Noradrenergic dysfunction and the psychopharmacology of posttraumatic stress disorder

Comparison of alpha-2 agonist versus alpha-1 antagonist for post-traumatic stress disorder-associated nightmares in pediatric patients

Introduction

Posttraumatic stress disorder (PTSD) in children and adolescents has a high prevalence of accompanying sleep disturbances. Currently, pediatric treatment of PTSD-related nightmares is extrapolated from adult studies. This study aims to determine the effectiveness and safety of clonidine and guanfacine compared with prazosin for the treatment of PTSD-related nightmares.

Methods

This was a retrospective, single-center, medical record review of patients 5 to 17 years old admitted to an inpatient psychiatric unit from January 2015 to September 2021. Patients with a new initiation of an alpha-2 agonist (clonidine or guanfacine) or an alpha-1 antagonist (prazosin) with a diagnosis of PTSD, other trauma- or stressor-related disorder or unspecified anxiety disorder were included. The primary endpoint was the percentage of patients with a decrease in the frequency of nightmares.

Results

A total of 59 patients were included in the study: 37 in the alpha-2 agonist group and 22 in the alpha-1 antagonist group. There was no statistically significant difference in reduction of nightmares with both groups having a high percentage of patients showing response (alpha-2 agonist: 91.9%, alpha-1 antagonist: 86.4%). Time to decrease in nightmares was comparable between groups with a relatively quick onset. Within the alpha-2 agonist group, clonidine (1.59 ± 1.06 days) compared with guanfacine (3.18 ± 1.74 days) had a statistically significant faster time to reduction in nightmares (p = .005).

Discussion

Both pharmacologic classes of medications were effective treatment options for pediatric PTSD-associated nightmares with a low incidence of adverse effects. There was a quick time to onset seen with all agents.

Contextual memory engrams, and the neuromodulatory influence of the locus coeruleus

Here, we review the basis of contextual memory at a conceptual and cellular level. We begin with an overview of the philosophical foundations of traversing space, followed by theories covering the material bases of contextual representations in the hippocampus (engrams), exploring functional characteristics of the cells and subfields within. Next, we explore various methodological approaches for investigating contextual memory engrams, emphasizing plasticity mechanisms. This leads us to discuss the role of neuromodulatory inputs in governing these dynamic changes. We then outline a recent hypothesis involving noradrenergic and dopaminergic projections from the locus coeruleus (LC) to different subregions of the hippocampus, in sculpting contextual representations, giving a brief description of the neuroanatomical and physiological properties of the LC. Finally, we examine how activity in the LC influences contextual memory processes through synaptic plasticity mechanisms to alter hippocampal engrams. Overall, we find that phasic activation of the LC plays an important role in promoting new learning and altering mnemonic processes at the behavioral and cellular level through the neuromodulatory influence of NE/DA in the hippocampus. These findings may provide insight into mechanisms of hippocampal remapping and memory updating, memory processes that are potentially dysregulated in certain psychiatric and neurodegenerative disorders.

Alpha-2 Agonists in Children and Adolescents With Post-traumatic Stress Disorder: A Systematic Review

Exposure to traumatic stress is common among children. Post-traumatic stress disorder (PTSD) is a debilitating chronic mental disorder that can develop following exposure to a traumatic event. Psychopharmacological research in pediatric PTSD is limited. There is some evidence supporting the use of alpha-2 (α2) agonists for symptoms associated with PTSD. This systematic review identified published studies evaluating the effectiveness of α2 agonists in treating PTSD symptoms in children and adolescents. We conducted an extensive literature search on PubMed, MEDLINE, EMBASE, Cochrane Collaboration, and PsycINFO databases for published articles that evaluated the use of α2 agonists (clonidine and guanfacine) for treating symptoms of PTSD in children and adolescents. The study protocol was registered in Prospero (ID: CRD42021273692) and followed the PRISMA guidelines. A total of 10 published articles about clonidine or guanfacine use in PTSD in children and adolescents were identified. Studies found clonidine effective in reducing PTSD symptoms; however, the effects were variable. Clonidine and guanfacine showed effectiveness in treating nightmares, hyperarousal, aggression, and sleep disturbances and reducing re-experiencing, avoidant, and hyperarousal symptom clusters. No randomized, double-blind, placebo-controlled trials were found during the literature search. α2 agonists' effectiveness in treating symptoms associated with PTSD in children and adolescents is preliminary. Future placebo-controlled trials are needed to assess the efficacy and safety of α2 agonists.

Renin-angiotensin system: The underlying mechanisms and promising therapeutical target for depression and anxiety

Emotional disorders, including depression and anxiety, contribute considerably to morbidity across the world. Depression is a serious condition and is projected to be the top contributor to the global burden of disease by 2030. The role of the renin-angiotensin system (RAS) in hypertension and emotional disorders is well established. Evidence points to an association between elevated RAS activity and depression and anxiety, partly through the induction of neuroinflammation, stress, and oxidative stress. Therefore, blocking the RAS provides a theoretical basis for future treatment of anxiety and depression. The evidence for the positive effects of RAS blockers on depression and anxiety is reviewed, aiming to provide a promising target for novel anxiolytic and antidepressant medications and/or for improving the efficacy of currently available medications used for the treatment of anxiety and depression, which independent of blood pressure management.

Propranolol versus Other Selected Drugs in the Treatment of Various Types of Anxiety or Stress, with Particular Reference to Stage Fright and Post-Traumatic Stress Disorder

Propranolol, a non-cardioselective β_1,2 blocker, is most commonly recognised for its application in the therapy of various cardiovascular conditions, such as hypertension, coronary artery disease, and tachyarrhythmias. However, due to its ability to cross the blood–brain barrier and affinity towards multiple macromolecules, not only adrenoreceptors, it has also found application in other fields. For example, it is one of the very few medications successfully applied in the treatment of stage fright. This review focuses on the application of propranolol in the treatment of various types of anxiety and stress, with particular reference to stage fright and post-traumatic stress disorder (PTSD). Both mechanisms of action as well as comparison with other therapies are presented. As those indications for propranolol are, in most countries, considered off-label, this review aims to gather information that can be useful while making a decision about the choice of propranolol as a drug in the treatment of those mental conditions.

Twice Daily Prazosin and Valproic Acid in the Treatment of Flashbacks in PTSD

Posttraumatic stress disorder (PTSD) is a debilitating stress disorder occurring in the context of a traumatic event and is characterized by intrusive and avoidance symptoms, negative alterations in cognition and mood, and arousal and reactivity changes. Despite its representation throughout literature, the pathophysiology of PTSD remains incompletely understood, thus contributing to broad, variable, and at times, experimental treatment options. The authors present the first documented case of the rapid and successful management of PTSD using valproic acid and twice daily dosing of prazosin aimed at targeting symptoms of hyperarousal and both daily and nightly intrusive symptoms of flashbacks and nightmares, respectively. The authors also discuss postulations of the underlying mechanisms of action responsible for such symptom alleviation. Further investigation is needed to expand upon our knowledge of the use of such agents in the treatment of PTSD to improve upon existing clinical guidelines, especially in the acute setting, thus providing better overall prognosis.

Pharmacological Implications of Adjusting Abnormal Fear Memory: Towards the Treatment of Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a unique clinical mental abnormality presenting a cluster of symptoms in which patients primarily experience flashbacks, nightmares and uncontrollable thoughts about the event that triggered their PTSD. Patients with PTSD may also have comorbid depression and anxiety in an intractable and long-term course, which makes establishing a comprehensive treatment plan difficult and complicated. The present article reviews current pharmacological manipulations for adjusting abnormal fear memory. The roles of the central monoaminergic systems (including serotonin, norepinephrine and dopamine) within the fear circuit areas and the involvement of the hypothalamic-pituitary-adrenal (HPA) axis and glucocorticoid receptor (GR) are explored based on attempts to integrate current clinical and preclinical basic studies. In this review, we explain how these therapeutic paradigms function based on their connections to stages of the abnormal fear memory process from condition to extinction. This may provide useful translational interpretations for clinicians to manage PTSD.

