Time elapsed since loss or grief persistency? Prevalence and predictors of ICD-11 prolonged grief disorder using different applications of the duration criterion

Background. Prolonged grief disorder (PGD), included in the ICD-11, encompasses a six-month duration criterion, but whether this covers 'time since loss' or 'grief persistency' is unclear. The study estimated prevalence and predictors of probable ICD-11 PGD using different applications of the duration criterion. Methods. A register-sampled cohort of bereaved spouses completed self-report questionnaires at two (T1, N=847), six (T2, N=777), and eleven months (T3, N=753) post-loss. The duration criterion was operationalized as single-point PGD (meeting criteria minimally six months post-loss; T2 or T3) and dual-point PGD (meeting criteria at two assessments separated by months; T1+T2 or T2+T3). Results. Single-point PGD prevalence rates (similar to 15-20%) were significantly higher than dual-point prevalence rates (similar to 10%). While single assessments of PGD varied between T2 and T3, the dual-point prevalence rates did not significantly differ. Early probable grief caseness emerged as the strongest predictor for later PGD. Limitations. Without a structured clinical interview, only probable cases of PGD were identified. Caseness relied on a diagnostic algorithm, created by mapping items from different self-report questionnaires. Time frames between assessments did not cover an entire six-month period. Conclusions. Momentarily assessed, six-month PGD symptomatology may represent a fluctuating, but remitting grief process for some individuals. Further research could test whether multiple diagnostic indicators during the first year of bereavement improve the identification of genuinely prolonged grief reactions.