A meta-analysis of the association between posttraumatic stress disorder and suicidality: the role of comorbid depression

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Comprehensive Psychiatry 53 (2012) 915 – 930 www.elsevier.com/locate/comppsych

A meta-analysis of the association between posttraumatic stress disorder and suicidality: the role of comorbid depression Maria Panagioti a , Patricia A. Gooding a,⁎, Nicholas Tarrier a, b b

a School of Psychological Sciences, University of Manchester, United Kingdom Department of Psychology, Institute of Psychiatry, Kings College London, United Kingdom

Abstract Objective: A considerable number of studies have reported an increased frequency of suicidal behaviors among individuals diagnosed with posttraumatic stress disorder (PTSD). This study aims, first, to provide a comprehensive systematic review and meta-analysis of the association between a PTSD diagnosis and frequency of suicidality and, second, to examine the role of comorbid depression in the association between suicidality and PTSD. Methods: Searches of Medline (June 2010), EMBASE (June 2010), PsycINFO (June 2010), PILOTS (June 2010), and Web of Science (June 2010) were conducted to identify studies that examined the association between PTSD and suicidality. The studies had to include an effect size of the association between PTSD and suicidality to be included in the meta-analysis. Sixty-three studies were eligible for inclusion in the meta-analysis. Overall and subgroup effect sizes were examined. Results: A highly significant positive association between a PTSD diagnosis and suicidality was found. The PTSD-suicidality association persisted across studies using different measures of suicidality, current and lifetime PTSD, psychiatric and nonpsychiatric samples, and PTSD populations exposed to different types of traumas. Comorbid major depression significantly compounded the risk for suicide in PTSD populations. Conclusion: The current meta-analysis provides strong evidence that a PTSD diagnosis is associated with increased suicidality. The crucial role of comorbid major depression in the etiology of suicidality in PTSD is also supported. © 2012 Elsevier Inc. All rights reserved.

1. Introduction Increased frequency of suicidal behaviors (suicidal thoughts, suicidal plans, or suicidal acts) has been reported in posttraumatic stress disorder (PTSD) [1-4]. Similar to other common Axis I psychiatric disorders, such as major depression, substance use disorders, and psychoses, PTSD is strongly associated with increased frequency of suicidality [510]. Comorbid psychiatric disorders and especially comorbid major depression have been found to substantially increase the levels of suicidality in those with PTSD [4,11-13]. There is also some evidence that comorbid major depression mediates the relationship between suicidal ideation and PTSD [14]. One comprehensive narrative review has been published in the area of PTSD and suicidality, which aimed to summarize the ⁎ Corresponding author. Division of Psychology, School of Psychological Sciences, Coupland Building 1, Oxford Road, University of Manchester, Manchester M13 9PL. Tel.: +44 161 275 1971; fax: +44 161 275 8584. E-mail address: [email protected] (P.A. Gooding). 0010-440X/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.comppsych.2012.02.009

available research findings on the relationship between suicidality and PTSD. Most of the studies indicated a strong positive association between PTSD and suicidality. The association between suicidality and PTSD appeared to hold across different populations, such as war veterans, victims of interpersonal victimization in childhood and/or in adulthood, PTSD samples with mixed traumas, psychiatric populations, and nonpsychiatric community samples. A considerable proportion of the studies also indicated that apart from PTSD, a diagnosis of major depression significantly increased suicidal risk. Moreover, the presence of PTSD and major depression comorbidity was associated with substantially increased suicidal risk compared with a PTSD diagnosis alone [15]. One important limitation of the above narrative review is that it was largely descriptive. Meta-analytic procedures offer the best means of summarizing and statistically estimating the overall significance of findings derived from individual studies. One existing systematic review in the area of PTSD and suicidality indicated that a diagnosis of PTSD is positively associated with increased suicide attempts, and suicidal ideation, but not

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completed suicides. These findings were based on extracting and computing φ coefficients from 25 independent studies. This is a limited number of studies considering that more than 60 published studies have reported an association between PTSD and suicidality. In addition, no subgroup analyses were conducted to examine further the association of PTSD and suicidality. Finally, the authors concluded that the association between PTSD and suicidality remained after controlling for comorbid disorders including depression but also reported evidence that depression mediates the relationship between PTSD and suicidality [16]. Both of these contradictory outcomes concerning the role of depression in the association between suicidality and PTSD were based on a narrative interpretation of the extant literature and not by applying meta-analytic procedures. Therefore, we conducted a comprehensive meta-analysis that aimed to expand and update the findings in the literature concerning the association between suicidality and PTSD. The term suicidality in this meta-analysis comprised a range of suicidal tendencies including suicidal thoughts, behaviors, plans, attempts, and successful suicides. The broad definition of suicidality used in this meta-analysis is justified by the following 2 reasons. First, the aim of this meta-analysis was to adopt an inclusive approach to provide a comprehensive quantitative account of the extant literature findings on PTSD and suicidality. After the results of the initial analysis of the link between suicidality and PTSD, a series of subsequent analyses (eg, subgroup analyses and meta-regression analyses) were planned to examine potential sources of heterogeneity among the studies included in the meta-analysis. Second, 2 previous reviews (1 narrative review and 1 systematic but less comprehensive review) in the area of PTSD and suicidality have been conducted, both of which used an equivalent definition of the term suicidality [15,16]. The adoption of the same methodology with previous reviews in defining suicidality facilitates the direct comparison of the current findings with the results of these 2 reviews. The specific objectives of this meta-analysis were to (1) systematically quantify the research findings on the association of PTSD and suicidality across a large number of studies, (2) examine the association of suicidality and PTSD across different PTSD populations (ie, index trauma, psychiatric vs community samples) and across studies using different measures of PTSD (current vs lifetime, interviews vs questionnaires), and (3) examine the role of comorbid depression in the association between PTSD and suicidality by applying meta-regression procedures. Based on the existing literature, it was predicted that PTSD would be significantly positively associated with increased levels of suicide attempts and suicidal ideation. It was also predicted that the association between suicidality and PTSD would pertain across psychiatric and nonpsychiatric samples and across different trauma populations. Finally, it was hypothesized that the presence of comorbid depression would increase suicide risk in those with PTSD.