Effects of propranolol on the modification of trauma memory reconsolidation in PTSD patients: A systematic review and meta-analysis

Post-traumatic stress disorder (PTSD) develops after an exposure to a life-threatening event and is characterized by intrusive memories. According to memory reconsolidation theory retrieval of memory under certain conditions leads to its labilization and subsequent re-storage which could be disrupted by drugs. Propranolol has been the most commonly investigated drug for memory reconsolidation therapy in clinical trials. Intervention with propranolol have shown mixed results in PTSD patients with some studies showing improvement in symptoms while other failing to replicate these findings. We conducted a systematic review and meta-analysis to determine the efficacy of trauma memory disruption by propranolol on PTSD symptoms and physiological responses in PTSD patients. 3224 publications were assessed for eligibility. Seven studies on effects of propranolol on PTSD symptoms and 3 studies on effects of propranolol on physiological responses were incorporated in the meta-analyses. Overall, results indicate that propranolol did not show a beneficial effect on PTSD symptoms (standardized mean difference: 1.29; 95% CI = -2.16 - 0.17). Similarly, propranolol did not influence skin conductance (standardized mean difference: 0.77; 95% CI = -1.85 - 0.31) or EMG response (standardized mean difference: 0.16; 95% CI = -0.65 - 0.33). However, propranolol significantly reduced heart rate after trauma memory recall compared to placebo (standardized mean difference: 0.67; 95% CI = -1.27 to -0.07). This study finds a lack of evidence for the efficacy of propranolol on traumatic memory disruption, in PTSD patients, to recommend its routine clinical use. However, a high level of heterogeneity, variation in propranolol dosage and inadequate sample sizes mean that these findings require cautious interpretation.

Diverse therapeutic developments for post-traumatic stress disorder (PTSD) indicate common mechanisms of memory modulation

Post-traumatic stress disorder (PTSD), characterized by abnormally persistent and distressing memories, is a chronic debilitating condition in need of new treatment options. Current treatment guidelines recommend psychotherapy as first line management with only two drugs, sertraline and paroxetine, approved by U.S. Food and Drug Administration (FDA) for treatment of PTSD. These drugs have limited efficacy as they only reduce symptoms related to depression and anxiety without producing permanent remission. PTSD remains a significant public health problem with high morbidity and mortality requiring major advances in therapeutics. Early evidence has emerged for the beneficial effects of psychedelics particularly in combination with psychotherapy for management of PTSD, including psilocybin, MDMA, LSD, cannabinoids, ayahuasca and ketamine. MDMA and psilocybin reduce barrier to therapy by increasing trust between therapist and patient, thus allowing for modification of trauma related memories. Furthermore, research into the memory reconsolidation mechanisms has allowed for identification of various pharmacological targets to disrupt abnormally persistent memories. A number of pre-clinical and clinical studies have investigated novel and re-purposed pharmacological agents to disrupt fear memory in PTSD. Novel therapeutic approaches like neuropeptide Y, oxytocin, cannabinoids and neuroactive steroids have also shown potential for PTSD treatment. Here, we focus on the role of fear memory in the pathophysiology of PTSD and propose that many of these new therapeutic strategies produce benefits through the effect on fear memory. Evaluation of recent research findings suggests that while a number of drugs have shown promising results in preclinical studies and pilot clinical trials, the evidence from large scale clinical trials would be needed for these drugs to be incorporated in clinical practice.

Resilience to the effects of social stress on vulnerability to developing drug addiction

We review the still scarce but growing literature on resilience to the effects of social stress on the rewarding properties of drugs of abuse. We define the concept of resilience and how it is applied to the field of drug addiction research. We also describe the internal and external protective factors associated with resilience, such as individual behavioral traits and social support. We then explain the physiological response to stress and how it is modulated by resilience factors. In the subsequent section, we describe the animal models commonly used in the study of resilience to social stress, and we focus on the effects of chronic social defeat (SD), a kind of stress induced by repeated experience of defeat in an agonistic encounter, on different animal behaviors (depression- and anxiety-like behavior, cognitive impairment and addiction-like symptoms). We then summarize the current knowledge on the neurobiological substrates of resilience derived from studies of resilience to the effects of chronic SD stress on depression- and anxiety-related behaviors in rodents. Finally, we focus on the limited studies carried out to explore resilience to the effects of SD stress on the rewarding properties of drugs of abuse, describing the current state of knowledge and suggesting future research directions.

Clonidine Use for the Treatment of Nightmares in Posttraumatic Stress Disorder

Introduction

While clonidine is used clinically for the treatment of nightmares in posttraumatic stress disorder (PTSD), few case reports demonstrating this indication exist, and there have been few studies investigating clonidine's mechanism of action for controlling nightmare symptoms. Case Report. In order to further characterize clonidine's role in treating nightmare symptoms in PTSD, we offer this case report describing one United States veteran who presented to an inpatient psychiatric unit after a suicide attempt. At that time, she described a remote history of PTSD symptoms, including nightmares, flashbacks, hyperarousal, and avoidance behaviors which had been well controlled on sertraline and clonidine. Upon her admission, her home sertraline and alprazolam were continued but her home clonidine was not continued. On day two of her hospital stay, she stated that her nightmares had returned. Her home clonidine was restarted on day two. On day three and thereafter, the patient no longer complained of nightmares.

Conclusion

Our patient's nightmare symptoms had been controlled for years after beginning clonidine as an outpatient, but off clonidine, she had a return of her nightmare symptoms. Her nightmares again resolved once clonidine was resumed. Given this pattern in the patient's response to clonidine, this case may serve as additional evidence in the literature that clonidine has a role in treating nightmares in PTSD. Current proposed mechanisms of action for clonidine's ability to control nightmare symptoms in PTSD include that clonidine may alter the proportions of REM and non-REM sleep in a dose-dependent manner or that clonidine may play a role in memory consolidation. Further formal medication trials are the ideal future direction for establishing this role for clonidine.

Neurophysiological dynamics for psychological resilience: A view from the temporal axis

When an individual is faced with adversity, the brain and body work cooperatively to adapt to it. This adaptive process is termed psychological resilience, and recent studies have identified several neurophysiological factors ("neurophysiological resilience"), such as monoamines, oscillatory brain activity, hemodynamics, autonomic activity, stress hormones, and immune systems. Each factor is activated in an interactive manner during specific time windows after exposure to stress. Thus, the differences in psychological resilience levels among individuals can be characterized by differences in the temporal dynamics of neurophysiological resilience. In this review, after briefly introducing the frequently used approaches in this research field and the well-known factors of neurophysiological resilience, we summarize the temporal dynamics of neurophysiological resilience. This viewpoint clarifies an important time window, the more-than-one-hour scale, but the neurophysiological dynamics during this window remain elusive. To address this issue, we propose exploring brain-wide oscillatory activities using concurrent functional magnetic resonance imaging (fMRI) and electroencephalogram (EEG) techniques.

Behavioral and pharmacological interventions for the prevention and treatment of psychiatric disorders with children exposed to maltreatment

There is a well-established relation between exposure to child maltreatment and the onset and course of multiple, comorbid psychiatric disorders. Given the heterogeneous clinical presentations at the time services are initiated, interventions for children exposed to maltreatment need to be highly effective to curtail the lifelong burden and public health costs attributable to psychiatric disorders. The current review describes the most effective, well-researched, and widely-used behavioral and pharmacological interventions for preventing and treating a range of psychiatric disorders common in children exposed to maltreatment. Detailed descriptions of each intervention, including their target population, indicated age range, hypothesized mechanisms of action, and effectiveness demonstrated through randomized controlled trials research, are presented. Current limitations of these interventions are noted to guide specific directions for future research aiming to optimize both treatment effectiveness and efficiency with children and families exposed to maltreatment. Strategic and programmatic future research can continue the substantial progress that has been made in the prevention and treatment of psychiatric disorders for children exposed to maltreatment.

MicroRNAs as biomarker and novel therapeutic target for posttraumatic stress disorder in Veterans

Posttraumatic stress disorder (PTSD) is a common psychiatric disorder for military Veterans, characterized by hyperarousal, intrusive thoughts, flashbacks, hypervigilance, and distress after experiencing traumatic events. Some of the known physiological effects of PTSD include hypothalamic-pituitary-adrenal (HPA)-axis imbalance, a cortical function resulting in neuronal deficit and changes in behavior. Moreover, excessive discharge of inflammatory molecules and a dysregulated immune system are implicated in the pathophysiology of PTSD. Due to complex nature of this disorder, the biological underpinnings of PTSD remain inexplicable. Investigating novel biomarkers to understanding the pathogenesis of PTSD may reflect the underlying molecular network for therapeutic use and treatment. Circulatory microRNAs (miRNAs) and exosomes are evolving biomarkers that have shown a key role in psychiatric and neurological disorders including PTSD. Given the unique nature of combat trauma, as well as evidence that a large portion of Veterans do not benefit from frontline treatments, focus on veterans specifically is warranted. In the present review, we delineate the identification and role of several miRNAs in PTSD among veterans. An association of miRNA with HPA-axis regulation through FKBP5, a key modulator in PTSD is discussed as an emerging molecule in psychiatric diseases. We conclude that miRNAs may be used as circulatory biomarker detection in Veterans with PTSD.

