Elevated rates of memory impairment in military service-members and veterans with posttraumatic stress disorder

Associations Among PTSD, Cognitive Functioning, and Health-Promoting Behavior in Post-9/11 Veterans

INTRODUCTION

PTSD is associated with negative health behaviors that increase chronic disease risk, yet health behaviors and their determinants are not well investigated in this context. One understudied mechanism of health behaviors is cognitive functioning. Deficits in cognitive functioning may undermine engagement in health-promoting behavior, thereby increasing the negative impact of PTSD. We tested three hypotheses: (1) Greater PTSD symptom severity is associated with less health-promoting behavior; (2) greater PTSD symptom severity is associated with poorer cognitive functioning across verbal memory, processing speed, attention, and executive functioning domains; and (3) verbal memory and executive functioning exhibit indirect effects on the relationship between PTSD and health-promoting behavior.

MATERIALS AND METHODS

We examined associations between PTSD symptom severity (Clinician-Administered PTSD Scale for DSM-IV), cognitive functioning, and health-promoting behavior (Health-Promoting Lifestyle Profile II) in 124 post-9/11 veterans (average age = 37.82; 85.5% male; 63.7% White; 18.5% Black; 26.6% Hispanic). Cognitive domains examined included verbal memory (California Verbal Learning Test), processing speed (Digit Symbol Coding), attention and working memory (Digit Span), and executive functions (Trail Making Test and Stroop Interference).

RESULTS

Regression analyses indicated that greater PTSD symptom severity was associated with less health-promoting behavior (B = -.0101, SE = 0.0016, P < .0001; R2 = 0.3052). Path analyses revealed that verbal learning and memory partially accounted for this relationship (R2 = 0.037- 0.043; P < .05).

CONCLUSIONS

Therapeutic targeting of these relationships may have implications for the prevention of long-term disease impact in veterans; longitudinal research is needed to elucidate the potential impact on chronic disease.

Posttraumatic Stress and Traumatic Brain Injury: Cognition, Behavior, and Neuroimaging Markers in Vietnam Veterans

BACKGROUND

Posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) are common in Veterans and linked to behavioral disturbances, increased risk of cognitive decline, and Alzheimer's disease.

OBJECTIVE

We studied the synergistic effects of PTSD and TBI on behavioral, cognitive, and neuroimaging measures in Vietnam war Veterans.

METHODS

Data were acquired at baseline and after about one-year from male Veterans categorized into: PTSD, TBI, PTSD+TBI, and Veteran controls without PTSD or TBI. We applied manual tractography to examine white matter microstructure of three fiber tracts: uncinate fasciculus (N = 91), cingulum (N = 87), and inferior longitudinal fasciculus (N = 95). ANCOVAs were used to compare Veterans' baseline behavioral and cognitive functioning (N = 285), white matter microstructure, amyloid-β (N = 230), and tau PET (N = 120). Additional ANCOVAs examined scores' differences from baseline to follow-up.

RESULTS

Veterans with PTSD and PTSD+TBI, but not Veterans with TBI only, exhibited poorer behavioral and cognitive functioning at baseline than controls. The groups did not differ in baseline white matter, amyloid-β, or tau, nor in behavioral and cognitive functioning, and tau accumulation change. Progression of white matter abnormalities of the uncinate fasciculus in Veterans with PTSD compared to controls was observed; analyses in TBI and PTSD+TBI were not run due to insufficient sample size.

CONCLUSIONS

PTSD and PTSD+TBI negatively affect behavioral and cognitive functioning, while TBI does not contribute independently. Whether progressive decline in uncinate fasciculus microstructure in Veterans with PTSD might account for cognitive decline should be further studied. Findings did not support an association between PTSD, TBI, and Alzheimer's disease pathology based on amyloid and tau PET.