2. Methods 2.1. Inclusion and exclusion criteria Studies were included in the meta-analysis if they met the following criteria: (a) They were published in a peer-reviewed journal in the English language. (b) They reported original research findings regarding the relationship between PTSD and suicidality. (c) The sample comprised participants 15 years or older. (d) They included any measure of PTSD and any measure of suicidality (suicidal ideation, plans, behaviors, attempts, and successful suicides). (e) They contained outcome measures that reflected the association between PTSD and suicidality. 2.2. Search strategy Searches of the databases of EMBASE (1966 to June 2010), PILOT (1966 to June 2010), Medline (1966 to June 2010), PsycINFO (1966 to June 2010), and Web of Science (1966 to June 2010) were made with text words including PTSD and suicide or suicidal or suicidal behavior, posttraumatic and suicide or suicidal or suicidal behavior, post traumatic and suicide or suicidal or suicidal behavior. Both the first and the second author identified and screened for suitability the included/excluded studies. In cases where the results of a study were reported in more than 1 article, the most recent article was included in the meta-analysis. 2.3. Data analysis The results of the studies were combined using the Hedges g effect size statistic. It has been suggested that the Cohen d statistic tends to overestimate the absolute value of the standardized mean difference (δ) [17–19]. Hedges g was chosen because it is the unbiased estimate of δ and it tends to control for small sample sizes [19]. The between-study heterogeneity was tested using Cochran Q. 95% confidence intervals (CIs) were computed. Meta-analytic analyses were conducted with Comprehensive Meta-Analysis version 2.2.034 [19]. A fully random effects model was used because there was considerable heterogeneity in the variables of interest. Initially, the overall effect sizes were calculated. Subsequently, subgroup calculations were performed, and meta-regression analyses were computed to examine the associations between effect sizes and key predictor variables. 3. Results The search strategy yielded 246 results. Of these, 165 studies were empirical English-language studies. Of the 165 studies, 85 were identified as meeting the initial inclusion criteria. However, of the 85 studies, 19 did not provide an outcome measure of the association between

M. Panagioti et al. / Comprehensive Psychiatry 53 (2012) 915–930

PTSD and suicidality, and thus, they were excluded from further analysis. Two studies [1,20] were excluded because they reported the same data in more recent articles [21,22]. Finally, 5 studies assessed the association between PTSD and suicidality only in terms of odds ratios. Because the odds ratio statistic cannot be transformed into Hedges g coefficients (the statistic used to combine the results of the current meta-analysis), these studies were also excluded [9,23–26] . A total of 59 studies fully met the inclusion criteria and were retained for the meta-analysis. Four studies provided 2 independent samples of the association between PTSD and suicidality [3,27–29]. Thus, the association between PTSD and suicidality was examined across 63 independent samples. The process of the metaanalysis is presented in Fig. 1. 3.1. Characteristics of the studies Table 1 presents the characteristics of the 63 studies that were included in the meta-analysis [2–8,10,11,14,21,22,27– 73]. As shown, most of the studies were conducted in the United States (n = 43) and adopted cross-sectional designs (n = 50). Thirty studies comprised predominately female samples, 27 studies comprised predominantly male samples, 2 studies included an equal number of male and female participants, and 4 studies did not provide information about the sex characteristics of the total samples. Forty-five studies provided information about sex characteristics of their study groups (PTSD group or suicidal behavior group). Across these studies, 31 studies comprised predominately female participants, and 13 studies comprised predominantly male participants. Information regarding the mean age of the total sample was provided by 48 studies. Thirty-seven studies used Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), criteria, 16 studies used DSM-III-R criteria, 4 studies used DSM-III criteria, and 1 study used International Statistical Classification of Diseases, 10th Revision (ICD-10) to diagnose the presence of PTSD. Most of the studies used standardized structured/semistructured interviews to screen for, or confirm, the PTSD diagnosis. The most frequently used screening instruments were the Structured Clinical Interview (SCID-IV or III-R) [74,75] and the Composite International Diagnostic Interview (CIDI for DSM-IV or IIIR) [76,77]. Five studies did not provide information about the diagnostic criteria used for the diagnosis of PTSD. Three of these studies used information derived from the patients' psychiatric case notes [35,65,71], 1 study used a screening questionnaire developed for the purposes of the study [49], and 1 study was based on the participants' self-report of whether they received a diagnosis of PTSD [8]. More details about the screening instruments used by the individual studies to diagnose PTSD are presented in Table 1. Suicidality was assessed in terms of the frequency of successful suicides, suicide attempts, and/or the presence of suicidal ideation and in terms of mean scores on a general

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Inclusion/exclusion criteria set and search strategy established. Run search-246 results yielded.

81 results were conceptual or theoretical papers rather than empirical studies.

The abstracts of the 165 studies or the full papers (if necessary) were reviewed and categorised for inclusion/exclusion criteria.

85 studies were identified as meeting the initial inclusion/exclusion criteria.

19 studies did not provide information to extract effect sizes of the PTSDsuicidality association. Five studies included odds ratios and 2 studies were based on the same data with more recently published studies.

59 studies were included in the Meta-analysis. Data from 63 samples were extracted.

Fig. 1. The selection process used in the meta-analysis.

measure of suicidal behavior. Four studies included a measure of successful suicides, 25 studies included a measure of suicide attempts, 13 studies included a measure of suicidal ideation, 17 studies included measures of both suicide attempts and suicidal ideation, and 4 studies included mean scores on a general measure of suicidality including thoughts, plans, and/or suicide acts. A wide range of scales were used to assess suicidality. Asking questions about the presence and/or the intensity of suicidality during the assessment interview or using the suicidal behavior items of standardized diagnostic interviews were the most common methods applied by the studies (n = 38) to ascertain the presence and/or the levels of suicidality. In addition, a considerable number of studies (n = 20) used self-reports to assess suicidality. Only 1 study did not include details of the method used to measure suicidality [3]. Further details concerning the specific diagnostic instruments that were used to assess suicidality across the 63 independent samples are presented in Table 1.

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Table 1 Characteristics of the 59 studies (and 63 independent samples) included in the meta-analysis Study design Depression in PTSD group and controls

Target population

Bernal et al [5], Europe

Crosssectional

Nonpsychiatric NA sample

Bullman and Kang [11], United States Cacciola et al [27] US

Retrospective NA cohort

Primary PTSD War veterans diagnosis

Crosssectional

n/a

NonPsychiatric Sample

War veterans

Caldera et al [30] US

Crosssectional

n/a

Campbell et al [21] US

Crosssectional

Exposed to Natural Disasters War Veterans

Clum and Weaver [31] US

Crosssectional

PTSD group (M): 17.4, Controls(M): 14.7 n/a

NonPsychiatric Sample Other Primary Psychiatric Diagnosis/es NonPsychiatric Sample

n/a

Cougle et al [6] US

Crosssectional

n/a

NonPsychiatric Sample

n/a

Cougle et al [28] US

Crosssectional

n/a

NonPsychiatric Sample

n/a

Darke et al [3] Australia

Crosssectional

n/a

n/a

Davidson et al [7] US

Crosssectional

Desai et al [32] US

Prospective

PTSD group(%): 30.8, Controls (%): 3.7 n/a

Eggleston et al [33] US

Crosssectional

NonPsychiatric Sample NonPsychiatric Sample Psychiatric sample with various diagnoses NonPsychiatric Sample

