MBF received consultant fees over the past 5 years from Roche, Corcept, Wyeth, Cephalon, Astra-Zeneca, Shire, GSK, and Eli Lilly for preparing diagnostic interviews and/or conducting diagnostic trainings at investigator meetings.
Holly Prigerson and colleagues tested the psychometric validity of criteria for prolonged grief disorder (PGD) to enhance the detection and care of bereaved individuals at heightened risk of persistent distress and dysfunction.
Bereavement is a universal experience, and its association with excess morbidity and mortality is well established. Nevertheless, grief becomes a serious health concern for a relative few. For such individuals, intense grief persists, is distressing and disabling, and may meet criteria as a distinct mental disorder. At present, grief is not recognized as a mental disorder in the
A total of 291 bereaved respondents were interviewed three times, grouped as 0–6, 6–12, and 12–24 mo post-loss. Item response theory (IRT) analyses derived the most informative, unbiased PGD symptoms. Combinatoric analyses identified the most sensitive and specific PGD algorithm that was then tested to evaluate its psychometric validity. Criteria require reactions to a significant loss that involve the experience of yearning (e.g., physical or emotional suffering as a result of the desired, but unfulfilled, reunion with the deceased) and at least five of the following nine symptoms experienced at least daily or to a disabling degree: feeling emotionally numb, stunned, or that life is meaningless; experiencing mistrust; bitterness over the loss; difficulty accepting the loss; identity confusion; avoidance of the reality of the loss; or difficulty moving on with life. Symptoms must be present at sufficiently high levels at least six mo from the death and be associated with functional impairment.
The criteria set for PGD appear able to identify bereaved persons at heightened risk for enduring distress and dysfunction. The results support the psychometric validity of the criteria for PGD that we propose for inclusion in
Virtually everyone loses someone they love during their lifetime. Grief is an unavoidable and normal reaction to this loss. After the death of a loved one, bereaved people may feel sadness, anger, guilt, anxiety, and despair. They may think constantly about the deceased person and about the events that led up to the person's death. They often have physical reactions to their loss—problems sleeping, for example—and they may become ill. Socially, they may find it difficult to return to work or to see friends and family. For most people, these painful emotions and thoughts gradually diminish, usually within 6 months or so of the death. But for a few people, the normal grief reaction lingers and becomes increasingly debilitating. Experts call this complicated grief or prolonged grief disorder (PGD). Characteristically, people with PGD have intrusive thoughts and images of the deceased person and a painful yearning for his or her presence. They may also deny their loss, feel desperately lonely and adrift, and want to die themselves.
PGD is not currently recognized as a mental disorder although it meets the requirements for one given in the American Psychiatric Association's
The researchers used “item response theory” (IRT) to derive the most informative PGD symptoms from structured interviews of nearly 300 people who had recently lost a close family member. These interviews contained questions about the consensus list of symptoms; each participant was interviewed two or three times during the two years after their spouse's death. The researchers then used “combinatoric” analysis to identify the most sensitive and specific algorithm for the diagnosis of PGD. This algorithm specifies that a bereaved person with PGD must experience yearning (physical or emotional suffering because of an unfulfilled desire for reunion with the deceased) and at least five of nine additional symptoms. These symptoms (which include emotional numbness, feeling that life is meaningless, and avoidance of the reality of the loss) must persist for at least 6 months after the bereavement and must be associated with functional impairment. Finally, the researchers show that individuals given a diagnosis of PGD 6–12 months after a death have a higher subsequent risk of mental health and functional impairment than people not diagnosed with PGD.
These findings validate a set of symptoms and a diagnostic algorithm for PGD. Because most of the study participants were elderly women who had lost their husband, further validation is needed to check that these symptoms and algorithm also apply to other types of bereaved people such as individuals who have lost a child. For now, though, these findings support the inclusion of PGD in
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Bereavement is a universal experience to which most individuals adequately adjust. Nevertheless, numerous studies have shown that bereaved individuals have higher rates of disability and medication use than their nonbereaved counterparts
Following a major loss, such as the death of a spouse, a noteworthy minority of bereaved individuals experiences “a clinically significant behavioral or psychological syndrome or pattern that occurs in an individual and that is associated with present distress or disability”
The
PGD symptomatology—variously referred to as “complicated grief” (CG)
The set of risk factors and clinical correlates of PGD includes a history of childhood separation anxiety
PGD symptoms also demonstrate incremental validity in that they are associated with elevated rates of suicidal ideation and attempts, cancer, immunological dysfunction, hypertension, cardiac events, functional impairments, hospitalization, adverse health behaviors, and reduced quality of life in adults
The course and response to treatment of PGD differ from those of normal grief
Although the results above suggest that symptoms of grief constitute a syndrome that operationally defines a mental disorder, no agreed upon and tested diagnostic algorithm for PGD exists. Psychiatrists such as Lindemann
As a first step toward the development of consensus criteria for PGD, we convened a group of experts in bereavement, mood and anxiety disorders, and psychiatric nosology to review the evidence justifying the development of diagnostic criteria
Here, we report the results of a field trial designed specifically to develop and evaluate diagnostic algorithms for PGD based on symptoms proposed by the consensus panel. The aim of this study was to establish the psychometric validity of, and propose criteria for, a new syndrome, PGD.