Reduced working memory performance in PTSD and suicide among veterans presenting for treatment

Suicide is among the leading causes of death in the United States, underscoring the continued need to understand the mechanisms underlying suicide risk. A growing body of research has examined the role of working memory deficits in suicidal thoughts and behaviors (STBs), yet little research has evaluated putative pathways via which working memory impairments may heighten suicide risk. Elevated posttraumatic stress symptoms (PTSS) represent one plausible mechanism through which poor working memory performance may increase STBs. The present study utilized data from 140 treatment-seeking veterans who presented for an intake evaluation in the PTSD Clinical Team of a large VA Medical Center. Veterans completed self-report measures, a semi-structured PTSD evaluation, and a digit span working memory test. In addition to concurrent suicidal ideation assessed during the intake, additional information regarding past suicide attempts, presence of a safety plan, documentation of past suicidal behaviors, and engagement with suicide crisis lines were collected via electronic medical records. Consistent with hypotheses, a significant indirect path emerged such that poor working memory performance predicted greater suicidal ideation, greater likelihood of a past suicide attempt, and greater latent suicide risk via increased PTSS. However, no direct effect of working memory on STBs or indirect paths of PTSS on STBs via working memory emerged. These findings suggest that the relation between working memory and STBs may be explained by PTSS severity.

Environmental enrichment mitigates PTSD-like behaviors in adult male rats exposed to early life stress by regulating histone acetylation in the hippocampus and amygdala

Early life stress (ELS) can cause long-term changes in gene expression, affect cognition, mood, and behavior, and increase susceptibility to post-traumatic stress disorder (PTSD) in adulthood, in which the histone acetylation plays a crucial role. Studies have found that environmental enrichment (EE) mitigated the unfavorable outcomes of ELS. However, the underlying mechanism of the histone acetylation is not yet completely clear. The purpose of this study was to explore the effect of EE on the histone acetylation after ELS. In this study, using single prolonged stress (SPS) paradigm in early adolescent rats explored the long-term effects of ELS on behavior, the activity of histone acetyltransferases (HATs) and histone deacetylases (HDACs), as well as the acetylation levels of the lysine 9 site of histone H3 (H3K9) and lysine 12 site of histone H4 (H4K12) in the hippocampus and amygdala. Meanwhile, the protective effects of EE intervention were examined. We found that adult male rats exposed to ELS showed behavioral changes, including reduced locomotor activity, increased anxiety-like behaviors, impaired spatial learning and memory, enhanced contextual and cued fear memory, and the HATs/HDACs ratio and acetyl H3K9 (Ac-H3K9) and acetyl H4K12 (Ac-H4K12) were increased in the hippocampus and decreased in the amygdala. Furthermore, EE attenuated the behavioral abnormalities from ELS, possibly through down-regulating the activity of HATs in the hippocampus and up-regulating HDACs activities in the amygdala. These finding suggested that EE could ameliorate ELS-induced PTSD-like behaviors by regulating histone acetylation in the hippocampus and amygdala, reducing the susceptibility to PTSD in adulthood.

Contributory Etiologies to Cognitive Performance in Multimorbid Post-9/11 Veterans: The Deployment Trauma Phenotype

OBJECTIVE

This study examined cognitive functioning in post-9/11 Veterans with the deployment trauma phenotype (DTP), comprised of co-occurring diagnoses of depressive disorder (major depressive disorder and or persistent depressive disorder/dysthymia), posttraumatic stress disorder (PTSD), and mild traumatic brain injury (mTBI), using objective neuropsychological measures.

METHOD

Participants included a cross-sectional sample of 399 post-9/11 Veterans who completed clinical interviews and neuropsychological tests as part of a larger study at VA Boston Healthcare System. Confirmatory factor analysis identified four cognitive domains: attention, cognitive control/processing speed, episodic memory, and cognitive flexibility. Veterans with DTP and its constituent diagnoses in isolation, two-way diagnostic combinations, and no constituent diagnoses were compared.

RESULTS

Veterans with DTP had a twofold increased prevalence for below average performance in cognitive control/processing speed compared with those with no constituent diagnoses (prevalence ratios [PRs] = 2.04; 95% confidence interval [CI]: 1.03-4.05). The PTSD + depressive disorder group also had a twofold increased prevalence for below average performance in episodic memory (PR = 2.16; 95% CI: 1.05-4.43).

CONCLUSIONS

The deployment trauma phenotype is associated with clinically significant decrease in cognitive control/processing speed in post-9/11 Veterans. Comorbid PTSD and depressive disorder negatively impacted performances in episodic memory. Mild TBI alone showed no cognitive deficits. Clinical interventions should target psychiatric symptoms with a transdiagnostic approach to address this multimorbid population.

