Taiwanese Journal of Psychiatry

ORIGINAL ARTICLE
Year
: 2021  |  Volume : 35  |  Issue : 4  |  Page : 180--187

Depression, posttraumatic stress, and suicidal ideation: A linkage study in Taiwanese army


Fu- Shun Chang1, Hui- Ying Chou1, Yueh- Ming Tai2, Szu- Nian Yang2,  
1 Department of Psychiatry, Beitou Branch, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
2 Department of Psychiatry, Beitou Branch, Tri-Service General Hospital, National Defense Medical Center; Military Suicide Prevention Center, Taipei, Taiwan

Correspondence Address:
M.D., Ph.D Yueh- Ming Tai
No. 60, Shin-Ming Road, Beitou District, Taipei 112
Taiwan

Abstract

Background: Symptoms of poststress traumatic stress disorder (PTSD) and depression are intertwined in suicide ideation (SI) in military personnel. The interpersonal psychological theory (IPT) of suicide is proposed that the presence of thwarted belongingness (TB) and perceived burdensomeness (PB) produces the desire for suicide. To clarify the putative moderating effect of IPT on the complex-mediated moderation relationship among symptoms of soldiers' PTSD, depression, and SI, we did a cross-section study through recruiting military personnel in three camps in northern Taiwan. Methods: We recruited 759 active-duty soldiers (male: female = 579: 180) from three troops in northern Taiwan. They were asked to fill out copies of questionnaire according to their current two-week situation for our analyzing the study data. Results: In this study, we found that the pathway from soldiers' PTSD symptom to SI was positively and significantly mediated through their depression (p < 0.001), and that the pathway from their PTSD to depression was positively and significantly moderated by both PB (p < 0.05) and thwarted belongingness (p < 0.05). Comparing with male counterparts, the female soldiers, although significantly and relatively younger in age (p < 0.001), suffered from significantly higher levels of depression (p < 0.05) without significant sex difference in the magnitudes of PTSD symptoms. Conclusion: This study revealed the moderating effects of IPT on the pathway from PTSD to depression and SI among soldiers. Sex difference, although is subtle, can be essential in military suicide prevention and treatments for cases with PTSD symptoms.



How to cite this article:
Chang FS, Chou HY, Tai YM, Yang SN. Depression, posttraumatic stress, and suicidal ideation: A linkage study in Taiwanese army.Taiwan J Psychiatry 2021;35:180-187


How to cite this URL:
Chang FS, Chou HY, Tai YM, Yang SN. Depression, posttraumatic stress, and suicidal ideation: A linkage study in Taiwanese army. Taiwan J Psychiatry [serial online] 2021 [cited 2022 May 29 ];35:180-187
Available from: http://www.e-tjp.org/text.asp?2021/35/4/180/332965


Full Text



 Introduction



Growing concern is at the rise in suicide rates among soldiers in Taiwan [1] and United States military personnel [2] as well as at the high rates of posttraumatic stress disorder (PTSD) experience [3]. The association between PTSD and suicide risk among active military personnel has been getting attention [4] because investigators have suggested elevated rates of PTSD among service members as a potential explanation for suicidality [5]. Nevertheless, a study showed that veterans with PTSD have more frequent suicidal ideation and die from committing suicide than those veteran counterparts without PTSD [6].

PTSD and depression are closely intertwined, as both may result from the experience of trauma [7]. A recent study of suicide among military personnel was found that of those who committed suicide, 52% have shown depressed mood or mental health problems before the act [8]. Both PTSD and depression share some overlapping symptoms, including rumination, dysphoria, and sleep difficulties [9]. Some authors even found that the relations between symptoms of PTSD and suicide risk are interfered with some other mediators and moderators, especially through depression [4]. Even more, some authors proposed that PTSD may be a more salient predictor of suicide ideation (SI) than depression [10].

