Randomized Controlled Trial of Riluzole Augmentation for Posttraumatic Stress Disorder: Efficacy of a Glutamatergic Modulator for Antidepressant-Resistant Symptoms

Neuroinflammation in the prefrontal-amygdala-hippocampus network is associated with maladaptive avoidance behaviour

Maladaptive avoidance behaviour is often observed in patients suffering from anxiety and trauma- and stressor-related disorders. The prefrontal-amygdala-hippocampus network is implicated in learning and memory consolidation. Neuroinflammation in this circuitry alters network dynamics, resulting in maladaptive avoidance behaviour. The two-way active avoidance test is a well-established translational model for assessing avoidance responses to stressful situations. While some animals learn the task and show adaptive avoidance (AA), others show strong fear responses to the test environment and maladaptive avoidance (MA). Here, we investigated if a distinct neuroinflammation pattern in the prefrontal-amygdala-hippocampus network underlies the behavioural difference observed in these animals. Wistar rats were tested 8 times and categorized as AA or MA based on behaviour. Brain recovery followed for the analysis of neuroinflammatory markers in this network. AA and MA presented distinct patterns of neuroinflammation, with MA showing increased astrocyte, EAAT-2, IL-1β, IL-17 and TNF-ɑ in the amygdala. This neuroinflammatory pattern may underlie these animals' fear response and maladaptive avoidance. Further studies are warranted to determine the specific contributions of each inflammatory factor, as well as the possibility of treating maladaptive avoidance behaviour in patients with psychiatric disorders with anti-inflammatory drugs targeting the amygdala.

Treatment of Posttraumatic Stress Disorder: A State-of-the-art Review

This narrative state-of-the-art review paper describes the progress in the understanding and treatment of Posttraumatic Stress Disorder (PTSD). Over the last four decades, the scientific landscape has matured, with many interdisciplinary contributions to understanding its diagnosis, etiology, and epidemiology. Advances in genetics, neurobiology, stress pathophysiology, and brain imaging have made it apparent that chronic PTSD is a systemic disorder with high allostatic load. The current state of PTSD treatment includes a wide variety of pharmacological and psychotherapeutic approaches, of which many are evidence-based. However, the myriad challenges inherent in the disorder, such as individual and systemic barriers to good treatment outcome, comorbidity, emotional dysregulation, suicidality, dissociation, substance use, and trauma-related guilt and shame, often render treatment response suboptimal. These challenges are discussed as drivers for emerging novel treatment approaches, including early interventions in the Golden Hours, pharmacological and psychotherapeutic interventions, medication augmentation interventions, the use of psychedelics, as well as interventions targeting the brain and nervous system. All of this aims to improve symptom relief and clinical outcomes. Finally, a phase orientation to treatment is recognized as a tool to strategize treatment of the disorder, and position interventions in step with the progression of the pathophysiology. Revisions to guidelines and systems of care will be needed to incorporate innovative treatments as evidence emerges and they become mainstream. This generation is well-positioned to address the devastating and often chronic disabling impact of traumatic stress events through holistic, cutting-edge clinical efforts and interdisciplinary research.

Effects of riluzole on psychiatric disorders with anxiety or fear as primary symptoms: A systematic review

AIM

Previous behavioral pharmacology studies involving rodents suggested riluzole had potential to be an ideal psychotropic drug for psychiatric disorders with anxiety or fear as primary symptoms. Several clinical studies have recently been conducted. The purpose of this study was to gather information about the efficacy and tolerability of riluzole for patients with those symptoms.

METHODS

We searched PubMed, PsycINFO, CINAHL, EMBASE, and the Cochrane database from inception until April 2021, and performed manual searches for additional relevant articles. This review included: (1) studies involving participants that were patients with generalized anxiety disorder (GAD), social anxiety disorder, panic disorder, obsessive-compulsive disorder (OCD), posttraumatic stress disorder (PTSD), acute stress disorder, or phobias; and (2) randomized controlled trials (RCTs) or intervention studies (e.g., single arm trials) examining the effects and safety of riluzole.

