Pharmacological interventions for preventing post-traumatic stress disorder (PTSD)

Serotonin regulates brain-derived neurotrophic factor expression in select brain regions during acute psychological stress

Previous studies suggest that serotonin (5-HT) might interact with brain-derived neurotrophic factor (BDNF) during the stress response. However, the relationship between 5-HT and BDNF expression under purely psychological stress is unclear. In this study, one hour before psychological stress exposure, the 5-HT1A receptor agonist 8-OH-DPAT or antagonist MDL73005, or the 5-HT2A receptor agonist DOI or antagonist ketanserin were administered to rats exposed to psychological stress. Immunohistochemistry and in situ hybridization revealed that after psychological stress, with the exception of the ventral tegmental area, BDNF protein and mRNA expression levels were higher in the 5-HT1A and the 5-HT2A receptor agonist groups compared with the solvent control no-stress or psychological stress group in the CA1 and CA3 of the hippocampus, prefrontal cortex, central amygdaloid nucleus, dorsomedial hypothalamic nucleus, dentate gyrus, shell of the nucleus accumbens and the midbrain periaqueductal gray. There was no significant difference between the two agonist groups. In contrast, after stress exposure, BDNF protein and mRNA expression levels were lower in the 5-HT1A and 5-HT2A receptor antagonist groups than in the solvent control non-stress group, with the exception of the ventral tegmental area. Our findings suggest that 5-HT regulates BDNF expression in a rat model of acute psychological stress.

The Microbiota, Immunoregulation, and Mental Health: Implications for Public Health

The hygiene or "Old Friends" hypothesis proposes that the epidemic of inflammatory disease in modern urban societies stems at least in part from reduced exposure to microbes that normally prime mammalian immunoregulatory circuits and suppress inappropriate inflammation. Such diseases include but are not limited to allergies and asthma; we and others have proposed that the markedly reduced exposure to these Old Friends in modern urban societies may also increase vulnerability to neurodevelopmental disorders and stress-related psychiatric disorders, such as anxiety and affective disorders, where data are emerging in support of inflammation as a risk factor. Here, we review recent advances in our understanding of the potential for Old Friends, including environmental microbial inputs, to modify risk for inflammatory disease, with a focus on neurodevelopmental and psychiatric conditions. We highlight potential mechanisms, involving bacterially derived metabolites, bacterial antigens, and helminthic antigens, through which these inputs promote immunoregulation. Though findings are encouraging, significant human subjects' research is required to evaluate the potential impact of Old Friends, including environmental microbial inputs, on biological signatures and clinically meaningful mental health prevention and intervention outcomes.

Understanding posttraumatic stress disorder through fear conditioning, extinction and reconsolidation

Careaga MBL, Girardi CEN, Suchecki D. Understanding posttraumatic stress disorder through fear conditioning, extinction and reconsolidation. NEUROSCI BIOBEHAV REV -Posttraumatic stress disorder (PTSD) is a psychopathology characterized by exacerbation of fear response. A dysregulated fear response may be explained by dysfunctional learning and memory, a hypothesis that was proposed decades ago. A key component of PTSD is fear conditioning and the study of this phenomenon in laboratory has expanded the understanding of the underlying neurobiological changes in PTSD. Furthermore, traumatic memories are strongly present even years after the trauma and maintenance of this memory is usually related to behavioral and physiological maladaptive responses. Persistence of traumatic memory may be explained by a dysregulation of two memory processes: extinction and reconsolidation. The former may explain the over-expression of fear responses as an imbalance between traumatic and extinction memory. The latter, in turn, explains the maintenance of fear responses as a result of enhancing trauma-related memories. Thus, this review will discuss the importance of fear conditioning for the establishment of PTSD and how failure in extinction or abnormal reconsolidation may contribute to the maintenance of fear response overtime.

Impact of 2, 3, 5, 4'-tetrahydroxystilbene-2-O-β-D-glucoside on cognitive deficits in animal models of Alzheimer's disease: a systematic review

BACKGROUND

The efficacy of 2, 3, 5, 4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) treatment on cognitive decline in individuals with Alzheimer's disease (AD) has not been investigated. Therefore, we systematically reviewed the effect of TSG on cognitive deficits in a rodent model of AD.

