A Harm-Based Framework for Defining Mental Illness: Moving Beyond Wakefield’s Dysfunction Model

The definition of mental illness remains contested within the philosophy of psychiatry. Jerome Wakefield’s “harmful dysfunction” account provides valuable insight by combining scientific and evaluative components. However, his reliance on biological dysfunction is problematic, as it excludes conditions without evolutionary dysfunctions and fails to separate scientific and value-laden components of mental illness. This article proposes a new framework for mental illness, defining it for functional rather than folk purposes. It argues that mental illness for psychiatric intervention should be defined as any mental framework that harms an individual or others more than psychiatric intervention would. This harm-based model removes biological dysfunction from the definition, focusing instead on the comparative evaluation of harm and benefit. It preserves Wakefield’s emphasis on value judgments while offering greater practical applicability and inclusivity. By removing dependence on the “selected effect” view, this definition accounts for disorders without evolutionary dysfunction, such as dyslexia and aggression disorders derived from naturally selected processes. Ultimately, this framework provides a more functional basis for mental illness in society, emphasizing harm reduction and clinical utility over evolutionary essentialism.