-location to spatiotemporal environmental data derived from remote sensing satellites, climate models, regional-socioeconomic data and digital health applications, our interdisciplinary team will develop a neurocognitive model of multimodal environmental signatures related to transdiagnostic symptom groups that are characterised by shared brain mechanisms. We will uncover the molecular basis underlying these mechanisms using multi-modal -omics analyses, brain organoids and virtual brain simulations, thus providing an integrated perspective for each individual across the lifespan and spectrum of functioning. The insight gained will be applied to developing risk biomarkers and stratification markers. We will then screen for pharmacological compounds targeting the molecular mechanisms discovered. We will also reduce symptom development and progression using virtual reality interventions based on the adverse environmental features - developed in close collaboration with stakeholders. Overall, this project will lead to objective biomarkers and evidence-based pharmacologic and VR-based interventions that will significantly prevent and improve outcomes of environmentally-related mental illnesses, and empower EU citizens to manage better their mental health and well-being.