Search

Background: Attention-deficit/hyperactivity disorder (ADHD) and posttraumatic stress disorder (PTSD) are associated, but it is unclear if this is a causal relationship or confounding. We used genetic analyses and sibling comparisons to clarify the direction of this relationship. Methods: Linkage disequilibrium score regression and 2-sample Mendelian randomization were used to test for genetic correlation (r g) and bidirectional causal effects using European ancestry genome-wide association studies of ADHD (20,183 cases and 35,191 controls) and 6 PTSD definitions (up to 320,369 individuals). Several additional variables were included in the analysis to verify the independence of the ADHD-PTSD relationship. In a population-based sibling comparison (N = 2,082,118 individuals), Cox regression models were fitted to account for time at risk, a range of sociodemographic factors, and unmeasured familial confounders (via sibling comparisons). Results: ADHD and PTSD had consistent r g (r g range, 0.43–0.52; p < .001). ADHD genetic liability was causally linked with increased risk for PTSD (β = 0.367; 95% CI, 0.186–0.552; p = 7.68 × 10 −5). This result was not affected by heterogeneity, horizontal pleiotropy (Mendelian randomization Egger intercept = 4.34 × 10 −4, p = .961), or other phenotypes and was consistent across PTSD datasets. However, we found no consistent associations between PTSD genetic liability and ADHD risk. Individuals diagnosed with ADHD were at a higher risk for developing PTSD than their undiagnosed sibling (hazard ratio = 2.37; 95% CI, 1.98–3.53). Conclusions: Our findings add novel evidence supporting the need for early and effective treatment of ADHD, as patients with this diagnosis are at significantly higher risk to develop PTSD later in life.

Suicide is a major public health problem affecting US Veterans and the US in general. Many variables (e.g., demographic, clinical, biological, geographic) have been associated with risk for suicide and suicidal behavior, including altitude; however, the exact nature of the relationship between altitude and suicide remains unclear in part due to the fact that previous studies have used either geospatial data or individual-level data, but not both. Prior research has also failed to consider the full range of suicidal thoughts and behaviors, ranging from suicidal ideation to suicide deaths. Accordingly, the objective of the present research was to use both geospatial data (county and zip codes) and individual-level data to comprehensively assess the association between altitude and suicide mortality, suicide attempts, and suicidal ideation among US Veterans between 2000 and 2018. Taken together, our results demonstrate that there is a strong correlation between altitude and suicide rates at all the levels investigated and using different statistical analyses and even after controlling for significant covariates such as percent of age50yr, percent male, percent white, percent non-Hispanic, median household income, and population density. We show that there is a positive correlation between altitude and suicide attempts especially when controlling by the covariates and a weak correlation between altitude and suicide ideation and the combination of suicide, suicide attempts and suicide ideation.

Cannabis use has been indicated as a risk factor for suicide in veterans. This study of Gulf War veterans tested the relationship between self-report past year cannabis use and (a) past year suicidal ideation and (b) risk for suicidal behavior. Data were from a national sample (

Due to occupational stress and exposure to potentially traumatic events, firefighters are at an increased risk for the development of many behavioral health conditions. While volunteer and career firefighters represent two distinct subgroups, little research has examined differences in the availability of, and barriers to, behavioral health care between these populations. This study examined perceived availability and barriers to behavioral health care services among 2,156 career and 227 volunteer firefighters. Volunteer firefighters were less likely to report availability of drug and alcohol or family and couple services, but more likely to report availability of a trained peer support system and follow-up care compared to career firefighters. Volunteer firefighters were over five times more likely to consider cost a barrier to accessing behavioral health services compared to career firefighters; however, they were less likely to report lack of support from leadership, fear of breach of confidentiality, and clinicians who are unaware of work culture as barriers. Volunteer and career firefighters were equally likely to report stigma as a barrier. These findings have important implications for understanding how to strengthen departmental resources and to design targeted interventions to increase access to behavioral health services. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The onset and persistence of life events (LE) such as housing instability, job instability, and reduced social connection have been shown to increase risk of suicide. Predictive models for suicide risk have low sensitivity to many of these factors due to under-reporting in structured electronic health records (EHR) data. In this study, we show how natural language processing (NLP) can help identify LE in clinical notes at higher rates than reported medical codes. We compare domain-specific lexicons formulated from Unified Medical Language System (UMLS) selection, content analysis by subject matter experts (SME) and the Gravity Project, to data-driven expansion through contextual word embedding using Word2Vec. Our analysis covers EHR from the Veterans Affairs (VA) Corporate Data Warehouse (CDW) and measures the prevalence of LE across time for patients with known underlying cause of death in the National Death Index (NDI). We found that NLP methods had higher sensitivity of detecting LE relative to structured EHR (S-EHR) variables. We observed that, on average, suicide cases had higher rates of LE over time when compared to patients who died of non-suicide related causes with no previous history of diagnosed mental illness. When used to discriminate these outcomes, the inclusion of NLP derived variables increased the concentration of LE along the top 0.1%, 0.5% and 1% of predicted risk. LE were less informative when discriminating suicide death from non-suicide related death for patients with diagnosed mental illness.

