Among cancers, haematological malignancies are unique in that a curative treatment is haematopoietic stem cell transplantation (HSCT). After allogeneic (donor sourced) HSCT, graft-versus host disease (GvHD) is a serious medical complication associated with increased psychological distress, anxiety, and depression in patients. Our objective was to conduct a systematic literature review in adults treated with allogeneic HCST and characterise whether GvHD was related to levels of psychological distress. Using the HiTOPS model, psychological distress was defined as encapsulating the symptoms of anxiety, depression, and low wellbeing. All published English language articles were searched using Ovid MEDLINE, APA PsycINFO, Elsevier Scopus, and Embase. Inclusion criteria required patients to be 18+ years, undergone HSCT and diagnosed with GvHD, with psychological distress measured by a psychometric tool or emotional wellbeing domain from a quality-of-life questionnaire. Extraction was conducted using Covidence with 5575 imported, 1882 duplicates removed, 3690 articles screened by title and abstract with 3460 rejected and 230 screen by full text. Articles with HSCT haematological cancer patients with GvHD and a measure of psychological distress were selected (k = 34). Risk of bias and quality was assessed with the JBI critical
appraisal tools. Preliminary findings suggest most cross-sectional and longitudinal articles reported increased anxiety or depression symptoms or worsening emotional wellbeing in patients with moderate to severe chronic GvHD. In contrast, where patients were diagnosed with active or acute GvHD the results appear conflicting. Results also demonstrated a lack of consistency in measurement tools, varying assessment timepoints and limited strategies to address compounding factors, all challenging interpretation. The heterogeneity of articles and contradictory findings, highlight the existing gaps in the literature and indicate further research is needed into psychological distress of HSCT patients with GvHD.