The number of people seeking help for mental illness is increasing across all ages, creating a major burden for individuals, families, and society. While personalized medicine is advancing in other fields, the diagnosis and treatment of mental disorders remain largely symptom-based and fail to capture individual, sex, and gender differences in risk, manifestation, and treatment response. Early signs of illness often go unnoticed due to the lack of monitoring tools, and stigma continues to hinder prevention and care. During certain endocrine-sensitive phases of life, susceptibility to mental illness may be heightened due to changes in endocrine signalling. To address these challenges, the EU research project Building REsilience against MEntal illness during ENDocrine-sensitive life stages (RE-MEND), coordinated by Uppsala University, has implemented an interdisciplinary approach focusing on four critical endocrine-sensitive life stages: prenatal, puberty, peripartum, and older age. RE-MEND integrates longitudinal population-based cohorts with experimental and clinical studies to identify genetic, environmental, and endocrine factors shaping susceptibility and resilience to mental illness. Multi-omics data (genomics, epigenomics, transcriptomics, proteomics, metabolomics, lipidomics, and adductomics) are combined with neurobiological, clinical, and behavioural measures and analysed using advanced biostatistics and machine learning. The project seeks to i) identify risk and resilience factors affecting mental health; ii) deliver biomarker panels for susceptibility, disease progression, and treatment response across sensitive life stages; iii) discover novel drug targets through repurposing strategies; and iv) promote mental health literacy and reduce stigma. By integrating biological research with communication science, RE-MEND aims to generate translatable findings that support earlier intervention and more effective care. The "Re-MEND Betula"-project, specifically focuses on the transition into older age, using data from the population-based Betula study at Umeå University (partner in Re-MEND) to investigate factors influencing mental health, susceptibility, and resilience during ageing. The Betula study is a large longitudinal cohort study initiated in the late 1980s that follows participants across adulthood and older age, with repeated assessments of cognitive function, mental health, lifestyle, social factors, medical history, and biological samples. The rich longitudinal design enables the study of trajectories of ageing and mental health over time, as well as individual differences in vulnerability and resilience. Within this project, these data will be complemented with selected multi-omics analyses, including molecular profiling approaches such as genomics, epigenomics, proteomics, and metabolomics, to improve the understanding of biological mechanisms underlying mental health during ageing. For the "Re-MEND Betula"- project we apply for here, we plan to store the Betula data within NAISS to facilitate secure data management and enable collaborative analyses with other researchers involved in the RE-MEND project.