Journal of Affective Disorders 99 (2007) 203–211www.elsevier.com/locate/jad

Research report

Comparison of two diagnostic systems for Complicated Grief

Simon Forstmeier ⁎, Andreas Maercker

Department of Psychology, Psychopathology and Clinical Intervention, University of Zurich,Binzmühlestr. 14/17, 8050 Zurich, Switzerland

Received 28 February 2006; received in revised form 6 September 2006; accepted 8 September 2006Available online 18 October 2006

Abstract

Background: To date, there are mainly two diagnostic systems that have been proposed for the diagnosis of Complicated Grief[Horowitz, M.J., Siegel, B., Holen, A., Bonanno, G.A., Milbrath, C., Stinson, C.H., 1997. Diagnostic criteria for complicatedgrief disorder. American Journal of Psychiatry 154, 904–910; Prigerson, H.G., Shear, M.K., Jacobs, S.C., Reynolds, C.F.,Maciejewski, P.K., Davidson, J.R., Rosenheck, R., Pilkonis, P.A.,Wortman, C.B.,Williams, J.B., Widiger, T.A., Frank, E., Kupfer,D.J., Zisook, S., 1999. Consensus criteria for traumatic grief: A preliminary empirical test. British Journal of Psychiatry 174,67–73]. There is also no data about prevalence rates of Complicated Grief in a representative sample. The purpose of this studywas to compare the diagnostic systems with regard to prevalence, conditional probabilities, and agreement.Methods: In a sample of elderly persons, features of bereavement, diagnoses of Complicated Grief and related symptoms wereassessed. Agreement between the diagnostic systems was determined by kappa statistics.Results: 18.9% of the sample had experienced a major bereavement, in average 15 years before measurement. The prevalence rateswere 4.2% (Horowitz et al.) and 0.9% (Prigerson et al.). The agreement was poor (kappa= .13), i.e. the minority of cases receivedboth diagnoses. The conditional probabilities of developing CG after experiencing a major bereavement were 22.2% (Horowitzet al.) and 4.6% (Prigerson et al.).Limitations: The findings are constrained to an elderly, urban population. Screening instruments, no clinical interviews, were usedto assess psychopathology.Conclusions: The Horowitz et al. criteria set is more inclusive and less strict than the Prigerson et al. criteria set. The importance offunctional impairment and the number of symptoms needed account for this difference. Further research should integrate diagnosticsystems in order to achieve international standardization of diagnostic criteria for Complicated Grief.© 2006 Elsevier B.V. All rights reserved.

Keywords: Complicated Grief; Prevalence; Diagnostic systems

1. Introduction

In the recent years, Complicated Grief (CG) has beendiscussed as stress-related disorder distinct from MajorDepression, Adjustment Disorder, Acute Stress Disor-

⁎ Corresponding author. Tel.: +41 44 635 73 05; fax: +41 44 635 73 19.E-mail address: s.forstmeier@psychologie.unizh.ch

(S. Forstmeier).

0165-0327/$ - see front matter © 2006 Elsevier B.V. All rights reserved.doi:10.1016/j.jad.2006.09.013

der, and Posttraumatic Stress Disorder (Horowitz et al.,1993, 1997; Prigerson et al., 1999; Jacobs et al., 2000;Stroebe et al., 2000; Prigerson and Jacobs, 2001a;Lichtenthal et al., 2004). Similar sets of symptoms thatmay specifically characterizeCG (e.g., yearning, searching,disbelief, loneliness, emptiness, numbness, avoidance)have been proposed independently by the researchers andclinicians mentioned above, which suggests a generalagreement about the symptoms that Complicated Grief

204 S. Forstmeier, A. Maercker / Journal of Affective Disorders 99 (2007) 203–211

would comprise. However, by analyzing the two maindiagnostic systems for CG, important differences in thecriteria structure can be observed:

The Prigerson et al. consensus criteria differentiatebetween two categories of symptoms (Prigerson et al.,1999; Prigerson and Jacobs, 2001a,b): (1) separationdistress, e.g., preoccupation with thoughts of the deceased,longing and searching for the deceased, loneliness; and (2)traumatic distress, e.g., feeling disbelief about the death,mistrust, anger, feeling shocked by the death, and theexperience of somatic symptoms of the deceased. Inaddition, there must be disturbance that causes clinicallysignificant impairment. Horowitz et al. (1997) differentiatebetween three categories of symptoms: (1) intrusion, e.g.,unbidden memories, emotional spells, strong yearning; (2)avoidance, e.g., avoiding places that are reminders of thedeceased, emotional numbness towards others; and (3)failure to adapt symptoms, e.g., feeling lonely or empty,having trouble sleeping.

One main difference in the symptom structure of thetwo systems is the role of avoidance symptoms. WhileHorowitz et al. (1997) regard avoidance as an importantcriterion for CG, Prigerson and Jacobs (2001b) removedthe avoidance item (after having included it in an earlierversion of their syndrome definition), in order to im-prove the internal consistency and diagnostic accuracyof the traumatic distress category. This is in accordancewith a finding by Raphael and Martinek (1997): incontrast to PTSD patients who avoid reminders of thetrauma, CG patients avoid reminders of the absence ofthe person and hence actively seek for reminders of thedeceased person.