Asthma and posttraumatic stress disorder (PTSD): Emerging links, potential models and mechanisms

Posttraumatic stress disorder (PTSD) is a highly prevalent, debilitating mental health condition. A better understanding of contributory neurobiological mechanisms will lead to effective treatments, improving quality of life for patients. Given that not all trauma-exposed individuals develop PTSD, identification of pre-trauma susceptibility factors that can modulate posttraumatic outcomes is important. Recent clinical evidence supports a strong link between inflammatory conditions and PTSD. A particularly strong association has been reported between asthma and PTSD prevalence and severity. Unlike many other PTSD-comorbid inflammatory conditions, asthma often develops in children, sensitizing them to subsequent posttraumatic pathology throughout their lifetime. Currently, there is a significant need to understand the neurobiology, shared mechanisms, and inflammatory mediators that may contribute to comorbid asthma and PTSD. Here, we provide a translational perspective of asthma and PTSD risk and comorbidity, focusing on clinical associations, relevant rodent paradigms and potential mechanisms that may translate asthma-associated inflammation to PTSD development.

Traumatic memory reactivation with or without propranolol for PTSD and comorbid MD symptoms: a randomised clinical trial

Post-traumatic stress disorder (PTSD) is difficult to treat but one promising strategy is to block memory reconsolidation of the traumatic event. This study aimed to evaluate the efficacy of traumatic memory reactivation under the influence of propranolol, a noradrenergic beta-receptor blocker, in reducing PTSD symptoms as well as comorbid major depression (MD) symptoms. We conducted a double blind, placebo-controlled, randomised clinical trial in 66 adults diagnosed with longstanding PTSD. Propranolol or a placebo was administered 90 min before a brief memory reactivation session, once a week for 6 consecutive weeks. Measures included the SCID PTSD module, the PTSD Check List (PCL-S) and the Beck Depression Inventory-II (BDI-II). PTSD symptoms decreased both in the pre-reactivation propranolol group (39.28%) and the pre-reactivation placebo group (34.48 %). During the 6 treatment sessions, PCL-S and BDI-II scores decreased to similar extent in both groups and there were no treatment differences. During the 3-month follow-up period, there were no treatment effects for the mean PCL-S and BDI-II scores. However, in patients with severe PTSD symptoms (PCL-S ≥ 65) before treatment, PCL-S and BDI-II scores continued to decline 3 months after the end of treatment in the propranolol group while they increased in the placebo group. Repeated traumatic memory reactivation seemed to be effective for PTSD and comorbid MD symptoms. However, the efficacy of propranolol was not greater than that of placebo 1 week post treatment. Furthermore, in this traumatic memory reactivation, PTSD symptom severity at baseline might have influenced the post-treatment effect of propranolol.

Symptom profiles and treatment status of older adults with chronic post-traumatic stress disorder

OBJECTIVE

Failure to diagnose and treat post-traumatic stress disorder (PTSD) may help explain the substantial disability, increased cognitive decline, and adverse health outcomes suffered by older adults with this disorder. To evaluate this possibility, we examined symptom differences among older and younger individuals with PTSD and measured the frequency with which older adults receive standard of care treatment.

METHODS

Clinician-Administered PTSD Scale for DSM (CAPS) scores were compared between younger and older adults with PTSD. Profiles were calculated for the most dominant CAPS symptom cluster reported by each participant, and the age cutoff best differentiating symptom clusters between individuals was determined. Clinical interview data (older adult sample only) were evaluated by trained raters to determine rates at which PTSD participants accessed treatment.

RESULTS

Among 108 individuals with PTSD, 69% of participants <67 years old had Criterion C (avoidance) symptoms as the most dominant cluster compared to 39% of participants ≥67 (p = 0.016). Eight percent of participants <67 years had Criterion E (hyperarousal) symptoms as the most dominant cluster compared to 30% of participants ≥67 (p = 0.016). Less than 25% of the older adults (N = 53 subsample) were receiving a first-line pharmacotherapy option for PTSD, and 0% of participants were currently participating in an evidence-based psychotherapy for PTSD.

CONCLUSIONS

Clinicians evaluating patients should be aware that different symptom profiles may be present between younger and older adults with PTSD. Despite their high risk for adverse neuropsychiatric and other health consequences, older adults with PTSD appear to infrequently receive first-line clinical treatment.

Neuro-pharmacological reinstatement of ovulation and associated neurobiology in a macaque model of functional hypothalamic amenorrhoea

STUDY QUESTION

What is the underlying neuropathology in a cynomolgus macaque model of functional hypothalamic amenorrhoea (FHA) and can it be normalized to restore ovulation?

SUMMARY ANSWER

Anovulatory monkeys exhibited increased hypothalamic norepinephrine (NE), kisspeptin and gonadotropin-releasing hormone (GnRH) in the early follicular phase, but administration of the NE reuptake inhibitor (NRI), reboxetine (REB), restored ovulation during stress and normalized NE, kisspeptin and GnRH.

WHAT IS KNOWN ALREADY

Female cynomolgus macaques, like women, show individual reproductive sensitivity to modest psychosocial and metabolic stress. During stress, resilient females ovulate through two menstrual cycles whereas stress-sensitive (SS) macaques immediately cease ovulation. On Day 5 of a non-stressed menstrual cycle, resilient macaques have less NE synthesizing enzyme [dopamine β-hydroxylase (DBH)], kisspeptin and GnRH innervation of the medial basal hypothalamus but more endogenous serotonin than SS macaques. Stress increased DBH/NE, kisspeptin and GnRH but did not alter serotonin.

STUDY DESIGN, SIZE, DURATION

In a longitudinal design, 27 adult (7-13 years) female cynomolgus macaques (Macaca fascicularis) with three different levels of sensitivity to stress were monitored with daily vaginal swabs and frequent serum progesterone (P) measurements. Three 90-day experimental periods called 'Cycle Sets' were monitored. A Cycle Set consisted of one ovulatory menstrual cycle without stress, and two cycles, or 60 days, with modest stress. Each Cycle Set was followed by a rest period. During a Cycle Set, individuals were either untreated (placebo) or administered escitalopram (CIT) or REB. Ultimately, half of each sensitivity group was euthanized during stress with CIT or REB treatment and the hypothalamus was obtained. Neurobiological endpoints were compared between CIT and REB treatment groups in stress resilient and SS monkeys.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The monkeys were housed at the University of Pittsburgh primate facility for the duration of the experiments. Upon euthanasia, their brains and serum samples were shipped to the Oregon National Primate Research Center. The hypothalamus was examined with immunohistochemistry for the expression of DBH (a marker for NE axons), kisspeptin and GnRH. P was measured in the serum samples by radioimmunoassay.

MAIN RESULTS AND THE ROLE OF CHANCE

Daily administration of REB restored ovulation in 9 of 10 SS animals during stress. Of note, REB significantly increased P secretion during stress in the most sensitive group (P = 0.032), which indicates ovulation. CIT lacked efficacy. REB significantly reduced DBH/NE, kisspeptin and GnRH axon density in the hypothalamus relative to CIT treatment (P = 0.003. 0.018 and 0.0001, respectively) on Day 5 of the menstrual cycle in resilient and sensitive groups.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The US FDA has not approved REB for human use, although it is used in Europe for the treatment of depression/anxiety as EdronaxTR. Whether REB could be useful for the treatment of FHA in women has not been determined.

WIDER IMPLICATIONS FOR THE FINDINGS

The use of an NRI to treat FHA is a novel approach and the potential reinstatement of ovulation could be straightforward compared to current treatment protocols. The underlying neurobiology provides a compelling case for treating the origin of the pathology, i.e. elevated NE, rather than circumventing the hypothalamus altogether with gonadotropins, which have associated risks such as hyperstimulation syndrome or multiple births.

