Gender and PTSD: What Can We Learn from Female Police Officers?

Studies of civilians typically find that female gender is a risk factor for posttraumatic stress disorder (PTSD). Police and military studies often find no gender differences in PTSD. We compared 157 female police officers and 124 female civilians on several variables including trauma exposure, peritraumatic emotional distress, current somatization, and cumulative PTSD symptoms. We found that despite greater exposure to assaultive violence in the officer group, female civilians reported significantly more severe PTSD symptoms. Elevated PTSD symptoms in female civilians were explained by significantly more intense peritraumatic emotional distress among female civilians. We also found that female officers showed a stronger direct relationship between peritraumatic emotional distress and current somatization. Our findings suggest that apparent gender differences in PTSD may result from differences in peritraumatic emotionality, which influence subsequent PTSD and somatization symptoms. Emotionality may be more important than biological sex in understanding gender differences in PTSD

Prospective Prediction of Posttraumatic Stress Disorder Symptoms Using Fear Potentiated Auditory Startle Responses

Background: Posttraumatic stress disorder (PTSD) has been most consistently associated with exaggerated physiologic reactivity to startling sounds when such sounds occur in threatening contexts. There is conflicting evidence about whether startle hyperreactivity is a preexisting vulnerability factor for PTSD or an acquired result of posttrauma neural sensitization. Until now, there have been no prospective studies of physiologic reactivity to startling sounds in threatening contexts as predictors of PTSD symptoms. Methods: One hundred and thirty-eight police academy cadets without current psychopathology were exposed to repeated 106-dB startling sounds under increasing (low, medium, or high) threat of mild electric shock while their eye-blink electromyogram, skin conductance, heart rate, and subjective fear responses were recorded. Measures of response habituation were also calculated. Following 1 year of exposure to police-related trauma, these participants were assessed for PTSD symptom severity. Results: After accounting for other baseline variables that were predictive of PTSD symptom severity (age and general psychiatric distress), more severe PTSD symptoms were prospectively and independently predicted by the following startle measures: greater subjective fear under low threat, greater skin conductance under high threat, and slower skin conductance habituation. Conclusions: These results imply that hypersensitivity to contextual threat (indexed by greater fear under low threat), elevated sympathetic nervous system reactivity to explicit threat (indexed by larger responses under high threat), and failure to adapt to repeated aversive stimuli (evidenced by slower habituation) are all unique preexisting vulnerability factors for greater PTSD symptom severity following traumatic stress exposure. These measures may eventually prove useful for preventing PTSD

Polygenic risk associated with post-traumatic stress disorder onset and severity.

Post-traumatic stress disorder (PTSD) is a psychiatric illness with a highly polygenic architecture without large effect-size common single-nucleotide polymorphisms (SNPs). Thus, to capture a substantial portion of the genetic contribution, effects from many variants need to be aggregated. We investigated various aspects of one such approach that has been successfully applied to many traits, polygenic risk score (PRS) for PTSD. Theoretical analyses indicate the potential prediction ability of PRS. We used the latest summary statistics from the largest published genome-wide association study (GWAS) conducted by Psychiatric Genomics Consortium for PTSD (PGC-PTSD). We found that the PRS constructed for a cohort comprising veterans of recent wars (n = 244) explains a considerable proportion of PTSD onset (Nagelkerke R2 = 4.68%, P = 0.003) and severity (R2 = 4.35%, P = 0.0008) variances. However, the performance on an African ancestry sub-cohort was minimal. A PRS constructed with schizophrenia GWAS also explained a significant fraction of PTSD diagnosis variance (Nagelkerke R2 = 2.96%, P = 0.0175), confirming previously reported genetic correlation between the two psychiatric ailments. Overall, these findings demonstrate the important role polygenic analyses of PTSD will play in risk prediction models as well as in elucidating the biology of the disorder

Frequency and Severity Approaches to Indexing Exposure to Trauma: The Critical Incident History Questionnaire for Police Officers

The Critical Incident History Questionnaire indexes cumulative exposure to traumatic incidents in police by examining incident frequency and rated severity. In over 700 officers, event severity was negatively correlated (rs = -61) with frequency of exposure. Cumulative exposure indices that varied emphasis on frequency and severity-using both nomothetic and idiographic methods-all showed satisfactory psychometric properties and similar correlates. All indices were only modestly related to posttraumatic stress disorder (PTSD) symptoms. Ratings of incident severity were not influenced by whether officers had ever experienced the incident. Because no index summarizing cumulative exposure to trauma had superior validity, our findings suggest that precision is not increased if frequency is weighted by severity

Hippocampal Volume Differences in Gulf War Veterans with Current Versus Lifetime Posttraumatic Stress Disorder Symptoms