Experiential avoidance (EA) is associated with posttraumatic stress disorder (PTSD) and self-injurious thoughts and behaviors (SITBs) across different populations, and extant literature has demonstrated a strong relationship between PTSD and SITBs. However, no study has explored the potential moderating role EA plays in the association of PTSD with nonsuicidal self-injury (NSSI), suicidal ideation, and suicide attempts. The objective of the present study was to determine if EA would moderate the association with PTSD and SITBs such that the association between PTSD and individuals SITBs would be stronger among individuals with higher EA. In a large national sample of Gulf War Era veterans (N = 1,138), EA was associated with PTSD, lifetime and past-year NSSI, current suicidal ideation, and lifetime suicide attempts in bivariate analyses. Multivariate analyses detected a significant EA by PTSD interaction on lifetime NSSI (AOR = 0.96), past-year NSSI (AOR = 1.03), and suicide attempts (AOR =1.03). Probing of the interactions revealed that the respective associations between PTSD, lifetime and past-year NSSI, and suicide attempts were stronger at lower levels of EA (i.e., better), counter to our hypotheses. These preliminary findings contextualize the relationship between these variables in a Gulf War veterans sample and signal the need to further investigate these relationships. Further, these findings highlight the need for advancement in assessment and intervention of EA and SITBs.

Military sexual assault (MSA) is a prevalent issue among military personnel that can have direct implications on postmilitary mental health. Gulf War era U.S. veterans represent the first cohort in which women veterans were integrated into most aspects of military service except for combat. The present study sought to build on prior studies by identifying characteristics associated with the occurrence of MSA and clinical correlates of MSA and examining how these differ between men and women. This study analyzed cross-sectional survey data from a national sample of treatment-seeking Gulf War era veterans. Participants (N = 1,153) reported demographic information, clinical outcomes, military background, and history of MSA. MSA was more common among female veterans (n = 100, 41.3%) than male veterans (n = 32, 3.6%). The odds of experiencing MSA were approximately 19 times higher for female veterans relative to their male peers, OR = 18.92, p.001. Moreover, as expected, MSA was robustly associated with probable current posttraumatic stress disorder, probable current depression, and past-year suicidal ideation in female veterans, whereas combat exposure was robustly associated with these sequelae in male veterans. The present findings confirm that a large proportion of female veterans from the Gulf War era experienced MSA and highlight the deleterious correlates of MSA on veterans' mental health. Sex differences of correlates of MSA and subsequent clinical associations are highlighted.

Nonsuicidal self-injury (NSSI) has been identified as one of the strongest predictors of suicide attempts. Wall/object punching is a particularly prevalent form of NSSI among male veterans that has been linked to both impulsivity and anger. The objective of the present study was to examine the indirect effect of impulsivity on wall/object punching via anger. Participants included 124 veterans (32 identified as women, 92 identified as men) with at least one psychiatric disorder. A third of the sample met criteria for NSSI disorder (33.1%) with nearly a half of the remaining sample endorsing NSSI. Almost half (41.94%) of the sample endorsed wall/object punching. Consistent with our hypothesis, impulsivity was significantly associated with anger, which was, in turn, significantly associated with wall/object punching. Impulsivity was found to be indirectly related to wall/object punching via anger. These findings underscore the significance of assessing and treating anger among veterans engaging in wall/object punching. Improving our knowledge of anger and impulsivity and their relationship with this particularly prevalent form of NSSI among veterans may lead to a better understanding of suicide risk among veterans and inform future treatments.