Independent and Synergistic Associations Between TBI Characteristics and PTSD Symptom Clusters on Cognitive Performance and Postconcussive Symptoms in Iraq and Afghanistan Veterans

OBJECTIVE

The investigators sought to evaluate the independent and interactive associations between mild traumatic brain injury (mTBI) characteristics and posttraumatic stress disorder (PTSD) symptoms with regard to postconcussive symptoms and cognition among treatment-seeking veterans of the U.S. conflicts in Iraq and Afghanistan.

METHODS

Sixty-seven Iraq and Afghanistan veterans who had a history of mTBI and comorbid PTSD were grouped based on injury mechanism (blast versus nonblast) and number of lifetime mTBIs (one to two versus three or more). Independent associations between mTBI characteristics and PTSD symptom clusters were evaluated with regard to cognition and postconcussive symptoms. Follow-up analyses were conducted to determine any interactive associations between TBI characteristics and PTSD symptom clusters.

RESULTS

Higher PTSD symptoms, particularly hyperarousal, were associated with poorer executive functioning and higher postconcussive symptoms. No direct relationships were observed between PTSD symptom clusters and memory or processing speed. The relationship between hyperarousal and processing speed was moderated by lifetime mTBIs, such that those with a history of at least three mTBIs demonstrated a negative association between hyperarousal and processing speed. Blast-related mTBI history was associated with reduced processing speed, compared with non-blast-related mTBI. However, an interaction was observed such that among those with blast-related mTBI history, higher re-experiencing symptoms were associated with poorer processing speed, whereas veterans without history of blast-related mTBI did not demonstrate an association between processing speed and re-experiencing symptoms.

CONCLUSIONS

Higher hyperarousal and re-experiencing symptoms were associated with reduced processing speed among veterans with repetitive and blast-related mTBI history, respectively. PTSD symptoms, specifically hyperarousal, were associated with poorer executive functioning and higher postconcussive symptoms. Limited associations were found between injury characteristics and cognition chronically following mTBI. However, these results support synergistic effects of specific PTSD symptom clusters and TBI characteristics.

Impaired episodic memory in PTSD patients - A meta-analysis of 47 studies

Episodic memory impairments beyond the traumatic event might be a characteristic hallmark of post-traumatic stress disorder (PTSD). Although several studies support such a claim, empirical findings are inconsistent. Therefore, we performed a random-effects meta-analysis including data from a total of 47 studies and 3,062 subjects. As main finding, we can show that PTSD patients show episodic memory deficits compared to all controls. This effect was significantly stronger for PTSD vs. non-traumatized healthy controls as compared to PTSD vs. traumatized controls without PTSD. Finally, episodic memory impairments in PTSD were most pronounced in verbal memory tests as compared to non-verbal memory tests. Our results provide new evidence that PTSD is characterized by impaired episodic long-term memory beyond the traumatic event, and these deficits are particularly pronounced in verbal memory. We will discuss our findings in the context of physiological, psychological and trauma related memory models. From a broader perspective, our findings may have implications for the treatment of PTSD by suggesting that the assessment and, if necessary, training of memory deficits could be included as part of diagnostics and psychotherapeutic treatment.

Structural brain features signaling trauma, PTSD, or resilience? A systematic exploration

BACKGROUND

Studies have searched for neurobiological markers of trauma exposure, posttraumatic stress disorder (PTSD) diagnosis, and resilience to trauma to identify therapeutic targets for PTSD. Despite some promising results, findings are inconsistent.

AIMS

The present study adopted a data-driven approach to systematically explore whether structural brain markers of trauma, PTSD, or resilience emerge when all are explored.

MATERIALS & METHODS

Differences between clusters in the proportion of PTSD, healthy controls (HC), and trauma-exposed healthy controls (TEHC) served to indicate the presence of PTSD, trauma, and resilience markers, respectively. A total of 129 individuals, including 46 with PTSD, 49 TEHCs, and 34 HCs not exposed to trauma were scanned. Volumes, cortical thickness, and surface areas of interest were obtained from T1 structural MRI and used to identify data-driven clusters.

RESULTS

Two clusters were identified, differing in the proportion of TEHCs but not of PTSDs or HCs. The cluster with the higher proportion of TEHCs, referred to as the resilience cluster, was characterized by higher volume in brain regions implicated in trauma exposure, especially the thalamus and rostral middle frontal gyrus. Cross-validation established the robustness and consistency of the identified clusters.