STUDY FUNDING/COMPETING INTEREST(S)

Portions of this study were supported by NIH grant HD062864 to C.L.B., NIH grant HD62618 to J.L.C. and C.L.B. and 1P51 OD011092 for the operation of the Oregon National Primate Research Center. There were no competing interests.

Sleep abnormalities in individuals at clinical high risk for psychosis

Youth at clinical high risk (CHR) represent a unique population enriched for precursors of major psychiatric disorders. Sleep disturbances are consistently reported in CHR individuals. However, there is a dearth of studies investigating quantifiable objective measures of sleep dysfunction in CHR youth. In this study, sleep high density (hd)-EEG recordings were collected in twenty-two CHR and twenty healthy control (HC) subjects. Sleep architecture parameters, as well as sleep EEG power spectra in five frequency bands, were computed and compared between CHR and HC groups during non-rapid eye movement (NREM) sleep. Furthermore, correlation analyses between sleep EEG power spectra, sleep architecture parameters, and clinical symptoms, assessed with the scale of prodromal symptoms (SOPS), were conducted in CHR participants. Our results show that CHR individuals had more wakefulness after sleep onset (WASO) compared to HC participants. CHR also showed a higher NREM sleep gamma EEG power, which was observed in a large fronto-parieto-occipital area, relative to HC. Additionally, higher NREM gamma activity in lateral fronto-occipital regions was associated with more WASO, and increased NREM gamma power in medial fronto/parietal areas correlated with worse SOPS negative symptoms. Altogether, these findings suggest that topographically specific increases in EEG gamma activity during NREM sleep represent neurophysiological signatures underlying some of the objectively assessed sleep disturbances and clinical symptoms of CHR individuals.

Pupillometry provides a psychophysiological index of arousal level and cognitive effort during the performance of a visual-auditory dual-task in individuals with a history of concussion

Research shows that concussions cause long-term deficits in executive functions when tested using challenging tasks with high cognitive load. The neurophysiological mechanism(s) associated with executive dysfunction are not well understood. Pupillometry provides a non-invasive index of arousal and cognitive load; therefore, the current study investigated whether pupillometry could help explain the persistent deficits in dual-task performance in individuals with a history of concussion (n = 14) compared to controls (n = 13). Participants were tested using a computerized Corsi block task which increased in difficulty as a function of set size (i.e., number of blocks to be remembered) and task condition (i.e., performed alone and concurrently with an auditory task). Pupil size was measured during the initial fixation prior to the Corsi task to assess arousal level, and during the encoding phase to assess task evoked pupil response. Results showed that: 1) in contrast to the control group, pupil size was not modulated by task condition in the concussed group indicating that arousal level was similar in the single and dual task; 2) task evoked pupil dilation increased as a function of set size in the single task in both groups, 3) in contrast to the control group, those with a history of concussion had similar pupil size during the single and dual task conditions. One interpretation of these results is that individuals with a history of concussion exert greater effort when performing relatively easier tasks, and they reach capacity limits when the cognitive load is lower in comparison to non-concussed individuals. In conclusion, pupillometry may provide insight into persisting deficits in executive functions following concussion(s).

The Relative Effects of Prazosin on Individual PTSD Symptoms: Evidence for Pathophysiologically-Related Clustering

Background

The α₁-adrenoreceptor antagonist prazosin has in many but not all studies been found to be effective for PTSD associated nightmares, hyperarousal symptoms, and total symptom severity. The particular efficacy of prazosin for nightmares and hyperarousal symptoms suggests there may be a subset of PTSD symptoms that are more tightly associated with an α₁-adrenoreceptor mediated noradrenergic mechanism, but cross traditional diagnostic symptom clusters. However, the efficacy of prazosin for individual symptoms other than nightmares and sleep disruption has not previously been examined.

Methods

In a post hoc reanalysis of a previously published, randomized controlled trial of twice daily prazosin for PTSD, we examined the relative effect of prazosin on individual items of the CAPS for DSM-IV, and tested whether prazosin responsiveness predicted the partial correlation of the changes in symptom intensity at the level of individual subjects. Results were not adjusted for multiple comparisons.

Results

Prazosin showed the largest effect for distressing dreams, anhedonia, difficulty falling or staying asleep, difficulty concentrating, and hypervigilance. These items were also (a) of higher baseline severity in the underlying population, and (b) more related in how they fluctuated at the level of individual subjects. Covariance analysis did not support a clear cutoff between highly prazosin responsive items and those showing a smaller, not statistically significant response.

Conclusions

In this data set, twice daily prazosin substantially reduced not only nightmares and sleep disruption, but the majority of hyperarousal symptoms, with some evidence of efficacy for avoidance symptoms. The relationship of baseline symptom distribution to which symptoms showed significant response to prazosin reinforces the possibility that differences in a clinical trial's participant populations may significantly influence trial outcome. The pattern of symptom endorsement at the level of individual subjects was consistent with prazosin-responsive items sharing a common pathophysiologic mechanism.

Rat models for low and high adaptive response to exercise differ for stress-related memory and anxiety

Physical exercise and fitness may serve as resilience factors to stress exposure. However, the extreme range in human exercise performance suggests that genetic variation for exercise capacity could be a confounding feature to understanding the connection between exercise and stress exposure. To test this idea, we use laboratory rat models selectively bred for a low and high gain in aerobic running capacity in response to training to examine whether an inherent capacity to respond to physical exercise reflects how stress changes neurobiological functioning and regulates fear-associated memory processing. Utilization of this contrasting rat model system of low and high responders has the potential to guide the interpretation of the reported association with exercise involvement and the reduction of stress-induced anxiety disorders. Our data show that aerobic fitness may be linked to the ability to regulate fear-associated memories. We also show that acquired exercise capacity may play a key role in regulating responses to an acute stressor. Exercise sensitivity plays a significant role in the activation of the plasticity-associated molecule extracellular signal-regulated kinase, changes in stress hormone activity, and anatomical modifications to the noradrenergic locus coeruleus. These data identify a unique operational mechanism that may serve as translational targets for lessening symptoms of stress and anxiety.

Treatment Response Biomarkers in Anxiety Disorders: From Neuroimaging to Neuronally-Derived Extracellular Vesicles and Beyond

Multiple and diverse psychotherapeutic or psychopharmacologic treatments effectively reduce symptoms for many patients with anxiety disorders, but the trajectory and magnitude of response vary considerably. This heterogeneity of treatment response has invigorated the search for biomarkers of treatment response in anxiety disorders, across the lifespan. In this review, we summarize evidence for biomarkers of treatment response in children, adolescents and adults with generalized, separation and social anxiety disorders as well as panic disorder. We then discuss the relationship between these biomarkers of treatment response and the pathophysiology of anxiety disorders. Finally, we provide context for treatment response biomarkers of the future, including neuronally-derived extracellular vesicles in anxiety disorders and discuss challenges that must be overcome prior to the debut of treatment response biomarkers in the clinic. A number of promising treatment response biomarkers have been identified, although there is an urgent need to replicate findings and to identify which biomarkers might guide clinicians in selecting from available treatments rather than just simply identifying patients who may be less likely to respond to a given intervention.

Enhanced Retrieval of Taste Associative Memory by Chemogenetic Activation of Locus Coeruleus Norepinephrine Neurons

The ability of animals to retrieve memories stored in response to the environment is essential for behavioral adaptation. Norepinephrine (NE)-containing neurons in the brain play a key role in the modulation of synaptic plasticity underlying various processes of memory formation. However, the role of the central NE system in memory retrieval remains unclear. Here, we developed a novel chemogenetic activation strategy exploiting insect olfactory ionotropic receptors (IRs), termed "IR-mediated neuronal activation," and used it for selective stimulation of NE neurons in the locus coeruleus (LC). Drosophila melanogaster IR84a and IR8a subunits were expressed in LC NE neurons in transgenic mice. Application of phenylacetic acid (a specific ligand for the IR84a/IR8a complex) at appropriate doses induced excitatory responses of NE neurons expressing the receptors in both slice preparations and in vivo electrophysiological conditions, resulting in a marked increase of NE release in the LC nerve terminal regions (male and female). Ligand-induced activation of LC NE neurons enhanced the retrieval process of conditioned taste aversion without affecting taste sensitivity, general arousal state, and locomotor activity. This enhancing effect on taste memory retrieval was mediated, in part, through α₁- and β-adrenergic receptors in the basolateral nucleus of the amygdala (BLA; male). Pharmacological inhibition of LC NE neurons confirmed the facilitative role of these neurons in memory retrieval via adrenergic receptors in the BLA (male). Our findings indicate that the LC NE system, through projections to the BLA, controls the retrieval process of taste associative memory.SIGNIFICANCE STATEMENT Norepinephrine (NE)-containing neurons in the brain play a key role in the modulation of synaptic plasticity underlying various processes of memory formation, but the role of the NE system in memory retrieval remains unclear. We developed a chemogenetic activation system based on insect olfactory ionotropic receptors and used it for selective stimulation of NE neurons in the locus coeruleus (LC) in transgenic mice. Ligand-induced activation of LC NE neurons enhanced the retrieval of conditioned taste aversion, which was mediated, in part, through adrenoceptors in the basolateral amygdala. Pharmacological blockade of LC activity confirmed the facilitative role of these neurons in memory retrieval. Our findings indicate that the LC-amygdala pathway plays an important role in the recall of taste associative memory.