NA

n/a

Traumatic populations

Measure of Suicidality instrument suicidality

PTSD diagnostic Instrument

Study Control Total n, Total n, group, n group, n women mean age (%)

Questions in a computer -assisted personal interview

The Composite International Diagnostic Interview (CIDI-3) according to DSM-IV

411

20834

52

47

Veterans databases: BIRLS, SSA, IRS or NDI

4247

12010

0

31

Addiction Severity Index (ASI)

Veterans Affairs (VA) databases for DSM-III-R or DSM-III The Structured Clinical Interview (SCID) for DSM-IV

221 61

22 162

0 0

42.5 n/a

An item was added to Harvard Trauma Questionnaire (HTQ) The suicide item of the PHQ-9 was dichotomized

The Harvard Trauma Questionnaire (HTQ) for DSM-IV The Primary Care PTSD Screen (PC-PTSD) for DSM-IV

29

467

81

n/a

244

433

3.9

65

Suicide attempts

The Scale for Suicide Ideation (SSI)

9

75

55.1

19.86

Suicide attempts & Suicidal ideation Suicide attempts & Suicidal ideation Suicide attempts

Questions in the Assessment Interview

The Structured Clinical Interview for DSM-IIIR/Nonpatient Version (SCID-IIIR) The World Mental Health Survey of Composite International Interview (WMH-CIDI) for DSM-IV As part of phone interview according to DSM-IV

298

3833

56

49.88

50 292

1757 986

100 100

44.8 n/a

82

533

34

29.3

39

2946

54.4

n/a

Psychiatric VA inpatients discharged with a diagnosis of PTSD

481

121933

5.6

48.17

The Structured Clinical Interview (SCID) for DSM-IV

27

35

100

29.6

Suicide attempts & suicidal ideation Successful suicides Suicide attempts & Suicidal ideation Suicidal ideation Suicidal ideation

As part of the assessment (phone) interview

Questions in the Structured Assessment Interview

n/a

Suicide attempts

The suicidality items of the Diagnostic Interview Schedule (DIS-III) Social Security numbers merged in the National Death Index

War veterans

Successful suicides

n/a

Suicide Addiction Severity attempts & Index (ASI) Suicidal ideation

The Composite International Diagnostic Interview (CIDI) for DSM-IV The Diagnostic Interview Schedule, Version III (DIS-III)

M. Panagioti et al. / Comprehensive Psychiatry 53 (2012) 915–930

Study

Crosssectional

n/a

Primary PTSD War-related diagnosis traumas

Suicidal behavior

Crosssectional Crosssectional

Other Primary Psychiatric Diagnosis/es Other Primary Psychiatric Diagnosis/es NonPsychiatric sample

Suicidal ideation

Fordwood et al [36] US

PTSD group(%): 25, Controls (%): 20 n/a

Modified Structured Interview by the National Board of Health and Welfare Questions in the Assessment Interview

Suicide attempts

Two items from the Youth/Young self-report

Suicide attempts & suicidal ideation Suicide attempts & Suicidal ideation Successful suicides

Questions in the assessment interview

Fu et al [37] US Retrospective n/a cohort

Giaconia et al [38] US

Crosssectional

PTSD group (%): Non25, Controls Psychiatric (%): 8 Sample

Gradus et al Retrospective n/a [39] Denmark cohort Haller and Mills Cross[40] US sectional

n/a

Holdzheimer et al [41] US

Case-control study

n/a

Jakupcak et al [42] US

Crosssectional

n/a

Joiner et al [43] US

Crosssectional

n/a

Kaslow et al [44] US

Case-control study

n/a

Kotler et al [22] Israel

Crosssectional

n/a

Kramer et al [45] US

Crosssectional

n/a

Leiner et al [14] CrossUS sectional

n/a

Samples with Various Traumas n/a

War veterans

Samples with Various Traumas

Cause of Death Register

117

32

30

n/a

Information from the patients' psychiatric journal

9

130

53

40

395

78.7

17.21

5627

0

n/a

24

114

50

17.9

9612

199306

28.2

n/a

50

140

32

37.33

587

587

64

35.5

187

220

8.6

32

272

5566

50

33.2

148

137

100

30.8

47

42

20

41

91

141

0

36

n/a

n/a

100

32.9

56 The Primary Care PTSD Screen (PC-PTSD) for DSM-IV Diagnostic Interview Schedule, 163 Version 3, Revised (DIS-III-R), based on DSMIII-R criteria The NIMH Diagnostic Interview Schedule Version IIIR (DSM-III-R)

International Statistical Classification of Diseases (ICD-10) n/a Suicidal The 1st item of a The University of Michigan ideation 7-item Structured Interview Composite International developed for the study Diagnostic Interview (UM-CIDI) for DSM-IV Other Primary n/a Suicide The 23-item Psychiatric The 23-item behaviorally Psychiatric attempts Symptom Assessment Scale anchored Psychiatric Diagnosis/es Symptom Assessment Scale for DSM-IV Other Primary War veterans Suicidal Scale for Suicide The military version of the Psychiatric ideation Ideation (SSI) PTSD Checklist (PCL-M) Diagnosis/es for DSM-IV n/a Suicide Questions in the The Composite International Nonattempts Assessment Interview Diagnostic Interview (CIDI) Psychiatric Sample for DSM-III-R NonVictims of Suicide Suicide attempt National Women Study PTSD Psychiatric Physical/Sexual attempts statues ascertained Module for DSM-III-R Sample Abuse by a clinical psychologist Primary PTSD Samples with Suicide Suicide Risk Scale (SRS) Diagnosed by a senior Diagnosis Various Traumas attempts psychiatrist at intake according to DSM-IV criteria Mixed Sample War Veterans Suicide Personality Diagnostic A modified version of attempts & Questionnaire (PDQ) Schedule of Affective Disorders Suicidal and Schizophrenia, Lifetime ideation Version (SADS-L) for DSM-III NonVictims of Suicidal The 19- item Beck Scale The 17 -item Posttraumatic Psychiatric Physical/Sexual ideation for Suicide Ideation (BSS) Diagnostic Scale (PDS) for Sample Abuse DSM-IV NonPsychiatric Sample Other Primary Psychiatric Diagnosis/es

n/a

The suicidality items of NIMH Diagnostic Interview Schedule (DIS-IIIR)

