Prolonged grief disorder: Its co-occurrence with adjustment disorder and post-traumatic stress disorder in a bereaved Israeli general-population sample

Background: Prolonged grief disorder (PGD) is a new disorder included in the WHO International Classification of Diseases 11th version (ICD-11). This study is the first to use these new ICD-11 PGD guidelines to examine prevalence rates, predictors of PGD and disorder co-occurrence with other stress-related disorders in a survey of 544 bereaved Israelis. Methods: Descriptive statistics, correlation, linear regression and mediation analysis examined the validity of the ICD-11 diagnostic algorithm. Results: Prevalence of PGD in the Israeli population sample is low (2%). The prevalence rate of post-traumatic stress disorder (PTSD) was 7.2% and for adjustment disorder (AjD) was 17.8%. A significant positive correlation found between scores on these measures indicates concurrent validity. Mediation analysis found that symptoms of PGD were predicted by serious life events, and significantly mediated by symptoms of PTSD and AjD. A regression analysis found significant predictors of PGD symptom severity, including socio-demographic and person-specific predictors. Limitations: This study did not assess the index-death of the grief questionnaire. No conclusions could be made regarding the relationship between the type of loss and grief severity. Furthermore, the time since loss (time criterion) was not assessed. Conclusions: This study is the first to examine prevalence rates of ICD-11 PGD in a population-based survey. The mediation relationship between serious life events, AjD, PTSD and PGD supports a vulnerability model of stress related disorders whereby the number of stressful life events may predict symptoms of stress related disorders.