Another difference between the symptom structuresof the two systems becomes obviously when looking atthe disturbance item. Disturbance in social living is onepossible item in the avoidance cluster of the Horowitzet al. criteria that does not necessarily have to be fulfilledfor a diagnosis. In contrast, the presence of functionaldisturbance is considered an integral part within thePrigerson et al. consensus criteria. They justify the in-tegration of a disturbance criterion by citing studies thathave shown that symptoms of CG predict clinicallysignificant impairment (e.g., Prigerson et al., 1995, 1997;Chen et al., 1999).

In addition, in their newer formulation (e.g., Prigersonand Jacobs, 2001a), the Prigerson et al. consensus criteriaassume a symptom duration of more than six monthsbefore a diagnosis should be made, whereas the Horowitzet al. criteria suggest the loss to be at least 14 months ago.

Recent reviews have gathered evidence in favour ofboth of two criteria sets (Jacobs et al., 2000; Stroebe et al.,2000; Lichtenthal et al., 2004). Most studies about CG

applied the Prigerson et al. criteria. They have shown that(a) CG forms an unidimensional symptom cluster with thetwo subfactors of separation and traumatic distress; (b)CG symptoms have proven to be distinct from depressiveand anxiety clusters; (c) CGpredicts substantial morbiditysuch as risk of cancer, cardiac events, increased alcoholconsumption, and suicidal ideation; and (d) CG symp-toms do not respond to antidepressive psychotherapy ortricylic antidepressants.

Studies applying the Horowitz et al. criteria haveshown that (a) CG symptoms can be classified intointrusion, avoidance, and failure-to-adapt categories; (b)CG has proven to be distinct from depression; (c) the CGdiagnosis showed a meaningful correlational pattern tomeasures of psychopathology and normal grief reactions(Langner and Maercker, 2005); and (d) patients with CGshowed better improvement after an internet-basedcognitive–behavioral therapy compared to a controlgroup (Wagner et al., 2006).

In the present study, we compared the two diagnosticsystems in a representative sample of elder people(n=570) with regard to prevalence rates of CG, condi-tional probabilities (i.e., prevalence of developing CGafter experiencing a major bereavement), and the poten-tial overlap in prevalence of the two systems.

2. Methods

2.1. Sample and procedures

The data used in this report are derived from the ZurichOlder Age Study on trauma-, bereavement-, and stress-related disorders (Maercker et al., 2003, submitted forpublication). The recruitment was carried out in a two-phase process. A random sample of older, not specificallybereaved people (65–96 years) stratified for age, genderand living situation, was provided by the residents'registration office of the city of Zurich. Initially, 1225persons were identified and deemed eligible for the study.

In the first phase, telephone interviewswere conductedwith 712 persons of the 1225 verifiable addresses.Reasons for non-participation were refusal (n=428),suspected dementia (n=26), other health reasons (n=17),language problems (n=17), lack of time (n=6), and otherreasons (n=13). The telephone interview comprised ascreening for CG and other stress-related disorders. In thesecond phase (questionnaire), the sample was reduced to570 persons with complete data. After comprehensivedescription of the study to the subjects, a written informedconsent was obtained.

The representativeness of the study sample was testedwith regard to the recruitment criteria. Table 1 shows that

Table 1Test of representativeness of the study samples (in two phases) incomparison with the stratified random sample

Randomsample:Verifiableaddresses(N=1225)

Phase-1sample:Telephoneinterview(N=712)

Phase-2sample:Completeprotocol(N=570)

Age at time of study 75.2(S.D. 7.0)

74.6(S.D. 6.8)

74.0⁎

(S.D. 6.7)Gender (% female) 63.5 61.5 57.7⁎

Living alone (%) 35.0 37.1 34.6Living with partner (%) 57.3 58.7 62.5⁎⁎

Living in institution forolder people (%)

7.8 4.2 3.0⁎

Note: Tests of differences: multiple T-test for age at time of study; Chi-Square tests for all other variables; level of significance: ⁎pb .05,⁎⁎pb .01.

205S. Forstmeier, A. Maercker / Journal of Affective Disorders 99 (2007) 203–211

phase-2 participants were somewhat younger; thesample included more men; comprised more subjectswho lived with partners and fewer who lived in in-stitutions for older people, compared to the stratifiedrandom sample. However, the differences were not con-siderable (e.g., the effect size for the age difference isd=0.16).

3. Measures

3.1. General questions on major bereavements

The questionnaire begins with four general questionson possible major bereavements: the trigger event (“Isthere an important person in your life (spouse, partner,close relative or friend) whose death you have not yetgot over with?” with a Yes/No answer format); the kindof relationship to the deceased (“Who?” with a free textanswer format); the duration of mourning (“How manymonths ago did he/she die?”); and the context of deathwith “unexpected, illness, and traumatic (e.g. accident,suicide)” as answer options.