Sexual assault is associated with increased psychological distress. It is possible that military sexual assault (MSA) is associated with heightened psychological distress compared to adult sexual assault that occurs pre- or postmilitary service due to the nature of the military setting. Veterans and service members (N = 3,114; 19.6% women) who participated in the Post-Deployment Mental Health Study completed self-report measures of sexual assault history, symptoms of posttraumatic stress disorder (PTSD), symptoms of depression, hazardous alcohol use, drug use, and suicidal ideation. Women who reported a history of MSA endorsed higher levels of all types of psychological distress than women who did not experience adult sexual assault. Women who reported a history of MSA also endorsed higher levels of PTSD and depression symptoms than women who experienced pre- or postmilitary adult sexual assault. Men who reported a history of adult sexual assault, regardless of setting, reported higher levels of PTSD and depression symptoms than individuals who did not experience adult sexual assault. MSA was associated with higher psychological distress than pre- or postmilitary adult sexual assault among women. Among men, distress associated with MSA was comparable to sexual assault outside the military. Women may face unique challenges when they experience sexual assault in the military, and men may face additional stigma (compared to women) when they experience sexual assault, regardless of setting. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Objectives As a malleable risk-factor, psychological inflexibility is implicated in the development and maintenance of posttraumatic stress symptoms (PTS). Unfortunately, limited research has addressed whether changes in psychological inflexibility are antecedent to changes in PTS severity over time, or whether such changes are mutually dependent. Methods Utilizing bivariate latent difference score modeling, this longitudinal study sequenced intraindividual changes in psychological inflexibility and PTS severity within a sample of 305 returning US veterans. Veterans' self-reported psychological inflexibility and PTS severity were assessed quarterly over 1 year. Results Results indicated that early reductions in psychological inflexibility potentiated later declines in veterans' PTS severity, accounting for veterans' prior levels of psychological inflexibility and PTS severity. Conclusions These findings underscore the unique role of changes in psychological inflexibility as an important mechanism of change in PTS severity and provide empirical support for an antecedent model of the role of psychological inflexibility in PTS recovery.

An association has been found between cannabis use disorder (CUD) and violence in several clinical populations, including veterans with posttraumatic stress disorder (PTSD), and there is evidence that CUD has been increasing among veterans since September 11, 2001. There is also evidence that some veterans may be attempting to self-medicate psychological problems including PTSD and aggression with cannabis, despite the lack of safety and efficacy data supporting this use. To date, however, the association between CUD and aggression has yet to be examined in a large, non-clinic sample of veterans. The present study examined the association between cannabis use disorder, anger, aggressive urges, and difficulty controlling violence in a large sample of Iraq/Afghanistan-era veterans (N = 3,028). Results of multivariate logistic regressions indicated that current CUD was significantly positively associated with difficulty managing anger (OR = 2.93, p < 0.05), aggressive impulses/urges (OR = 2.74, p < 0.05), and problems controlling violence in past 30 days (OR = 2.71, p < 0.05) even accounting for demographic variables, comorbid symptoms of depression and PTSD, and co-morbid alcohol and substance use disorders. Lifetime CUD was also uniquely associated with problems controlling violence in the past 30 days (OR = 1.64, p < 0.05), but was not significantly associated with difficulty managing anger or aggressive impulses/urges. Findings indicated that the association between CUD and aggression needs to be considered in treatment planning for both CUD and problems managing anger and aggressive urges, and point to a critical need to disentangle the mechanism of the association between CUD and violence in veterans.

Suicidal ideation (SI) is a prevalent issue in the veteran population. A number of factors have been identified as risk factors for suicidal ideation (SI) in veterans, including suicide attempts, depression, posttraumatic stress disorder (PTSD), and drug use. However, clinicians’ ability to predict suicide is poor, particularly given the interplay between various factors such as previous suicide attempts. As such, there is a gap in our knowledge of which factors most saliently predict suicide risk and which should be targets for interventions designed to lower SI. Network analysis, a method allowing for an examination of how variables relate within the context of a network of factors, may bridge this gap by simultaneously evaluating the interrelationships between risk factors for suicide in veterans. current study used network analysis and data from 2,268 Iraq/Afghanistan-era military veterans to examine the relationships between suicidal ideation and several factors related to suicide risk, such as past suicide attempts, PTSD symptoms, depression, drug use, trauma exposure. Partial correlation network results showed suicidal ideation to be strongly related to depression, with smaller connections to past suicide attempts and anger. Additionally, past suicide attempts was strongly related to history of childhood trauma and weakly related to problematic drug use and PTSD symptoms. These results offer valuable information for both predicting suicide risk and differentiating targets for interventions lowering suicide risk in veterans.