Protective effects of morphine in a rat model of post-traumatic stress disorder: Role of hypothalamic-pituitary-adrenal axis and beta- adrenergic system

Post-traumatic stress disorder (PTSD) arises after tremendous traumatic experiences. Recently, we have reported that morphine has time-dependent protective effects against behavioral and morphological deficits in the single prolonged stress (SPS) as an experimental model of PTSD in adult male rats. To find the mechanisms underlying the protective effects of morphine against SPS-induced PTSD-like symptoms, the present study investigated the interaction between morphine and hypothalamic-pituitary-adrenal (HPA) axis and beta - adrenergic system, which crucially involved in the stress response, on PTSD-like symptoms in male rats. The animals were exposed to the SPS procedure (restraint for 2 h, forced swimming for 20 min, and ether anesthesia) and morphine (10 mg/kg) or saline was injected 24 h following the SPS. The glucocorticoid receptor antagonist RU486 (20 mg/kg), the mineralocorticoid receptor antagonist spironolactone (50 mg/kg), and the corticosterone synthesis inhibitor metyrapone (50 mg/kg) were injected 90 min before morphine administration to block the HPA axis activity. The beta - adrenergic receptor blocker propranolol (10 mg/kg) and the peripheral beta-adrenergic receptor blocker nadolol (5 mg/kg) were administered 30 min before morphine injection to block the beta - adrenergic system. Anxiety-like behaviors were evaluated using the elevated plus maze (EPM) 11 days after the SPS. After that, animals were conditioned in a fear-conditioning task and extinction training was performed on days 1, 2, 3, 4 and 11 after fear conditioning. SPS increased anxiety-like behaviors and impaired fear extinction. Morphine injection 24 h after SPS significantly improved anxiety-like behaviors and enhanced fear extinction. The RU486, spironolactone and metyrapone prevented the protective effects of morphine on both SPS-induced anxiety-like behaviors and impaired fear extinction. The propranolol, and nadolol did not prevent the effect of morphine on anxiety-like behaviors, but the propranolol prevented morphine effects on fear extinction in SPS animals. These findings together suggest that the protective effects of morphine on PTSD-like symptoms in rats require a certain level of the HPA axis and central beta - adrenergic activity and any alteration in the function of these systems can impede the protective effects of morphine.

Rodent models of post-traumatic stress disorder: behavioral assessment

Although the etiology and expression of psychiatric disorders are complex, mammals show biologically preserved behavioral and neurobiological responses to valent stimuli which underlie the use of rodent models of post-traumatic stress disorder (PTSD). PTSD is a complex phenotype that is difficult to model in rodents because it is diagnosed by patient interview and influenced by both environmental and genetic factors. However, given that PTSD results from traumatic experiences, rodent models can simulate stress induction and disorder development. By manipulating stress type, intensity, duration, and frequency, preclinical models reflect core PTSD phenotypes, measured through various behavioral assays. Paradigms precipitate the disorder by applying physical, social, and psychological stressors individually or in combination. This review discusses the methods used to trigger and evaluate PTSD-like phenotypes. It highlights studies employing each stress model and evaluates their translational efficacies against DSM-5, validity criteria, and criteria proposed by Yehuda and Antelman's commentary in 1993. This is intended to aid in paradigm selection by informing readers about rodent models, their benefits to the clinical community, challenges associated with the translational models, and opportunities for future work. To inform PTSD model validity and relevance to human psychopathology, we propose that models incorporate behavioral test batteries, individual differences, sex differences, strain and stock differences, early life stress effects, biomarkers, stringent success criteria for drug development, Research Domain Criteria, technological advances, and cross-species comparisons. We conclude that, despite the challenges, animal studies will be pivotal to advances in understanding PTSD and the neurobiology of stress.

α 2-Adrenoceptors: Challenges and Opportunities-Enlightenment from the Kidney

It was indeed a Don Quixote-like pursuit of the mechanism of essential hypertension when we serendipitously discovered α₂-adrenoceptors (α₂-ARs) in skin-lightening experiments in the frog. Now α₂-ARs lurk on the horizon involving hypertension causality, renal denervation for hypertension, injury from falling in the elderly and prazosin's mechanism of action in anxiety states such as posttraumatic stress disorder (PTSD). Our goal here is to focus on this horizon and bring into clear view the role of α₂-AR-mediated mechanisms in these seemingly unrelated conditions. Our narrative begins with an explanation of how experiments in isolated perfused kidneys led to the discovery of a sodium-retaining process, a fundamental mechanism of hypertension, mediated by α₂-ARs. In this model system and in the setting of furosemide-induced sodium excretion, α₂-AR activation inhibited adenylate cyclase, suppressed cAMP formation, and caused sodium retention. Further investigations led to the realization that renal α₂-AR expression in hypertensive animals is elevated, thus supporting a key role for kidney α₂-ARs in the pathophysiology of essential hypertension. Subsequent studies clarified the molecular pathways by which α₂-ARs activate prohypertensive biochemical systems. While investigating the role of α₁-adrenoceptors (α₁-ARs) versus α₂-ARs in renal sympathetic neurotransmission, we noted an astonishing result: in the kidney α₁-ARs suppress the postjunctional expression of α₂-ARs. Here, we describe how this finding relates to a broader understanding of the role of α₂-ARs in diverse disease states. Because of the capacity for qualitative and quantitative monitoring of α₂-AR-induced regulatory mechanisms in the kidney, we looked to the kidney and found enlightenment.

The role of catecholamines in modulating responses to stress: Sex-specific patterns, implications, and therapeutic potential for post-traumatic stress disorder and opiate withdrawal

Emotional arousal is one of several factors that determine the strength of a memory and how efficiently it may be retrieved. The systems at play are multifaceted; on one hand, the dopaminergic mesocorticolimbic system evaluates the rewarding or reinforcing potential of a stimulus, while on the other, the noradrenergic stress response system evaluates the risk of threat, commanding attention, and engaging emotional and physical behavioral responses. Sex-specific patterns in the anatomy and function of the arousal system suggest that sexually divergent therapeutic approaches may be advantageous for neurological disorders involving arousal, learning, and memory. From the lens of the triple network model of psychopathology, we argue that post-traumatic stress disorder and opiate substance use disorder arise from maladaptive learning responses that are perpetuated by hyperarousal of the salience network. We present evidence that catecholamine-modulated learning and stress-responsive circuitry exerts substantial influence over the salience network and its dysfunction in stress-related psychiatric disorders, and between the sexes. We discuss the therapeutic potential of targeting the endogenous cannabinoid system; a ubiquitous neuromodulator that influences learning, memory, and responsivity to stress by influencing catecholamine, excitatory, and inhibitory synaptic transmission. Relevant preclinical data in male and female rodents are integrated with clinical data in men and women in an effort to understand how ideal treatment modalities between the sexes may be different.