The PTSD Interview (PTSD-I) for DSM-IV or DSM-III-R

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Ferrada-Noli et al [34] Sweden Floen and Elklit [35] Norway

(continued on next page) 919

920

Table 1 (continued) Study design Depression in PTSD group and controls

Target population

Traumatic populations

Measure of Suicidality instrument suicidality

Lewis [46] US

Crosssectional

NonPsychiatric Sample

n/a

Suicide attempts

NonPsychiatric Sample NonPsychiatric Sample NonPsychiatric Sample NonPsychiatric Sample

n/a

Suicide attempts

n/a

Suicidal ideation

n/a

Suicide attempts

n/a

Suicidal ideation

Other Primary Psychiatric Diagnosis/es

n/a

Suicide attempts

NonPsychiatric Sample

Samples with Suicide Various Traumas attempts

Loughrey et al [47] Ireland Maia et al [48] Brazil

PTSD group (%): 55, Controls (%): 28 Retrospective n/a

Crosssectional

n/a

Maloney et al Case-control [29] Australia study

n/a

Marshall et al [49] US

PTSD group (M): 0.82, Controls(M): 0.43 n/a

Crosssectional

Mcfarlane et al Cross[50] Australia sectional

Mills et al Prospective [51] Australia

Moylan et al [52] US

Crosssectional

Nad et al [2] Croatia

Case-control study

PTSD group (%): 33.3, Controls (%): 16.9 n/a

n/a

Nepon et al [53] CrossCanada sectional

n/a

Olley et al [54] South Africa

Crosssectional

Oquendo et al [55] US

Crosssectional

Oquendo et al [3] US

Crosssectional

PTSD group (%): 29, Controls (%): 7 PTSD group (%): 72.9, Controls (%): 63.6 n/a

Nonn/a Psychiatric Sample Primary PTSD War Veterans Diagnosis NonPsychiatric Sample NonPsychiatric Sample

n/a

Other Primary Psychiatric Diagnosis/es

n/a

Other Primary Psychiatric Diagnosis/es

Victims of Physical/Sexual Abuse

Questions in the Assessment The Structured Clinical Interview Interview/Patient Version (SCID-P) for DSM-IV, CAPS

One section of a questionnaire designed for the purposes of the study A section of a 16-items Structured Interview for the purposes of the study Part of a Screening Questionnaire developed for the purposes of the study Suicidality section of Mini International Neuropsychiatric Interview (MINI) Questions in the Assessment Interview

Suicide attempts

Part of the Addictions Severity Index (ASI)

Suicide attempts

Suicidal Assessment Scale (SAS)

Suicide attempts

As part of the clinical interview (AUDADIS-IV)

Samples with Suicidal Various Traumas behavior

PTSD diagnostic Instrument

Part of the Mini International Neuropsychiatric Interview (MINI)

Suicide The Suicide Intent Scale attempts & (SIS), the Scale for Suicidal Suicidal Ideation (SSI) ideation Suicide n/a attempts & Suicidal ideation

Study Control Total n, Total n, group, n group, n women mean age (%) 60

21

100

38.2

116

383

53

37.3

14

116

0

32.9

223 77

503 322

40 60

36.6 33.2

809

6,465

70

n/a

The Composite International Diagnostic Interview (CIDI) for DSM-IV

52

61

43.9

36.3

The Composite International Diagnostic Interview (CIDI-2.1) for DSM-IV

18

166

38

29

The Structured Clinical Interview (SCID) for DSM-IV The Structured Clinical Interview (SCID) for DSM-IV Alcohol Use Disorders and Associated Disabilities Interview (AUDADIS-IV) The NIMH Diagnostic Interview Schedule (NIMI) for DSM-IV

24

99

100

30.2

45

32

0

41.5

1265

33298

52.1

n/a

22

127

75

29

The Structured Clinical Interview (SCID) for DSM-IV

59

171

86

43

The Structured Clinical Interview (SCID) for DSM-III-R

15 24

117 117

n/a n/a

n/a n/a

A comprehensive symptom checklist according to DSM-III The Post-Traumatic Stress Disorder Checklist-Civilian Version (PCL-C) for DSM-IV Sections adopted and modified of COGA-SSAGA-2 for DSM-IV As part of a Screening Brief Questionnaire developed for the purposes of the study

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Study

Crosssectional

Philips et al [57] US

Crosssectional

Pietrzak et al [58] US

Crosssectional

Prigerson and Slimack [59] US Sareen et al [8] Canada

Crosssectional Crosssectional

Sharhabani-Arzy Crosset al [60] Israel sectional Strauss et al [61] US

PTSD group (%):77.5, Controls(%): 59.3 n/a

n/a

PTSD group (%): 37.2, Controls (%): 4.5 n/a

NonPsychiatric Sample

n/a

Suicide attempts

Other Primary Psychiatric Diagnosis/es

n/a

NonPsychiatric Sample NonPsychiatric Sample NonPsychiatric Sample

War Veterans

Suicide BDD Form attempts & (K.A.P. Unpublished) Suicidal used in previous studies ideation with BDD Suicidal As part of the Patient Health ideation Questionnaire-9 (PHQ-9)

NonPsychiatric Sample Other Primary Psychiatric Diagnosis/es

n/a

Suicidal ideation

n/a

Suicide Questions in the attempts & Assessment Interview Suicidal ideation Suicidal Suicide Risk Scale (SRS) behavior

Victims of Physical/Sexual Abuse War Veterans

Crosssectional

n/a

Tarrier and CrossGregg [4] UK sectional

n/a

Primary PTSD Samples with Diagnosis Various Traumas

Thompson et al [62] US

Crosssectional

n/a

Thompson et al [63] US

Case-control study

n/a

NonPsychiatric Sample NonPsychiatric Sample NonPsychiatric Sample Other Primary Psychiatric Diagnosis/es NonPsychiatric Sample

Thoresen and CrossMehlum [64] sectional Norway Tiet et al [65] US Crosssectional

n/a

n/a

Ullman and Brecklin [66] US

Crosssectional

n/a

Villagomez et al [67] US

Crosssectional

PTSD group (%): 38.3, Controls (%): 9.6

NonPsychiatric Sample

As part of the clinical interview (AUDADIS-IV)

Victims of Physical/Sexual Abuse Victims of Physical/Sexual Abuse War Veterans

War Veterans

Victims of Physical/Sexual Abuse Samples with Various Traumas

The Scale for suicidal Ideation (SSI)