3.2. Complicated Grief following Prigerson et al.

Criteria of CG following Prigerson et al. were measuredby items of the Inventory of Traumatic Grief- Revised(ITG-R, Prigerson and Jacobs, 2001b), a validated 32-itemquestionnaire with high internal consistency (Cronbach'sα= 0.92). Items of the ITG-R were applied to consensuscriteria of CG. The original consensus criteria (Prigersonet al., 1999; Prigerson and Jacobs, 2001b) included 4separation distress symptoms and 11 traumatic distresssymptoms. Three traumatic distress symptoms (“frequentefforts to avoid reminders”, “feeling stunned”, and

“difficulty imagining a fulfilling life”) that performedpoorly in receiver operating characteristic (ROC) analyseswere excluded from the original criteria set, resulting in a“refined” criteria set (Prigerson et al., 1999; Prigerson andJacobs, 2001a,b). It has a considerable diagnostic power(sensitivity=0.93; specificity=0.93).

Our shortened version of the ITG comprised onlythose items that assess the refined consensus criteria (seeTable 3): one item for the triggering event (death of asignificant other; criterion A1), four items for separationdistress (criterion A2), eight items for traumatic distress(criterion B), one for duration of more than 6 months asused in the newer version (e.g., Prigerson and Jacobs,2001a, criterion C), and one for disturbance that causesclinically significant impairment (criterion D). We ap-plied a reduced 4-point scale (1 = no/never to 4 = over-whelming/always) in order to have the same scaling forall instruments used in the Zurich Older Age Study. AsPrigerson et al. (1999) proposed, we diagnosed CG if, inSeparation Distress, at least 3 out of 4 symptoms weregreater than or equal to 3, and, in Traumatic Distress, atleast 4 out of 8 symptoms were greater than or equal to 3.In addition, the trigger, duration and disturbance criteriahad to be fulfilled.

3.3. Complicated Grief following Horowitz et al.

Criteria of CG following Horowitz et al. were mea-sured by items of the Complicated Grief Module (CGM)(Horowitz et al., 1997), a list of 30 symptoms of CG in aSCID module format. The items were formulated asquestions, including the three categories grief-relatedintrusions, behaviors that avoid grief-related emotionalstress, and difficulties or failure to adapt to the loss(Cronbach's α=0.49 – 0.58). After an LCM analysis,Horowitz et al. (1997) selected seven items of the CGMas a short set for diagnosing CG. The German version ofthe CGM transformed the original questions into state-ments and used a seven-point Likert-type severity scale(Langner and Maercker, 2005). The proposed algorithmof 3 out of 7 symptoms achieved considerable diagnosticpower (sensitivity = 0.60; specificity = 0.99; total pre-dictive value = 0.96) using the German CGM.

Our shortened version of the CGM comprised onlyseven items (three intrusion, two avoidance, and twofailure-to-adapt items, see Table 3). One additional itemmeasured the duration (at least 14 months). We applied a4-point scale (1 = no/never to 4 = overwhelming/always). As Horowitz et al. (1997) proposed, CG wasdiagnosed if at least 3 out of 7 symptoms were greaterthan or equal to 3. In addition, the trigger and durationcriteria had to be fulfilled.

Table 2Characteristics of all mourning individuals (N=108)

All (n=108) Female (n=78) Male (n=30) Test for gender diff.

% (N ) or M (S.D.) % (N ) or M (S.D.) % (N ) or M (S.D.) χ2 / t-test ( p)

Age at time of study (M) 73.7 (6.5) 73.7 (6.6) 73.8 (6.3) t=.13 (.899)Living situationLiving alone 55.6 (60) 65.4 (51) 30.0 (9)Living with partner or family 41.7 (45) 32.1 (25) 66.7 (20) χ2=11.16 (.004⁎⁎)Living in institution for older people 2.8 (3) 2.6 (2) 3.3 (1)

Relationship to the deceasedSpouse (%) 46.3 (50) 50.6 (39) 37.9 (11)Parent (%) 15.7 (17) 15.6 (12) 17.2 (5)Sibling (%) 9.3 (10) 7.8 (6) 13.8 (4) χ2=4.52 (.340)Child (%) 17.6 (19) 19.5 (15) 13.8 (4)Other (e.g., friend, colleague, lover) (%) 9.3 (10) 6.5 (5) 17.2 (5)

Duration of mourning (in months) (M) 180.95 (206.1) 190.82 (212.7) 153.43 (187.5) t=−.82 (.413)≥6 months (%) 91.7 (99) 93.59 (73) 86.67 (26) χ2=1.36 (.260)≥14 months (%) 84.3 (91) 87.2 (68) 76.7 (23) χ2=1.81 (.237)

Context of deathUnprepared (%) 25.9 (28) 22.7 (17) 36.7 (11)Illness (%) 54.6 (59) 56.0 (42) 56.7 (17) χ2=4.27 (.119)Traumatic (e.g. accident, suicide) (%) 16.7 (18) 21.3 (16) 6.7 (2)

Depressive symptoms (CES-D) (range 0–60) (M) 8.16 (8.29) 8.39 (8.16) 7.57 (8.72) t=−.46 (.645)Depressive disturbance (CES-D≥16) (%) 14.8 (16) 15.4 (12) 13.3 (4) χ2= .07 (1.00)PTSD symptoms (SSS) (range 0–7) (M) .36 (.88) .33 (.83) .43 (1.01) t= .53 (.599)Probable PTSD diagnosis (SSS≥4) (%) 1.9 (2) 1.3 (1) 3.3 (1) χ2= .50 (.480)

Note: ⁎⁎pb .01.