DISCUSSION & CONCLUSION

Findings support the existence of structural brain markers of resilience.

Repeated cocaine exposure prior to fear conditioning induces persistency of PTSD-like symptoms and enhancement of hippocampal and amygdala cell density in male rats

Pre- and post-trauma drug use can interfere with recovery from post-traumatic stress disorder (PTSD). However, the biological underpinnings of this interference are poorly understood. Here we examined the effect of pre-fear conditioning cocaine self-administration on PTSD-like symptoms in male rats, and defined impairment of fear extinction as difficulty to recover from PTSD. We also examined cell density changes in brain regions suspected of being involved in resistance to PTSD recovery. Before footshock stress testing, rats were trained to self-administer cocaine during 20 consecutive days, after which they were exposed to footshocks, while other rats continued to self-administer cocaine until the end of the experiment. Upon assessment of three PTSD-like symptoms (fear during situational reminders, anxiety-like behavior, and impairment of recognition memory) and fear extinction learning and memory, changes in cell density were measured in the medial prefrontal cortex, hippocampus, and amygdala. Results show that pre-footshock cocaine exposure did not affect fear during situational reminders. Fear conditioning did not lead to an increase in cocaine consumption. However, in footshock stressed rats, cocaine induced a reduction of anxiety-like behavior, an aggravation of recognition memory decline, and an impairment of extinction memory. These behavioral alterations were associated with increased cell density in the hippocampal CA1, CA2, and CA3 regions and basolateral amygdala, but not in the medial prefrontal cortex. Our findings suggest that enhancement of cell density in the hippocampus and amygdala may be changes associated with drug use, interfering with PTSD recovery.

Impaired executive function exacerbates neural markers of posttraumatic stress disorder

BACKGROUND

A major obstacle in understanding and treating posttraumatic stress disorder (PTSD) is its clinical and neurobiological heterogeneity. To address this barrier, the field has become increasingly interested in identifying subtypes of PTSD based on dysfunction in neural networks alongside cognitive impairments that may underlie the development and maintenance of symptoms. The current study aimed to determine if subtypes of PTSD, based on normative-based cognitive dysfunction across multiple domains, have unique neural network signatures.

METHODS

In a sample of 271 veterans (90% male) that completed both neuropsychological testing and resting-state fMRI, two complementary, whole-brain functional connectivity analyses explored the link between brain functioning, PTSD symptoms, and cognition.

RESULTS

At the network level, PTSD symptom severity was associated with reduced negative coupling between the limbic network (LN) and frontal-parietal control network (FPCN), driven specifically by the dorsolateral prefrontal cortex and amygdala Hubs of Dysfunction. Further, this relationship was uniquely moderated by executive function (EF). Specifically, those with PTSD and impaired EF had the strongest marker of LN-FPCN dysregulation, while those with above-average EF did not exhibit PTSD-related dysregulation of these networks.

CONCLUSION

These results suggest that poor executive functioning, alongside LN-FPCN dysregulation, may represent a neurocognitive subtype of PTSD.

Distress Tolerance and Symptom Severity as Mediators of Symptom Validity Failure in Veterans With PTSD

OBJECTIVE

Performance validity tests (PVTs) and symptom validity tests (SVTs) are necessary in clinical and research contexts. The extent to which psychiatric distress contributes to failure on these tests is unclear. The authors hypothesized that the relation between posttraumatic stress disorder (PTSD) and validity would be serially mediated by distress tolerance and symptom severity.

METHODS

Participants included 306 veterans, 110 of whom met full criteria for current PTSD. PVTs included the Medical Symptom Validity Test (MSVT) and b Test. The Structured Inventory of Malingered Symptomatology (SIMS) was used to measure symptom validity.

RESULTS

MSVT failure was significantly and directly associated with PTSD severity (B=0.05, CI=0.01, 0.08) but not distress tolerance or PTSD diagnosis. b Test performance was not significantly related to any variable. SIMS failure was significantly associated with PTSD diagnosis (B=0.71, CI=0.05, 1.37), distress tolerance (B=-0.04, CI=-0.07, -0.01), and symptom severity (B=0.07, CI=0.04, 0.09). The serial mediation model significantly predicted all SIMS subscales.

