Prolonged grief disorder in an inpatient psychiatric sample: psychometric properties of a new clinical interview and preliminary prevalence

Background: Prolonged Grief Disorder (PGD) was newly included in the ICD-11 and DSM-5-TR. It is not yet part of the standard assessments in many healthcare systems, including psychiatric wards. Because disordered grief is associated with suicidality, sleep problems and substance use disorders, an investigation into PGD in psychiatric inpatients is warranted. Method: We interviewed N = 101 psychiatric inpatients who were admitted to the open psychiatric wards and the day hospital of a German psychiatric hospital and who had lost a person close to them. Assessments comprised clinical interviews and self-report instruments covering PGD and other mental disorders. We specifically developed the International Interview for Prolonged Grief Disorder according to ICD-11 (I-PGD-11) for the study and examined its psychometric properties. Results: The prevalence rate of PGD among bereaved patients according to ICD-11 was 16.83% and according to DSM-5-TR 10.89%. The I-PGD-11 showed good psychometric properties (Mc Donald’s ω = 0.89, ICC = 0.985). Being female, having lost a child or spouse, and unnatural or surprising circumstances of the death were associated with higher PGD scores. Trial registration: Approval was obtained by the ethics committee of the of the Goethe University Frankfurt (2021-62, 2023-17) and the Chamber of Hessian Physicians (2021-2730-evBO). The study was preregistered (https://doi.org/10.17605/OSF.IO/K98MF). Limitations: We only assessed inpatients of one psychiatric clinic in Germany, limiting the generalizability of our findings. Conclusion: The present study underlines the importance of exploring loss and grief in psychiatric inpatients and including PGD in the assessments. Given that a significant minority of psychiatric inpatients has prolonged grief symptoms, more research into inpatient treatment programs is needed.