Background: Decreased hippocampal volume is described in posttraumatic stress disorder (PTSD) and depression. However, it is not known whether it is a risk factor for the development of PTSD or a consequence of PTSD. We sought to determine the effects of PTSD and depressive symptoms on hippocampal volume. Methods: Clinical and magnetic resonance imaging data were collected in a cross sectional study of 244 GulfWarveterans. Measures included lifetime and current Clinician Administered PTSD Scale, Hamilton Depression Scale, Life Stressor Checklist, and Lifetime Drinking History. Magnetic resonance imaging data were acquired with a 1.5-T scanner and analyzed with automated and semiautomated image processing techniques. Results: Eighty-two veterans had lifetime PTSD, 44 had current PTSD, and 38 had current depression. In the linear regression analysis, current PTSD symptoms (standardized coefficient B= .25, p =.03) but neither lifetime PTSD symptoms nor current depression were associated with smaller hippocampal volume. Gender, age, history of early life trauma, education, lifetime and current alcohol use, current marijuana use, and treatment with antidepressants did not have independent effects. Participants with chronic PTSD had, on average, a smaller hippocampus compared with those with remitted PTSD. Conclusions: The finding that current but not lifetime PTSD symptom severity explains hippocampal size raises two possibilities: either a small hippocampus is a risk factor for lack of recovery from PTSD (trait) or PTSD effects on hippocampal volume are reversible once PTSD symptoms remit and the patient recovers (state)

High-field side scrape-off layer investigation: Plasma profiles and impurity screening behavior in near-double-null configurations

New experiments on Alcator C-Mod reveal that the favorable impurity screening characteristics of the high-field side (HFS) scrape-off layer (SOL), previously reported for single null geometries, is retained in double null configurations, despite the formation of an extremely thin SOL. In balanced double-null, nitrogen injected locally into the HFS SOL is better screened by a factor of 2.5 compared to the same injection into the low field side (LFS) SOL. This result is insensitive to plasma current and Greenwald fraction. Nitrogen injected into the HFS SOL is not as well screened (only a factor of 1.5 improvement over LFS) in unbalanced double-null discharges, when the primary divertor is in the direction of B×∇B. In this configuration, impurity ‘plume’ emission patterns indicate that an opposing E × B drift competes with the parallel impurity flow to the divertor. In balanced double-null plasmas, the dispersal pattern exhibits a dominant E × B motion. Unbalanced discharges with the primary divertor opposite the direction of B×∇B exhibit excellent HFS screening characteristics – a factor of 5 enhancement compared to LFS. These data support the idea that future tokamaks should locate all RF actuators and close-fitting wall structures on the HFS and employ near-double-null magnetic topologies, both to precisely control plasma conditions at the antenna/plasma interface and to maximally mitigate the impact of local impurity sources arising from plasma-material interactions. Keywords: Alcator C-Mod; Impurity screening; Double null; High field side scrape-off layerUnited States. Department of Energy (Contract DE-FC02-99ER54512

International meta-analysis of PTSD genome-wide association studies identifies sex- and ancestry-specific genetic risk loci.

The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robust common variants have yet to be identified. In a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. We demonstrate SNP-based heritability estimates of 5-20%, varying by sex. Three genome-wide significant loci are identified, 2 in European and 1 in African-ancestry analyses. Analyses stratified by sex implicate 3 additional loci in men. Along with other novel genes and non-coding RNAs, a Parkinson's disease gene involved in dopamine regulation, PARK2, is associated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantly predictive of re-experiencing symptoms in the Million Veteran Program dataset, although specific loci did not replicate. These results demonstrate the role of genetic variation in the biology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses and expanding GWAS beyond European ancestry populations

Mental Health Diagnoses and Utilization of VA Non-Mental Health Medical Services Among Returning Iraq and Afghanistan Veterans

Over 35% of returned Iraq and Afghanistan veterans in VA care have received mental health diagnoses; the most prevalent is post-traumatic stress disorder (PTSD). Little is known about these patients’ use of non-mental health medical services and the impact of mental disorders on utilization. To compare utilization across three groups of Iraq and Afghanistan veterans: those without mental disorders, those with mental disorders other than PTSD, and those with PTSD. National, descriptive study of 249,440 veterans newly utilizing VA healthcare between October 7, 2001 and March 31, 2007, followed until March 31, 2008. We used ICD9-CM diagnostic codes to classify mental health status. We compared utilization of outpatient non-mental health services, primary care, medical subspecialty, ancillary services, laboratory tests/diagnostic procedures, emergency services, and hospitalizations during veterans’ first year in VA care. Results were adjusted for demographics and military service and VA facility characteristics. Veterans with mental disorders had 42–146% greater utilization than those without mental disorders, depending on the service category (all P < 0.001). Those with PTSD had the highest utilization in all categories: 71–170% greater utilization than those without mental disorders (all P < 0.001). In adjusted analyses, compared with veterans without mental disorders, those with mental disorders other than PTSD had 55% higher utilization of all non-mental health outpatient services; those with PTSD had 91% higher utilization. Female sex and lower rank were also independently associated with greater utilization. Veterans with mental health diagnoses, particularly PTSD, utilize significantly more VA non-mental health medical services. As more veterans return home, we must ensure resources are allocated to meet their outpatient, inpatient, and emergency needs