Social determinants of health (SDoHs) are increasingly recognized as important contributors to the development, course, and outcomes of psychiatric disorders. However, their integration into clinical psychiatry and mechanistic models remains limited. This overview synthesizes emerging evidence on the biopsychosocial mechanisms through which SDoHs influence mental health. There is a need to distinguish between individual-level, clinically actionable health-related social needs and family-, community-, and society-level structural SDoHs, and to consider both adverse and protective social factors. Converging research demonstrates that social experiences are biologically embedded through interacting pathways, including exposomics, epigenetics, allostatic load, accelerated inflammaging, immune dysregulation, and gut-brain-microbiome signaling. These mechanisms influence neural circuitry underlying stress regulation, reward processing, and social cognition. Psychological processes-including individual differences in resilience, wisdom, compassion, and purpose in life-shape responses to SDoHs and are supported by identifiable neurobiological substrates. Social connection has emerged as a central, potentially modifiable SDoH that is strongly associated with whole health and longevity. Loneliness and social isolation have become major global public health challenges. The authors propose a biopsychosocial framework that integrates social exposures, biological mechanisms, neural systems, and psychological processes to better understand the risk, course, and prevention of mental illnesses. Clinical and public health implications include the need for routine assessment of SDoHs, incorporation of protective factors at individual and societal levels, and development of pragmatic, multidomain interventions. Finally, rapidly evolving digital technologies, including artificial intelligence, offer new opportunities but also require careful governance. Advancing toward human-centered "artificial wisdom" may enhance the capacity of technology to promote whole health in individuals with mental illnesses globally.