Nathan A. Kimbrel

Neuropsychological Sequelae of PTSD and TBI Following War Deployment among OEF/OIF Veterans

Posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) are highly prevalent among Veterans of the conflicts in Iraq and Afghanistan. These conditions are associated with common and unique neuropsychological and neuroanatomical changes. This review synthesizes neuropsychological and neuroimaging studies for both of these disorders and studies examining their co-occurrence. Recommendations for future research, including use of combined neuropsychological and advanced neuroimaging techniques to study these disorders alone and in concert, are presented. It is clear from the dearth of literature that addiitonal studies are required to examine and understand the impact of specific factors on neurocognitive outcome. Of particular relevance are temporal relationships between PTSD and mTBI, risk and resilience factors associated with both disorders and their co-occurrence, and mTBI-specific factors such as time since injury and severity of injury, utilizing comprehensive, yet targeted cognitive tasks.

Deployment-related TBI, persistent postconcussive symptoms, PTSD, and depression in OEF/OIF veterans.

OBJECTIVE A substantial proportion of the more than 2 million service members who have served in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) have experienced a traumatic brain injury (TBI). Understanding the long-term impact of TBI is complicated by the nonspecific nature of postconcussive symptoms (PCSs) and the high rates of co-occurrence among TBI, posttraumatic stress disorder (PTSD), and depression. The goal of the present research was to examine the relations among TBI, persistent PCSs, and symptoms of PTSD and depression among returning OEF/OIF veterans. METHOD 213 OEF/OIF veterans (87% male) completed a semistructured screening interview assessing deployment-related TBI and current, persistent PCSs. Participants also completed self-report measures of combat exposure and current symptoms of PTSD and depression. RESULTS Nearly half (46%) of sampled veterans screened positive for TBI, the majority of whom (85%) reported at least one persistent PCS after removing PCSs that overlapped with PTSD and depression. Veterans with deployment-related TBI reported higher levels of combat exposure and symptoms of PTSD and depression. Structural equation modeling was used to assess the fit of 3 models of the relationships among TBI, combat exposure, persistent PCSs, PTSD, and depression. Consistent with hypotheses, the best-fitting model was one in which the effects of TBI on both PTSD and depression were fully mediated by nonoverlapping persistent PCSs. CONCLUSIONS These findings highlight the importance of addressing persistent PCSs in order to facilitate the functional recovery of returning war veterans.

An analysis of reinforcement sensitivity theory and the five-factor model

Reinforcement Sensitivity Theory (RST) and the Five‐Factor Model (FFM) are two prominent personality accounts that have emerged from different backgrounds. Although the two accounts are applied to similar research topics, there is limited empirical work examining the correspondence between them. The current study explored the relationship between RST‐based personality traits and the FFM domains and facets in an undergraduate sample (n = 668). Regression analyses indicated that Sensitivity to Punishment (SP) was positively associated with Neuroticism and Agreeableness, and negatively associated with Extraversion, Openness, and Conscientiousness. In contrast, Sensitivity to Reward (SR) was positively associated with Extraversion and Neuroticism, and negatively associated with Agreeableness and Conscientiousness. Exploratory analyses at the facet level specified the relationship between SP, SR, and each domain. A factor analysis was also conducted to explore the higher‐order factor structure of RST and the FFM domains. Three factors emerged, which we labelled SP, Stability‐Impulsivity, and Sensation Seeking. Taken together, these findings suggest that there is substantial overlap between these two accounts of personality. Copyright

An examination of the relationship between behavioral approach system (BAS) sensitivity and social interaction anxiety.

BACKGROUND Both behavioral inhibition system (BIS) and behavioral approach system (BAS) sensitivity have been proposed to play a role in social anxiety; however, findings concerning the relationship between BAS and social anxiety have been mixed. Moreover, recent evidence suggests that low levels of BAS may only be associated with the social interaction subdimension of social anxiety. METHOD Measures of BIS, BAS, social interaction anxiety, and social observation anxiety were administered to three large analogue samples. RESULTS As hypothesized, BAS was inversely related to social interaction anxiety, but was unrelated to social observation anxiety across all three samples. In addition, individuals with generalized social fears were found to report both higher levels of BIS and lower levels of BAS compared to individuals with few or specific social fears. CONCLUSION These findings suggest that a complete motivational account of generalized social anxiety should include both BIS and BAS.

Genome-wide association study of posttraumatic stress disorder in a cohort of Iraq-Afghanistan era veterans.

BACKGROUND Posttraumatic stress disorder (PTSD) is a psychiatric disorder that can develop after experiencing traumatic events. A genome-wide association study (GWAS) design was used to identify genetic risk factors for PTSD within a multi-racial sample primarily composed of U.S. veterans. METHODS Participants were recruited at multiple medical centers, and structured interviews were used to establish diagnoses. Genotypes were generated using three Illumina platforms and imputed with global reference data to create a common set of SNPs. SNPs that increased risk for PTSD were identified with logistic regression, while controlling for gender, trauma severity, and population substructure. Analyses were run separately in non-Hispanic black (NHB; n = 949) and non-Hispanic white (NHW; n = 759) participants. Meta-analysis was used to combine results from the two subsets. RESULTS SNPs within several interesting candidate genes were nominally significant. Within the NHB subset, the most significant genes were UNC13C and DSCAM. Within the NHW subset, the most significant genes were TBC1D2, SDC2 and PCDH7. In addition, PRKG1 and DDX60L were identified through meta-analysis. The top genes for the three analyses have been previously implicated in neurologic processes consistent with a role in PTSD. Pathway analysis of the top genes identified alternative splicing as the top GO term in all three analyses (FDR q < 3.5 × 10(-5)). LIMITATIONS No individual SNPs met genome-wide significance in the analyses. CONCLUSIONS This multi-racial PTSD GWAS identified biologically plausible candidate genes and suggests that post-transcriptional regulation may be important to the pathology of PTSD; however, replication of these findings is needed.

