Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

The Chemical and Biological Warfare Environment: Psychological Responses and Social Supports in a High-Stress Environment

In order to better understand psychological responses to high-stress environments and the contributions of social supports to mediating the effects of this stress, we conducted a preliminary investigation of a health care delivery team in a simulated chemical and biological warfare (CBW) environment. Our data suggest that state anxiety prior to the exercise, perceived social support from family and friends, and active training stand out as predictors of psychological outcome, even after trait and pre-exercise psychological variables are considered. Interventions directed at state anxiety and active training may offer mechanisms to decrease the psychological distress of the high-stress environment. Future research should examine variables which are amenable to intervention to determine if they are causally related to health outcome in high-stress environments.     

Measurement of depression in a military sample

Using the responses of 250 Navy health care providers, we considered the sensitivity and specificity of the SCL-90-R Depression subscale and the Global Severity Index in predicting mild, moderate, and severe depression in a deployed military sample. Using the 90th percentile norms to identify caseness for both measures, each performs with 100% certainty in ascertaining severe depression and with less certainty in pinpointing a nonevent (specificity). Results are further considered by sex.     

Cognitive and Behavioral Responses to Trauma

In order to identify cognitive and behavioral responses to trauma, we have studied responses to mass casualty body handling following the Gander, Newfoundland, plane crash of 1985 and the 1989 USS Iowa disaster, and responses to a simulated chemical and biological warfare environment. Individual and group trauma behaviors show prominent: (a) thinking by similarity (identification, and looking for the familiar/ seeing the past in the present); (b) attribution of meaning (rituals, symbols, language, and rumors); and (c) contagion of behavior. These processes highlight the importance of the study of responses to different traumatic stressors in order to identify cognitive mechanisms and behaviors activated by trauma. Such phenomena may be important to our understanding of the effects of traumatic stress and their acute and long-term health outcomes.     

Social Support and Mental Health Outcomes Among U.S. Army Special Operations Personnel

Mental health disorders continue to plague service members and veterans; thus, new approaches are required to help address such outcomes. The identification of risk and resilience factors for these disorders in specific populations can better inform both treatment and prevention strategies. This study focuses on a unique population of U.S. Army Special Operations personnel to assess how specific avenues of social support and personal morale are related to mental health outcomes. The results indicate that, whereas personal morale and friend support reduce the relationship between combat experiences and posttraumatic stress disorder (PTSD), strong unit support exacerbates the negative effects of combat experiences in relation to PTSD. The study thus shows that although informal social support can lessen postdeployment mental health concerns, military populations with strong internal bonds may be at greater risk of PTSD because the support that they receive from fellow service members may heighten the traumatic impact of combat experiences.     

Neurocognitive Function and Suicide in U.S. Army Soldiers

This prospective cohort study used administrative data from the Army Study to Assess Risk and Resilience in Servicemembers to examine associations between neurocognitive functioning and subsequent suicidal events among Regular Army enlisted soldiers during the years 2004–2009. Cases were all soldiers who completed the Army's Automated Neuropsychological Assessment Metrics (ANAM) computerized testing battery prior to documented suicide attempt (n = 607), ideation (n = 955), or death (n = 57). Controls were an equal‐probability sample of 9,893 person‐months from other soldiers. Exploratory factor analysis of five ANAM tests identified a general neurocognitive factor that excluded the mathematic processing test (MTH). When examined separately in logistic regression analyses that controlled for sociodemographics and prior mental health diagnosis, both the general neurocognitive factor (logit [β] = ?.197 to ?.521; p < .01) and MTH (β = ?.024 to ?.064; p < .05) were associated with all outcomes. When both predictors were examined simultaneously, the general neurocognitive factor continued to be associated with all outcomes (β = ?.164 to ?.417; p < .05) and MTH continued to be associated with suicide attempt (β = ?.015; p = .046) and ideation (β = ?.014; p = .018). These small but robust associations suggest that future research must continue to examine the extent to which objective neurocognitive tests may enhance understanding and prediction of suicide risk.     

Mental Disorders,Comorbidity, and Pre‐enlistment Suicidal Behavior Among New Soldiers in the U.S. Army: Results from the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS)

We examined the associations between mental disorders and suicidal behavior (ideation, plans, and attempts) among new soldiers using data from the New Soldier Study (NSS) component of the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS; N = 38,507). Most new soldiers with a pre‐enlistment history of suicide attempt reported a prior mental disorder (59.0%). Each disorder examined was associated with increased odds of suicidal behavior (ORs = 2.6–8.6). Only PTSD and disorders characterized by irritability and impulsive/aggressive behavior (i.e., bipolar disorder, conduct disorder, oppositional defiant disorder, and attention‐deficit/hyperactivity disorder) predicted unplanned attempts among ideators. Mental disorders are important predictors of pre‐enlistment suicidal behavior among new soldiers and should figure prominently in suicide screening and prevention efforts.     

An Examination of Potential Misclassification of Army Suicides: Results from the Army Study to Assess Risk and Resilience in Servicemembers

Debate continues about the accuracy of military suicide reporting due to concerns that some suicides may be classified as accidents to minimize stigma and ensure survivor benefits. We systematically reviewed records for 998 active duty Army deaths (510 suicides; 488 accident, homicide, and undetermined deaths; 2005‐2009) and, using research criteria, reclassified 8.2% of the nonsuicide cases to definite suicide (1), suicide probable (4), or suicide possible (35). The reclassification rate to definite suicide was only 0.2% (1/488). This low rate suggests that flagrant misclassification of Army deaths is uncommon and surveillance reports likely reflect the “true” population of Army suicides.