Regarding to SI, the evidence from previous studies showed that the above-mentioned associations are mixed according to a current meta-analysis review [2]. For example, several studies were found that symptoms of PTSD are positively correlated with SI [11],[12], but studies of Ben-Ya'acov and Amir [13] showed that SI is associated with low levels of PTSD symptoms. The most possible reason of the inconsistent evidence of the relationship between PTSD and SI is the inclusion of other important correlates of SI, namely psychiatric comorbidities, psychosocial functioning (e.g., socioeconomic status, social support), and sociodemographic factors [2]. Many studies have reported no relationships between PTSD and SI using electronic medical records [2] with sizable variability in the diagnostic validity compared to diagnostic interviews [14].

The interpersonal psychological theory (IPT) of suicide [15],[16] proposes that an individual will not die through suicide unless s/he has both the desire to die through suicide and the ability to do so, as outlined in Why People Die by Suicide written by Joiner [15]. The theory consists of three components that together lead to suicide attempts: first and second, the simultaneous presence of thwarted belongingness (TB) and perceived burdensomeness (PB) produces the desire for suicide, while the desire for suicide is necessary, but not causes death through suicide. Third, Joiner asserted that one must also have acquired capability (that is, the acquired ability) to overcome one's natural fear of death from SI to behaviors [16]. Many trials exist in integrating IPT and PTSD suicide risks [17]. In a study, based on 216 college students, investigators examined the IPT components, depression in conjunction with interpersonal trauma and SI, and investigators found that mediation effects exist for TB and PB at all [18].

Exposures to stressful life experiences, including combat experience, are well-known risk factors contributing to major depression [19],[20] and PTSD [21]. Many soldiers exposed to military stressors including deployment and combat, do not experience symptoms of depression or related problems [22]. Many studies showed that people showing greater resilience are more resistant to the ill effects of extreme stress, while people low in them are more vulnerable [22],[23]. A study was examining the differential prospective associations of PTSD symptom and SI as well as the impact of TB, PB in a trauma-exposed community sample. The investigators found that some of the PTSD symptoms, e.g., the hyperarousal symptom cluster, predict SI three months later, after controlling for baseline risk and receiving treatment [2],[24]. Interestingly, only PB has an impact on the relation between PTSD symptoms and SI [24]. TB has a main effect on SI directly, suggesting that a more complex mechanism exists for SI among trauma-exposed individuals, independent of depression symptoms [24]. Those inspired us to consider some alternative and advanced statistic models in their relations, e.g., the moderated mediation model.

In this study, we intended to study the linkage of PTSD and suicide among military personnel, and to find the possible putative moderating effects of TB and PB on the associations of PTSD to depression and to SI. We hypothesized that IPT would be associated with the pathway from PTSD, that suicidality furthermore could influence the subjects' vulnerability to depression, and that sex difference for the above influence could exist.

 Methods



Study participants

The experimental protocol of this cross-section survey study was approved by the institutional review board at the Tri Service General Hospital, National Defense Medical Center in Taipei, Taiwan (TSGHIRB no = 1-108-05-147 and date of approval = September 18, 2019) with the need for obtaining informed consent from the study participants.

The study participants were recruited from active service military personnel in three camps in the northern Taiwan. First, we did a one-hour education program and introduction lecture, and then all participants in the audience were invited to join this study. We recruited 759 qualified participants. No dropouts or withdrawals were found in this study.

Study procedures

All study participants, military active-duty personnel, were recruited in three military bases in the North Taiwan during March 2020. They received a series of two-hour suicide prevention psycho-education programs. After that, all participants in the audience were invited to join this study, and they filled out a series of copies of questionnaire, including their basic demographic data, Brief Symptom Rating Scale-5 (BSRS-5), Beck's Depression Inventory-Second Edition (BDI-II) for subjects' depression level, Davidson Trauma Scale (DTS) for subjects' symptoms of posttraumatic stress syndromes, and Interpersonal Needs Questionnaire (INQ) for subject's “perceived burdensomeness” and “thwarted belongingness,” respectively. The subject's suicidal ideation was derived from the sixth item of BSRS-5.