A mechanistic model for individualised treatment of anxiety disorders based on predictive neural biomarkers

Increased amygdala responsiveness is the hallmark of fear and a characteristic across patients with anxiety disorders. The amygdala is embedded in a complex regulatory circuit. Multiple different mechanisms may elevate amygdala responsiveness and lead to the occurrence of an anxiety disorder. While top-down control by the prefrontal cortex (PFC) downregulates amygdala responses, the locus coeruleus (LC) drives up amygdala activation via noradrenergic projections. This indicates that the same fearful phenotype may result from different neural mechanisms. We propose a mechanistic model that defines three different neural biomarkers causing amygdala hyper-responsiveness in patients with anxiety disorders: (a) inherent amygdala hypersensitivity, (b) low prefrontal control and (c) high LC drive. First-line treatment for anxiety disorders is exposure-based cognitive behavioural therapy, which strengthens PFC recruitment during emotion regulation and thus targets low-prefrontal control. A treatment response rate around 50% (Loerinc et al., 2015, Clinical Psychological Reviews, 42, 72-82) might indicate heterogeneity of underlying neurobiological mechanisms among patients, presumably leading to high variation in treatment benefit. Transforming insights from cognitive neuroscience into applicable clinical heuristics to categorise patients based on their underlying biomarker may support individualised treatment selection in psychiatry. We review literature on the three anxiety-related mechanisms and present a mechanistic model that may serve as a rational for pathology-based diagnostic and biomarker-guided treatment selection in psychiatry.

Effects of chronic prazosin, an alpha-1 adrenergic antagonist, on anxiety-like behavior and cortisol levels in a chronic unpredictable stress model in zebrafish (Danio rerio)

Post-traumatic stress disorder (PTSD) is often associated with significant neuroendocrine dysfunction and a variety of other symptoms. Today, there are limited efficacious treatment options for PTSD, none of which directly target the dysfunction observed with the hypothalamic-pituitary-adrenal (HPA) axis. The development of new pharmacological treatments is expensive and time consuming; thus, there is utility in repurposing compounds already approved for use in other conditions. One medication in particular that has shown promise for the alleviation of PTSD symptoms is prazosin, an alpha-1 adrenergic receptor antagonist used to treat hypertension. While there have been many studies indicating the efficacy of prazosin in the treatment of PTSD symptoms, no studies fully elucidate mechanisms elicited by this treatment, nor is it clear if prazosin normalizes neuroendocrine dysfunction associated with trauma exposure. The use of zebrafish (Danio rerio) has been growing in popularity, in part, due to the homology of the stress response system with mammals. In this study, the zebrafish model was utilized to determine behavioral and biological changes induced by chronic unpredictable stress (CUS) and how these effects could be modulated by chronic prazosin treatment. The results indicated that 7d of CUS increased anxiety-like behavior in the novel tank test and decreased basal levels of cortisol. Chronic (7d) prazosin treatment decreased anxiety-like behaviors overall but did not appear to affect CUS-induced changes in behavior and basal cortisol levels. This suggests that the clinical effectiveness of prazosin may not normalize dysregulated stress responses prevalent in many patients with PTSD, but that prazosin-induced relief from anxiety in stress-related conditions may involve an alternative mechanism other than by normalizing neuroendocrine dysfunction.

Safety and Security in International Humanitarian Missions - Assessing the Stress Level of Responders in Critical Situations during a Realistic Full-Scale Training

INTRODUCTION

Crises, wars, and disasters are remarkably increasing across the world. Responders are frequently tackled with an ever-greater number of challenges, and undoubtedly, they are physically and mentally affected during and after their missions, during which posttraumatic stress disorder (PTSD) is considered high-risk. To the authors' knowledge, no studies have addressed which type of incident has the greatest influence to trigger stress, and consequently, to cause PTSD for the responders after their missions.

METHODS

A prospective longitudinal study was conducted with 69 participants of the "Safety and Security" course at the Federal Office for Civil Protection and Disaster Aid of the Federal Ministry of Interior Affairs (Berlin, Germany). The course is certified by the Hostile Environment Awareness Training (HEAT) guidelines of Europe's New Training Initiative for Civilian Crisis Management (ENTRi; Center for International Peace Operations; Berlin, Germany). Four incidents were evaluated: hostage-taking, carjacking, evacuation, and border-crossing. The participants completed the Positive and Negative Affect Schedule (PANAS) before and after each incident. For each incident, the delta of the PANAS scores was calculated. The differences between the described incidents, as well as the differences between novice and experienced responders, were evaluated.

RESULTS

The hostage-taking incident had the greatest influence on the participants' temper, followed by carjacking and evacuation. Ultimately, the border-crossing event had the least effect on the responders. Novices were more affected by hostage-taking than experienced responders; however, no significant difference had been demonstrated between novices and experienced responders for the other evaluated incidents.

CONCLUSION

Different incidents have big psychological impacts on humanitarian responders, in which consequences vary from short-term effects to PTSD. Therefore, humanitarian responders should be selected very carefully. They should also have more specific preparation for their missions. Mental after-care should be obligatory. Further studies are needed to understand and avoid reasons for the development of PTSD or other potential problems of responders.

Posttraumatic Stress Disorder Is Associated with Increased Risk of Ovarian Cancer: A Prospective and Retrospective Longitudinal Cohort Study

Ovarian cancer is the deadliest gynecologic cancer. Chronic stress accelerates tumor growth in animal models of ovarian cancer. We therefore postulated that posttraumatic stress disorder (PTSD) may be associated with increased risk of ovarian cancer. We used data from the Nurses' Health Study II, a longitudinal cohort study with 26 years of follow-up, conducted from 1989 to 2015 with 54,710 subjects. Lifetime PTSD symptoms were measured in 2008. Self-reported ovarian cancer was validated with medical records. Risk of ovarian cancer was estimated with Cox proportional hazards models and further adjusted for known ovarian cancer risk factors (e.g., hormonal factors) and health risk factors (e.g., smoking). Fully prospective secondary analyses examined incident ovarian cancer occurring after PTSD assessment in 2008. In addition, we examined associations by menopausal status. During follow-up, 110 ovarian cancers were identified. Women with high PTSD symptoms had 2-fold greater risk of ovarian cancer versus women with no trauma exposure [age-adjusted HR = 2.10; 95% confidence interval (CI), 1.12-3.95]. Adjustment for health and ovarian cancer risk factors moderately attenuated this association (HR = 1.86; 95% CI, 0.98-3.51). Associations were similar or moderately stronger in fully prospective analyses (age-adjusted HR = 2.38; 95% CI, 0.98-5.76, N cases = 50) and in premenopausal women (HR = 3.42; 95% CI, 1.08-10.85). In conclusion, we show that PTSD symptoms are associated with increased risk of ovarian cancer. Better understanding of the underlying molecular mechanisms could lead to interventions that reduce ovarian cancer risk in women with PTSD and other stress-related mental disorders. SIGNIFICANCE: PTSD is associated with ovarian cancer risk, particularly in premenopausal women. Understanding the underlying molecular mechanisms will aid in formulating ways to reduce ovarian cancer risk associated with chronic stress.

Common pathways and communication between the brain and heart: connecting post-traumatic stress disorder and heart failure

Psychiatric illnesses and cardiovascular disease (CVD) contribute to significant overall morbidity, mortality, and health care costs, and are predicted to reach epidemic proportions with the aging population. Within the Veterans Administration (VA) health care system, psychiatric illnesses such as post-traumatic stress disorder (PTSD) and CVD such as heart failure (HF), are leading causes of hospital admissions, prolonged hospital stays, and resource utilization. Numerous studies have demonstrated associations between PTSD symptoms and CVD endpoints, particularly in the Veteran population. Not only does PTSD increase the risk of HF, but this relationship is bi-directional. Accordingly, a VA-sponsored conference entitled "Cardiovascular Comorbidities in PTSD: The Brain-Heart Consortium" was convened to explore potential relationships and common biological pathways between PTSD and HF. The conference was framed around the hypothesis that specific common systems are dysregulated in both PTSD and HF, resulting in a synergistic acceleration and amplification of both disease processes. The conference was not intended to identify all independent pathways that give rise to PTSD and HF, but rather identify shared systems, pathways, and biological mediators that would be modifiable in both disease processes. The results from this conference identified specific endocrine, autonomic, immune, structural, genetic, and physiological changes that may contribute to shared PTSD-CVD pathophysiology and could represent unique opportunities to develop therapies for both PTSD and HF. Some recommendations from the group for future research opportunities are provided.