206 S. Forstmeier, A. Maercker / Journal of Affective Disorders 99 (2007) 203–211

3.4. Depressive symptoms

Depressive symptoms were measured by the “Centerfor Epidemiological Studies Depression Scale —Revised Version” (CES-D-R, Gallo and Rabins, 1999).This revised version of the original CES-D (Radloff,1977) consists of 20 items which describe typical de-pressive symptoms. In this study, we applied the 4-pointscale (0 = never or seldom to 3 = always or almostalways), which was used in the original version. The sumscore ranges from 0 to 60, with a value of 16 or higherpointing to a depressive disturbance.

3.5. Screening for symptoms of PTSD

The Short Screening Scale for DSM-IV Posttrau-matic Stress Disorder (SSS, Breslau et al., 1999) wasused for the screening of PTSD symptoms. The sevenitems include five symptoms from the avoidance andnumbing group and two from the hyperarousal group.All items refer to the most upsetting event as indicated inthe Traumatic Events Checklist (Wittchen and Pfister,1997). One item is scored as 1 if answered as “twice ormore times a week” and 0 if “once a week or less”. Asum score of 4 or more has the following characteristicsfor diagnosing DSM-IV PTSD: sensitivity 80%, spec-

ificity 97%, positive predictive value 71%, and negativepredictive value 98% (Breslau et al., 1999).

4. Data analysis

Data were analyzed using the Statistical Package forSocial Sciences, Version 14 for PC. Frequencies of di-agnoseswere calculated (generally, aswell as separated bygender), and conditional probabilities given severalcontextual and psychopathological aspects. The χ2 testor univariate ANOVAwere used to test gender differences.Agreement between the diagnostic systems was deter-mined by kappa statistics, whereby kappa values of b .20indicated poor agreement, .21–.40 fair agreement, .41–.60moderate agreement, and .61–.80 good agreement.

5. Results

5.1. Characteristics of mourning individuals

18.9% (108) of the phase-2 sample had experienced amajor bereavement, comprising significantly morewomen than men (23.7% vs. 12.4%; χ2[1,570]=11.48;pb .01). The characteristics of the individuals who hadexperienced a major bereavement are illustrated inTable 2. Almost half of the mourning elderly persons

207S. Forstmeier, A. Maercker / Journal of Affective Disorders 99 (2007) 203–211

had lost their spouse, mostly after a period of illness. Theelapsed time from the point of loss was 15 years inaverage, ranging from 1 month to 72 years. In this sub-sample of mourning individuals, 15% had an increasedCES-D value (≥16) and 2% showed increased PTSDsymptoms (SSS≥4). There were no gender differences.

5.2. Prevalence of CG

The prevalence of CG differs greatly between the twodiagnostic systems: It was found to be 4.2% (24) whenusing the Horowitz et al. criteria, and 0.9% (5) whenusing the Prigerson et al. consensus criteria (Table 3).

Table 3Prevalence rates of Complicated Grief symptoms following Horowitz et al.

A

N

Person has experienced the death of a significant other 1

Criteria of CG following Horowitz et al.Intrusion

1) Unbidden memories2) Emotional spells3) Strong yearnings

Avoidance4) Avoiding places that remind of deceased5) Loss of interest in important activities to a maladaptive degree

Failure to adapt6) Feeling alone or empty7) Trouble sleeping

Duration ≥14 monthsDiagnosis of CG following Horowitz et al.

Criteria of CG following Prigerson et al.Separation Distress (A2): 3 of 4

Intrusive thoughts about the deceased (A2a)Yearning for deceased (A2b)Searching for the deceased (A2c)Loneliness since the death (A2d)

Traumatic Distress (B): 4 of 8Purposelessness (B1)Sense of numbness (B2)Difficulty acknowledging death (B3)Feeling that life is empty or meaningless (B4)Feeling that part of oneself has died (B5)Shattered world view (e.g. trust) (B6)Assumes symptoms of deceased (B7)Excessive irritability (B8)

Duration ≥6 months (C)Disturbance causes clinically significant impairment…(D)Diagnosis of CG following Prigerson et al. (A, B, C fulfilled)Diagnosis of CG following Prigerson et al. (A, B, C, and D fulfilled)

Note: ⁎pb .05, ⁎⁎pb .01, ⁎⁎⁎pb .001.

