The coexistence of mental and physical disorders- multimorbidity - is a growing global challenge, driven by rapidly changing demographics and lifestyles across the world. Multimorbidity worsens outcomes for both mental and physical health conditions, increasing mortality, morbidity and poverty, and reducing quality of life for people living with multiple conditions. In the past 20 years, an increasing body of research has found that mental disorders are associated with premature mortality, including an almost two-fold higher risk of cardiovascular mortality, with life expectancy shortened by 10-20 years in people with schizophrenia spectrum disorders or bipolar disorders. Specific general medical conditions occur disproportionately within clinical populations with severe mental disorders, through three main pathways: (a) pathogenetic links (e.g., disorders of the metabolic or immune system), (b) changes in lifestyle, and (c) adverse effects of drug treatment, since antipsychotic drugs, lithium and other medicines commonly used to treat severe mental disorders can have important adverse consequences for these patients and contribute to comorbidities. In this symposium, we present three studies relevant to this theme, which between them (i) document the adverse physical health outcomes and poorer access to healthcare for people with severe mental illness, (ii) describe pharmacological interventions for tackling increased metabolic risks associated with antipsychotic use in this population, and (iii) review approaches to study multimorbidity. The symposium showcases a range of methods to study and address mental-physical multimorbidity, which will help to address the unacceptable gap in health and life expectancy for people with mental illness.