RESULTS

Of the 795 identified articles, four RCTs, one RCT subgroup-analysis, and three open-label trials without control groups met the inclusion criteria. Most trials evaluated the efficacy of riluzole as an augmentation therapy with selective serotonin reuptake inhibitors and other antidepressants for PTSD, OCD, or GAD. However, there was insufficient evidence to confirm the effects of riluzole for patients with these psychiatric disorders. Most trials demonstrated adequate study quality.

CONCLUSIONS

This review found insufficient evidence to confirm the effects of riluzole for psychiatric disorders with anxiety or fear as primary symptoms. It would be worthwhile to conduct studies that incorporate novel perspectives, such as examining the efficacy of riluzole as a concomitant medication for psychotherapy.

Administration of the glutamate-modulating drug, riluzole, after stress prevents its delayed effects on the amygdala in male rats

Extracellular glutamate levels are elevated across brain regions immediately after stress. Despite sharing common features in their genesis, the patterns of stress-induced plasticity that eventually take shape are strikingly different between these brain areas. While stress causes structural and functional deficits in the hippocampus, it has the opposite effect on the amygdala. Riluzole, an FDA-approved drug known to modulate glutamate release and facilitate glutamate clearance, prevents stress-induced deficits in the hippocampus. But whether the same drug is also effective in countering the opposite effects of stress in the amygdala remains unexplored. We addressed this question by using a rat model wherein even a single 2-h acute immobilization stress causes a delayed expression of anxiety-like behavior, 10 days later, alongside stronger excitatory synaptic connectivity in the basolateral amygdala (BLA). This temporal profile-several days separating the acute stressor and its delayed impact-allowed us to test if these effects can be prevented by administering riluzole in drinking water after acute stress. Poststress riluzole not only prevented the delayed increase in anxiety-like behavior on the elevated plus maze but also blocked the increase in spine density on BLA neurons 10 days later. Further, stress-induced increase in the frequency of miniature excitatory postsynaptic currents recorded in BLA slices, 10 days later, was also blocked by the same poststress riluzole administration. Together, these findings underscore the importance of therapeutic strategies, aimed at glutamate uptake and modulation, in correcting the delayed behavioral, physiological, and morphological effects of stress on the amygdala.

Alleviating anxiety and taming trauma: Novel pharmacotherapeutics for anxiety disorders and posttraumatic stress disorder

Psychiatric disorders associated with psychological trauma, stress and anxiety are a highly prevalent and increasing cause of morbidity worldwide. Current therapeutic approaches, including medication, are effective in alleviating symptoms of anxiety disorders and posttraumatic stress disorder (PTSD), at least in some individuals, but have unwanted side-effects and do not resolve underlying pathophysiology. After a period of stagnation, there is renewed enthusiasm from public, academic and commercial parties in designing and developing drug treatments for these disorders. Here, we aim to provide a snapshot of the current state of this field that is written for neuropharmacologists, but also practicing clinicians and the interested lay-reader. After introducing currently available drug treatments, we summarize recent/ongoing clinical assessment of novel medicines for anxiety and PTSD, grouped according to primary neurochemical targets and their potential to produce acute and/or enduring therapeutic effects. The evaluation of putative treatments targeting monoamine (including psychedelics), GABA, glutamate, cannabinoid, cholinergic and neuropeptide systems, amongst others, are discussed. We emphasize the importance of designing and clinically assessing new medications based on a firm understanding of the underlying neurobiology stemming from the rapid advances being made in neuroscience. This includes harnessing neuroplasticity to bring about lasting beneficial changes in the brain rather than - as many current medications do - produce a transient attenuation of symptoms, as exemplified by combining psychotropic/cognitive enhancing drugs with psychotherapeutic approaches. We conclude by noting some of the other emerging trends in this promising new phase of drug development.