METHODS

We identified eligible studies published from January 1980 to April 2015 by searching seven electronic databases. We assessed the study quality, evaluated the efficacy of TSG treatment, and performed a stratified meta-analysis and meta-regression analysis to assess the influence of study design on TSG efficacy.

RESULTS

Among a total of 381 publications, 18 fulfilled our inclusion criteria. The overall methodological quality of these studies was poor. The meta-analysis revealed a statistically significant benefit of TSG on acquisition memory (standardized mean difference [SMD] = -1.46 (95 % CI: -1.81 to -1.10, P < 0.0001) and retention memory (SMD =1.93 (95 % CI: 1.40 to 2.46, P < 0.0001) in experimental models of AD. The stratified analysis revealed a significantly higher effect size for both acquisition and retention memory in studies that used mixed sex models and a significantly higher effect size for acquisition memory in studies that used transgenic models.

CONCLUSIONS

Our meta-analysis highlights a significantly better treatment effect in rodent AD models that received TSG that in those that did not. These findings indicate a potential therapeutic role of TSG in AD therapy. However, additional well-designed and detailed experimental studies are needed to evaluate the safety of TSG.

Locus Ceruleus Norepinephrine Release: A Central Regulator of CNS Spatio-Temporal Activation?

Norepinephrine (NE) is synthesized in the Locus Coeruleus (LC) of the brainstem, from where it is released by axonal varicosities throughout the brain via volume transmission. A wealth of data from clinics and from animal models indicates that this catecholamine coordinates the activity of the central nervous system (CNS) and of the whole organism by modulating cell function in a vast number of brain areas in a coordinated manner. The ubiquity of NE receptors, the daunting number of cerebral areas regulated by the catecholamine, as well as the variety of cellular effects and of their timescales have contributed so far to defeat the attempts to integrate central adrenergic function into a unitary and coherent framework. Since three main families of NE receptors are represented-in order of decreasing affinity for the catecholamine-by: α2 adrenoceptors (α2Rs, high affinity), α1 adrenoceptors (α1Rs, intermediate affinity), and β adrenoceptors (βRs, low affinity), on a pharmacological basis, and on the ground of recent studies on cellular and systemic central noradrenergic effects, we propose that an increase in LC tonic activity promotes the emergence of four global states covering the whole spectrum of brain activation: (1) sleep: virtual absence of NE, (2) quiet wake: activation of α2Rs, (3) active wake/physiological stress: activation of α2- and α1-Rs, (4) distress: activation of α2-, α1-, and β-Rs. We postulate that excess intensity and/or duration of states (3) and (4) may lead to maladaptive plasticity, causing-in turn-a variety of neuropsychiatric illnesses including depression, schizophrenic psychoses, anxiety disorders, and attention deficit. The interplay between tonic and phasic LC activity identified in the LC in relationship with behavioral response is of critical importance in defining the short- and long-term biological mechanisms associated with the basic states postulated for the CNS. While the model has the potential to explain a large number of experimental and clinical findings, a major challenge will be to adapt this hypothesis to integrate the role of other neurotransmitters released during stress in a centralized fashion, like serotonin, acetylcholine, and histamine, as well as those released in a non-centralized fashion, like purines and cytokines.

Post-traumatic stress disorder associated with life-threatening motor vehicle collisions in the WHO World Mental Health Surveys

BACKGROUND

Motor vehicle collisions (MVCs) are a substantial contributor to the global burden of disease and lead to subsequent post-traumatic stress disorder (PTSD). However, the relevant literature originates in only a few countries, and much remains unknown about MVC-related PTSD prevalence and predictors.

METHODS

Data come from the World Mental Health Survey Initiative, a coordinated series of community epidemiological surveys of mental disorders throughout the world. The subset of 13 surveys (5 in high income countries, 8 in middle or low income countries) with respondents reporting PTSD after life-threatening MVCs are considered here. Six classes of predictors were assessed: socio-demographics, characteristics of the MVC, childhood family adversities, MVCs, other traumatic experiences, and respondent history of prior mental disorders. Logistic regression was used to examine predictors of PTSD. Mental disorders were assessed with the fully-structured Composite International Diagnostic Interview using DSM-IV criteria.