Time since loss was 15 years in average (range 19 mo.–65 yr.) using the Horowitz criteria and 14 years (range10 mo.– 50 yr.) using the Prigerson criteria.

There is only a partial overlap between the twodiagnostic systems: Of the 27 (4.7%) individuals beingdiagnosed with CG using either one of the two systems,22 (3.9%) can be diagnosed according to Horowitz et al.only, 3 (0.5%) receive a diagnosis following Prigersonet al. only, and 2 (0.4%) receive both CG diagnoses. Thefrequencies of these three categories differ significantly(χ2 =16.02; pb .01). Fig. 1 shows a Venn diagram dem-onstrating the small overlap between the two systems.Agreement between the Horowitz et al. and the Prigerson

and Prigerson et al. in the phase-2 sample (N=570)

ll (n=570) Female(n=329)

Male(n=241)

Test for genderdiff.

% N % N % Chi-square ( p) /Fisher's exacttest ( p)

08 18.9 78 23.7 30 12.4 11.48 (.001⁎⁎⁎)

11 1.9 7 2.1 4 1.7 .16 (.77)29 5.1 24 7.3 5 2.1 7.85 (.01⁎⁎)77 13.5 59 17.9 18 7.5 13.04 (.00⁎⁎⁎)

10 1.8 7 2.1 3 1.2 .63 (.53)6 1.1 5 1.5 1 .4 1.63 (.41)

43 7.5 32 9.7 11 4.6 5.32 (.02⁎)20 3.5 16 4.9 4 1.7 4.22 (.04⁎)91 16.0 68 20.7 23 9.5 12.83 (.00⁎⁎⁎)24 4.2 19 5.8 5 2.1 4.72 (.03⁎)

26 4.6 18 5.5 8 3.3 1.48 (.22)46 8.1 33 10.0 13 5.4 4.03 (.05⁎)77 13.5 59 17.9 18 7.5 13.04 (.00⁎⁎⁎)20 3.5 15 4.6 5 2.1 2.54 (.11)43 7.5 32 9.7 11 4.6 5.32 (.02⁎)14 2.5 10 3.0 4 1.7 1.11 (.29)14 2.5 10 3.0 4 1.7 1.11 (.29)4 .7 4 1.2 0 .0 2.95 (.14)58 10.2 40 12.2 18 7.5 3.35 (.07)12 2.1 9 2.7 3 1.2 1.50 (.22)40 7.0 29 8.8 11 4.6 3.85 (.05⁎)11 1.9 7 2.1 4 1.7 .16 (.77)12 2.1 9 2.7 3 1.2 1.50 (.22)15 2.6 8 2.4 7 2.9 .12 (.73)99 17.4 73 22.2 26 10.8 12.60 (.00⁎⁎⁎)19 3.3 13 4.0 6 2.5 .92 (.34)9 1.6 6 1.8 3 1.2 .30 (.74)5 .9 4 1.2 1 .4 1.03 (.40)

Fig. 1. Venn diagram showing the overlap of the two diagnosticsystems for Complicated Grief.

208 S. Forstmeier, A. Maercker / Journal of Affective Disorders 99 (2007) 203–211

et al. systems was poor, albeit statistically significant(kappa= .13; pb .001).

Gender differences were only found using theHorowitz et al. system, with more diagnoses for women(χ2=4.72; pb .05). Table 3 shows the prevalence for eachitem. In the Horowitz et al. system, there were gender

Table 4Comparisons between Complicated Grief diagnoses following Horowitz et a

Subjects with CG followingHorowitz et al. (n=22)

Subjects wiPrigerson e

% (N ) or M (S.D.) % (N ) or M

Relationship to the deceasedSpouse (%) 13 1Parent (%) 2 1Sibling (%) 2 0Child (%) 4 1Other (e.g., friend,colleague, lover) (%)

1 0

Duration of mourning(in months) (M)

165.4 71.0

≥6 months (%) 100.0 (22) 100.0 (3)≥14 months (%) 100.0 (22) 33.3 (1)

Context of deathUnprepared (%) 27.3 (6) 0.0Illness (%) 54.5 (12) 66.7 (2)Traumatic (e.g. accident,suicide) (%)

13.6 (3) 33.3 (1)

Depressive symptoms (CES-D)(range 0–60) (M)

9.1 (10.0) 18.7 (8.1)

Depressive disturbance(CES-D≥16) (%)

18.2 (4) 33.3 (1)

PTSD symptoms (SSS)(range 0–7) (M)

.4 (1.0) 1.7 (2.9)

Probable PTSD (SSS≥4) (%) 4.5 (1) 33.3 (1)

Note: ⁎pb .05, ⁎⁎⁎pb .001.

differences for the intrusion and failure to adaptsymptoms, but not for the avoidance symptoms. Usingthe Prigerson et al. consensus criteria, 4.6% meet thecriterion of separation distress, and 2.5% the criterion oftraumatic distress. Women showed more separationdistress symptoms thanmen, but similar traumatic distresssymptoms.

