Ethical and procedural pathways to end-of-life care for patients with serious mental illness and decisional incapacity: a systematic review

This review synthesizes how the U.S. literature frames three overlapping pathways that shape access to palliative and end-of-life care for patients with serious mental illness and decisional incapacity: end-of-life care in the context of terminal medical illness, the contested construct of terminal psychiatric illness, and capacity assessment as a procedural gateway to treatment refusal, surrogate decision-making, and de-escalation of life-prolonging care. We conducted a mixed-method systematic review following PRISMA 2020 guidance. MEDLINE, Embase, APA PsycINFO, and CINAHL Complete were searched for English-language, U.S.-based records addressing serious mental illness, decisional incapacity, and access to palliative or end-of-life care. Records focused primarily on physician-assisted death or euthanasia, non-U.S. settings, or non-English-language publications were excluded. Dual independent screening was performed at title/abstract and full-text levels, with adjudication of conflicts. Summative content analysis was used to code ethical concepts and decision-making factors. Formal risk-of-bias assessment was not performed because the review synthesized heterogeneous empirical and nonempirical records, including commentaries, legal analyses, policy statements, and narrative reports. Of 3253 records identified, 154 records were eligible. Most records framed EOL eligibility for psychiatrically incapacitated patients in relation to terminal medical illness. Capacity assessment was frequently treated as a gatekeeping step for treatment limitation or hospice enrollment, yet discussions highlighted variability in thresholds, potential assessor bias, and fluctuating psychopathology. The concept of terminal psychiatric illness lacked actionable consensus; most records did not define criteria, and those that did invoked heterogeneous determinants. Psychiatric advance directives were variably endorsed but commonly described as difficult to implement and of uncertain applicability to medical EOL decisions. Psychiatrically incapacitated patients face ethical and procedural barriers to goal-concordant EOL care. Access is most consistently enabled when a terminal medical illness is recognized and when surrogate decision-making pathways are established. Definitions of terminal psychiatric illness remain inconsistent and difficult to operationalize. Because the evidence base is conceptually and methodologically heterogeneous, reported frequencies should be interpreted as indicators of concepts appearing in the literature rather than measures of clinical prevalence, consensus strength, or normative validity. Clarifying standards for capacity assessment, surrogate authority, and criteria for nonbeneficial psychiatric treatment remains a priority for equitable access to EOL care.