BACKGROUND: Although psychiatric comorbidities are common among individuals at end of life, their impact on outcomes is poorly understood.

METHODS: We conducted a systematic literature review of six databases following preferred reporting items for systematic reviews and meta-analyses guidelines and aimed at assessing the relationship between psychiatric comorbidities and outcomes in palliative and end-of-life care. Six databases were included in our search. This review is registered on PROSPERO (CRD42022335922).

RESULTS: Our search generated 7472 unique records. Eighty-eight full texts were reviewed for eligibility and 43 studies were included in the review. Clinically, psychiatric comorbidity was associated with poor quality of life, increased physical symptom burden, and low function. The impact of psychiatric comorbidity on health utilization varied, though many studies suggested that psychiatric comorbidity increased utilization of palliative care services. Quality of evidence was limited by lack of consistent approach to confounding variables as well as heterogeneity of the included studies.

CONCLUSION: Psychiatric comorbidity is associated with significant differences in care utilization and clinical outcome among patients at end of life. In particular, patients with psychiatric comorbidity and serious illness are at high risk of poor quality of life and high symptom burden. Our finding that psychiatric comorbidity is associated with increased utilization of palliative care likely reflects the complexity and clinical needs of patients with serious illness and mental health needs. These data suggest that greater integration of mental health and palliative care services may enhance quality-of-life among patients at end of life.