5.3. Conditional probabilities

Relative to all individuals that had experienced loss,the conditional probability of developing CG afterexperiencing a major bereavement is 22.2% whenusing the Horowitz et al. criteria, and 4.6% when usingthe Prigerson et al. consensus criteria. To compare thetwo diagnostic systems with regard to several contextualand psychopathological aspects, people with CGfollowing Horowitz et al., with CG following Prigersonet al., and with CG following both systems werecontrasted (Table 4). In relative terms, there are morepeople with CG following Prigerson et al. who have aCES-D value ≥16 (χ2 =6.49; pb .05), respectively oftheir baserate in the sample. There are no significant

l. and Prigerson et al. (N=108)

th CG followingt al. (n=3)

Subjects with CG followingHorowitz et al. andPrigerson et al. (n=2)

Test for systemdiff.

(S.D.) % (N ) or M (S.D.) χ2 /ANOVA ( p)

200 χ2=3.95 (.862)00

309.5 F(2)= .96 (.397)

100.0 (2) –100.0 (2) χ2=17.28 (.000⁎⁎⁎)

100.0 (2)0.0 (0) χ2=6.24 (.182)0.0 (0)

21.5 (7.8) F(2)=2.45 (.110)

100.0 (2) χ2=6.49 (.039⁎)

0.0 (0.0) F(2)=1.50 (.243)

0.0 (0) χ2=3.36(.186)

209S. Forstmeier, A. Maercker / Journal of Affective Disorders 99 (2007) 203–211

differences regarding relationship to the deceased,context of death, and PTSD symptoms.

6. Discussion

The Zurich Older Age Study on trauma-, bereave-ment-, and stress-related disorders (Maercker et al.,2003, submitted for publication) was the first study toreport prevalence rates of CG (using the Horowitz et al.criteria) in a representative sample. The reason for thislack of prevalence studies might be traced back to theabsence of standardized criteria. Therefore, it is notsurprising that the two diagnostic systems led to quitedifferent prevalence rates: 4.2% when using theHorowitz et al. (1997) criteria and 0.9% when usingthe Prigerson et al. (1999) refined criteria.

One reason for the different prevalences might be thedisturbance criterion, which has to be fulfilled in thePrigerson et al. system but not in the Horowitz et al.system. After omitting the disturbance criterion in thePrigerson et al. system, the prevalence increases from0.9% to 1.6%. Another reason for the lower prevalencerate in the Prigerson et al. system lies in the fact thatpatients must have seven out of twelve symptoms, incontrast to only three out of seven symptoms in theHorowitz et al. system. Thus, the Prigerson et al.consensus criteria are stricter than the Horowitz et al.criteria; following Prigerson et al., a person must bemore impaired to receive a CG diagnosis. This is alsoreflected in our observation that individuals with CGfollowing Prigerson et al. tend to be more depressivethan individuals with CG following Horowitz et al.

The difference in criteria structure also leads to amerely small overlap between the two diagnostic sys-tems, which is reflected by the poor agreementcoefficient (kappa = .13). Two of the three subjectswho receive a Prigerson et al. CG diagnosis only have aduration of mourning of less than 14 months (whichexcludes them from the Horowitz CG diagnosis), thethird shows only 2 and not 3 of 7 symptoms needed for aHorowitz et al. CG diagnosis.

The difference in prevalence leads to a smaller con-ditional probability of developing CG after experiencinga major bereavement when using the Prigerson et al.consensus criteria compared to the Horowitz et al.criteria. Previous studies found varying conditional pre-valences depending on the subpopulation (community-based sample of bereaved individuals vs. clinical sam-ple), elapsed time since loss, and age range. The onlystudy using the Horowitz et al criteria set in a volunteersample of bereaved subjects (age 21–55 years)14 months after the death of their partners evidenced a

prevalence of 41% of CG (Horowitz et al., 1997). Ourconditional prevalence of 22.2%might be lower becauseour sample was based on a random drawing (and notrecruited through newspaper advertisements) or com-prised older people with longer time spans since loss (inaverage 15 year).

This latter explanation is supported by the studieswhich applied the Prigerson et al criteria set: In a com-munity sample of bereaved individuals (age 40 to 80,mean 62 years) the prevalence decreases with increasingtime spans since loss from 57% at 2 months post-lossover 20% at 6 months, 6% at 13 months, and 7% at25 months post-loss (Prigerson et al., 1997). Similarly,Latham and Prigerson (2004) found a prevalence of 11%at 6 months and 7% at 11 months post-loss in a com-munity sample of recently widowed people (age 20 to 91,mean 62 years). In a sample of people whose spousesdied 2 to 34months before (age 23 to 78, mean 64 years),a prevalence of 18% was evidenced (Silverman et al.,2000). Our prevalence value of 4.6% is in agreementwith these findings since the mean time span since loss is14 years. Finally, from a sample of psychiatry patients inPakistan, 83% experienced violent deaths, and 34% hadCG (Prigerson et al., 2002). The diagnosis of CG seemsto be more prevalent with the presence of more severecomorbid disorders (Maercker et al., submitted forpublication).