Preclinical findings on the potential of intranasal neuropeptide Y for treating hyperarousal features of PTSD

Acoustic startle response (ASR) assesses hyperarousal, a core symptom of posttraumatic stress disorder (PTSD). Intranasal neuropeptide Y (NPY) administration was shown to prevent hyperarousal in single prolonged stress (SPS) rodent PTSD model. However, it is unclear how ASR itself alters responses to stress. Rats (A-S-A) were exposed to acoustic startle (AS) 1 day before SPS (ASR1) and 2 weeks afterward (ASR2). Other groups were exposed in parallel to either AS (A-A) or SPS or neither. SPS enhanced ASR2. In relevant brain areas, mRNA levels were determined by qRT-PCR. In mediobasal hypothalamus, AS or SPS each increased CRH mRNA levels without an additive effect. Exposure to AS appeared to dampen some responses to SPS. The SPS-triggered reduction of GR and FKBP5 gene expression was not observed in A-S-A group. In locus coeruleus, SPS increased CRHR1 and reduced Y2R mRNAs, but not in A-S-A group. In both regions, AS altered NPY receptor gene expression, which may mediate dampening responses to SPS. In second experiment, intranasal NPY administered 2 weeks after SPS reversed hyperarousal symptoms for at least 7 days. This study reveals important effects of AS on the NPY system and demonstrates that intranasal NPY elicits long-lasting reversal of traumatic stress-triggered hyperarousal.

A review on inflammatory cytokine-induced alterations of the brain as potential neural biomarkers in post-traumatic stress disorder

The heterogeneity of post-traumatic stress disorder (PTSD) symptoms indicates that multiple neurobiological mechanisms underlie the pathophysiology of the condition. However, no generally accepted PTSD biomarkers in clinical practice currently exist. The sequential responses to recurrent and chronic stress by the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) system are considered to play a significant role in the onset and progression of PTSD. Decreased activity of the HPA axis and parasympathetic nervous system, along with increased activity of the sympathetic nervous system, have been observed in PTSD, which may lead to increased levels of proinflammatory cytokines. Such heightened activity of the immune system may cause alterations in the structure and function of brain regions-for example, the amygdala, hippocampus, medial prefrontal cortex, anterior cingulate cortex, and insula-through changes in levels of serotonin and kynurenine pathway metabolites, and direct neurotoxic effects of cytokines. Although chronic inflammation-induced alterations in brain regions critical in controlling emotional behavior and fear regulation may represent a strong candidate biomarker of PTSD, future studies are necessary to further elucidate inflammation-associated neural biomarkers of PTSD. Continued research on therapeutic methods that involve the normalization of the HPA axis, ANS, and immune system is expected to contribute to the development of novel ways to treat PTSD.

Locus coeruleus toggles reciprocal prefrontal firing to reinstate fear

Fear relapse represents a significant problem for individuals suffering from stress- and trauma-related disorders such as posttraumatic stress disorder. Here, we show that locus coeruleus norepinephrine activation produces fear relapse in rats. In addition, locus coeruleus activation inverts neuronal firing properties of the prelimbic and infralimbic cortices to drive this fear relapse. Elevated noradrenergic tone and subsequent changes in prefrontal firing properties represent a therapeutic target for combating fear relapse.

The medial prefrontal cortex (mPFC) plays an essential role in regulating emotion, including inhibiting fear when danger has passed. The extinction of fear, however, is labile and a number of factors, including stress, cause extinguished fear to relapse. Here we show that fear relapse in rats limits single-unit activity among infralimbic (IL) neurons, which are critical for inhibiting fear responses, and facilitates activity in prelimbic (PL) neurons involved in fear expression. Pharmacogenetic activation of noradrenergic neurons in the locus coeruleus mimics this shift in reciprocal IL–PL spike firing, increases the expression of conditioned freezing behavior, and causes relapse of extinguished fear. Noradrenergic modulation of mPFC firing represents a mechanism for relapse and a potential target for therapeutic interventions to reduce pathological fear.

Potential of Intranasal Neuropeptide Y (NPY) and/or Melanocortin 4 Receptor (MC4R) Antagonists for Preventing or Treating PTSD

There is a great need for effective treatment options for post-traumatic stress disorder (PTSD). Neuropeptide Y (NPY) is associated with resilience to traumatic stress. MC4R antagonists, such as HS014, also reduce response to stress. Both regulate stress-responsive systems - the hypothalamic-pituitary-axis (HPA) and the noradrenergic nervous system and their associated behaviors. Therefore, we examined if their intranasal delivery to brain could attenuate development of PTSD-related symptoms in single prolonged stress (SPS) rodent PTSD model. Three regimens were used: (1) prophylactic treatment 30 min before SPS stressors, (2) early intervention right after SPS stressors, (3) therapeutic treatment when PTSD behaviors are manifested 1 wk or more after the traumatic stress. NPY delivered by regimen 1 or 2 prevented SPS-triggered elevation in anxiety, depressive-like behavior, and hyperarousal and reduced dysregulation of HPA axis. Hypothalamic CRH mRNA and GR in ventral hippocampus were significantly induced in vehicle- but not NPY-treated group. NPY also prevented hypersensitivity of LC/NE system to novel mild stressor and induction of CRH in amygdala. Some of these impairments were also reduced with HS014, alone or together with NPY. When given after symptoms were manifested (regiment 3), NPY attenuated anxiety and depressive behaviors. This demonstrates strong preclinical proof of concept for intranasal NPY, and perhaps MC4R antagonists, for non-invasive early pharmacological interventions for PTSD and comorbid disorders and possibly also as therapeutic strategy.

The opioid system in stress-induced memory disorders: From basic mechanisms to clinical implications in post-traumatic stress disorder and Alzheimer's disease

Cognitive and emotional impairment are a serious consequence of stress exposure and are core features of neurological and psychiatric conditions that involve memory disorders. Indeed, acute and chronic stress are high-risk factors for the onset of post-traumatic stress disorder (PTSD) and Alzheimer's disease (AD), two devastating brain disorders associated with memory dysfunction. Besides the sympathetic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis, stress response also involves the activation of the opioid system in brain regions associated with stress regulation and memory processing. In this context, it is possible that stress-induced memory disorders may be attributed to alterations in the interaction between the neuroendocrine stress system and the opioid system. In this review, we: (1) describe the effects of acute and chronic stress on memory, and the modulatory role of the opioid system, (2) discuss the contribution of the opioid system to the pathophysiology of PTSD and AD, and (3) present evidence of current and potential therapies that target the opioid receptors to treat PTSD- and AD-associated symptoms.

Prescribing With a Trauma-Informed Perspective

As a survival strategy, trauma arouses intensive neurobiological mechanisms that, if unchecked, contribute to severe chronic stress responses and disability. Although posttraumatic stress disorder can be considered a distinctive psychiatric disorder, it likely underlies many psychiatric disorders, including depression and mood, anxiety, substance use, and personality disorders. Psychiatric-mental health nurses need to carefully assess for trauma symptomatology in all patients and diverse populations, such as children; adolescents; immigrants; active and inactive military personnel; women; and lesbian, gay, bisexual, transgender, queer individuals. Pharmacotherapy should focus on priority of target symptoms with first-line medications including serotonin reuptake inhibitors, serotonin norepinephrine reuptake inhibitors, and adrenergic blocking agents. Serotonin antagonists (i.e., second-generation antipsychotic agents) and benzodiazepine drugs are contraindicated and should be used sparingly and with caution. Psychotherapy is an effective adjunct to pharmacotherapy in treating trauma-related conditions. [Journal of Psychosocial Nursing and Mental Health Services, 56(8), 7-10.].

Research domain criteria and the study of trauma in children: Implications for assessment and treatment research

By definition, the Diagnostic and Statistical Manual (DSM) diagnosis of posttraumatic stress disorder (PTSD) requires exposure to a traumatic event. Yet, the DSM diagnostic requirements for children and adolescents for PTSD may fail to capture traumatized youth with significant distress and functional impairment. Many important studies have utilized PTSD diagnosis as a mechanism for grouping individuals for comparative studies examining brain functioning, neuroendocrinology, genetics, attachment, and cognition; however, focusing only on those with the diagnosis of PTSD can miss the spectrum of symptoms and difficulties that impact children who experience trauma and subsequent impairment. Some studying child trauma have focused on examining brain and biology of those with exposure and potential impairment rather than only those with PTSD. This line of inquiry, complementary to PTSD specific studies, has aided our understanding of some of the changes in brain structure and neuroregulatory systems at different developmental periods following traumatic exposure. Application of the Research Domain Criteria (RDoC) framework proposed by NIMH to the study of child trauma exposure and subsequent impairment is an opportunity to examine domains of function and how they are impacted by trauma. Research to date has focused largely in the areas of negative valence, regulatory, and cognitive systems, however those studying complex or developmental trauma have identified an array of domains that are impacted which map onto many of the RDoC categories. This paper will review the relevant literature associated with child trauma as it relates to the RDoC domains, outline areas of needed research, and describe their implications for treatment and the advancement of the field.

