Prolonged grief disorder (PGD) is a new disorder included in the 11th edition of the International classification of diseases (ICD-11). An important remit of the new ICD-11 is the global applicability of the mental health disorder guidelines or definitions. Although previous definitions and descriptions of disordered grief have been assessed worldwide, this new definition has not yet been systematically validated.
Here we assess the validity and applicability of core items of the ICD-11 PGD across five international samples of bereaved persons from Switzerland (N = 214), China (N = 325); Israel (N = 544), Portugal (N = 218) and Ireland (N = 830).
The results confirm that variation in the diagnostic algorithm for PGD can greatly impact the rates of disorder within and between international samples. Different predictors of PGD severity may be related to sample differences. Finally, a threshold for diagnosis of clinically relevant PGD symptoms using a new scale, the International Prolonged Grief Disorder Scale (IPGDS), in three samples was confirmed.
Although this study was limited by lack of questionnaire data points across all five samples, the findings for the diagnostic threshold and algorithm iterations have implications for clinical use of the new ICD-11 PGD criteria worldwide.
The first study to explore core items of the ICD-11 PGD definition in five large international samples Comparison of three different diagnostic algorithms Preliminary analysis of different thresholds for diagnosis in different groups Preliminary estimates of PGD prevalence
In 2019 prolonged grief disorder (PGD) was included in the International Classification of Diseases (ICD-11) for the first time. The diagnostic criteria for a disorder of grief have a long history and there are several previous definitions and iterations (
The WHO working groups for the ICD-11 adopted a two-phase strategy to update disorder definitions. The first phase involved developing the structure of the definition based on a large international survey of psychologists and psychiatrists (
Previous research has confirmed that PGD may have different prevalence rates in different samples. For example, worldwide rates of a disorder of grief may range from 1% to 10% (
This paper explores core items of the new ICD-11 PGD disorder criteria along with some of the supplementary items indicating emotional distress, across five international samples. The aims include: firstly, the examination of rates of possible PGD caseness using the same core items and diagnostic formulations in each country. Secondly, examination of criterion validity through the identification of predictors of PGD across and between countries. Thirdly, to find provisional cut-off scores and assess the thresholds for the best sensitivity and specificity in each country using the receiver operating characteristic analysis (ROC).
Data from participants who experienced the loss of a loved one were analyzed. Data sets were obtained from five different countries: Switzerland (
Across all of the studies participants were recruited using online survey methods. In addition, the Portuguese data also includes a clinical outpatient sample.
To assess prolonged grief disorder, the International Prolonged Grief Disorder Scale with 15 items (
Life Events Checklist (LEC) (
Gender (measured in all 5 samples)
Age (measured in all 5 samples)
Cultural criteria (measured in Swiss, Chinese, Portuguese samples)
Severe human suffering (measured in Swiss, Chinese, Israeli samples with LEC, and in Irish sample with ITEM)
Sudden, violent or accidental death (measured in Swiss, Chinese, Israeli samples with LEC and in Irish sample with ITEM)
Serious injury, harm or death you caused to someone (measured in Swiss, Chinese, Israeli samples with LEC and in Irish sample with ITEM)
To estimate possible PGD rates, three different diagnostic algorithms were applied; PGD strict criteria set, PGD moderate criteria set, and the criteria set according to
Logistic regression was used to examine the associations between PGD (strict criteria) and some items representing traumatic life events, gender (male/female), age, and cultural caveat item using odds ratio (OR) and 95% CI. The outcome was the endorsement of PGD strict criteria; coded as binary variable “yes, possible PGD caseness” (1) or “no” (2). Of note, due to the use of heterogeneous questionnaires across the samples, we could only include a few traumatic life event items. In terms of missing values, the default settings of SPSS were used whereby cases were deleted in a list wise manner. Third, Receiver operating characteristic analysis (ROC) was used to examine cut-off scores for the IPGDS and ICG-R, i.e. the threshold for the best fit in terms of sensitivity (high > .80) and specificity (.80). This analysis is presented as an initial exploration and may be highly dependent upon the samples used. ROC curves and logistic regression were calculated only for PGD strict criteria (i.e. 12 symptom items plus functional impairment). Statistical analyses were performed using SPSS version 23.