CONCLUSIONS

PTSD severity was associated with failing a memory-based PVT but not an attention-based PVT. Neither PVT was associated with distress tolerance or PTSD diagnosis. SVT failure was associated with PTSD diagnosis, poor distress tolerance, and high symptomatology. For veterans with PTSD, difficulty managing negative emotional states may contribute to symptom overreporting. This may reflect exaggeration or an inability to tolerate stronger negative affect, rather than a "cry for help."

PTSD and Depressive Symptoms as Potential Mediators of the Association between World Trade Center Exposure and Subjective Cognitive Concerns in Rescue/Recovery Workers

We observed that World Trade Center (WTC) exposure, post-traumatic stress disorder (PTSD) symptoms and depressive symptoms were associated with subjective cognitive concerns in Fire Department of the City of New York (FDNY) rescue/recovery workers. This follow-up study examined whether PTSD symptoms and/or depressive symptoms mediate the observed association between WTC exposure and subjective cognitive concerns. We included WTC-exposed FDNY workers who completed the Cognitive Function Instrument (CFI), measuring self-perceived cognitive decline (N = 9516). PTSD symptoms and depressive symptoms were assessed using the PCL-S and CES-D, respectively. Multivariable linear regression estimated the association between WTC exposure and CFI score, adjusting for confounders. Mediation analyses followed the methods of Vanderweele (2014). Participants’ average age at CFI assessment was 56.6 ± 7.6 years. Higher-intensity WTC exposure was associated with worse CFI score, an effect that was entirely mediated by PTSD symptoms (%mediated: 110.9%; 95%CI: 83.1–138.9). When substituting depressive symptoms for PTSD symptoms, the WTC exposure–CFI association was largely mediated (%mediated: 82.1%; 95%CI: 60.6–103.7). Our findings that PTSD symptoms and depressive symptoms mediate the association between WTC exposure and subjective cognitive concerns indicate that in the absence of these symptoms, WTC exposure in rescue/recovery workers would not be associated with subjective cognition. Interventions targeting PTSD and depression may have additional value in mitigating cognitive decline in WTC-exposed populations.

Neuropsychological Impact of Trauma-Related Mental Illnesses: A Systematic Review of Clinically Meaningful Results

A trauma history is present in approximately 90% of adults in the United States. Comparatively, lifetime post-traumatic stress disorder (PTSD) prevalence is only 8.3% (Kilpatrick et al. Journal of Traumatic Stress, 26, 537-547, 2013). A neuropsychological understanding of trauma is essential to effective trauma-informed assessments and treatments. Prior reviews have focused on PTSD, specific neuropsychological domains, and statistically rather than clinically significant results. The current systematic review investigated standardized test performance across neuropsychological domains in participants with trauma histories and any psychiatric diagnosis. The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. From 2350 records, the search returned 21 eligible studies: 8 for combat trauma, 2 for childhood trauma, 2 for intimate partner violence and sexual assault, 2 for accidental trauma, 1 for refugee trauma, and 6 for unspecified trauma. Mean neuropsychological scores ranged from low to high average, with one mean verbal memory score in the borderline range. These findings diverge from reports of between-group differences or experimental task performance, which suggest greater levels of static cognitive impairment. Current results are limited by lack of distinction between trauma types in the literature, a dearth of cognitive domains examined, wide use of self-report trauma measures, and publication and outcome reporting biases. Clinical implications for assessment and rehabilitation are discussed in relation to clinical significance, state versus trait based changes, intra-individual variability, changes from pre- to post-trauma, and within-group variability in resilience. Future directions are recommended in consideration of cultural factors, prospective and follow-up designs, and psychiatric diagnosis.

World Trade Center exposure, post-traumatic stress disorder, and subjective cognitive concerns in a cohort of rescue/recovery workers

OBJECTIVE

To determine whether World Trade Center (WTC)-exposure intensity and post-traumatic stress disorder (PTSD) are associated with subjective cognitive change in rescue/recovery workers.