Persistent Stress-Induced Neuroplastic Changes in the Locus Coeruleus/Norepinephrine System

Neural plasticity plays a critical role in mediating short- and long-term brain responses to environmental stimuli. A major effector of plasticity throughout many regions of the brain is stress. Activation of the locus coeruleus (LC) is a critical step in mediating the neuroendocrine and behavioral limbs of the stress response. During stressor exposure, activation of the hypothalamic-pituitary-adrenal axis promotes release of corticotropin-releasing factor in LC, where its signaling promotes a number of physiological and cellular changes. While the acute effects of stress on LC physiology have been described, its long-term effects are less clear. This review will describe how stress changes LC neuronal physiology, function, and morphology from a genetic, cellular, and neuronal circuitry/transmission perspective. Specifically, we describe morphological changes of LC neurons in response to stressful stimuli and signal transduction pathways underlying them. Also, we will review changes in excitatory glutamatergic synaptic transmission in LC neurons and possible stress-induced modifications of AMPA receptors. This review will also address stress-related behavioral adaptations and specific noradrenergic receptors responsible for them. Finally, we summarize the results of several human studies which suggest a link between stress, altered LC function, and pathogenesis of posttraumatic stress disorder.

Closed Loop Deep Brain Stimulation for PTSD, Addiction, and Disorders of Affective Facial Interpretation: Review and Discussion of Potential Biomarkers and Stimulation Paradigms

The treatment of psychiatric diseases with Deep Brain Stimulation (DBS) is becoming more of a reality as studies proliferate the indications and targets for therapies. Opinions on the initial failures of DBS trials for some psychiatric diseases point to a certain lack of finesse in using an Open Loop DBS (OLDBS) system in these dynamic, cyclical pathologies. OLDBS delivers monomorphic input into dysfunctional brain circuits with modulation of that input via human interface at discrete time points with no interim modulation or adaptation to the changing circuit dynamics. Closed Loop DBS (CLDBS) promises dynamic, intrinsic circuit modulation based on individual physiologic biomarkers of dysfunction. Discussed here are several psychiatric diseases which may be amenable to CLDBS paradigms as the neurophysiologic dysfunction is stochastic and not static. Post-Traumatic Stress Disorder (PTSD) has several peripheral and central physiologic and neurologic changes preceding stereotyped hyper-activation behavioral responses. Biomarkers for CLDBS potentially include skin conductance changes indicating changes in the sympathetic nervous system, changes in serum and central neurotransmitter concentrations, and limbic circuit activation. Chemical dependency and addiction have been demonstrated to be improved with both ablation and DBS of the Nucleus Accumbens and as a serendipitous side effect of movement disorder treatment. Potential peripheral biomarkers are similar to those proposed for PTSD with possible use of environmental and geolocation based cues, peripheral signs of physiologic arousal, and individual changes in central circuit patterns. Non-substance addiction disorders have also been serendipitously treated in patients with OLDBS for movement disorders. As more is learned about these behavioral addictions, DBS targets and effectors will be identified. Finally, discussed is the use of facial recognition software to modulate activation of inappropriate responses for psychiatric diseases in which misinterpretation of social cues feature prominently. These include Autism Spectrum Disorder, PTSD, and Schizophrenia-all of which have a common feature of dysfunctional interpretation of facial affective clues. Technological advances and improvements in circuit-based, individual-specific, real-time adaptable modulation, forecast functional neurosurgery treatments for heretofore treatment-resistant behavioral diseases.

Pharmacogenetics and Pharmacotherapy of Military Personnel Suffering from Post-traumatic Stress Disorder

Background:

Posttraumatic stress disorder (PTSD) is a severe problem among soldiers with combating experience difficult to treat. The pathogenesis is still not fully understood at the psychological level. Therefore, genetic research became a focus of interest. The identification of single nucleotide polymorphisms (SNPs) may help to predict, which persons are at high risk to develop PTSD as a starting point to develop novel targeted drugs for treatment.

Methods:

We conducted a systematic review on SNPs in genes related to PTSD pathology and development of targeted pharmacological treatment options based on PubMed database searches. We focused on clinical trials with military personnel.

Results:

SNPs in 22 human genes have been linked to PTSD. These genes encode proteins acting as neurotransmitters and receptors, downstream signal transducers and metabolizing enzymes. Pharmacological inhibitors may serve as drug candidates for PTSD treatment, e.g. β2 adrenoreceptor antagonists, dopamine antagonists, partial dopamine D2 receptor agonists, dopamine β hydroxylase inhibitors, fatty acid amid hydrolase antagonists, glucocorticoid receptor agonists, tropomyosin receptor kinase B agonists, selective serotonin reuptake inhibitors, catechol-O-methyltransferase inhibitors, gamma-amino butyric acid receptor agonists, glutamate receptor inhibitors, monoaminoxidase B inhibitors, N-methyl-d-aspartate receptor antagonists.

Conclusion:

The combination of genetic and pharmacological research may lead to novel target-based drug developments with improved specificity and efficacy to treat PTSD. Specific SNPs may be identified as reliable biomarkers to assess individual disease risk. Focusing on soldiers suffering from PTSD will not only help to improve treatment options for this specific group, but for all PTSD patients and the general population.

Propranolol produces short-term facilitation of extinction in a rabbit model of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a learning-based anxiety disorder with significant public health challenges due to difficulties in treating the complex, multiple symptomology. We have developed an animal model of PTSD, based on Pavlovian eyeblink conditioning in rabbits, that addresses two key features: conditioned responses (CRs) to cues associated with an aversive event and a form of conditioned hyperarousal referred to as conditioning-specific reflex modification (CRM). We have found previously that unpaired extinction is ideal for reducing both CRs and CRM simultaneously and shows sensitivity to systemic serotonergic and glutamatergic manipulations. The following study aimed to extend our work to examine the role of the noradrenergic system, dysregulation of which is strongly implicated as part of the neurobiology of PTSD and which may also play a role in the balance shift from fear reconsolidation to extinction during treatment. The goal of the following two studies was to examine whether the β-adrenergic receptor antagonist propranolol combined with either a full or brief course of unpaired extinction treatment could enhance extinction of CRs and/or CRM. Results showed a within-session facilitation of propranolol on extinction of CRs, particularly during the first extinction session, and a short-term enhancement of extinction of CRM when extinction treatment was brief. However, neither benefit translated to long-term extinction retention for the majority of subjects. Findings suggest that propranolol may provide the most therapeutic benefit in situations of high arousal early in treatment, which may be more important for future patient compliance rather than long-term treatment outcomes.

Noradrenergic Modulation of Fear Conditioning and Extinction

The locus coeruleus norepinephrine (LC-NE) system plays a broad role in learning and memory. Here we begin with an overview of the LC-NE system. We then consider how both direct and indirect manipulations of the LC-NE system affect cued and contextual aversive learning and memory. We propose that NE dynamically modulates Pavlovian conditioning and extinction, either promoting or impairing learning aversive processes under different levels of behavioral arousal. We suggest that under high levels of stress (e.g., during/soon after fear conditioning) the locus coeruleus (LC) promotes cued fear learning by enhancing amygdala function while simultaneously blunting prefrontal function. Under low levels of arousal, the LC promotes PFC function to promote downstream inhibition of the amygdala and foster the extinction of cued fear. Thus, LC-NE action on the medial prefrontal cortex (mPFC) might be described by an inverted-U function such that it can either enhance or hinder learning depending on arousal states. In addition, LC-NE seems to be particularly important for the acquisition, consolidation and extinction of contextual fear memories. This may be due to dense adrenoceptor expression in the hippocampus (HPC) which encodes contextual information, and the ability of NE to regulate long-term potentiation (LTP). Moreover, recent work reveals that the diversity of LC-NE functions in aversive learning and memory are mediated by functionally heterogeneous populations of LC neurons that are defined by their projection targets. Hence, LC-NE function in learning and memory is determined by projection-specific neuromodulation that accompanies various states of behavioral arousal.