Data were obtained for the Yale Bereavement Study (YBS) (e.g.,
Recruitment involved locating family survivors bereaved 6 mo or less found on contact lists of the Greater Bridgeport/Fairfield American Association of Retired Persons (AARP) Widowed Persons Service (WPS), a community-based outreach program. The contact lists provided names of recently widowed persons who a volunteer widowed person would contact to describe the WPS program. Fewer than 5% of those contacted participated in any WPS program; the lists included those approached, but not necessarily actively involved in, the WPS. A comparison between vital records and the WPS contact list revealed that WPS listings provide an unbiased and comprehensive ascertainment of recently widowed people. Participants were also recruited from pastoral care offices in the New Haven area. Participants from this alternative source (117/317 = 37.0% of study participants) did not differ significantly from WPS participants (200/317 = 63.0% of study participants) on gender, income, education, race/ethnicity, or quality of life, but they were younger than WPS participants (
Of the 575 potential participants contacted, 317 (55.1%) agreed to participate. Reasons for nonparticipation included reluctance to participate in research (
The 317 YBS participants were interviewed at baseline an average of 6.3 mo (SD = 7.0 mo) post-loss. First follow-up interviews (
Symptoms of PGD were assessed with the rater version of the Inventory of Complicated Grief—Revised (ICG-R)
Psychiatric disorders were assessed using the Structured Clinical Interview for
Positive responses to one or more of the four Yale Evaluation of Suicidality
The psychometric validation of diagnostic criteria for PGD proceeded through a cumulative series of analyses, with each phase in the overall analysis having a distinct aim. In Phase 1 of the analysis, the aim was to limit the set of candidate symptoms for PGD to those that were informative and unbiased. In Phase 2 of the analysis, the goal was to construct an objective, reliable, valid symptom criterion standard for PGD by which to evaluate alternative diagnostic algorithms for meeting symptom criteria for PGD. The aim of Phase 3 of the analysis was to identify a specific, optimum diagnostic algorithm for meeting symptom criteria for PGD among a large set of candidate algorithms. Phase 4 of the analysis was designed to evaluate the predictive validity for temporal subtypes of meeting the optimal symptom criteria for PGD as an empirical means to inform the specification of a “timing criterion” for the diagnosis of PGD. In Phase 5, the goal was to propose a complete set of “
IRT
IRT IIF analysis of 22 binary candidate symptoms for PGD was performed using a 2-PL IRM. This figure displays item information as a function of the PG attribute for all 22 of these symptoms included in this IRM, relative to the maximum information for the most informative symptom, “inability to care about others since the death.” The horizontal line in the figure represents the standard used to discriminate between 16 informative candidate symptoms retained for further analysis, and six uninformative candidate symptoms excluded from further analysis (as indicated in
IRT DIF analysis of candidate symptoms for PGD was performed with respect to age (less than 65 y versus greater than or equal to 65 y), gender (male versus female), education (beyond versus not beyond high school), relationship to the deceased (spouse versus nonspouse), and time from loss (0–6 mo versus 6–12 mo post-loss). This figure displays IRT item characteristic curves (ICCs) for two symptoms found to differ with respect to relationship to the deceased (spouse versus nonspouse). The horizontal error bar associated with each ICC represents the standard error in the estimate of the location of the ICC with respect to the PG attribute. Of 16 informative symptoms examined, four symptoms displayed DIF and were excluded from further analysis (as indicated in
Candidate PGD Symptom | Rate (%) | IRT IIF Analysis |
IRT DIF Analysis |
|||
Θmax |
Sex | Spouse | Time | |||
6.6 | 1.00 | 1.70 | ||||
Yearning for, or preoccupation with, deceased | 68.3 | 0.94 | −0.53 | |||
Life empty, meaningless without deceased | 34.8 | 0.93 | 0.46 | |||
Stunned, dazed, or shocked about the death | 19.2 | 0.58 | 1.07 | |||
Trouble accepting the death | 32.7 | 0.56 | 0.56 | |||
Feel part of you died along with the deceased | 37.6 | 0.49 | 0.41 | |||
Difficulty moving on with life without deceased | 18.1 | 0.46 | 1.17 | |||
Sense of numbness since the death | 13.6 | 0.46 | 1.41 | |||
14.6 | 0.38 | 1.40 | ||||
Hard for you to trust others since the death | 7.0 | 0.36 | 2.00 | |||
Avoid reminders of deceased | 12.5 | 0.26 | 1.67 | |||
Survivor guilt | 8.4 | 0.25 | 2.04 | |||
57.1 | 0.24 | −0.26 | ||||
23.3 | 0.23 | 1.09 | ||||
Bitterness or anger related to the death | 25.1 | 0.23 | 1.01 | |||
On edge, jumpy since the death | 11.5 | 0.20 | 1.88 | |||
7.0 | 2.51 | |||||
22.6 | 1.31 | |||||
31.0 | 0.86 | |||||
23.3 | 1.28 | |||||
28.6 | 1.02 | |||||
16.4 | 1.93 |
Relatively uninformative (
IRT IIF analysis was performed using all 22 symptoms, showing 16 to be informative (
IRT DIF analysis was restricted to 16 relatively informative symptoms, showing four to be biased.