METHOD

The population included 7875 rescue/recovery workers who completed a subjective cognition measure, the Cognitive Function Instrument (CFI), between 3/1/2018 and 2/28/2019 during routine monitoring, indicating whether they had experienced cognitive and functional difficulties in the past year. Higher scores indicated greater self-perceived cognitive change. Probable PTSD, depression, and alcohol abuse were evaluated by validated mental health screeners. Logistic regression assessed the associations of WTC exposure and current PTSD with top-quartile (≥2) CFI score, and of early post-9/11 PTSD with top-quartile CFI in a subpopulation (N = 6440). Models included demographics, smoking, depression, and alcohol abuse as covariates.

RESULTS

Mean age at CFI completion was 56.7 ± 7.7 (range: 36-81). Participants with high-intensity WTC exposure had an increased likelihood of top-quartile CFI score (odds ratio[OR] vs. low exposure: 1.32, 95%CI: 1.07-1.64), controlling for covariates. Current and early PTSD were both associated with top-quartile CFI (OR: 3.25, 95%CI: 2.53-4.19 and OR: 1.56, 95%CI: 1.26-1.93) respectively.

CONCLUSIONS

High-intensity WTC exposure was associated with self-reported cognitive change 17 years later in rescue/recovery workers, as was PTSD. Highly WTC-exposed subgroups may benefit from additional cognitive evaluation and monitoring of cognition over time.

Risk of Dementia and Depression in Young and Middle-aged Men Presenting with Nonmetastatic Prostate Cancer Treated with Androgen Deprivation Therapy

BACKGROUND

Previous studies have found an association between androgen deprivation therapy (ADT) and an increased risk of dementia and depression in elderly men. This association remains controversial, and little is known about the effects of ADT in younger men.

OBJECTIVE

To examine the association between the receipt of ADT and these outcomes in young men aged 40-64 yr presenting with nonmetastatic prostate cancer (PCa).

DESIGN, SETTING, AND PARTICIPANTS

For this observational study, we identified 9117 men aged 40-64 yr diagnosed with localized PCa between 2007 and 2014, without a pre-existing neurocognitive diagnosis, using the TRICARE military database.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Kaplan-Meier curves were fitted to compare ADT versus no ADT. We also performed a subgroup analysis in patients undergoing ADT for ≥12 mo. The association between ADT and new-onset dementia or depression was evaluated using inverse-probability-of treatment-weight-adjusted Cox proportional hazards regression analysis.

RESULTS AND LIMITATIONS

Patients receiving ADT had a significantly higher incidence of depression (30.2 vs 15.8 per 1000 person years) and dementia (17.9 vs 7.5 per 1000 person years). The risk of developing either outcome was higher in the ADT cohort (depression: hazard ratio [HR] 2.07, p < 0.001; dementia: HR 1.70, p = 0.052). Additionally, there was a dose-response relationship between the duration of ADT and either outcome.

CONCLUSIONS

In our cohort of young men with PCa, the receipt of ADT was associated with an increased risk of developing dementia and depression. Long-term use of ADT was associated with the highest risk of neurocognitive outcomes.

PATIENT SUMMARY

In this study, we looked at the risk of dementia and depression in patients <65 yr of age undergoing androgen deprivation therapy (ADT) for prostate cancer. We found that these patients had a higher risk of dementia and depression than those who did not undergo ADT.

Concurrent Mild Traumatic Brain Injury and Posttraumatic Stress Disorder Is Associated With Elevated Tau Concentrations in Peripheral Blood Plasma

Concurrent mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) are common in U.S. military service members and veterans. Tau and amyloid-beta-42 (Aβ42) are proteins that have been linked to cognitive impairment, neurological hallmarks of Alzheimer's disease, and may also relate to recovery from mTBI. However, the role of these proteins in the maintenance or resolution of chronic symptoms has not yet been determined. Participants in the current study were 102 service members and veterans who had sustained an mTBI (n = 84) or injured controls (IC) without TBI (n = 18). They were categorized into three groups based on the presence or absence of mTBI and PTSD: IC/PTSD-Absent (n = 18), mTBI/PTSD-Absent (n = 63), and mTBI/PTSD-Present (n = 21). Concentrations of tau and Aβ42 in peripheral blood plasma were measured using Simoa^TM , an ultrasensitive technology, and compared across groups. Tau concentrations were highest in the mTBI/PTSD-Present group, F(2, 99) = 4.33, p = .016, compared to the other two groups. Linear multiple regression was conducted to determine the independent effects of PTSD and mTBI on tau concentrations, controlling for gender and sleep medication. PTSD was a significant and independent predictor of tau concentrations, β = .25, p = .009, η_p ² = .26. Aβ42 concentrations did not differ between the groups. The results indicated that PTSD was associated with an elevation of tau in peripheral blood and suggest that there may be increased biological effects of PTSD in this young cohort of service members and veterans following mTBI.

