A Systematic Review of Dimensional and Categorical Models of Grief Related Disorders

Since the inclusion of Prolonged Grief Disorder (PGD) in the ICD-11 and DSM-5-TR, many studies have employed factor analyticand mixture modeling approaches to explore whether PGDsymptoms are best explained by a single dimension, multiplefactors, or distinct subgroups. However, no review to date hassystematically synthesized these findings. A pre-registered systematicreview of psychometric studies of PGD symptoms wasconducted by searching Web of Science, PubMed, Scopus, andPsycINFO. Two researchers independently identified eligible studiesthat met inclusion and exclusion criteria, and methodologicalrigor was evaluated using a refined COSMIN risk of bias checklist.The retained studies were grouped into four categories: (1) single-factor validation studies, (2) latent structures and dimensionalmodels, (3) diagnostic criteria evaluations, and (4) longitudinaltrajectory analyses. Across studies, 10 grief measures were used,with 89% relying on three legacy instruments (ICG, PG-13, TGI-SR)developed pre ICD-11/DSM-5-TR and not consistently implementingcurrent symptom and impairment requirements.Evidence more consistently supported PGD as a graded, multidimensionalconstruct, with class or trajectory findings best interpretedas pragmatic risk strata along an underlying continuum.Methodological quality varied, with only 25% rated very good,alongside sparse longitudinal work and uneven cross-culturalcoverage. A criteria-aligned instrument such as the TGI-SR+ thatimplements ICD-11 and DSM-5-TR algorithms and explicit casenessrules is the strongest current candidate to anchor crossstudycomparability and clinical assessment. With a sharedstandard, dimensional and categorical models, including factormixture approaches, can test whether categorical distinctionsadd value beyond continuous symptom severity.