The proportion of people in each sample who met the criteria for possible PGD caseness differed within the country depending on (1) whether strict, moderate or
Variable | Swiss |
Chinese |
Israel |
Portuguese |
Irish |
|||||
---|---|---|---|---|---|---|---|---|---|---|
Gender | ||||||||||
Male | 33 | 15.4 | 104 | 32 | 246 | 45.2 | 43 | 17.5 | 411 | 49.5 |
Female | 178 | 83.2 | 212 | 65.2 | 298 | 54.8 | 203 | 82.5 | 419 | 50.5 |
Other | 3 | 2 | 0 | 0 | 0 | |||||
Item | ||||||||||
Severe human suffering (LEC Item 13) | 83 | 38.8 | 65 | 20.0 | 39 | 7.1 | – | – | – | – |
Sudden, violent death (LEC Item 14)a | 62 | 29.0 | 53 | 16.3 | 71 | 13.0 | – | – | – | – |
Accidental death (LEC Item 15) | 57 | 26.6 | 99 | 30.5 | 173 | 31.8 | – | – | – | – |
Serious injury, harm or death you caused (LEC Item 16) | 6 | 2.8 | 49 | 15.1 | 11 | 2.0 | – | – | – | – |
Serious injury, harm or death you caused (ITEM Item 12) | – | – | – | – | – | – | – | – | 35 | 4.2 |
Sudden, violent or accidental death (ITEM Item 13) | – | – | – | – | – | – | – | – | 224 | 27.0 |
aLEC items 14 and 15 were merged in the logistic regression. Data was not collected for the Portuguese sample.
Scale | Swiss |
China |
Israela |
Portugueseb |
Irish |
||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
% | 95% CI |
% | 95% CI |
% | 95% CI |
% | 95% CI |
% | 95% CI |
||||||
IPGDS | |||||||||||||||
Strict criteria | 7.0 | 4.0 | 11.3 | 12.6 | 9.2 | 16.7 | – | – | – | 6.9 | 3.9 | 11.1 | – | – | – |
Moderate criteria | 21.5 | 16.2 | 27.6 | 37.5 | 32.3 | 43.1 | – | – | – | 27.5 | 21.7 | 34.0 | – | – | – |
Maciejewski criteria | 15.9 | 11.3 | 21.5 | 33.5 | 28.4 | 39.0 | – | – | – | 23.4 | 17.9 | 29.6 | – | – | – |
ICG-R | |||||||||||||||
Strict criteria | 5.1 | 2.6 | 9.0 | 7.1 | 4.5 | 10.4 | 2.0 | 1.0 | 3.6 | 21.1 | 14.2 | 29.7 | 4.1 | 2.9 | 5.7 |
Moderate criteria | 18.2 | 13.3 | 24.1 | 29.2 | 24.3 | 34.5 | 8.5 | 6.3 | 11.1 | 48.3 | 39.0 | 57.7 | 13.9 | 11.6 | 16.4 |
Maciejewski criteria | 6.1 | 3.3 | 10.2 | 10.5 | 7.4 | 14.3 | 4.2 | 2.7 | 6.3 | 7.6 | 3.5 | 14.0 | 4.7 | 3.4 | 6.4 |
aIn Israel dataset for ICG-R – no time criteria applied.
bIn Portuguese dataset for ICG-R – no time criteria applied, no functional criteria (Item 8) applied; for IPGDS - no time criteria applied, pooled across the general and clinical groups.