Θmax represents location of
The following 12 informative, unbiased ICG-R symptoms were retained for consideration in a diagnostic algorithm: yearning; avoidance of reminders of the deceased; disbelief or trouble accepting the death; a perception that life is empty or meaningless without the deceased; bitterness or anger; emotional numbness or detachment from others; feeling stunned, dazed or shocked; feeling part of oneself died along with the deceased; difficulty trusting others; difficulty moving on with life; on edge or jumpy; survivor guilt (Cronbach's α = 0.82).
In the absence of an established, standard method for diagnosing PGD, there was a need to develop a criterion standard for “caseness” of PGD by which the performance of alternative algorithms for PGD could be evaluated. As a potential criterion standard for PGD, the rater determination of caseness of PGD had the advantage of reflecting experienced clinical judgment. However, rater assessments of PGD were subjective, were made without explicit reference to any established criteria, and were not always consistent with more objective, reliable assessments of PG as measured with IRM scores for the underlying PG attribute (i.e., raters assign PGD to some individuals with low scores, and not to others with high scores, on the PG attribute scale). It was decided that a criterion standard for caseness should be informed by clinical judgment, but should also be a function of PG symptom severity. Dichotomized IRM PG attribute scores, informed by rater assessments of PGD, would provide objective, reliable, valid criterion standard diagnoses for PGD.
Scores from a 2-PL IRM for PG based on the 12 informative, unbiased symptoms were used to order individuals in terms of PG symptom severity. Agreement between rater and minimum-threshold PG attribute assessments of caseness of PGD was maximized to establish an optimum minimum threshold for caseness of PGD along this IRM scale. As illustrated in
Dichotomized IRM PG attribute scores provide objective, reliable criterion standard diagnoses for PGD. This figure illustrates how rater diagnoses were used to establish a minimum-threshold cutoff PG attribute score for diagnosis of PGD (i.e., PG attribute score≥minimum-threshold cutoff PG attribute score). An optimal cutoff PG attribute score of 1 maximized agreement between rater diagnoses and dichotomized IRM PG attribute score diagnoses of PGD.
Based on consensus opinion of the previously mentioned expert panel
Each data point in this figure represents the performance, in terms of sensitivity and specificity with respect to a criterion standard for PGD, of a unique “
Three subtypes of PGD were defined in terms of patterns of meeting diagnostic criteria for PGD at 0–6 and 6–12 mo post-loss: acute = meeting the symptom criteria for PGD at 0–6 mo, but not at 6–12 mo, post-loss; delayed = meeting the symptom criteria for PGD at 6–12 mo, but not at 0–6 mo, post-loss; and persistent = meeting the symptom criteria for PGD both at 0–6 and at 6–12 mo post-loss. In
Outcome (12–24 Mo Post-Loss) | Relative Risk for Outcome Associated with PGD Temporal Subtype: | |||||||
Acute (15/172 [8.7%]) |
Delayed (6/172 [3.5%]) |
Persistent (12/172 [7.0%]) |
Delayed or persistent (28/242 [11.6%]) |
|||||
RR | 95% CI | RR | 95% CI | RR | 95% CI | RR | 95% CI | |
MDD, PTSD, or GAD | 1.54 | (0.20–11.98) | 3.86 | (0.55–27.22) | 11.58*** | (4.41–30.43) | 10.19*** | (4.72–21.99) |
Suicidal ideation ( |
1.97 | (0.64–6.09) | 4.93*** | (1.92–12.64) | 3.29* | (1.28–8.43) | 4.44*** | (2.62–7.53) |
Functional disability ( |
0.51 | (0.18–1.45) | 1.54 | (0.73–3.25) | 1.40 | (0.79–2.50) | 1.65** | (1.16–2.34) |
Poor quality of life ( |
0.76 | (0.20–2.89) | 3.78*** | (1.93–7.40) | 2.58* | (1.23–5.41) | 3.17*** | (2.03–4.95) |
Acute = meeting symptom criteria at 0–6 mo, but not at 6–12 mo, post-loss; Delayed = not meeting symptom criteria at 0–6 mo, but meeting symptom criteria at 6–12 mo post-loss; Persistent = meeting symptom criteria at 0–6 and 6–12 mo post-loss.
