State of Ohio Adversity and Resilience (SOAR) study protocol: a comprehensive, multimodal, family-based, longitudinal observational investigation of risk and resilience in mental health and substance use disorders.

INTRODUCTION: Deaths related to drug overdose and suicide in the USA have increased 500% and 35%, respectively, over the last two decades. The human and economic costs to society associated with these 'deaths of despair' are immense. Great efforts and substantial investments have been made in treatment and prevention, yet these efforts have not abated these increasing trajectories of deaths over time. The COVID-19 pandemic has exacerbated and highlighted these problems. Notably, some geographical areas (eg, Appalachia, farmland) and some communities (eg, low-income persons, 'essential workers', minoritised populations) have been disproportionately affected. Risk factors have been identified for substance use and suicide deaths: forms of adversity, neglect, opportunity indexes and trauma. Yet, the biological, psychological and social mechanisms driving risk are not uniform. Notably, most people exposed to risk factors do not become symptomatic and could broadly be considered resilient. Achieving a better understanding of biological, psychological and social mechanisms underlying both pathology and resilience will be crucial for improving approaches for prevention and treatment and creating precision medicine approaches for more efficient and effective treatment.

METHODS AND ANALYSIS: The State of Ohio Adversity and Resilience (SOAR) study is a prospective, longitudinal, multimodal, integrated familial study designed to identify biological, psychological and social risk and resilience factors and processes leading to mental health disorders, substance use disorders, substance overdose, suicide and associated psychological/medical comorbidities which reduce life expectancy and quality of life. It includes two nested longitudinal samples: (1) WD Survey: an address-based random population epidemiological sample of 15 000 individuals (unique households) representative of the state of Ohio assessed for psychosocial, psychiatric, behavioural health and substance use factors and (2) Brain Health Study: a family-based, multimodal, deep-phenotyping study conducted in 1200 families (up to 3600 persons aged 12-72 years) including MRI, electroencephalography, blood biomarkers and psychiatric diagnostic interviews, as well as neuropsychological, psychosocial functioning and family/community history, dynamics and support assessments. SOAR is designed to discover, develop and deploy advanced predictive analytics and interventions to transform mental health prevention, diagnosis, treatment and recovery.

ETHICS AND DISSEMINATION: All participants will provide written informed consent (or parental permission and assent for minors). The study was approved by The Ohio State University Institutional Review Board (study numbers 2023H0316 (Brain Health) and 2023H0350 (Wellness Survey). The Brain Health study was also approved by institutional review boards at each partnering institution involved in conducting participant assessments. Findings will be disseminated to academic peers, clinicians and healthcare consumers, policymakers and the general public, using local and international academic channels (academic journals, evidence briefs and conferences) and outreach (workshops and seminars).