Results from the logistic regression analyses showed that PGD assessed with IPGDS was significantly associated with the cultural caveat criteria in Switzerland,
Variable | Swiss |
China |
||||
---|---|---|---|---|---|---|
95% CI |
95% CI |
|||||
IPGDS | ||||||
Gendera | 1.240 | 0.331 | 4.646 | 0.508* | 0.259 | 0.998 |
Age | 1.018 | 0.989 | 1.049 | 1.022 | 0.996 | 1.048 |
Cultural criteria | 2.463*** | 1.707 | 3.554 | 3.152*** | 2.361 | 4.209 |
Severe human suffering | 2.321 | 0.898 | 6.000 | 1.256 | 0.507 | 3.111 |
Sudden, violent or accidental death | 1.821 | 0.734 | 4.517 | 0.703 | 0.342 | 1.448 |
Serious injury, harm or death you caused | 14.016* | 1.856 | 105.854 | 1.471 | 0.534 | 4.055 |
aFemale compared to male.
*
When PGD was assessed with ICG-R, the logistic regression analyses revealed significant associations with the cultural caveat criteria within Switzerland,
The ROC analysis was used to determine a cut-off score for those participants meeting the strict criteria for the IPGDS and ICG-R. The results can be found in
Variable | Swiss |
China |
Israel |
Irish |
||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
95% CI |
95% CI |
95% CI |
95% CI |
|||||||||
ICG-R | ||||||||||||
Gendera | 1.319 | 0.109 | 15.984 | 0.407 | 0.139 | 1.192 | 0.847 | 0.347 | 2.068 | 0.303** | 0.967 | 1.020 |
Age | 1.060 | 1.000 | 1.124 | 1.023 | 0.984 | 1.063 | 0.964* | 0.933 | 0.966 | 0.993 | 0.133 | 0.692 |
Cultural criteria | 8.148*** | 2.629 | 24.782 | 4.501*** | 2.671 | 7.586 | – | – | – | – | – | – |
Severe human suffering | 1.495 | 0.290 | 7.708 | 0.286 | 0.057 | 1.428 | 5.095** | 1.670 | 15.547 | 0.535 | 0.249 | 1.149 |
Sudden, violent or accidental death | 0.779 | 0.147 | 4.117 | 0.809 | 0.247 | 2.648 | 3.271* | 1.178 | 9.086 | 0.297** | 0.127 | 0.694 |
Serious injury, harm or death you caused | 19.536 | 0.266 | 1433.830 | 5.494* | 1.309 | 23.050 | 0.964 | 0.079 | 11.748 | 0.339 | 0.102 | 1.131 |
aFemale compared to male.
*
Scale | Swiss |
China |
Israel |
Portuguese |
Irish |
|||||
---|---|---|---|---|---|---|---|---|---|---|
cut-off |
sensitivity/ |
cut-off |
sensitivity/ |
cut-off |
sensitivity/ |
cut-off |
sensitivity/ |
cut-off |
sensitivity/ |
|
IPGDS | 37.5 |
0.933/ |
42.5 |
0.902/ |
N/A | N/A | 36.5 |
0.933/ |
N/A | N/A |
ICG-R | 24.5 |
0.818/ |
25.5 |
0.957/ |
24.5 |
1.000/ |
16.5 |
0.920/ |
22.5 |
0.941/ |
This paper provides the first systematic exploration of core items of the new ICD-11 PGD criteria across five international samples. The results confirm large differences in the rates between and within samples depending on the diagnostic algorithm used; predictors of PGD severity may vary across samples due to the type of loss (violent or nonviolent) and the cultural caveat item of the IPGDS may be an important risk screening item; finally, a threshold for a clinically relevant diagnosis may be different depending on cultural group.