Measures

Brief Symptom Rating Scale

The five-item BSRS-5 is originally designed as a screen tool for psychiatric illness screening in nonpsychiatric health settings [25]. BSRS-5 has five symptom items of anxiety, depression, hostility, interpersonal sensitivity/inferiority, and insomnia, with responders' rating scores from 0 to 4 indicating none to extreme severity level. The modified BSRS-5 through adding the sixth item of current SI has been used for an effective screening instrument for SI [26]. In this study, we summarized the score of the sixth item as SI (zero for negative and others for positive symptom). The validity and reliability of BSRS have been published by Lee et al. in 1990 [27].

Beck's Depression Inventory-Second Edition

The BDI-II is a self-report 21-item instrument evaluating the existence and severity of depressive symptoms listed in the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) during the past two weeks. Each item is scored from 0 for “not at all” to 3 for “almost always” [28]. The Chinese version of the BDI-II has been demonstrated to have substantial internal consistency, reliability, and stability of Hong Kong adolescents [20] and in a study of military population in Taiwan [29].

Davidson Trauma Scale

The DTS is a 17-item self-report questionnaire of general severity of PTSD and intensity of specific symptoms developed for trauma survivors. Respondents are first asked to recall “The trauma that is most disturbing to you.” Next, respondents were asked to read each of the 17 items, and “Consider how often in the last week the symptom troubled you and how severe it was.” The measure includes a total score and scores for three subscales (re-experiencing, avoidance/numbing, and hyperarousal). The instrument was used to assess the worst symptoms in the lifetime. The DTS yields a frequency score (ranging from 0 to 68), severity score (ranging from 0 to 68), and total score (ranging from 0 to 136). Scores can also be calculated for each of the three PTSD symptoms [30]. The Chinese version of DTS was introduced in 2000, and it has been proven to have good reliability and validity [31].

Interpersonal Needs Questionnaire

The measurements of PB and thwarted belongingness (TB) are using the Chinese version of INQ [32]. The INQ is a 15-item self-report assessment of “recent” TB (nine items; e.g., “These days I feel disconnected from people”) and PB (six items; e.g., “These days I feel like a burden to the people in my life”) from the interpersonal theory (IPT) of suicide. Respondents endorse items using a seven-point scale ranging from 1 (not at all true for me) to 7 (very true for me). Higher scores on the INQ reflect greater TB or PB. The INQ has been demonstrated to have good psychometric properties among college samples [32]. Cronbach's alphas for the current sample were 0.83 for the TB subscale and 0.94 for the PB subscale. The Chinese version of INQ has been widely used in the Taiwanese community [33], and military [32] populations.

Statistical analysis

All measures including SI were treated as continuous variables. The descriptive analyses were used to present demographic characteristics of the total sample and different sex. We compared sex differences in demographic variables with independent t-test models for continuous variables and Pearson correlations.

Moderation and mediation analyses are two commonly used techniques to address questions of when and why variables are related, respectively. Moderation occurs when the magnitude and/or direction of a relationship between independent variable (X) and dependent variable (Y) are/is conditional on a third variable (moderator, W), and tests of moderation can be useful in evaluating the boundary conditions under which associations between two (or more) variables occur [34]. By contrast, mediation analysis gives the means to test how a mediating variable (mediator, M) intervenes in the relationship between two or more other variables (X, Y), acting as a mechanism, through which one variable's effect (indirect effect) is transmitted to another [35]. Although moderation and mediation are each useful on their own, integrating both into a single model enables researchers to examine even more nuanced relationships among variables. These combined forms are commonly referred to as moderated mediation or conditional process models [36], and allow for evaluations whether an indirect effect is moderated through another variable (W).

Moderated mediation models are particularly useful when an interest exists in understanding both why and under what conditions variables are related to one another. This combined model provides an opportunity to simultaneously study contingent and indirect effects. As recommended by both Preacher et al. [37] and Hayes and Preacher [36], we estimated the conditional indirect effects of three arbitrarily categorized levels of moderators, e.g., “relative low,” “relatively moderate,” and “relatively high,” using PROCESS program using ordinary least squares regression [36], and tested these effects using bootstrap confidence intervals (CIs), assessing whether the indirect effects differ from zero at various values of the moderator.

All the statistical analyses were done using the Statistical Package for Social Science version 25 (SPSS Inc., Chicago, Illinois, USA). The differences between groups were considered significant if p-values were smaller than 0.05.