Suicide Part of a Validated attempts & Structured Interview Suicidal ideation Suicide Questions in the Assessment attempts & Interview Suicidal ideation Suicide Suicide attempt status attempts ascertained by the principal investigator Suicide Suicide attempt status attempts ascertained by the principal investigator Suicidal 4 items from the ideation Norwegian General Health Questionnaire (GHQ) Suicide As part of Addiction attempts Severity Index (ASI) Suicide Questions in the attempts & Assessment Interview Suicidal ideation Suicide Addiction Severity attempts Index (ASI)

Alcohol Use Disorders and Associated Disabilities Interview (AUDADIS-IV)

643

1290

53.8

n/a

The Structured Clinical Interview (SCID) for DSM-IV

55

145

68.5

32.6

The military version of the PTSD Checklist (PCL-M) for DSM-IV The Revised Impact of Events Scale (RIES) for DSM-IV All participants asked if they had received a diagnosis of PTSD by a health care professional The PTSD Scale for Family Violence for DSM-III-R

34

233

10.7

36.1

n/a

n/a

58

23.8

478

36476

53.5

n/a

47

127

100

37

The PTSD Checklist (PCL) for DSM-IV

80

85

0

48

The Clinical Administrated PTSD Scale (CAPS) for DSM-III-R

94

GPN

42.5

36

The National Women's Study (NWS) for DSM-III-R The National Women's Study (NWS) for DSM-III-R The Posttraumatic Symptom Scale (PTSS-10) for DSM-III-R Information from Nationwide VA databases PTSD assessed during interview using DSM-III-R criteria

119

85

100

35

157

178

100

32.17

106

1066

0

33.8

1120

32048

2.9

46.6

82

545

100

34.04

107

625

36.6

37.1

Quick Diagnostic Interview Schedule (DIS) for DSM-III-R

921

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Pagura et al [56] US

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Table 1 (continued) Study design Depression in PTSD group and controls

Target population

Traumatic populations

Measure of Suicidality instrument suicidality

PTSD diagnostic Instrument

Study Control Total n, Total n, group, n group, n women mean age (%)

Violanti [68] US

Crosssectional

n/a

The 19-item Scale for Suicide Ideation (SSI)

88

39.1

39.5

n/a

Suicidal ideation

Suicidal Ideation Index (SII)

256

905

n/a

n/a

Wilcox et al [10] US

Crosssectional

n/a

As part of standardized interview ascertained by trained interviewers

100

1173

50.2

21

Yen et al [70] US

Prospective

n/a

n/a

563

n/a

33

Retrospective n/a cohort

War Veterans

Successful suicides

As part of Longitudinal Interval Follow-Up Evaluation (LIFE) National Death Index cause of death indicators

58

Zivin et al [71] US

Other Primary Psychiatric Diagnosis/es Other Primary Psychiatric Diagnosis/es

Suicide attempts & Suicidal ideation Suicide attempts

357

1326

10

n/a

Zlotnic et al [72] US

Crosssectional

Other Primary Psychiatric Diagnosis/es

Samples with Various Traumas

Suicide attempts

Questions in the Assessment Interview

The Impact of Events Scale (IES) for DSM-III-R Harvard Trauma Questionnaire (HTQ) for DSM-IV As part of standardized interview according to DSM-IV ascertained by trained interviewers The Structured Clinical Interview/Patient Version (SCID-P) for DSM-IV Charlson Comorbidity Index (A weighted index designed to classify comorbid conditions) The Structured Clinical Interview (SCID) for DSM-IV

27

Crosssectional

Samples with Various Traumas War-related

Suicidal ideation

Wenzel et al [69] Kosovo

NonPsychiatric Sample NonPsychiatric Sample NonPsychiatric Sample

156

460

64

38.4

PTSD group (%): 61.5, Controls (%): 45.2

NA, information not available in the article.

Samples with Various Traumas

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Study

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3.3.1. The association between different modes of suicidality and PTSD The overall effect sizes of the subgroups showed that all modes of suicidality apart from successful suicides were significantly positively associated with PTSD (see Table 2). The magnitude of the association between PTSD and suicidality was equivalent across the subgroups of suicidal ideation, suicidal behavior, and suicide attempts. However, within the subgroup of the 4 studies examining the association between successful suicides and PTSD, the association was not significant. In the previous analysis, the association of PTSD with the most proximal suicide measure was examined. A further independent analysis was computed to examine the association of PTSD with suicidal ideation, regardless of whether it was the most proximal suicide measure. A total of 30 studies included an outcome of the association between suicidal ideation and PTSD. Consistent with the findings above, a significant positive association of PTSD with suicidal ideation was found (see Table 2).

3.2. Results of the meta-analysis 3.2.1. The association between suicidality and PTSD Initially, the magnitude of the association between suicidality and PTSD was calculated. A considerable number of studies (n = 17) provided information regarding the association of PTSD with more than 1 measure of suicidality (suicide attempts and suicidal ideation). In these cases, the measure of suicidality that was most proximal to successful suicide (suicide attempts) was included in the analysis. The overall Hedges g coefficient was 0.783 (z = 10.558; P b .0001; 95% CI, 0.637-0.928; Heterogeneity, Q-value = 2006, 369, P b .0001). Within these studies, the Hedges g coefficients across 55 studies indicated a significant positive association between suicidality and PTSD (with P values ranging from .01 to .0001), the Hedges g coefficients across 6 studies did not show a significant association between suicidality and PTSD [3,27,39,42,55,61], and the Hedges g coefficient of 2 studies indicated a significant negative association between suicidality and PTSD (P b .0001) [32,71]. 3.3. Subgroup analyses

3.3.2. The impact of the PTSD screening tool on the association between suicidality and PTSD Forty-one studies used standardized structured/semistructured interviews to screen or to confirm a diagnosis of PTSD, and 16 studies used a standardized or nonstandardized questionnaire to screen for PTSD. The results showed that the effect sizes were statistically significant across the 2 subgroups indicating that the association between PTSD and

A series of subgroup analyses were computed to examine if the association between PTSD and suicidality differed across studies using different measures of suicidal behavior, different screening tools for suicidal behavior, among psychiatric and nonpsychiatric populations, and among PTSD populations exposed to different types of traumas. The results of the subgroup analyses are presented in Table 2.