To Predict, Prevent, and Manage Post-Traumatic Stress Disorder (PTSD): A Review of Pathophysiology, Treatment, and Biomarkers

Post-traumatic stress disorder (PTSD) can become a chronic and severely disabling condition resulting in a reduced quality of life and increased economic burden. The disorder is directly related to exposure to a traumatic event, e.g., a real or threatened injury, death, or sexual assault. Extensive research has been done on the neurobiological alterations underlying the disorder and its related phenotypes, revealing brain circuit disruption, neurotransmitter dysregulation, and hypothalamic–pituitary–adrenal (HPA) axis dysfunction. Psychotherapy remains the first-line treatment option for PTSD given its good efficacy, although pharmacotherapy can also be used as a stand-alone or in combination with psychotherapy. In order to reduce the prevalence and burden of the disorder, multilevel models of prevention have been developed to detect the disorder as early as possible and to reduce morbidity in those with established diseases. Despite the clinical grounds of diagnosis, attention is increasing to the discovery of reliable biomarkers that can predict susceptibility, aid diagnosis, or monitor treatment. Several potential biomarkers have been linked with pathophysiological changes related to PTSD, encouraging further research to identify actionable targets. This review highlights the current literature regarding the pathophysiology, disease development models, treatment modalities, and preventive models from a public health perspective, and discusses the current state of biomarker research.

Prophylactic Efficacy of Riluzole against Anxiety- and Depressive-Like Behaviors in Two Rodent Stress Models

Introduction

Chronic stress-related illnesses such as major depressive disorder and post-traumatic stress disorder share symptomatology, including anxiety, anhedonia, and helplessness. Across disorders, neurotoxic dysregulated glutamate (Glu) signaling may underlie symptom emergence. Current first-line antidepressant drugs, which do not directly target Glu signaling, fail to provide adequate benefit for many patients and are associated with high relapse rates. Riluzole modulates glutamatergic neurotransmission by increasing metabolic cycling and modulating signal transduction. Clinical studies exploring riluzole's efficacy in stress-related disorders have provided varied results. However, the utility of riluzole for treating specific symptom dimensions or as a prophylactic treatment has not been comprehensively assessed.

Methods

We investigated whether chronic prophylactic riluzole (∼12-15 mg/kg/day p.o.) could prevent the emergence of behavioral deficits induced by unpredictable chronic mild stress (UCMS) in mice. We assessed (i) anxiety-like behavior using the elevated-plus maze, open-field test, and novelty-suppressed feeding, (ii) mixed anxiety/anhedonia-like behavior in the novelty-induced hypophagia test, and (iii) anhedonia-like behavior using the sucrose consumption test. Z-scoring summarized changes across tests measuring similar dimensions. In a separate learned helplessness (LH) cohort, we investigated whether chronic prophylactic riluzole treatment could block the development of helplessness-like behavior.

Results

UCMS induced an elevation in anhedonia-like behavior and overall behavioral emotionality that was blocked by prophylactic riluzole. In the LH cohort, prophylactic riluzole blocked the development of helplessness-like behavior.

Discussion/Conclusion

This study supports the utility of riluzole as a prophylactic medication for preventing anhedonia and helplessness symptoms associated with stress-related disorders.