The moderated mediation analyses were done using SPSS, including PROCESS macros created by Hayes and Preacher [36]. [Figure 1] shows the conceptual (a) and statistical (b) diagrams of the moderated mediation model based on the model 8 in Hay's book for PROCESS macros [38].{Figure 1}

 Results



A total of 759 soldiers on active duty were recruited in this study from January to December 2020. About three-quarters of them were male (n = 579, 76.28%). [Table 1] shows the demographic characteristics and correlations between variables among samples in both sexes. [Table 2] lists the results of the moderated mediation analysis with “perceived burdensomeness,” as the moderator (W) based on the statistical diagram of [Figure 1]b. [Table 3] lists the results of the moderated mediation analysis with “thwarted belongingness,” as the moderator (W) based on the statistical diagram of [Figure 1]b.{Table 1}{Table 2}{Table 3}

[Figure 2] depicts the simple mediation model to assess the potential influence of PTSD on SI [Figure 2] A1 and [Figure 2] A2, the rôle of depression as a mediator in this relation [Figure 2] B1 and [Figure 2] B2. In addition, we introduced the proposed moderator variable (PB and TB) [Figure 2] C1 and [Figure 2] C2.{Figure 2}

 Discussion



This study reconfirmed the significantly positive association between PTSD and SI in either male (p < 0.001, [Figure 2] A1) and female (p < 0.001, [Figure 2] A2) soldiers in Taiwan. Our findings support those published elsewhere [39] about the mediation rôle of depression between this pathway [Figure 2] B1 and [Figure 2] B2. But our findings only partially proved the claims by May and Klonsky [10] that PTSD is a more salient predictor of SI than depression because the depression incompletely mediates PTSD-SI pathway in male soldiers only, not in female soldiers. According to the conclusions of a previous systemic review in the US soldier and veteran groups [2], we suggest that the most probable reasons for the mixed and various results depend on the methodology and instruments used.

Comparing with male counterparts [Table 1], the female soldiers suffered from significantly higher level of depression (p < 0.05), although they were significantly younger in age (p < 0.001). This finding supports the previous observation in US soldiers that combat exposure is a stronger predictor of depression for women than men [21]. But no significant sex difference existed in the magnitudes evaluating their PTSD symptoms [Table 1]. As cited under the heading of study limitations, we suggest that the limitation of sample size and/or the difference in the age of female soldier group prohibit further conclusion before being strengthened in future further studies.

Robust and significant correlations existed between all variables in both sexes [Table 1] excepting the age variable. Unlike the independent effect of age in the females, symptoms of PTSD, SI, and depression were significantly and negatively associated with age in male soldiers (p < 0.01, p < 0.05, p < 0.05, respectively). The age of male soldiers was negatively associated with the severities of PTSD, SI and depression. But this phenomenon was not seen in female soldiers. That finding compels us to consider the difference in the service experience in both sexes. Regarding the sex difference in the perception of stress and/or environment in army, deployment-related experiences, such as combat, and sexual assault [40] can be mostly concerned. For example, Paley et al. [41] noted that deployment can be many challenges, including disruptions in family routine, extended separation from friends and family, and parenting challenges following return due to mental health sequelae [2]. These disruptions are particularly salient in driving PTSD symptoms following military-related trauma [42]. We suggest that these findings may cause differing clinical presentations in both sexes with military personnel that have been found to have associations of PTSD with SI [2]. Thus, further studies with more information about service experience of soldiers are warranted.

Although previous US veteran studies showed that only the PB is positively associated with SI in regression and/or mediation models [43]. In this study [Table 2], we found that the risk (95% CI) of PB for male soldiers was 0.0001 ± 0.0001 (< 0.0001 to 0.0003), p < 0.05, and the risk (95% CI) of PB for female soldiers was 0.0004 ± 0.0002 (< 0001 to 0.001), p < 0.05. Both male and female soldier groups had significant indexes of moderated mediation for PB.