Table 2 Results of the subgroup analyses (random-effects model) assessing the association between PTSD and suicidality Subgroup Modes of suicidality Suicidal ideation Suicidal behaviors Suicide attempts Successful suicides Suicidal ideation total Screening tool for PTSD Standardized interviews Screening questionnaires Target population differences Primary diagnosis of PTSD Other primary psychiatric Nonpsychiatric samples Different traumatic populations War veterans Physical/sexual abuse Mixed traumas Natural disasters Diagnosis of PTSD Current Lifetime Predictors of suicidality Depression PTSD

n

Hedges g effect size

z value

95% CI

P

Cochran Q value

P

13 4 42 4 30

1.091 0.650 0.752 0.188 0.954

5.163 3.852 12.949 0.447 9.774

0.677-1.505 0.320-0.981 0.638-0.866 −0.637-1.014 0.762-1.145

b.0001 b.0001 b.0001 NS b.0001

531.377 5.844 354.837 662.521 671.212

b.0001 NS b.0001 b.0001 b.0001

41 16

0.735 0.982

8.894 4.409

0.573-0.896 0.590-1.374

b.0001 b.0001

884.724 757.089

b.0001 b.0001

5 17 40

0.941 0.495 0.896

3.204 3.294 11.010

0.365-1.517 0.200-0.789 0.736-1.055

b.01 b.01 b.0001

28.045 575.342 979.520

b.0001 b.0001 b.0001

16 7 11 1

1.009 0.515 0.789 0.553

3.909 8.368 6.899 5.723

0.503-1.515 0.394-0.635 0.565-1.013 0.350-0.715

b.0001 b.0001 b.0001 b.0001

1365.397 7.713 35.428 –

b.0001 NS b.0001 –

36 21

0.880 0.725

7.945 9.193

0.663-1.97 0.570-0.880

b.0001 b.0001

1007.231 215.070

b.0001 b.0001

20 20

0.789 0.860

4.635 8.346

0.455-1.122 0.658-1.062

b.0001 b.0001

2605.702 446.251

b.0001 b.0001

n, number of included studies; NS, not significant.

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suicidality is strong, independent of the instrument used to assess PTSD (see Table 2).

suicidality with a current diagnosis of PTSD (as shown in Table 2).

3.3.3. The impact of target population differences on the association between suicidality and PTSD Forty studies were carried out with nonpsychiatric samples and general population samples, 5 studies were carried out with psychiatric patients primarily diagnosed with PTSD, and 17 studies were carried out with psychiatric patients primarily diagnosed with other Axis I or Axis II psychiatric diagnoses. One study was excluded from the analyses because it included partly clinical and partly community participants [45]. As can be seen from Table 2, the effect sizes were statistically significant across the 3 subgroups. The strongest association between suicidality and PTSD was found among primarily PTSD samples, and the weakest association was found among psychiatric populations with other primary diagnoses.

3.4. Meta-regression analyses

3.3.4. The effects of index trauma on the association between suicidality and PTSD Of the total number of studies, 7 were conducted with victims of sexual or physical abuse in adulthood and/or in childhood, 16 were conducted with war veterans or victims of wars, 1 was conducted with victims of hurricane Katrina, and 10 were conducted with populations with mixed traumas. Again, the effect sizes were significant across all of the subgroups (see Table 2). 3.3.5. The impact of current vs lifetime PTSD in the association between PTSD and suicidality Thirty-six studies examined the association between current diagnosis of PTSD and suicidality, whereas 21 studies examined the association between a lifetime diagnosis of PTSD and suicidality. Six studies did not provide information as to whether PTSD was assessed currently or across the lifetime. The association of PTSD with suicidality remained robust across those studies examining the association of suicidality with a lifetime diagnosis of PTSD and those examining the association of Hedges’ g 2.00 1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 0.43

1.29

2.15

3.01

3.87

4.73

5.60

6.46

7.32

8.18

9.04

Depression

Fig. 2. A scatter plot showing the relationship between effect sizes (Hedges g) and levels of depression.

Meta-regression analyses were conducted to examine the impact of the percentage of women and mean age on the association between PTSD and suicidality. The percentage of women was not a significant predictor of the effect size between PTSD and suicidality both in the total samples of 48 studies and in the PTSD subgroups of the studies. Similarly, the mean age was not a significant predictor of the effect size between PTSD and suicidality both in total samples of the studies included in the meta-analysis and in the PTSD subgroups. 3.4.1. Depression, PTSD, and suicidality One meta-regression analysis and 1 subgroup analysis were conducted to examine the impact of depression on the association of PTSD with suicidality. 3.4.2. Meta-regression analysis of the impact of depression on suicidality in PTSD Thirteen studies provided information about the levels of depression among PTSD participants and controls. A metaregression analysis was computed to examine whether the difference in levels of depression in the PTSD participants compared with the levels of depression in controls had any impact on the association of PTSD with suicidality. When the levels of depression, as a predictor variable, were regressed onto Hedges g effect sizes, the slope was significant (z = 5.26, P b .0001), indicating that the higher the levels of depression in PTSD participants compared with controls, the higher the levels of suicidality in PTSD participants compared with controls. A scatter plot showing the relationship between the levels of depression and the effect sizes of the PTSD-suicidality association is presented in Fig. 2. 3.4.3. Subgroup analysis of the impact of PTSD and depression in suicidality Twenty studies that examined a wide range of predictors of suicidality were identified. These studies, which were conducted either in general population samples or in samples with other primary psychiatric diagnoses, examined the effects of PTSD and depression on suicidality. Thus, they included an outcome of the contribution of both depression and PTSD in suicidality. To compare the magnitude of the PTSD-suicidality association with the magnitude of the depression-suicidality association, an independent subgroup analysis examining the effects of PTSD on suicidality and an independent subgroup analysis examining the effects of depression on suicidality were computed. As presented in Table 2, the overall effect sizes across these 20 studies indicated an equally significant contribution of both PTSD and depression on suicidality.

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3.5. Publication bias We examined the likelihood of publication bias by plotting the standard error as a function of Hedges g for each of the 63 effect sizes. The Egger test was significant (t = 2.21, P b .05). However, the Kendall τ test was insignificant, and the fail-safe N indicated that 2408 insignificant unpublished studies would be needed to nullify the effect found. 3.6. Methodological appraisal of the studies The current review and meta-analysis was not restricted to studies with particular methodological strengths. Because the research area of PTSD and suicidality has not been systematically investigated [15], we aimed to be as inclusive as possible to maximize the amount of data available for the meta-analysis and to offer the first quantitative account of the association between PTSD and suicidality. However, an increased probability for heterogeneity of results because of broad inclusion criteria should not be disregarded [78,79]. A retrospective assessment of the methodological quality of the included studies was applied in 7 domains proposed as fundamental in assessing the methodological quality of the Table 3 Assessment criteria of the methodological quality of the studies Domains of methodological quality 1. Study design Prospective Retrospective cohort Case-control study Cross-sectional 2. Sample quality N400 N200 N100 b100 3. Adequacy of comparisons Matched comparison Partly matched comparison group Unmatched comparison group 4. Sample selection method Stratified Consecutive Opportunistic 5. Control for confounders Clinical and sociodemographics Sociodemographics only None 6. Measure of PTSD Validated clinical interview administrated by a mental health professional Validated clinical interview administrated by trained research staff Validated self-report measure Invalidated interviews/questionnaires 7. Measure of suicidality Items of validated clinical interviews Validated self-report measure Questions the assessment interview Invalidated self-report measure/unspecified method