Depression and posttraumatic stress disorder (PTSD) are two of the most common mental health conditions experienced by veterans. It is unclear what individual and system level factors are associated with receiving mental health treatment for these concerns. Using a national sample of Gulf War Era veterans who endorsed lifetime diagnoses of either depression or PTSD (

BACKGROUND: Expanding on research that has identified nonsuicidal self-injury (NSSI) as a strong predictor of suicide risk, the present study examined NSSI disorder (NSSID) and borderline personality disorder (BPD) as unique contributors to lifetime suicide attempts. To our knowledge, the present study represents the first exploration of these associations among veterans. METHODS: Participants included 124 male (74%) and female (26%) veterans diagnosed with at least one mental health disorder. Posttraumatic stress disorder (93%) and major depression (86%) were the most common mental health diagnoses. Large proportions of the sample met criteria for NSSID (48%) and BPD (40%). Suicide attempts were reported by 28% of the sample. Chi-square tests determined the bivariate associations among NSSID, BPD, history of suicide attempts, and other variables. Significant diagnostic (i.e., MDD, BPD, and NSSID) and demographic (i.e., age) characteristics were included as covariates in a logistic regression model examining the associations of BPD and NSSID with suicide attempts. RESULTS: BPD, X(2)=11.1, p

Veterans have high rates of suicide, and nonsuicidal self-injury (NSSI) is one of the strongest predictors of suicide risk; however, there is presently little known about antecedents of NSSI that might inform intervention efforts. Accumulating research suggests that anger and hostility play an important role in NSSI, but whether these emotions precede and predict NSSI is currently unknown. The aim of the current study was to examine the temporal relationships between anger/hostility and NSSI urges and behavior among veterans diagnosed with NSSI disorder. Our hypothesis was that angry/hostile affect would predict subsequent NSSI urge and engagement, but not vice versa. Forty veterans with NSSI disorder completed a 28-day ecological momentary assessment study with three daily prompts to report on their affect and NSSI urges and engagement. Multilevel cross-lagged path modeling was used to determine the direction of effects between angry/hostile affect and NSSI urges and engagement over time. Consistent with our hypothesis, results indicated that the lagged effects of angry/hostile affect on subsequent NSSI urge and engagement were significant, whereas the lagged effects of NSSI urge and engagement on angry/hostile affect were not significant. Findings highlight the importance of assessing and treating anger among veterans who engage in NSSI.

Background While firefighter-emergency medical responders (FF-EMR) are important stakeholders in cities considering the implementation of a supervised injection facility (SIF), there is little information on perspectives of first responders who serve these communities. The aim of the present study was to identify FF-EMR perspectives on working near a SIF. Methods FF-EMRs from Vancouver Fire and Rescue Services completed an online survey that queried participant perspectives on working near a SIF. Results Four main themes were identified: positive effects, negative effects, duration of assignment, and sense of duty. Similar percentages of first responders reported positive (22.2%) and negative aspects (25.9%) of working near the SIF, while some (18.5%) indicated preference for a short-term assignment to the SIF area. FF-EMRs most commonly described a sense of duty (35.2%). Conclusions To our knowledge, our study is the first to identify FF-EMR perspectives related to work near a SIF. Perspectives and concerns of first responders should be considered in policy debates about implementation of new SIFs to guarantee an adequately-prepared first responder workforce.

BACKGROUND: Posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) are each common among Unites States (U.S.) military veterans and frequently co-occur (i.e., PTSD+AUD). Although comorbid PTSD+AUD is generally associated with worse outcomes relative to either diagnosis alone, some studies suggest the added burden of comorbid PTSD+AUD is greater relative to AUD-alone than to PTSD-alone. Furthermore, nonsuicidal self-injury (NSSI) is more common among veterans than previously thought but rarely measured as a veteran psychiatric health outcome. This study sought to replicate and extend previous work by comparing psychosocial functioning, suicide risk, and NSSI among veterans screening positive for PTSD, AUD, comorbid PTSD+AUD, and neither disorder. METHODS: This study analyzed data from a national sample of N = 1,046 U.S. veterans who had served during the Gulf War. Participants self-reported sociodemographic, functioning, and clinical information through a mailed survey. RESULTS: Veterans with probable PTSD+AUD reported worse psychosocial functioning across multiple domains compared to veterans with probable AUD, but only worse functioning related to controlling violent behavior when compared to veterans with probable PTSD. Veterans with probable PTSD+AUD reported greater suicidal ideation and NSSI than veterans with probable AUD, but fewer prior suicide attempts than veterans with probable PTSD. LIMITATIONS: This study was cross-sectional, relied on self-report, did not verify clinical diagnoses, and may not generalize to veterans of other military conflicts. CONCLUSIONS: Findings underscore the adverse psychiatric and functional outcomes associated with PTSD and comorbid PTSD+AUD, such as NSSI, and highlight the importance of delivering evidence-based treatment to this veteran population.