Comparative Effectiveness of Direct-Acting Antivirals for Posttraumatic Stress Disorder in Veterans Affairs Patients With Hepatitis C Virus Infection

We recently conducted an exploratory study that indicated that several direct-acting antivirals (DAAs), highly effective medications for hepatitis C virus (HCV) infection, were also associated with improvement in posttraumatic stress disorder (PTSD) among a national cohort of US Department of Veterans Affairs (VA) patients treated between October 1, 1999, and September 30, 2019. Limiting the same cohort to patients with PTSD and HCV, we compared the associations of individual DAAs with PTSD symptom improvement using propensity score weighting. After identifying patients who had available baseline and endpoint PTSD symptom data as measured with the PTSD Checklist (PCL), we compared changes over the 8-12 weeks of DAA treatment. The DAAs most prescribed in conjunction with PCL measurement were glecaprevir/pibrentasvir (GLE/PIB; n = 54), sofosbuvir/velpatasvir (SOF/VEL; n = 54), and ledipasvir/sofosbuvir (LDV/SOF; n = 145). GLE/PIB was superior to LDV/SOF, with a mean difference in improvement of 7.3 points on the PCL (95% confidence interval (CI): 1.1, 13.6). The mean differences in improvement on the PCL were smaller between GLE/PIB and SOF/VEL (3.0, 95% CI: -6.3, 12.2) and between SOF/VEL and LDV/SOF (4.4, 95% CI: -2.4, 11.2). While almost all patients were cured of HCV (92.5%) regardless of the agent received, PTSD outcomes were superior for those receiving GLE/PIB compared with those receiving LDV/SOF, indicating that GLE/PIB may merit further investigation as a potential PTSD treatment.

Riluzole prevents stress-induced spine plasticity in the hippocampus but mimics it in the amygdala

Stress elicits divergent patterns of structural plasticity in the amygdala and hippocampus. Despite these contrasting effects, at least one of the immediate consequences of stress – elevated levels of extracellular glutamate – is similar in both brain areas. This raises the possibility that the contrasting effects of stress on neuronal plasticity is shaped by differences in astrocytic glutamate clearance in these two brain areas. Although astrocytes play a key role in glutamate reuptake, past analyses of, and interventions against, stress-induced plasticity have focused largely on neurons. Hence, we tested the impact of riluzole, which potentiates glutamate clearance by astrocytic glutamate transporters, on principal neurons and astrocytes in the basal amygdala (BA) and hippocampal area CA1. Chronic immobilization stress reduced spine-density on CA1 pyramidal neurons of male rats. Riluzole, administered in the drinking water during chronic stress, prevented this decrease; but, the drug by itself had no effect. In contrast, the same chronic stress enhanced spine-density on BA principal neurons, and this effect, unlike area CA1, was not reversed by riluzole. Strikingly, riluzole treatment alone also caused spinogenesis in the BA. Thus, the same riluzole treatment that prevented the effect of stress on spines in the hippocampus, mimicked its effect in the amygdala. Further, chronic stress and riluzole alone decreased the neuropil volume occupied by astrocytes in both the BA and CA1 area. Riluzole treatment in stressed animals, however, did not reverse or further add to this reduction in either region. Thus, while the effects on astrocytes were similar, neuronal changes were distinct between the two areas following stress, riluzole and the two together. Therefore, similar to the impact of repeated stress, pharmacological potentiation of glutamate clearance, with or without stress, also leads to differential effects on dendritic spines in principal neurons of the amygdala and hippocampus. This highlights differences in the astrocytic glutamate reuptake machinery that are likely to have important functional consequences for stress-induced dysfunction, and its reversal, in two brain areas implicated in stress-related psychiatric disorders.

The safety and efficacy of Ketamine NMDA receptor blocker as a therapeutic intervention for PTSD review of a randomized clinical trial

OBJECTIVE

Posttraumatic stress disorder (PTSD) has long-lasting debilitating symptoms. PTSD causes a significant burden on healthcare workers and victims' families. The US Food Drug Administration (FDA) has approved only two Serotonin Selective Reuptake Inhibitors (SSRI), sertraline, and paroxetine as pharmacological interventions for PTSD. SSRI has a 50-60% response rate and up to 30% remission rate with a high relapse rate. Ketamine is an NMDA receptor blocker, has a rapid effective onset, a potent antidepressant with anti-suicidal, neuroprotective, and cognitive-enhancement properties.