Blast-Exposed Veterans With Mild Traumatic Brain Injury Show Greater Frontal Cortical Thinning and Poorer Executive Functioning

Objective: Blast exposure (BE) and mild traumatic brain injury (mTBI) have been independently linked to pathological brain changes. However, the combined effects of BE and mTBI on brain structure have yet to be characterized. Therefore, we investigated whether regional differences in cortical thickness exist between mTBI Veterans with and without BE while on deployment. We also examined whether cortical thickness (CT) and cognitive performance differed among mTBI Veterans with low vs. high levels of cumulative BE. Methods: 80 Veterans with mTBI underwent neuroimaging and completed neuropsychological testing and self-report symptom rating scales. Analyses of covariance (ANCOVA) were used to compare blast-exposed Veterans (mTBI+BE, n = 51) to those without BE (mTBI-BE, n = 29) on CT of frontal and temporal a priori regions of interest (ROIs). Next, multiple regression analyses were used to examine whether CT and performance on an executive functions composite differed among mTBI Veterans with low (mTBI+BE Low, n = 22) vs. high (mTBI+BE High, n = 26) levels of cumulative BE. Results: Adjusting for age, numer of TBIs, and PTSD symptoms, the mTBI+BE group showed significant cortical thinning in frontal regions (i.e., left orbitofrontal cortex [p = 0.045], left middle frontal gyrus [p = 0.023], and right inferior frontal gyrus [p = 0.034]) compared to the mTBI-BE group. No significant group differences in CT were observed for temporal regions (p's > 0.05). Multiple regression analyses revealed a significant cumulative BE × CT interaction for the left orbitofrontal cortex (p = 0.001) and left middle frontal gyrus (p = 0.020); reduced CT was associated with worse cognitive performance in the mTBI+BE High group but not the mTBI+BE Low group. Conclusions: Findings show that Veterans with mTBI and BE may be at risk for cortical thinning post-deployment. Moreover, our results demonstrate that reductions in CT are associated with worse executive functioning among Veterans with high levels of cumulative BE. Future longitudinal studies are needed to determine whether BE exacerbates mTBI-related cortical thinning or independently negatively influences gray matter structure.

Meta-Analysis of 89 Structural MRI Studies in Posttraumatic Stress Disorder and Comparison With Major Depressive Disorder

OBJECTIVE

The authors conducted a comprehensive meta-analysis of MRI region-of-interest and voxel-based morphometry (VBM) studies in posttraumatic stress disorder (PTSD). Because patients have high rates of comorbid depression, an additional objective was to compare the findings to a meta-analysis of MRI studies in depression.

METHOD

The MEDLINE database was searched for studies from 1985 through 2016. A total of 113 studies met inclusion criteria and were included in an online database. Of these, 66 were selected for the region-of-interest meta-analysis and 13 for the VBM meta-analysis. The region-of-interest meta-analysis was conducted and compared with a meta-analysis of major depressive disorder. Within the region-of-interest meta-analysis, three subanalyses were conducted that included control groups with and without trauma.

RESULTS

In the region-of-interest meta-analysis, patients with PTSD compared with all control subjects were found to have reduced brain volume, intracranial volume, and volumes of the hippocampus, insula, and anterior cingulate. PTSD patients compared with nontraumatized or traumatized control subjects showed similar changes. Traumatized compared with nontraumatized control subjects showed smaller volumes of the hippocampus bilaterally. For all regions, pooled effect sizes (Hedges' g) varied from -0.84 to 0.43, and number of studies from three to 41. The VBM meta-analysis revealed prominent volumetric reductions in the medial prefrontal cortex, including the anterior cingulate. Compared with region-of-interest data from patients with major depressive disorder, those with PTSD had reduced total brain volume, and both disorders were associated with reduced hippocampal volume.

CONCLUSIONS

The meta-analyses revealed structural brain abnormalities associated with PTSD and trauma and suggest that global brain volume reductions distinguish PTSD from major depression.