In this study [Table 3], we found that the risk (95% CI) of TB for male soldiers was 0.0002 ± 0.0001 (< 0.0001 to 0.0004), p < 0.05 which was significant, but that the risk (95% CI) of TB for female soldiers was 0.0002 ± 0.0002 (−0.0002 to 0.0007), which was nonsignificant. These findings mean that only the male soldier group had a significant index of moderated mediation for TB.

Furthermore, regarding the interaction terms of symptom of PTSD and PB for depression (a3 in [Table 2]-1), the magnitude of coefficient was significantly greater in the female group (0.025 ± 0.005) than the male group (0.009 ± 0.003). To our knowledge, it is the first time to report the discrepancy in the moderation effects in sex.

While comparing the combined moderated mediation effects of these two moderators (TB and PB) together [Figure 2] C1 and [Figure 2] C2, both showed significant effects on the path from PTSD to depression (male soldiers = 0.009, p < 0.01; female soldiers = 0.026, p < 0.001). Nevertheless, in the male group, the PB showed a remained moderated mediation effect on the pathway from PTSD to SI (0.006, p < 0.05), but that female group was nonsignificant. Again, this finding might indicate that the claims of May and Klonsky [10] that “PTSD may be a more salient predictor of SI than depression” might be only true for male soldiers but not for female soldiers.

In TB, our findings extended the findings of Kolnogorova et al. that only PB, but not TB, mediates the impact of PTSD symptom on suicidal ideation [43]. Instead, we found that it is moderating effects not mediating effects that TB influences the complex relations among symptoms of PTSD, depression, and SI [Table 2].

Study limitations

The readers are cautioned not to overinterpret the study findings because this study has seven major limitations:

The sex of the study participants are male dominant (male to female = 579 to 180).This study did not have a larger sample size.We recruited study participants from convenient samples from tree military camps. Therefore, the findings are doubtful for representation of our study sample if we generalize them to all military personnel in Taiwan.This study is a cross-section survey, prohibiting our results from generalization to other populations and examining the long-term effects without further examination.Therefore, we did not know chronological changes in adjustment and stress in troops on mental conditions and various environments that military active service involved.Our finding did not address specific subsymptoms of PTSD. The clinical presentation of PTSD can vary largely between patients based on heterogeneous symptom profiles. Some specific symptoms of PTSD, such as hyperarousal symptoms uniquely predicted SI [24], in community participants meeting diagnostic criteria for PTSD and military personnel, respectively [24].For data analyses, we did not use other moderated mediation models, e.g., second-stage model (moderation effects on the mediator's influence on outcome) and dual-stage model (moderation effects on both links from predictor to mediator and from mediator to outcomes).In this study, we did not collect detailed information about physical conditions and history of substance use.

Study summary

Our study findings reveal that soldiers' PTSD symptoms are associated with their SI through the influence of depression. In this pathway, both PB and thwarted belongingness played essential rôle as enhancers on the mediation effect of depression in both sex groups. Some subtle differences between both sexes in this study included that PTSD was a more salient predictor of SI than depression in male soldiers and that both PB and thwarted belongingness could also moderate the effect of PTSD to SI directly.

Clinicians might consider a specific psychotherapy and intervention on soldiers with symptoms of PTSD, especially through helping them deal with their feelings of burdensomeness and belongingness first in suicide prevention.

 Acknowledgments



The authors thank the kindness and contribution of all participants. The opinions expressed are the authors' personal opinions. They are unnecessarily reflecting on those of their hospitals or institutions. The grant supporter, the Military Suicide Prevention Center of Taiwan, did not participate in writing this article.

 Financial Support and Sponsorship



The authors received financial support from the Military Suicide Prevention Center of Taiwan.

 Conflicts of Interest



Yueh-Ming Tai, an executive editorial board member at Taiwan Journal of Psychiatry, had no rôle in the peer review process or decision to publish this article. The other authors declared no conflicts of interest in writing this paper.