METHOD

We retrieved randomized clinical trials (RCT) on PubMed, PubMed Central, and Medline Database of clinical trial studies until Jan/2022. We used the following keywords: "posttraumatic stress disorder. "AND "Ketamine." AND "Esketamine" AND "NMDA receptor antagonist" AND "treatment, pharmacological intervention, management. ". We used Medical Subject Heading [Mesh] Term for "ketamine" and "Esketamine" And "Receptors, N-Methyl-D-Aspartate" and "Stress Disorders, Post-Traumatic" and "Disease management.".

RESULT

All qualified five randomized clinical studies showed rapid and clear benefits of Ketamine infusion for PTSD symptoms resistant to conventional medications. The clinical improvements were evident in three of the four PTSD symptom categories, intrusions, avoidance, and negative alterations in cognitions and mood. In addition, Ketamine administration was safe well-tolerated, with transient dissociation as the main side effect reported. Ketamine infusion also positively affects comorbidities like chronic pain, alcohol use disorder, and major depression.

CONCLUSION

Ketamine showed fast, safe, highly effective pharmaceutical intervention for chronic PTSD symptoms. No correlation between ketamine potency and patient age, sex and/or body mass index. Further studies are needed to understand the appropriate therapeutic dose, onset, route of administration, duration of the treatment and comorbidity benefit.

The stressed synapse 2.0: pathophysiological mechanisms in stress-related neuropsychiatric disorders

Stress is a primary risk factor for several neuropsychiatric disorders. Evidence from preclinical models and clinical studies of depression have revealed an array of structural and functional maladaptive changes, whereby adverse environmental factors shape the brain. These changes, observed from the molecular and transcriptional levels through to large-scale brain networks, to the behaviours reveal a complex matrix of interrelated pathophysiological processes that differ between sexes, providing insight into the potential underpinnings of the sex bias of neuropsychiatric disorders. Although many preclinical studies use chronic stress protocols, long-term changes are also induced by acute exposure to traumatic stress, opening a path to identify determinants of resilient versus susceptible responses to both acute and chronic stress. Epigenetic regulation of gene expression has emerged as a key player underlying the persistent impact of stress on the brain. Indeed, histone modification, DNA methylation and microRNAs are closely involved in many aspects of the stress response and reveal the glutamate system as a key player. The success of ketamine has stimulated a whole line of research and development on drugs directly or indirectly targeting glutamate function. However, the challenge of translating the emerging understanding of stress pathophysiology into effective clinical treatments remains a major challenge.

Effectiveness, Acceptability and Safety of Pharmaceutical Management for Combat-Related PTSD in Adults Based on Systematic Review of Twenty-Two Randomized Controlled Trials

Objective: This study assessed the efficacy, acceptability, and safety of pharmaceutical management for combat-related post-traumatic stress disorder (PTSD) to provide a clinical decision-making basis for clinicians.

Method: A comprehensive search was conducted using Ovid MEDLINE, Ovid EMBASE, Cochrane Library, Scopus, ScienceDirect, and Web of Science for randomized controlled trails (RCTs), which reported pharmaceutical management and placobo for adults with combat-related PTSD, that were published until April 21, 2021. The effectiveness, acceptability, and adverse events (AEs), were designed as interested outcomes. The change in total symptoms of combat-related PTSD according to the clinician rating scale was defined as primary outcome, and the others were defined as secondary outcomes.

