Diagnosing social ills: Theorising social determinants of health as a diagnostic category.

Medicine, as an institution and discipline, has embraced social determinants of health as a key influence on clinical practice and care. Beyond simply acknowledging their importance, most recent versions of the International Classification of Diseases explicitly codify social determinants as a viable diagnostic category. This diagnostic shift is noteworthy in the United States, where 'Z-codes' were introduced to facilitate the documentation of illiteracy, unemployment, poverty and other social factors impacting health. Z-codes hold promise in addressing patients' social needs, but there are likely consequences to medicalising social determinants. In turn, this article provides a critical appraisal of Z-codes, focussing on the role of diagnoses as both constructive and counterproductive sources of legitimacy, knowledge and responsibility in our collective understanding of health. Diagnosis codes for social determinants are powerful bureaucratic tools for framing and responding to psychosocial risks commensurate with biophysiological symptoms; however, they potentially reinforce beliefs about the centrality of individuals for addressing poor health at the population level. I contend that Z-codes demonstrate the limited capacity of diagnoses to capture the complex individual and social aetiology of health, and that sociology benefits from looking further 'upstream' to identify the structural forces constraining the scope and utility of diagnoses.