7. Limitations

There are some limitations to the present study. First,this study makes no statement about the sensitivity andspecificity of the two diagnostic systems of CG. Theideal way to assess the sensitivity and specificity of a setof criteria is to compare it to a “gold standard” that iserror-free. However, there is no gold standard availablefor CG, as is the case for most psychiatric diagnosticsystems. One way to estimate sensitivity and specificityof the two different diagnostic systems is to use follow-up data as external criterion. Diagnostic criteria shouldidentify mourning people whose grief goes on todevelop an untoward course. Thus, having symptomsthat do not change very much over time might be auseful external criterion. Studies should apply this wayto estimate sensitivity and specificity of CG criteria inthe future.

Second, 58% of the random stratified sampleparticipated in the study and show a small tendencytowards younger olds, men, people who lived withpartners, and individuals who did not live in institutionsfor older people. CG is probably more prevalent inwomen and in individuals living alone and/or in

210 S. Forstmeier, A. Maercker / Journal of Affective Disorders 99 (2007) 203–211

institutions (e.g., Frans et al., 2005). However, the effectsizes for the relevant differences between random sampleand phase-2 sample are quite low (e.g., d=0.16 for theage difference).

Third, the results stem from an elderly population,with a mean time from loss of 15 years. As explicated inthe discussion, the prevalence of CG seems to decreasewith increasing time span since loss. Thus, higher ratesof CG would be expected in a younger sample closer tothe time of loss. Fourth, the prevalences found in thisstudy reflect the presence of the investigated disorders inan urban population. Thus, prevalences in a rural pop-ulation, which are usually lower (e.g., Chiu et al., 2005),are not reflected.

Fifth, short screening instruments were used to assessdepressive and PTSD symptoms. Clearly, these screen-ing scales are not substitutes for psychiatric diagnoses,and the scores cannot be interpreted in terms of DSM-IVdiagnoses of major depression and PTSD. Sixth, thedefinition of major bereavements as losses of importantothers in the life of the individual that he/she “did not yetgot over with” might have resulted in a selection biasand, in consequence, might lead to lower prevalences.However, we decided to use this formulation in order toensure that only psychological relevant losses arementioned.

Finally, the original rating format of the ITG andCGMwas changed in order to have the same scale for allinstruments used in the Zurich Older Age Study. Thishad a potential impact on the results. However, sinceboth the ITG and the CGM were affected by the samechanges, the main differences between the systemsremained untouched by this.

8. Conclusions

This is the first representative study of CG and thefirst study in which the two main diagnostic systems ofCG are tested. The Horowitz et al. criteria set is moreinclusive and less strict than the Prigerson et al. criteriaset and, thus, leads to a higher prevalence. The two mainreasons contributing to this difference are the distur-bance criterion and the number of symptoms that have tobe present in order to diagnose CG. Future efforts tointegrate the two criteria sets into one internationalstandard that might be established in DSM-V and ICD-11 should answer two questions: (1) How much im-paired must a patient be in social, occupational, andother areas of functioning to receive a diagnosis of CG?(2) Howmany symptoms must at least be present? In ouropinion, impairment should be assessed in a gradedmanner in order to allow a mildly impaired patient who

otherwise has a full-blown CG symptomatic to bediagnosedwith CG.With regard to the minimum numberof symptoms the most adequate number might liebetween 3 and 7.

Acknowledgments

We thank A. Enzler, G. Grimm, and E. Helfenstein fortheir help in data collection, as well as U. Ehlert forproviding resources and infrastructure. No grants receivedfor this study, no conflicts of interest.

References

Breslau, N., Peterson, E.L., Kessler, R.C., Schultz, L.R., 1999. Shortscreening scale for DSM-IV posttraumatic stress disorder.American Journal of Psychiatry 156, 908–911.

Chen, J.C., Bierhals, A.J., Prigerson, H.G., Kasl, S.V., Mazure, C.M.,Reynolds, C.F., Shear, M.K., Day, N., Jacobs, S.C., 1999. Genderdifferences in health outcomes resulting from bereavement-relatedemotional distress. Psychological Medicine 29, 367–380.

Chiu, H.C., Chen, C.M., Huang, C.J., Mau, L.W., 2005. Depressivesymptoms, chronic medical conditions and functional status: acomparison of urban and rural elders in Taiwan. InternationalJournal of Geriatric Psychiatry 20, 635–644.

Frans, O., Rimmo, P.A., Aberg, L., Fredrikson, M., 2005. Traumaexposure and post-traumatic stress disorder in the generalpopulation. Acta Psychiatrica Scandinavica 111, 291–299.

Gallo, J.J., Rabins, P.V., 1999. Depression without sadness: alternativepresentation of depression in late life. American Family Physician60, 820–826.

Horowitz, M.J., Bonnano, G.A., Holen, A., 1993. Pathological grief:diagnosis and explanation. Psychosomatic Medicine 55, 260–273.