Reviewer's rating Very good Good Adequate Inadequate Very good Good Adequate Inadequate Very good Adequate Inadequate Very good Adequate Inadequate Very good Adequate Inadequate Very good Good Adequate Inadequate Very good Good Adequate Inadequate

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included studies [78–81]: (1) size of the study group, (2) adequacy of comparators, (3) methodological design, (4) measure of PTSD, (5) measure of suicidality, (6) sample selection method, and (7) control of confounders. The results showed that only 8 studies adequately addressed 5 of the 7 above domains, and 16 studies adequately addressed 4 of the 7 domains. In contrast, the remaining studies were restricted by using cross-sectional designs, unmatched controls, opportunistic samples, less than 100 participants in the study groups, and some did not control for confounders. The methodological assessment of the studies was conducted by the first author. Details of the criteria used are presented in Table 3. An additional analysis examining the association of PTSD with suicidality among the 8 studies that adequately addressed 5 of the 7 criteria above was conducted. The results indicated that the association between PTSD and suicidality remained robust (the overall Hedges g coefficient was 0.656; z = 4.067; P b .0001; 95% CI, 0.342-0.977).

4. Discussion The aim of the current meta-analysis was 2-fold: first, to examine the association between PTSD and suicidality and, second, to investigate the impact of depression on the association between PTSD and suicidality. Overall, the findings fully supported our initial hypothesis that a PTSD diagnosis would be associated with heightened rates of suicidality. In addition, consistent with our prediction, higher levels of comorbid depression in the PTSD groups compared with controls were associated with a stronger PTSD and suicidality association. These findings confirm the main conclusions of an existing narrative review of PTSD and suicidal behavior [15]. The findings concerning the association between PTSD and suicidality are also consistent with the findings of a recent systematic review [16]. Nonetheless, the current results differ from the outcomes of that previous systematic review in that the current meta-analysis indicated a positive association between comorbid depression and suicidality in those with PTSD. The previous systematic review did not make a clear conclusion about the role of depression in the association between PTSD and suicidality [16]. One reason for these different findings is that the previous systematic review was based on a narrative description of the previous literature to examine the role of depression in the association between PTSD and suicidality, whereas the current study was based on computing metaregression analyses to examine the impact of depression on the PTSD and suicidality association. Further subgroup analyses demonstrated that (1) the relationship between suicidality and PTSD pertained across studies investigating the association of PTSD with suicide attempts, suicidal ideation, and suicidal behaviors but not successful suicides; (2) the association between suicidality and PTSD was strong across studies using standardized interviews to confirm a PTSD diagnosis and across studies

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using a screening questionnaire to identify PTSD; (3) a PTSD diagnosis was associated with increased frequency of suicidality across studies irrespective of whether they were carried out with psychiatric or nonpsychiatric populations; (4) the relationship between PTSD and suicidality persisted irrespective of the type of traumas that led to a PTSD diagnosis; and (5) both current and lifetime diagnoses of PTSD were strongly associated with increased levels of suicidality. These findings suggest that PTSD compounds suicidal risk in a wide range of circumstances. In addition, the association between PTSD and suicidality appeared independent of sex and age. This is only partly consistent with the results of a recent epidemiological study that showed that a diagnosis of PTSD significantly predicted suicidal ideation in both men and women and suicide attempts in women but not in men [6]. Consistent with the findings of a previous systematic review [16], we found that the association between successful suicides and PTSD was not significant. This subgroup analysis was based on combining the results of only 4 studies, and thus, there is the potential for the analysis to be underpowered. Two of the studies included in the metaanalysis studies showed a significant positive association between PTSD and successful suicides, whereas the other 2 showed a significant negative association between PTSD and successful suicides. Three other studies were identified in the literature examining the incidence rates of suicide among deceased veterans with PTSD. These studies consistently reported substantially increased incidence of suicides than would be expected in general population samples [23,82,83]. Two studies [82,83] were not included in the meta-analysis because they did not provide an outcome measure of the association between PTSD and suicide, and the third study [23] was rejected because it provided only odds ratios for the association of PTSD with suicide, which cannot be transformed into Hedges g coefficients. Thus, because of the small number of studies examining the association between PTSD and suicidality and the conflicting results, no clear conclusions can be reached about the relationship between PTSD and successful suicides. The findings confirmed our initial prediction that the presence of comorbid depression would have a significant impact on the association between PTSD and suicidality. The results of the meta-regression analysis showed that there was a linear positive relationship between depression and suicidality among PTSD samples, in that the probability of suicide increased proportionally with the levels of comorbid depression. The findings underscore the conclusion made by Panagioti et al [15] in their narrative review that depression potentially has a central role in the etiology of suicide risk among individuals diagnosed with PTSD. They are also in agreement with the findings of 3 studies that examined the frequency of suicidal behaviors in PTSD patients with comorbid depression compared with the frequency of suicidal behaviors in PTSD patients without comorbid

depression. All 3 studies consistently reported that suicidal risk was significantly higher in PTSD groups with comorbid depression compared with the PTSD groups without depression [12,13,84]. These studies were rejected from the meta-analysis because they did not include a comparison group. Finally, the subgroup analysis, which examined predictors of suicidality among general population samples or psychiatric patients with other primary diagnoses, demonstrated that both PTSD and major depression are highly positively related to suicidality. Although the last finding does not add to our knowledge of how comorbid depression influences the relationship between PTSD and suicidality, it further confirms that both PTSD and depression have a decisive influence on suicidal risk. Because PTSD and depression often co-occur, mental health professionals should be aware of the effects that this cooccurrence may have on the risk of suicide. This meta-analysis has a number of limitations. One important methodological limitation in meta-analyses concerns publication bias wherein studies with small sample sizes and large effect sizes have an excessive impact on the overall results [85]. In our study, although such a bias appeared to be operating, the large number of studies, which would have been needed to nullify the effects found, provides some reassurance that a large publication bias was not operating. A second limitation is that the methodological quality of most of the studies was low. This was an unavoidable cost of evaluating an inherently heterogeneous area and attempting to be inclusive. A third limitation is that the effect sizes in the current meta-analysis were mainly derived from studies with cross-sectional designs, and thus, no casual inferences can be made regarding the role of PTSD as compounding the risk for suicide. Fourth, although the definition of PTSD and what constitutes a traumatic event has evolved and developed over the years, these developments about PTSD and trauma conceptualization have not been considered in this metaanalysis. Because this meta-analysis included studies across 3 decades, different definitions of PTSD and trauma (as included in different versions of DSM) might have affected the outcomes of the meta-analysis. It should be noted, however, that this is an inherent research difficulty in the area of trauma and PTSD that continues to exist. For example, a number of revisions have been proposed to be included in DSM-5, which, if finally incorporated into DSM5, are expected to again alter the way that PTSD is conceptualized [86]. In this meta-analysis, most of the studies used DSM-IV (37 studies) and DSM-IIIR or DSM-III criteria (20 studies) to diagnose PTSD. Only 5 studies (of 63 studies) provided no information about the diagnostic criteria that they used, but these seem to pose a low threat to the overall analysis. In addition, the several subgroup and metaregression analyses and the retrospective methodological appraisals of the quality of the studies provide further reassurance for the validity of the findings. Fifth, despite our effort to control for factors that may account for the