Largest GWAS of PTSD (N=20 070) yields genetic overlap with schizophrenia and sex differences in heritability

The Psychiatric Genomics Consortium-Posttraumatic Stress Disorder group (PGC-PTSD) combined genome-wide case–control molecular genetic data across 11 multiethnic studies to quantify PTSD heritability, to examine potential shared genetic risk with schizophrenia, bipolar disorder, and major depressive disorder and to identify risk loci for PTSD. Examining 20 730 individuals, we report a molecular genetics-based heritability estimate (h2SNP) for European-American females of 29% that is similar to h2SNP for schizophrenia and is substantially higher than h2SNP in European-American males (estimate not distinguishable from zero). We found strong evidence of overlapping genetic risk between PTSD and schizophrenia along with more modest evidence of overlap with bipolar and major depressive disorder. No single-nucleotide polymorphisms (SNPs) exceeded genome-wide significance in the transethnic (overall) meta-analysis and we do not replicate previously reported associations. Still, SNP-level summary statistics made available here afford the best-available molecular genetic index of PTSD—for both European- and African-American individuals—and can be used in polygenic risk prediction and genetic correlation studies of diverse phenotypes. Publication of summary statistics for ∼10 000 African Americans contributes to the broader goal of increased ancestral diversity in genomic data resources. In sum, the results demonstrate genetic influences on the development of PTSD, identify shared genetic risk between PTSD and other psychiatric disorders and highlight the importance of multiethnic/racial samples. As has been the case with schizophrenia and other complex genetic disorders, larger sample sizes are needed to identify specific risk loci.

Combined PTSD and depressive symptoms interact with post-deployment social support to predict suicidal ideation in Operation Enduring Freedom and Operation Iraqi Freedom veterans

Rates of suicide are alarmingly high in military and veteran samples. Suicide rates are particularly elevated among those with post-traumatic stress disorder (PTSD) and depression, which share overlapping symptoms and frequently co-occur. Identifying and confirming factors that reduce, suicide risk among veterans with PTSD and depression is imperative. The proposed study evaluated, whether post-deployment social support moderated the influence of PTSD-depression symptoms on, suicidal ideation among Veterans returning from Iraq and Afghanistan using state of the art clinical, diagnostic interviews and self-report measures. Operations Enduring and Iraqi Freedom (OEF/OIF) Veterans (n=145) were invited to, participate in a study evaluating returning Veterans׳ experiences. As predicted, PTSD-depression, symptoms had almost no effect on suicidal ideation (SI) when post-deployment social support was high; however, when, post-deployment social support was low, PTSD-depression symptoms were positively associated with, SI. Thus, social support may be an important factor for clinicians to assess in the context of PTSD and, depressive symptoms. Future research is needed to prospectively examine the inter-relationship, between PTSD/depression and social support on suicidal risk, as well as whether interventions to, improve social support result in decreased suicidality.

Social support, stress, and suicidal ideation in professional firefighters.

OBJECTIVE To hypothesize that social support may protect against the effect of firefighter stress on suicidal ideation. METHODS Overall, 334 firefighters completed measures of occupational stress, social support, and suicidal ideation. RESULTS At high levels of social support, no association was observed between occupational stress and suicidal ideation (φ = -.06, ns); however, when social support was low, occupational stress showed a positive association with suicidal ideation (φ = .16, p < .05). CONCLUSIONS The association between occupational stress and suicidal ideation may be reduced by social support. Further research on this topic is warranted.

Sensitivity to punishment and low maternal care account for the link between bulimic and social anxiety symptomology.

OBJECTIVE The current study examined the joint effect of personality and parenting factors on the prediction of bulimia nervosa (BN) and social anxiety disorder (SAD) symptomology in a sample of female college students. The study also tested whether personality and parenting factors might account for the association between BN and SAD symptoms. METHOD One-hundred twenty-eight participants completed self-report measures assessing maternal care (MC), maternal overprotection, sensitivity to punishment (SP), sensitivity to reward (SR), and BN and SAD symptomology. RESULTS SP, SR, and MC each uniquely predicted BN symptoms, whereas only SP and MC predicted SAD symptoms. High SP interacted with low MC to predict BN and SAD symptoms over the main effects. In addition, SP, MC, and the interaction term SP x MC mediated the association between SAD and BN symptoms. CONCLUSION High SP and low MC appear to account for the link between BN and SAD symptomology, whereas high SR appears to distinguish the disorders.

The Invalidating Childhood Environment Scale (ICES): Psychometric Properties and Relationship to Borderline Personality Symptomatology

The objective of this study was to examine the psychometric properties of the Invalidating Childhood Environment Scale (ICES; Mountford, Corstorphine, Tomlinson, & Waller, 2004), a measure designed to retrospectively assess exposure to parental invalidation. The ICES was administered to a sample of female college students along with measures of parental bonding and borderline personality disorder (BPD) symptomatology. In contrast with previous findings, the ICES demonstrated excellent internal consistency within a nonclinical sample. It also correlated in the predicted directions with measures of parental bonding and BPD symptomatology. Taken together, these findings suggest that the ICES is a promising retrospective measure of parental invalidation. They also provide some support for the hypothesized link between parental invalidation and BPD symptomatology and suggest that additional research with clinical samples is needed.