The denominator included those assessed at both 0–6 and 6–12 mo post-loss.
The denominator included all those assessed at 6–12 mo post-loss, regardless of the 0–6-mo post-loss assessment.
Sample sizes (
*
CI, confidence interval; RR, relative risk.
To reduce further the likelihood of a false-positive diagnosis, a timing criterion (Criterion D) was added to specify that a diagnosis not be made until at least 6 mo have elapsed since the death. This would exclude the acute cases described above in which a person with initially high levels of grief in the first few months experiences declines in grief intensity at and beyond 6 mo post-loss. To be conservative in our diagnosis of PGD, we also added a requirement that the symptomatic distress be associated with functional impairment (Criterion E).
The ultimate consensus criteria set for PGD proposed for
Category | Definition |
A. | |
B. | |
C. | |
1. Confusion about one’s role in life or diminished sense of self (i.e., feeling that a part of oneself has died) | |
2. Difficulty accepting the loss | |
3. Avoidance of reminders of the reality of the loss | |
4. Inability to trust others since the loss | |
5. Bitterness or anger related to the loss | |
6. Difficulty moving on with life (e.g., making new friends, pursuing interests) | |
7. Numbness (absence of emotion) since the loss | |
8. Feeling that life is unfulfilling, empty, or meaningless since the loss | |
9. Feeling stunned, dazed or shocked by the loss | |
D. | |
E. | |
F. |
Among those not concurrently meeting
Outcome (12–24 Mo Post-Loss) | PGD Diagnosis (6–12 Mo Post-Loss) | |||
Yes (3.3%) | No (96.7%) | RR | 95% CI | |
MDD, PTSD, or GAD | 28.6% | 3.4% | 8.49** | (2.14–33.72) |
Suicidal ideation |
57.1% | 10.1% | 5.63*** | (2.64–12.03) |
Functional disability |
71.4% | 35.9% | 1.99** | (1.20–3.29) |
Poor quality of life |
83.3% | 14.7% | 5.67*** | (3.48–9.22) |
Sample sizes (
*
CI, confidence interval; RR, relative risk.
Our results indicate that PGD meets
Although the YBS data may appear unrepresentative of the general US population, a comparison with US Census 2005
Although there is a need to confirm the results in nonwidowed bereaved persons, we consider widowhood following an older spouse's death from natural causes to be the prototypical case of bereavement. In the US, 84% of all deaths occur among individuals who are 65 y and over
Although the sample size may appear modest, the study was designed and appropriately powered to evaluate a wide range of potential diagnostic criteria (i.e., the first phases of the analyses used the full sample [
Study participants may have been less distressed than study nonparticipants. Given the relatively low rates of MDD in the YBS sample and that 10.5% refused participation in the YBS due to being “too upset,” the prevalence rate of PGD reported here may be an underestimate. In addition, our statistical power to detect significant effects of PGD on mental health and functional impairment outcomes would be lower than would have been the case if more distressed nonparticipants with PGD had been included in the study sample.
This report provides psychometric validation of a diagnostic algorithm for PGD. Although further validation work will, no doubt, be needed, we consider the evidence sufficient to justify PGD's serious consideration for inclusion in
Although most bereaved individuals will eventually adapt to the loss of a significant other more or less successfully, a significant, identifiable minority will experience chronic and disabling grief. A PGD diagnosis has the potential to enhance the detection and effective treatment of a substantial cause of morbidity among persons who have experienced the loss of a significant other. The diagnosis and treatment of PGD offers the promise of reducing the personal and societal toll taken by prolonged grief.
two-parameter logistic
differential item functioning
generalized anxiety disorder
Inventory of Complicated Grief—Revised
item information function
item response model
item response theory
major depressive disorder
prolonged grief
prolonged grief disorder
posttraumatic stress disorder
Structured Clinical Interview for
Widowed Persons Service
Yale Bereavement Study