Core items of the new ICD-11 PGD criteria, as tested by the IPGDS (in Swiss, Chinese and Portuguese samples) and the ICG-R (in Irish and Israeli samples), revealed substantially different rates depending on the diagnostic algorithm used. Overall, the
The Portuguese sample consisted of a large proportion of bereaved people who experienced an unexpected loss (10%). Although not explicitly recorded, this would mostly include the unexpected loss of a child as participants were from the outpatient perinatal loss clinic. Loss of a child is known to predict high levels of PGD (
Lack of culturally sensitive assessment measures or items could explain differences in the symptom ratings and severity levels across the samples. For example, our previous study confirmed that Chinese bereaved may present with slightly different symptoms than those assessed by the ICD-11 (
In terms of predictors of PGD severity we assessed a limited selection of predictors available across the datasets. Interestingly, when the cultural caveat item was included (e.g. endorsement of Item 14 of the IPGDs), violating the cultural norms for grief was found to significantly predict more severe grief scores on the IPGDS and the ICG-R. Although we only had the data for the Swiss and Chinese participants, further examination of this item might indicate its importance as a screening item for grief severity. In both the Israeli and Irish sample grief severity was predicted by sudden violent or accidental death whereas this was not found for the Swiss and Chinese samples. This may be due to differences in sampling. The Israeli and Irish data are from large nationally representative samples that may include more instances of sudden violent or accidental death. The Chinese and Swiss samples are mostly student populations who experienced the loss of older relatives. The larger Israeli and Irish datasets contain participants who experienced a high level of violent loss (more than 25%) and this could explain the differences in predictors. Previous research has confirmed that violent loss is a strong predictor of PGD severity and chronicity (
The final research question was to determine a possible threshold for establishing a clinically significant severity score on the IPGDS. All five datasets could not be compared with the IPGDS however across the Swiss, Chinese and Portuguese data, a score above 36.5 will most likely represent clinically significant PGD symptoms. As a control, the ICG-R was also examined and a score above 22 for all datasets was consistently found, except for the Portuguese sample (16.5). This attests to the variation that can occur across different samples, even with gold standard clinical assessments (
Due to inconsistencies in data collection across the five international samples it was not possible to directly compare the IPGDS or the ICG-R across all data sets. The full ICD-11 PGD criteria could therefore not be assessed. In particular the time criterion was not assessed consistently across the datasets for example not in the Portuguese or Israeli datasets. Therefore, a diagnosis of PGD is not possible. However, the core items of the PGD (yearning and preoccupation) as well as some supplementary items of emotional distress could be evaluated and indications of possible caseness implied. It is important to include the time criterion for disorder as individuals may experience severe distress in the first weeks and months after a loss and this should not be pathologized. Importantly the estimates of prevalence rates for the Portuguese data must be interpreted with caution as there was a high amount of missing data. Furthermore, the Portuguese sample included a clinical subgroup. This may explain why the estimates of prevalence are significantly higher. Across the German, Portuguese and Chinese samples there is a high proportion of female responses. In the future it would be important to provide an analysis of a more representative sample. Additionally, there were only a limited number of similar predictors across all datasets. The data in each country was collected separately at different times, so only a cross sectional comparison is possible on some questionnaire items. Of note, the confidence intervals are very wide for some of the items in the logistic regression, particularly for the cultural criteria. This is perhaps due to a small number of values in some of the cells (response options). In the future a larger sample size should reveal more precise confidence intervals. Finally, in the future and with a more complete dataset the ROC analysis should also be conducted on the moderate and
This paper confirms the importance of establishing international guidance on the consistent use of a diagnostic algorithm for PGD in order to ensure reliability across heterogeneous samples. Currently, we recommend the use of the strict criteria as an indicator of PGD caseness, however this must be confirmed in a clinical sample. Future studies should examine the different PGD algorithms (moderate vs strict) in clinical and cultural samples and include important items that are missing in some of the current data (i.e. the impairment and time criteria as well as the cultural caveat). Additionally, clinicians should be aware of specific risk factors such as violent, sudden loss or screening ‘yes’ on the cultural caveat IPGDS item as these may predict clinically severe grief. In the future it may be important for clinicians to note that different cultural groups may need different cut-off thresholds for a clinical diagnosis on the IPGDS or other scales.
The supplementary information contains tables of additional demographic characteristics for each of the five samples (for access see
We would like to acknowledge the dedication of the participants who completed the questionnaires, the efforts of the grief and bereavement organizations that supported our recruitment, and the many student interns that assisted with data collection, input and coding.
The authors have no funding to report.
The authors have declared that no competing interests exist.