Funding Information: This work was supported by the National Institute of Mental Health / U.S. Army Medical Research and Development Command (Grant No. R01MH106595 [to CMN, IL, MBS, KJRe, and KCK], National Institutes of Health (Grant No. 5U01MH109539 to the Psychiatric Genomics Consortium ), and Brain & Behavior Research Foundation (Young Investigator Grant [to KWC]). Genotyping of samples was provided in part through the Stanley Center for Psychiatric Genetics at the Broad Institute supported by Cohen Veterans Bioscience . Statistical analyses were carried out on the LISA/Genetic Cluster Computer ( https://userinfo.surfsara.nl/systems/lisa ) hosted by SURFsara. This research has been conducted using the UK Biobank resource (Application No. 41209). This work would have not been possible without the financial support provided by Cohen Veterans Bioscience, the Stanley Center for Psychiatric Genetics at the Broad Institute, and One Mind. Funding Information: MBS has in the past 3 years received consulting income from Actelion, Acadia Pharmaceuticals, Aptinyx, Bionomics, BioXcel Therapeutics, Clexio, EmpowerPharm, GW Pharmaceuticals, Janssen, Jazz Pharmaceuticals, and Roche/Genentech and has stock options in Oxeia Biopharmaceuticals and Epivario. In the past 3 years, NPD has held a part-time paid position at Cohen Veterans Bioscience, has been a consultant for Sunovion Pharmaceuticals, and is on the scientific advisory board for Sentio Solutions for unrelated work. In the past 3 years, KJRe has been a consultant for Datastat, Inc., RallyPoint Networks, Inc., Sage Pharmaceuticals, and Takeda. JLM-K has received funding and a speaking fee from COMPASS Pathways. MU has been a consultant for System Analytic. HRK is a member of the Dicerna scientific advisory board and a member of the American Society of Clinical Psychopharmacology Alcohol Clinical Trials Initiative, which during the past 3 years was supported by Alkermes, Amygdala Neurosciences, Arbor Pharmaceuticals, Dicerna, Ethypharm, Indivior, Lundbeck, Mitsubishi, and Otsuka. HRK and JG are named as inventors on Patent Cooperative Treaty patent application number 15/878,640, entitled “Genotype-guided dosing of opioid agonists,” filed January 24, 2018. RP and JG are paid for their editorial work on the journal Complex Psychiatry. OAA is a consultant to HealthLytix. All other authors report no biomedical financial interests or potential conflicts of interest. Funding Information: This work was supported by the National Institute of Mental Health/ U.S. Army Medical Research and Development Command (Grant No. R01MH106595 [to CMN, IL, MBS, KJRe, and KCK], National Institutes of Health (Grant No. 5U01MH109539 to the Psychiatric Genomics Consortium), and Brain & Behavior Research Foundation (Young Investigator Grant [to KWC]). Genotyping of samples was provided in part through the Stanley Center for Psychiatric Genetics at the Broad Institute supported by Cohen Veterans Bioscience. Statistical analyses were carried out on the LISA/Genetic Cluster Computer (https://userinfo.surfsara.nl/systems/lisa) hosted by SURFsara. This research has been conducted using the UK Biobank resource (Application No. 41209). This work would have not been possible without the financial support provided by Cohen Veterans Bioscience, the Stanley Center for Psychiatric Genetics at the Broad Institute, and One Mind. This material has been reviewed by the Walter Reed Army Institute of Research. There is no objection to its presentation and/or publication. The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting true views of the U.S. Department of the Army or the Department of Defense. We thank the investigators who comprise the PGC-PTSD working group and especially the more than 206,000 research participants worldwide who shared their life experiences and biological samples with PGC-PTSD investigators. We thank Mark Zervas for his critical input. Full acknowledgments are in Supplement 1. MBS has in the past 3 years received consulting income from Actelion, Acadia Pharmaceuticals, Aptinyx, Bionomics, BioXcel Therapeutics, Clexio, EmpowerPharm, GW Pharmaceuticals, Janssen, Jazz Pharmaceuticals, and Roche/Genentech and has stock options in Oxeia Biopharmaceuticals and Epivario. In the past 3 years, NPD has held a part-time paid position at Cohen Veterans