M. Panagioti et al. / Comprehensive Psychiatry 53 (2012) 915–930

association between PTSD and suicidality, there are numerous factors that may exert an influence on the magnitude of the outcome and that we were unable to evaluate. For example, less than a quarter of the total number of the studies included in the meta-analysis provided information about the proportion of the participants who also had depression. Thus, our conclusion about the role of the comorbid depression on the PTSD-suicidality association is based on the outcomes of a limited proportion of the studies that examined the association of PTSD and suicidality. Nonetheless, the highly consistent findings concerning the impact of depression on the PTSD-suicidality association support our conclusions. Similarly, the influence of the levels of social support, severity of particular PTSD symptoms, and feelings of hopelessness that have been involved in increased risk for suicide among persons with PTSD [14,22,84,87,88] could not be examined because very few studies included such information. Finally, the number of studies included in some subgroup analyses was small. For instance, only 4 studies examined the association of PTSD with successful suicides, and 1 study examined the association of PTSD and suicidality among individuals exposed to a natural disaster [30].

5. Conclusions and implications Taken as a whole, this pattern of findings confirms that PTSD, either as a primary or secondary diagnosis, is significantly associated with an increased risk for suicide. In addition, the findings of this meta-analysis further contribute to the existing literature, which indicates that individuals having psychiatric disorders are at increased risk for suicide [5]. Similarly to PTSD, a considerable number of other psychiatric diagnoses have been identified in the literature to compound risk for suicide including major depression [5,89], psychosis [90], bipolar disorder [89,91], substance use disorders [92], and borderline personality disorder [93]. The current results indicated that a concurrent diagnosis of major depression appears to heighten the risk for suicide in PTSD. There are several alternative explanations for the contribution of depression in the PTSD-suicidality association between PTSD. One possibility might be that comorbid depression acts on suicidality via exaggerating the effects of PTSD symptoms. A second possibility is that major depression fully mediates the association between PTSD and suicidality. A third possibility is that both PTSD and depression increase the likelihood of suicide by contributing to the emergence of feelings hopelessness, defeat, entrapment, and negative appraisals, which may be the underlying factors that give rise to suicidal behavior [15,94,95]. The topic is of high priority given the enormous burden of suicide for individuals and society [96,97]. Future studies should concentrate on systematically investigating the putative mechanisms of suicidality in PTSD including the role of particular PTSD symptoms, comorbid major

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depression, feelings of hopelessness, levels of social support, and negative dysfunctional appraisals. Clinicians should routinely fully assess suicidal risk when working with individuals who have been traumatized. Despite the significance and consistency of the findings of this meta-analysis regarding the link between PTSD and suicidality, it should be noted that this meta-analysis had a series of limitations that recommend caution while interpreting the current findings. The present article focused on both mild suicidal behaviors such as suicidal thoughts and intent and more severe forms of suicidality such as past attempts and successful suicides. The focus on both nonlethal and lethal suicidality was deemed appropriate based on the idea that suicidality is best described as a continuum from mild suicidal ideas to deliberate plans, attempts, and successful suicides [98-100]. Some suicide researchers, however, argue that suicidal behaviors and completed suicides are 2 distinct phenomena [101]. Similarly, across the studies of this met-analysis, suicidality was measured using a wide range of different measures that differed considerably in their type (interviews/questionnaires), length, and psychometric properties (standardized/nonstandardized). Although the subgroup analyses of this meta-analysis attempted to account for the above discrepancies, there is still the possibility that the inconsistent measurement of suicidality had an impact on the current outcomes. Clearly, suicide researchers should focus on offering a clear conceptualization of suicidality and on developing suicidality measures that will be widely acceptable. References [1] Amir M, Kaplan Z, Efroni R, Kotler M. Suicide risk and coping styles in posttraumatic stress disorder patients. Psychother Psychosom 1999;68:76-81. [2] Nad S, Marcinko D, Vuksan-Eusa B, Jakovljevic M, Jakoljevic G. Spiritual well-being, intrinsic religiosity, and suicidal behavior in predominantly catholic Kroatian Vietnam veterans with chronic posttraumatic stress disorder. A case control study. J Nerv Ment Dis 2008;196:79-83. [3] Oquendo MA, Friend JM, Halberstam B, Brodsky BS, Burke AK. Association of comorbid posttraumatic stress disorder and major depression with greater risk for suicidal behavior. Am J Psychiatry 2003;160:580-2. [4] Tarrier N, Gregg L. Suicide risk in civilian PTSD patients. Predictors of suicide ideation, planning and attempts. Soc Psychiatry Psychiatr Epidemiol 2004;39:655-61. [5] Bernal M, Haro JM, Bernert S, Brugha T, de Graaf R, Bruffaerts R, et al. Risk factors for suicidality in Europe: results from the ESEMED study. J Affect Disord 2007;101:27-34. [6] Cougle JR, Keough ME, Riccardi CJ, Sachs-Ericsson N. Anxiety disorders and suicidality in the National Comorbidity SurveyReplication. J Psychiatr Res 2008;43:825-9. [7] Davidson JR, Hughes D, Blazer DJ, George LK. Post-traumatic stress disorder in the community: an epidemiological study. Psychol Med 1991;21:713-21. [8] Sareen J, Cox BJ, Stein MB, Afifi TO, Fleet C, Asmundson GJ. Physical and mental comorbidity, disability, and suicidal behavior associated with posttraumatic stress disorder in a large community sample. Psychosom Med 2007;69:242-8.

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