RESULTS

Prevalence of PTSD associated with MVCs perceived to be life-threatening was 2.5 % overall and did not vary significantly across countries. PTSD was significantly associated with low respondent education, someone dying in the MVC, the respondent or someone else being seriously injured, childhood family adversities, prior MVCs (but not other traumatic experiences), and number of prior anxiety disorders. The final model was significantly predictive of PTSD, with 32 % of all PTSD occurring among the 5 % of respondents classified by the model as having highest PTSD risk.

CONCLUSION

Although PTSD is a relatively rare outcome of life-threatening MVCs, a substantial minority of PTSD cases occur among the relatively small proportion of people with highest predicted risk. This raises the question whether MVC-related PTSD could be reduced with preventive interventions targeted to high-risk survivors using models based on predictors assessed in the immediate aftermath of the MVCs.

Prediction of individual differences in fear response by novelty seeking, and disruption of contextual fear memory reconsolidation by ketamine

Only a portion of the population exposed to trauma will develop persistent emotional alterations characteristic of posttraumatic stress disorder (PTSD), which illustrates the necessity for identifying vulnerability factors and novel pharmacotherapeutic alternatives. Interestingly, clinical evidence suggests that novelty seeking is a good predictor for vulnerability to the development of excessive and persistent fear. Here, we first tested this hypothesis by analyzing contextual and cued fear responses of rats selected for their high (high responders, HR) or low (low responders, LR) exploration of a novel environment, indicator of novelty seeking. While HR and LR rats exhibited similar sensitivity to the shock and cued fear memory retention, fewer extinction sessions were required in HR than LR animals to reach extinction, indicating faster contextual and cued memory extinction. In a second part, we found an effective disruption of contextual fear reconsolidation by the N-methyl-d-aspartate receptor antagonist ketamine, associated with a down-regulation of early growth response 1 (Egr1) in the hippocampal CA1 area, and up-regulation of brain-derived neurotrophic factor (Bdnf) mRNA levels in the prelimbic and infralimbic cortices. Altogether, these data demonstrate a link between novelty seeking and conditioned fear extinction, and highlight a promising novel role of ketamine in affecting established fear memory.

Glucocorticoids mediate stress-induced impairment of retrieval of stimulus-response memory

Acute stress and elevated glucocorticoid hormone levels are well known to impair the retrieval of hippocampus-dependent 'declarative' memory. Recent findings suggest that stress might also impair the retrieval of non-hippocampal memories. In particular, stress shortly before retention testing was shown to impair the retrieval of striatal stimulus-response associations in humans. However, the mechanism underlying this stress-induced retrieval impairment of non-hippocampal stimulus-response memory remains elusive. In the present study, we investigated whether an acute elevation in glucocorticoid levels mediates the impairing effects of stress on retrieval of stimulus-response memory. Male Sprague-Dawley rats were trained on a stimulus-response task in an eight-arm radial maze until they learned to associate a stimulus, i.e., cue, with a food reward in one of the arms. Twenty-four hours after successful acquisition, they received a systemic injection of vehicle, corticosterone (1mg/kg), the corticosterone-synthesis inhibitor metyrapone (35mg/kg) or were left untreated 1h before retention testing. We found that the corticosterone injection impaired the retrieval of stimulus-response memory. We further found that the systemic injection procedure per se was stressful as the vehicle administration also increased plasma corticosterone levels and impaired the retrieval of stimulus-response memory. However, memory retrieval was not impaired when rats were tested 2min after the systemic vehicle injection, before any stress-induced elevation in corticosterone levels had occurred. Moreover, metyrapone treatment blocked the effect of injection stress on both plasma corticosterone levels and memory retrieval impairment, indicating that the endogenous corticosterone response mediates the stress-induced memory retrieval impairment. None of the treatments affected rats' locomotor activity or motivation to search for the food reward within the maze. These findings show that stress may affect memory processes beyond the hippocampus and that these stress effects are due to the action of glucocorticoids.