Bioscience, has been a consultant for Sunovion Pharmaceuticals, and is on the scientific advisory board for Sentio Solutions for unrelated work. In the past 3 years, KJRe has been a consultant for Datastat, Inc. RallyPoint Networks, Inc. Sage Pharmaceuticals, and Takeda. JLM-K has received funding and a speaking fee from COMPASS Pathways. MU has been a consultant for System Analytic. HRK is a member of the Dicerna scientific advisory board and a member of the American Society of Clinical Psychopharmacology Alcohol Clinical Trials Initiative, which during the past 3 years was supported by Alkermes, Amygdala Neurosciences, Arbor Pharmaceuticals, Dicerna, Ethypharm, Indivior, Lundbeck, Mitsubishi, and Otsuka. HRK and JG are named as inventors on Patent Cooperative Treaty patent application number 15/878,640, entitled ?Genotype-guided dosing of opioid agonists,? filed January 24, 2018. RP and JG are paid for their editorial work on the journal Complex Psychiatry. OAA is a consultant to HealthLytix. All other authors report no biomedical financial interests or potential conflicts of interest. Publisher Copyright: © 2021 Society of Biological Psychiatry Background: Posttraumatic stress disorder (PTSD) is heritable and a potential consequence of exposure to traumatic stress. Evidence suggests that a quantitative approach to PTSD phenotype measurement and incorporation of lifetime trauma exposure (LTE) information could enhance the discovery power of PTSD genome-wide association studies (GWASs). Methods: A GWAS on PTSD symptoms was performed in 51 cohorts followed by a fixed-effects meta-analysis (N = 182,199 European ancestry participants). A GWAS of LTE burden was performed in the UK Biobank cohort (N = 132,988). Genetic correlations were evaluated with linkage disequilibrium score regression. Multivariate analysis was performed using Multi-Trait Analysis of GWAS. Functional mapping and annotation of leading loci was performed with FUMA. Replication was evaluated using the Million Veteran Program GWAS of PTSD total symptoms. Results: GWASs of PTSD symptoms and LTE burden identified 5 and 6 independent genome-wide significant loci, respectively. There was a 72% genetic correlation between PTSD and LTE. PTSD and LTE showed largely similar patterns of genetic correlation with other traits, albeit with some distinctions. Adjusting PTSD for LTE reduced PTSD heritability by 31%. Multivariate analysis of PTSD and LTE increased the effective sample size of the PTSD GWAS by 20% and identified 4 additional loci. Four of these 9 PTSD loci were independently replicated in the Million Veteran Program. Conclusions: Through using a quantitative trait measure of PTSD, we identified novel risk loci not previously identified using prior case-control analyses. PTSD and LTE have a high genetic overlap that can be leveraged to increase discovery power through multivariate methods. publishersversion published

OBJECTIVE: Previous studies of military veterans have produced mixed findings regarding whether combat exposure is directly related to suicidal ideation or is indirectly related to suicidal ideation via its influence on other factors. The present study used a longitudinal design to test the hypothesis that posttraumatic stress disorder (PTSD) symptom severity mediates the effect of combat exposure on suicidal ideation in veterans METHOD: Participants included 319 post-9/11 Veterans (83.4% male; 42.1% White/52.1% Black; M(age) = 39.7) assessed at baseline, 6 months, and 12 months. Structural equation modeling and bootstrapped confidence intervals were employed to examine the direct and indirect relationships between combat exposure, suicidal ideation, and PTSD symptom severity. RESULTS: Results from the mediation model, in which demographic variables and non-combat trauma were included as covariates, revealed that the indirect effect of combat exposure on suicidal ideation via PTSD symptom severity was statistically significant, accounting for 64.1% of the covariance between combat exposure and suicidal ideation. CONCLUSIONS: This study provides longitudinal evidence that the effects of combat exposure on suicidal ideation are mediated by PTSD symptom severity, suggesting the importance of targeting such symptoms in treatment to mitigate suicide risk among veterans with combat exposure.