References

1Ma CC, Tai YM: Cut-off values of five-item brief symptom rating scale in evaluating suicidality among military recruits. Taiwan J Psychiatry (Taipei) 2014; 28: 109-20.
2Holliday R, Borges LM, Stearns-Yoder KA, et al.: Posttraumatic stress disorder, suicidal ideation, and suicidal self-directed violence among U.S. military personnel and veterans: a systematic review of the literature from 2010 to 2018. Front Psychol 2020; 11: 1998.
3Dworkin ER, Gilmore AK, Bedard-Gilligan M, et al.: Predicting PTSD severity from experiences of trauma and heterosexism in lesbian and bisexual women: a longitudinal study of cognitive mediators. J Couns Psychol 2018; 65: 324-33.
4Wisco BE, Marx BP, Wolf EJ, et al.: Posttraumatic stress disorder in the US veteran population: results from the National Health and Resilience in Veterans Study. J Clin Psychiatry 2014; 75: 1338-46.
5Pompili M, Sher L, Serafini G, et al.: Posttraumatic stress disorder and suicide risk among veterans: a literature review. J Nerv Ment Dis 2013; 201: 802-12.
6Jakupcak M, Cook J, Imel Z, et al.: Posttraumatic stress disorder as a risk factor for suicidal ideation in Iraq and Afghanistan War veterans. J Trauma Stress 2009; 22: 303-6.
7Franklin CL, Zimmerman M: Posttraumatic stress disorder and major depressive disorder: investigating the role of overlapping symptoms in diagnostic comorbidity. J Nerv Ment Dis 2001; 189: 548-51.
8Logan JE, Fowler KA, Patel NP, et al.: Suicide among military personnel and veterans aged 18-35 years by county-16 states. Am J Prev Med 2016; 51: S197-208.
9Roley ME, Claycomb MA, Contractor AA, et al.: The relationship between rumination, PTSD, and depression symptoms. J Affect Disord 2015; 180: 116-21.
10May AM, Klonsky ED: What distinguishes suicide attempters from suicide ideators? a meta-analysis of potential factors. Clin Psychol Sci Pract 2016; 23: 5-10.
11Chan YY, Lim KH, Teh CH, et al.: Prevalence and risk factors associated with suicidal ideation among adolescents in Malaysia. Int J Adolesc Med Health 2016; 30:132-41.
12Guerra VS, Calhoun PS, Mid-Atlantic Mental Illness Research, et al.: Examining the relation between posttraumatic stress disorder and suicidal ideation in an OEF/OIF veteran sample. J Anxiety Disord 2011; 25: 12-8.
13Ben-Ya'acov Y, Amir M: Posttraumatic symptoms and suicide risk. Pers Individ Dif 2004; 36: 1257-64.
14Holowka DW, Marx BP, Gates MA, et al.: PTSD diagnostic validity in Veterans Affairs electronic records of Iraq and Afghanistan veterans. J Consult Clin Psychol 2014; 82: 569-79.
15Joiner T: Why People Die by Suicide. Cambridge, Massachusetts, USA: Harvard University Press, 2005.
16Van Orden KA, Witte TK, Cukrowicz KC, et al.: The interpersonal theory of suicide. Psychol Rev 2010; 117: 575-600.
17Pennings SM, Finn J, Houtsma C, et al.: Posttraumatic stress disorder symptom clusters and the interpersonal theory of suicide in a large military sample. Suicide Life Threat Behav 2017; 47: 538-50.
18Poindexter EK, Mitchell SM, Brown SL, et al.: Interpersonal trauma and suicide ideation: the indirect effects of depressive symptoms, thwarted belongingness, and perceived burden. J Interpers Violence 2020; 7: 1-13.
19Monroe SM, Reid MW: Life stress and major depression. Curr Dir Psychol Sci 2009; 18: 68-72.
20Seal KH, Bertenthal D, Miner CR, et al.: Bringing the war back home: mental health disorders among 103,788 US veterans returning from Iraq and Afghanistan seen at Department of Veterans Affairs facilities. Arch Intern Med 2007; 167: 476-82.
21Luxton DD, Skopp NA, Maguen S: Gender differences in depression and PTSD symptoms following combat exposure. Depress Anxiety 2010; 27: 1027-33.
22Bartone PT: Predictors of stress-related illness in city bus drivers. J Occup Med 1989; 31: 657-63.