Intranasal Oxytocin Affects Amygdala Functional Connectivity after Trauma Script-Driven Imagery in Distressed Recently Trauma-Exposed Individuals

Approximately 10% of trauma-exposed individuals go on to develop post-traumatic stress disorder (PTSD). Neural emotion regulation may be etiologically involved in PTSD development. Oxytocin administration early post-trauma may be a promising avenue for PTSD prevention, as intranasal oxytocin has previously been found to affect emotion regulation networks in healthy individuals and psychiatric patients. In a randomized double-blind placebo-controlled between-subjects functional magnetic resonance (fMRI) study, we assessed the effects of a single intranasal oxytocin administration (40 IU) on seed-based amygdala resting-state FC with emotion regulation areas (ventromedial prefrontal cortex (vmPFC), ventrolateral prefrontal cortex (vlPFC)), and salience processing areas (insula, dorsal anterior cingulate cortex (dACC)) in 37 individuals within 11 days post trauma. Two resting-state scans were acquired; one after neutral- and one after trauma-script-driven imagery. We found that oxytocin administration reduced amygdala-left vlPFC FC after trauma script-driven imagery, compared with neutral script-driven imagery, whereas in PL-treated participants enhanced amygdala-left vlPFC FC was observed following trauma script-driven imagery. Irrespective of script condition, oxytocin increased amygdala-insula FC and decreased amygdala-vmPFC FC. These neural effects were accompanied by lower levels of sleepiness and higher flashback intensity in the oxytocin group after the trauma script. Together, our findings show that oxytocin administration may impede emotion regulation network functioning in response to trauma reminders in recently trauma-exposed individuals. Therefore, caution may be warranted in administering oxytocin to prevent PTSD in distressed, recently trauma-exposed individuals.

Biological and psychological predictors of posttraumatic stress disorder onset and chronicity. A one-year prospective study

BACKGROUND

Few studies have prospectively examined risk factors for posttraumatic stress disorder (PTSD) in the aftermath of a traumatic exposure. The aim of this study is to identify the concurrent influence of psychological and biological diatheses on PTSD onset and maintenance, taking into account socio-demographic factors and psychiatric antecedents.

METHODS

A total of 123 civilians (61.8% of women) recruited in emergency units, were assessed using validated instruments during the first week and then at 1, 4, and 12 months post-trauma. Baseline assessment included evaluation of the psychological diathesis (i.e. psychiatric history and peritraumatic distress and dissociation), and the biological diathesis [i.e. cortisol, norepinephrine, epinephrine, c-reactive protein, total cholesterol, HDL cholesterol, glycosylated haemoglobin, waist-to-hip ratio (WHR), body mass index, diastolic and systolic blood pressure (SBP), and heart rate].

RESULTS

Multivariate logistic regression analyses demonstrated both psychological and biological diatheses to be independent risk factors for PTSD. Peritraumatic distress and dissociation predicted onset (1-month) and mid-term PTSD (4-months), respectively. PTSD risk was associated positively with SBP and negatively with WHR, throughout the follow-up. In addition, a higher level of 12 h-overnight urinary norepinephrine independently predicted mid-term PTSD (4-months).

CONCLUSIONS

This prospective study shows that peritraumatic psychological and biological markers are independent predictors of PTSD onset with specificities according to the stage of PTSD development; the psychological diathesis, i.e. peritraumatic distress and dissociation, being a better predictor of short-term dysfunction whereas biological diathesis was also predictive of development and maintenance of PTSD.

PTSD in solid organ transplant recipients: Current understanding and future implications

PTSS are quite prevalent in transplant recipients, although full-scale PTSD may not be that common. Those symptoms have been linked to poor transplant outcomes, perhaps owing to non-adherence to medications and other recommendations, brought about by the avoidance dimension of the PTSD/PTSS construct (patients may avoid taking their medications because they serve as reminder of the emotionally traumatic event--the transplant). It is possible to treat PTSD via specific psychotherapeutic techniques, and the treatment has been shown to be safe and likely effective in other populations. Therefore, practitioners who treat transplant recipients should be familiar with the presentation and treatment of those symptoms. This manuscript provides a systematic literature review of the PTSD/PTSS presentation in the pediatric transplant setting, a synthesis of available research findings, and suggestions for current care and future research.