Horowitz, M.J., Siegel, B., Holen, A., Bonanno, G.A., Milbrath, C.,Stinson, C.H., 1997. Diagnostic criteria for complicated griefdisorder. American Journal of Psychiatry 154, 904–910.

Jacobs, S., Mazure, C., Prigerson, H., 2000. Diagnostic criteria fortraumatic grief. Death Studies 24, 185–199.

Langner, R., Maercker, A., 2005. Complicated grief as a stressresponse disorder: evaluating diagnostic criteria in a Germansample. Journal of Psychosomatic Research 58, 235–242.

Latham, A.E., Prigerson, H.G., 2004. Suicidality and bereavement:complicated grief as psychiatric disorder presenting greatest riskfor suicidality. Suicide and Life-Threatening Behavior 34,350–362.

Lichtenthal, W.G., Cruess, D.G., Prigerson, H.G., 2004. A case forestablishing complicated grief as a distinct mental disorder inDSM-V. Clinical Psychology Review 24, 637–662.

Maercker, A., Enzler, A., Grimm, G., Helfenstein, E., Hintermann, D.,Horler, E., Kruesi, G., Maier, C., Ehlert, U., 2003. The Zurich olderage study on PTSD and grief-related disorders: first results from arepresentative sample. The Gerontologist 43 (1), 574 (Spec. Issue).

Maercker, A., Forstmeier, S., Enzler, A., Krüsi, G., Helfenstein, E.,Hörler, E., Maier, C., Ehlert, U., submitted for publication.Adjustment disorders, PTSD, and depressive disorders in old age:findings from a community survey.

Prigerson, H.G., Frank, E., Kasl, S.V., Reynolds, C.F., Anderson, B.,Zubenko, G.S., Houck, P.R., George, C.J., Kupfer, D.J., 1995.Complicated grief and bereavement-related depression as distinct

211S. Forstmeier, A. Maercker / Journal of Affective Disorders 99 (2007) 203–211

disorders: preliminary empirical validation in elderly bereavedspouses. American Journal of Psychiatry 152, 22–30.

Prigerson, H.G., Bierhals, A.J., Kasl, S.V., Reynolds, C.F., Shear, M.K.,Day, N., Beery, L.C., Newsom, J.T., Jacobs, S., 1997. Traumatic griefas a risk factor for mental and physical morbidity. American Journalof Psychiatry 154, 616–623.

Prigerson, H.G., Shear,M.K., Jacobs, S.C., Reynolds, C.F.,Maciejewski,P.K., Davidson, J.R., Rosenheck, R., Pilkonis, P.A., Wortman, C.B.,Williams, J.B., Widiger, T.A., Frank, E., Kupfer, D.J., Zisook, S.,1999. Consensus criteria for traumatic grief: a preliminary empiricaltest. British Journal of Psychiatry 174, 67–73.

Prigerson, H.G., Jacobs, S.C., 2001a. Perspectives on care at the closeof life. Caring for bereaved patients: “all the doctors just suddenlygo”. JAMA 286, 1369–1376.

Prigerson, H.G., Jacobs, S.C., 2001b. Traumatic grief as a distinctdisorder: a rationale, consensus criteria, and a preliminary empiricaltest. In: Stroebe, M.S., Hansson, R.O., Stroebe, W., Schut, H.(Eds.), Handbook of Bereavement Research. APA, Washington,DC, pp. 613–645.

Prigerson, H.G., Ahmed, I., Silverman, G.K., Saxena, A.K.,Maciejewski, P.K., Jacobs, S.C., Kasl, S.V., Aqeel, N., Hamirani,

N., 2002. Rates and risks of complicated grief among psychiatryclinic patients in Karachi, Pakistan. Death Studies 26, 781–792.

Radloff, L.S., 1977. The CES-D scale: a self-report depression scalefor research in the general population. Applied PsychologicalMeasurement 3, 385–401.

Raphael, B., Martinek, N., 1997. Assessing traumatic bereavement andPTSD. In: Wilson, J.P., Keane, T.M. (Eds.), Assessing Psycho-logical Trauma and PTSD, Guilford, New York, pp. 373–395.

Silverman, G.K., Jacobs, S.C., Kasl, S.V., Shear, M.K., Maciejewski,P.K., Noaghiul, F.S., Prigerson, H.G., 2000. Quality of life impair-ments associated with diagnostic criteria for traumatic grief.Psychological Medicine 30, 857–862.

Stroebe, M., van Son, M., Stroebe, W., Kleber, R., Schut, H., van denBout, J., 2000. On the classification and diagnosis of pathologicalgrief. Clinical Psychology Review 20, 57–75.

Wagner, B., Knaevelsrud, C., Maercker, A., 2006. Internet-basedcognitive–behavioral therapy for complicated grief: a randomizedcontrolled trial. Death Studies 30, 429–453.

Wittchen, H.-U., Pfister, H., 1997. DIA-X-Interviews: Manual fürScreening-Verfahren und Interview. Swets en Zeitlinger, Frankfurtam Main.