Effects of Acute Stress or Centrally Injected Interleukin-1beta on Neuropeptide Expression in the Immune System

Acute stress stimulates the expression and release of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) from the hypothalamus, and the pro-opiomelanocortin products beta-endorphin and ACTH from the anterior pituitary. These neuropeptides are also expressed in immune tissues, and it has been proposed that they may modulate immune responses to stress through paracrine mechanisms. We subjected rats to restraint stress or central injection of interleukin (IL)-1beta to determine whether these acute stimuli can alter the expression of neuropeptides in the spleen and thymus. Restraint stress significantly increased the contents of all these neuropeptides in thymic, but not splenic, extracts. A single icv injection of IL-1beta increased contents of CRH, AVP, ACTH and beta-endorphin in the spleens of both sham-operated and adrenalectomised (ADX) rats. IL-1beta increased thymic contents of CRH and ACTH in sham-operated rats but these increases were not observed in ADX rats. These results suggest that the effects of IL-1beta on neuropeptide expression in the spleen are independent of glucocorticoids, whereas IL-1beta stimulation of neuropeptide expression in the thymus is dependent on circulating glucocorticoids. There were significant correlations between increases in CRH, ACTH and beta-endorphin in the spleen, and between CRH and ACTH in the thymus, consistent with the suggestion that IL-1beta-induced increases in ACTH and beta-endorphin may be mediated through CRH. These results provide evidence that stressors can directly influence neuropeptide expression in immune tissues. Thus stress may influence immune functions through paracrine mechanisms involving locally synthesised neuropeptides as well as through activation of the hypothalamo-pituitary-adrenal axis.     

Healing and Harming

As part of a volunteering program, a medical student learns the story of a sick infant whose survival was wholly dependent on modern medicine. The family was pacified by believing, during pregnancy, that the fetus would be healthy. Poor counseling and unethical physician behavior led to the trauma of the family's struggle to keep its baby alive, happy, and as healthy as possible. The need for adequate, thorough, and individualized counseling is a critical and still unfulfilled need in patient care.     

The role of attentional biases in PTSD: is it interference or facilitation?

Although attentional biases have been demonstrated in individuals with posttraumatic stress disorder (PTSD), the cognitive methodologies used have not allowed for disambiguation of two types of attentional biases. It remains unclear if PTSD involves difficulty disengaging attention from threatening stimuli (interference) or facilitated detection. To differentiate between attentional interference and facilitation, 57 male Vietnam-era veterans (30 High PTSD and 27 Low PTSD) completed a visual search task with a lexical decision component. High PTSD veterans who engaged in the interference task first showed increased interference to threat-relevant words relative to Low PTSD veterans. However, no evidence was found for facilitated detection of threatening stimuli in PTSD.     

Trauma reactivity, avoidant coping, and PTSD symptoms: a moderating relationship?

In the immediate aftermath of a traumatic event, many individuals experience physiological reactivity in response to reminders of the traumatic event that typically lessens over time. However, an overreliance on avoidant coping strategies may interfere with the natural recovery process, particularly for those who are highly reactive to trauma reminders. In the current investigation, we examined avoidant coping as a moderator of the association between heart rate reactivity to a trauma monologue measured shortly after a traumatic event and severity of posttraumatic stress disorder (PTSD) symptoms measured several months later. Fifty-five female survivors of assault completed PTSD diagnostic interviews and a self-report coping measure and participated in a trauma monologue procedure that included continuous heart rate measurement. These procedures were completed within 1 month of the assault and again 3 months postassault. After we controlled for the effect of initial symptom levels, the interaction of heart rate reactivity to the trauma monologue and avoidant coping measured at Time 1 was associated with PTSD symptom severity at Time 2. Individuals who are relatively highly reliant on avoidant coping strategies and relatively highly reactive to trauma reminders may be at greatest risk of maintaining or potentially increasing their PTSD symptoms within the first few months following the trauma. These findings may help inform early intervention efforts for survivors of traumatic events.     

The influence of the menstrual cycle on reactivity to a CO2 challenge among women with and without premenstrual symptoms

Clinically significant premenstrual symptoms (PMS) is conceptualized as a depressive disorder in DSM-5, however, it may share pathophysiological processes with anxiety- and fear-related disorders. Specifically, women with PMS panic at higher rates during biological challenge procedures. It is unclear if this increased interoceptive sensitivity is a general vulnerability or specific to the premenstrual phase. The current study examined the role of menstrual cycle phase on reactivity to a CO₂ challenge among women with (n = 11) and without (n = 26) clinically significant PMS (N = 37). During the late follicular phase (days 6–12), women with and without PMS responded similarly to the CO₂ challenge, whereas during the premenstrual phase (within 5 days before menses), women with PMS reported significantly more intense panic symptoms in response to the challenge than women without PMS. Vulnerability to panic in women with PMS may be specific to the premenstrual phase. Potential psychological and neurobiological mechanisms underlying this phenomenon are discussed.     

Military Sexual Trauma in Treatment-Seeking Women Veterans

As the number of women serving in the military continues to grow, it is increasingly important to explore the sequelae of military sexual trauma (MST) among female veterans. The current study included 232 female veterans who sought outpatient mental health treatment at an urban Veterans Affairs hospital. The study's aims were to (a) describe and compare the demographic characteristics, health behaviors, and psychological symptoms of female veterans who have experienced MST to those veterans who do not report this experience; and (b) examine the associations between psychological symptoms and health behaviors in this sample, stratified by MST status. Results indicate that treatment-seeking women veterans who reported experiencing MST endorsed more psychological distress compared to those who did not report experiencing MST. In addition, psychological symptoms were associated with engaging in problematic health behaviors, such as binge eating and infrequent physical exercise among both those women who experienced MST and those who did not.     

Attentional biases in PTSD: More evidence for interference

Attentional biases to trauma-related stimuli have been widely demonstrated in individuals with posttraumatic stress disorder (PTSD). However, the majority of these studies used methods not suited to differentiating difficulty disengaging attention from threatening stimuli (interference) from facilitated detection of threat. In the current study, a visual search task (VST) with a lexical decision component was used to differentiate between attentional interference and facilitation. Forty-six sexual assault survivors with High PTSD or Low PTSD symptoms completed the VST with three types of stimuli (trauma-related, general threat-related, and semantically-related neutral words), to examine the specificity of attentional biases associated with PTSD symptoms. High PTSD participants showed increased interference to trauma-related words relative to Low PTSD participants. Furthermore, the increased attentional interference in High PTSD participants was specific to trauma-related stimuli. No evidence was found for facilitated detection of threatening stimuli in PTSD. These results provide additional support for attentional biases in PTSD relating to attentional interference with trauma-related cues rather than facilitated detection of threat. The implications for this pattern of results are discussed in relation to anxiety disorders that are characterized by rumination and/or intrusions (e.g., PTSD, GAD) rather than those more circumscribed to fight or flight response (e.g., phobias).     

Attentional biases to internal and external sources of potential threat in social anxiety

D. M. Clark and A. Wells (1995) proposed that a shift of attention inward toward interoceptive information is a central feature of social phobia. However, few studies have examined attentional biases toward internal physiological cues in social phobia. The current experiment assessed whether socially anxious individuals exhibit an attentional bias (a) toward cues for an internal source of potential threat (heart-rate information), (b) toward cues for an external source of potential threat (threatening faces) or (c) both. Ninety-one participants who were selected to form extreme groups based on a social anxiety screening measure performed a dot-probe task to assess location of attention. Results showed that socially anxious participants exhibited an attentional bias toward cues of internal, but not external, sources of potential threat.