New Developments in Intimate Partner Violence and Management of Its Mental Health Sequelae

Intimate partner violence (IPV) is a global public health and human rights problem that causes physical, sexual and psychological harms to men and women. IPV includes physical aggression, sexual coercion, psychological abuse and/or controlling behaviours perpetrated by a current or previous intimate partner in a heterosexual or same-sex relationship. IPV affects both men and women, but women are disproportionately affected with nearly one third reporting IPV during their lifetime. Physical and sexual harms from IPV include injury, increased risk for sexually transmitted diseases, pregnancy complications and sometimes death. Psychological consequences include depression, anxiety, posttraumatic stress disorder, substance abuse, impulsivity and suicidality and non-specific physical complaints thought to be related to the traumatic nature and chronic stress of IPV. Children who witness IPV are also negatively impacted in the short and long term. This paper reviews prevalence, risk factors, adverse effects and current evidence-based mental health treatment advice for IPV victims.

Prevention of Post-Traumatic Stress Disorder After Trauma: Current Evidence and Future Directions

Post-traumatic stress disorder (PTSD) is a frequent, tenacious, and disabling consequence of traumatic events. The disorder's identifiable onset and early symptoms provide opportunities for early detection and prevention. Empirical findings and theoretical models have outlined specific risk factors and pathogenic processes leading to PTSD. Controlled studies have shown that theory-driven preventive interventions, such as cognitive behavioral therapy (CBT), or stress hormone-targeted pharmacological interventions, are efficacious in selected samples of survivors. However, the effectiveness of early clinical interventions remains unknown, and results obtained in aggregates (large groups) overlook individual heterogeneity in PTSD pathogenesis. We review current evidence of PTSD prevention and outline the need to improve the disorder's early detection and intervention in individual-specific paths to chronic PTSD.

[Trauma-focused psychotherapy: Technique, area of application, and treatment outcome]

Traumatic events may lead to trauma-related disorders such as the posttraumatic stress disorder (PTSD) and constraints in quality of life. Meanwhile, there are different trauma-focused psychotherapies that aim to prevent PTSD shortly after experiencing a traumatic event and interventions that aim to treat PTSD. In Germany, cognitive-behavioral and psychodynamic trauma-focused approaches are commonly applied. While cognitive-behavioral programs aim at early exposure with the traumatic event, psychodynamic approaches emphasize the need of a period of stabilization before undergoing exposure. With regard to empirical evidence, cognitive-behavioral programs were able to prove their efficacy most often and are recommended in national and international guidelines. The German S3 guideline PTSD is currently under revision.

Sleep-dependent memory consolidation and its implications for psychiatry

Both sleep disturbance and memory impairment are very common in psychiatric disorders. Since sleep has been shown to play a role in the process of transferring newly acquired information into long-term memory, i.e., consolidation, it is important to highlight this link in the context of psychiatric disorders. Along these lines, after providing a brief overview of healthy human sleep, current neurobiological models on sleep-dependent memory consolidation and resultant opportunities to manipulate the memory consolidation process, recent findings on sleep disturbances and sleep-dependent memory consolidation in patients with insomnia, major depression, schizophrenia, and post-traumatic stress disorder are systematically reviewed. Furthermore, possible underlying neuropathologies and their implications on therapeutic strategies are discussed. This review aims at sensitizing the reader for recognizing sleep disturbances as a potential contributor to cognitive deficits in several disorders, a fact which is often overlooked up to date.

The impact of ginsenosides on cognitive deficits in experimental animal studies of Alzheimer's disease: a systematic review

Background

The efficacy of ginsenoside treatment on cognitive decline in individuals with Alzheimer’s disease (AD) has yet to be investigated. In this protocal, we conducted a systematic review to evaluate the effect of ginsenosides on cognitive deficits in experimental rodent AD models.

Methods

We identified eligible studies by searching seven electronic databases spanning from January 1980 to October 2014. We assessed the study quality, evaluated the efficacy of ginsenoside treatment, and performed a stratified meta-analysis and meta-regression analysis to assess the influence of the study design on ginsenoside efficacy.

Results

Twelve studies fulfilled our inclusion criteria from a total of 283 publications. The overall methodological quality of these studies was poor. The meta-analysis revealed that ginsenosides have a statistically significant positive effect on cognitive performance in experimental AD models. The stratified analysis revealed that ginsenoside Rg1 had the greatest effect on acquisition and retention memory in AD models. The effect size was significantly higher for both acquisition and retention memory in studies that used female animals compared with male animals.

Conclusions

We conclude that ginsenosides might reduce cognitive deficits in AD models. However, additional well-designed and well-reported animal studies are needed to inform further clinical investigations.