Adult treatment refusal can place respect for autonomy in tension with duties to prevent serious harm. The ethical problem is not resolved by labeling a refusal unwise because decisional authority, authenticity, professional obligation, proportionality, and the burdens of treatment over objection may diverge. To systematically identify, appraise, and synthesize normative arguments concerning when overriding an adult patient’s treatment refusal can be ethically defensible. Reproducible PubMed-domain searches and supplementary verification/citation-chaining routes covered 2018–2026. Eligible reports contained reconstructable arguments about adult treatment refusal or a necessary justificatory premise. Arguments were appraised for conclusion clarity, premise transparency, inferential connection, engagement with objections, and contextual boundaries. PRISMA 2020 guided reporting. Eighty-two records were identified; seven duplicates were removed and 75 unique records were screened. Thirty-two were excluded at screening, 43 reports were sought, four were not retrieved, 39 were assessed, nine were excluded, and 30 normative evidence units were included. Six recurrent argument families concerned decisional authority, preventable harm, authenticity and values, professional obligations, proportionality, and contextual exceptions. The literature supports a conditional approach. Override is most defensible when decisional authority is materially compromised, serious preventable harm is likely, treatment offers proportionate benefit, less restrictive responses are inadequate or infeasible, and coercive burdens do not defeat the justification.