Results: Twenty-two RCTs with 1,221 patients were involved. Compared with placebo, overall active comparators had statistical differences for all outcomes, including the change in total symptoms of combat-related PTSD [SMD = −0.36, 95%CI (−0.62,−0.09)], depression [SMD = −0.28, 95%CI (−0.45,−0.10)], anxiety [SMD = −0.44, 95%CI (−0.64,−0.23)], re-experience [SMD = −0.33, 95%CI (−0.52,−0.13)], avoidance [SMD = −0.24, 95%CI (−0.43,−0.05)], and hyper-arousal [SMD = −0.26, 95%CI (−0.48,−0.03)]. Compared with the placebo, in terms of acceptability, overall active comparators did not significantly decrease all-cause discontinuance rates [RR = 0.97, 95%CI (0.78,1.20)], and the significance decreased due to AEs [RR = 2.42, 95%CI (1.41,4.13)]. Nevertheless, overall there was no statistically significant difference for overall AEs, including somnolence, sedation, dizziness, paresthesia, anxiety, blurred vision, generalized anxiety disorder, and sleep disturbance. All funnel plots were symmetrical and no publication bias was found.

Conclusion: Active drugs, especially amitriptyline, imipramine, and quetiapine, had a positive effect on the improvement of combat-related PTSD symptoms. Despite there being no significant increase in the AEs of the active drugs, the fact that the discontinuation rates of these drugs, including risperidone, imipramine, and topiramate, were increased deserves attention. Furthermore, as active drugs were effective across ethnic groups and battlefields, active drug regimens were revealed to be more appropriate for treating people with symptoms of extreme severe PTSD (≥80) or PTSD that is at least 8 weeks old. In addition, current evidence was from adults under 60 years of age and male combat-related PTSD. Whether this evidence can be extended to other populations of combat-related PTSD needs to be confirmed by subsequent high-quality, large-sample studies.

Key Clinical Interest Outcomes of Pharmaceutical Administration for Veterans With Post-Traumatic Stress Disorder Based on Pooled Evidences of 36 Randomised Controlled Trials With 2,331 Adults

Background: The effects of drug treatment on veterans, who have a high risk of post-traumatic stress disorder (PTSD), are not clear, and the guidelines are different from the recommendations of the recent meta-analysis. Our goal was to find the efficacy and frequencies of complications of drugs that can treat PTSD in veterans. Method: We searched Ovid MEDLINE, Ovid Embase, The Cochrane Library and Web of Science until January 1, 2020. The outcomes were designed as the change of PTSD total scale, subsymptom score, response rate, frequencies of complications outcomes, and acceptability. Results: We included a total of 36 randomised controlled trials with a total of 2,331 adults. In terms of overall effect, drug treatment is more effective than placebo in change in total PTSD symptoms scale (SMD = -0.24, 95% CI [-0.42, -0.06]) and response (RR = 1.66, 95% CI [1.01, 2.72]). However, in terms of frequencies of complications, drugs generally had a higher withdrawal rate (RR = 1.02, 95% CI [0.86, 1.20]) and a higher frequencies of complications (RR = 1.72, 95% CI [1.20, 2.47]) than placebo. Risperidone showed a good curative effect in change in total PTSD symptoms scale (SMD = -0.22, 95% CI [-0.43, 0.00]) and acceptability (RR = 1.31, 95% CI [0.82, 2.59]). The drugs acting on 5-HT receptors, our results showed that symptoms of hyper-arousal (SMD = -0.54, 95% CI [-0.86, -0.21]), symptoms of re-experiencing (SMD = -0.62, 95% CI [-0.86, -0.39]) and symptoms of avoidance (SMD = -0.53, 95% CI [- 0.77,-0.3]), The drugs acting on dopamine receptors, our results showed that symptoms of re-experiencing (SMD = -0.35, 95% CI [-0.55, -0.16]) and the drugs acting on α2 receptor has a significant effect on reducing total PTSD symptoms scale (SMD = -0.34, 95% CI [-0.62, -0.06]). Conclusion: Drug therapy can effectively treat PTSD, but its frequencies of complications should be considered. Different from the guidelines for adult PTSD, this study supports atypical antipsychotics, selective serotonin reuptake inhibitors and receptors that act on 5-HT and dopamine for the treatment of PTSD in veterans. Based on evidence among these drugs, the risperidone is the most effective for veterans, otherwise, sertraline is used as an alternative.