23Eschleman KJ, Bowling NA, Alarcon GM: A meta-analytic examination of hardiness. Int J Stress Manage 2010; 17: 277-89.
24Morabito DM, Boffa JW, Bedford CE, et al.: Hyperarousal symptoms and perceived burdensomeness interact to predict suicidal ideation among trauma-exposed individuals. J Psychiatr Res 2020; 130: 218-23.
25Lee MB, Liao SC, Lee YJ, et al.: Development and verification of validity and reliability of a short screening instrument to identify psychiatric morbidity. J Formos Med Assoc 2003; 102: 687-94.
26Lung FW, Lee MB: The five-item Brief-Symptom Rating Scale as a suicide ideation screening instrument for psychiatric inpatients and community residents. BMC Psychiatry 2008; 8: 53.
27Lee MB, Lee YJ, Yen LL, et al.: Reliability and validity of using a Brief Psychiatric Symptom Rating Scale in clinical practice. J Formos Med Assoc 1990; 89: 1081-7.
28Beck AT, Steer RA: Internal consistencies of the original and revised Beck Depression Inventory. J Clin Psychol 1984; 40: 1365-7.
29Tai YM, Gau SS: Depression and quality of life mediating the association between attention deficit/hyperactivity disorder and suicidality in military recruits. Mil Med 2017; 182: e1912-9.
30Davidson JR, Tharwani HM, Connor KM: Davidson Trauma Scale (DTS): normative scores in the general population and effect sizes in placebo-controlled SSRI trials. Depress Anxiety 2002; 15: 75-8.
31Seo HJ, Chung SK, Lim HK, et al.: Reliability and validity of the Korean version of the Davidson Trauma Scale. Compr Psychiatry 2008; 49: 313-8.
32Van Orden KA, Cukrowicz KC, Witte TK, et al.: Thwarted belongingness and perceived burdensomeness: construct validity and psychometric properties of the Interpersonal Needs Questionnaire. Psychol Assess 2012; 24: 197-215.
33Zhang J, Lester D, Zhao S, et al.: Suicidal ideation and its correlates: testing the interpersonal theory of suicide in Chinese students. Arch Suicide Res 2013; 17: 236-41.
34Aguinis H: Methodology in the social sciences. In: Regression Analysis for Categorical Moderators. New York, USA: Guilford Press, 2004.
35Baron RM, Kenny DA: The moderator-mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. J Pers Soc Psychol 1986; 51: 1173-82.
36Hayes AF, Preacher KJ: Conditional Process Modeling: Using Structural Equation Modeling to Examine Contingent Causal Processes. Washington, DC, USA: IAP Information Age Publishing, 2013.
37Preacher KJ, Rucker DD, Hayes AF: Addressing moderated mediation hypotheses: theory, methods, and prescriptions. Multivariate Behav Res 2007; 42: 185-227.
38Hayes AF: Introduction to Mediation, Moderation, and Conditional Process Analysis: A Regression-Based Approach. New York, USA: Guilford Publications, 2017.
39Elhai JD, Gray MJ, Kashdan TB, et al.: Which instruments are most commonly used to assess traumatic event exposure and posttraumatic effects? a survey of traumatic stress professionals. J Trauma Stress 2005; 18: 541-5.
40Barth SK, Kimerling RE, Pavao J, et al.: Military sexual trauma among recent veterans: correlates of sexual assault and sexual harassment. Am J Prev Med 2016; 50: 77-86.
41Paley B, Lester P, Mogil C: Family systems and ecological perspectives on the impact of deployment on military families. Clin Child Fam Psychol Rev 2013; 16: 245-65.
42Polusny MA, Kumpula MJ, Meis LA, et al.: Gender differences in the effects of deployment-related stressors and pre-deployment risk factors on the development of PTSD symptoms in National Guard Soldiers deployed to Iraq and Afghanistan. J Psychiatr Res 2014; 49: 1-9.
43Kolnogorova K, Allan NP, Moradi S, et al.: Perceived burdensomeness, but not thwarted belongingness, mediates the impact of PTSD symptom clusters on suicidal ideation modeled longitudinally. J Affect Disord 2021; 282: 133-40.