Synaptic Loss and the Pathophysiology of PTSD: Implications for Ketamine as a Prototype Novel Therapeutic

Non-response to short-term ketamine use for treatment-resistant depression

BACKGROUND

Ketamine is currently gaining attention as a rapid-acting antidepressant for treatment-resistant depression (TRD). However, many patients fail to respond, and limited data exist on predictors of non-response. This study aims to characterize the sociodemographic and clinical features associated with non-response to ketamine among TRD patients.

METHODS

This is a post-hoc analysis of a naturalistic observational study, which enrolled 40 inpatients with treatment-resistant major depressive disorder and analyzed sociodemographic and clinical features in responders and non-responders stratified per Montgomery-Åsberg Depression Rating Scale (MADRS) during short-term ketamine administration (intravenous dosage: 0,5 mg/kg and orally: 2.0 or 2.5 mg/kg) that comprise over 4 weeks.

RESULTS

In this study, 30 patients (75%) were classified as non-responders. No significant differences were detected among sociodemographic and clinical features beyond the history of substance use disorder (SUD) - only 53.3% of non-responders reported prior SUD (vs. 100%; p = 0.0075) and a lower number of psychiatric comorbidities (p = 0.0381).

CONCLUSION

This study highlights key characteristics of TRD non-responders to ketamine, including lower rates of SUD and fewer psychiatric comorbidities. These findings suggest that a higher burden of traditional TRD risk factors may not limit ketamine efficacy and could even enhance response compared to "pure" major depressive disorder. Identifying potential non-responders early can optimize treatment decisions, reduce ineffective exposure, and guide future research on improving TRD management.

Chlorogenic acid improves SPS-induced PTSD-like behaviors in rats by regulating the crosstalk between Nrf2 and NF-κB signaling pathway

Post-traumatic stress disorder (PTSD) is a long-term delayed mental disorder caused by sudden, threatening or catastrophic life events. Chlorogenic acid (CGA) is a polyphenolic acid rich in Eucommia ulmoides and other plants with potential neuroprotective effects, effectively enhances learning and memory, and exerts a beneficial impact on improving mood and attention. However, the effects and mechanisms of CGA on PTSD-like behaviors remain uncertain. This study is to explore the effects and mechanisms of CGA on PTSD by using network pharmacology analysis, molecular docking and experimental validation, and try to provide new strategies for the treatment of PTSD. The results indicated that 9 core targets with a strong binding affinity with CGA were screened out, and they were mainly enriched in apoptosis, inflammation, and oxidative stress. The followed vivo experiments indicated that CGA could alleviate single prolonged stress (SPS)-induced PTSD-like behaviors, and improve hippocampal pathological damage, apoptosis and synaptic plasticity through antioxidant and anti-inflammatory effects by regulating Nrf2 and NF-κB pathways. Thus, CGA may inhibit hippocampal neuronal apoptosis, reduce neuroinflammatory and oxdiative stress response, and enhance hippocampal synaptic plasticity through regulating the crosstalk between Nrf2 and NF-κB signaling pathway, thereby improving SPS-induced PTSD-like behaviors.

Guilu Erxian Jiao remodels dendritic spine morphology through activation of the hippocampal TRPC6-CaMKIV-CREB signaling pathway and suppresses fear memory generalization in rats with post-traumatic stress disorder

ETHNOPHARMACOLOGICAL RELEVANCE

Guilu Erxian Jiao (GLEXJ) is a renowned traditional Chinese herbal formula used to tonify the kidney. It is employed to treat psychiatric disorders, and alleviate memory impairment, cognitive dysfunction, and behavioral disorders. Modern pharmacological studies have demonstrated GLEXJ's ability to significantly inhibit the fear response in post-traumatic stress disorder (PTSD) and facilitate the extinction of fear memory. However, the underlying pharmacological mechanisms remain elusive.

AIM OF THE STUDY

Fear memory generalization, a fundamental characteristic of PTSD, remains poorly understood, and optimal pharmacological treatments are lacking. This study aimed to investigate GLEXJ's inhibitory effects on fear memory generalization in PTSD rats and elucidate its underlying mechanisms.

MATERIALS AND METHODS

PTSD rats were induced using the single prolonged stress and electrical stimulation (SPS&S) protocol and treated with GLEXJ or paroxetine (PRX). Fear memory generalization was assessed using a contextual fear memory test. Hippocampal dendritic spine morphology was analyzed using Golgi-Cox staining. The chemical composition of GLEXJ was determined using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Network pharmacology was employed to predict GLEXJ's therapeutic mechanism in PTSD treatment. Western blotting and immunofluorescence were used to measure indicators of the transient receptor potential channel 6 (TRPC6)-mediated calcium/calmodulin-dependent protein kinase IV-cAMP response element-binding protein (CaMKIV-CREB) signaling pathway. In vitro, TRPC6 was suppressed in rat adrenal pheochromocytoma (PC12) cells using lentiviral vectors, and phalloidin staining was employed to examine changes in Fibros actin (F-actin), elucidating the mechanistic effects of GLEXJ-containing serum.

RESULTS

GLEXJ significantly mitigated fear memory generalization in PTSD rats, even with repeated stress exposure. It also alleviated abnormal hippocampal dendritic spine morphology. Network pharmacology analysis confirmed that GLEXJ was closely related to the Ca2+ signaling pathway in PTSD treatment. PTSD rats exhibited disrupted TRPC6-mediated CaMKIV-CREB signaling and impaired synaptic plasticity. GLEXJ upregulated TRPC6 expression, reactivated the CaMKIV-CREB pathway, and promoted synaptic remodeling. In vitro studies confirmed that TRPC6 suppression reduced F-actin levels while GLEXJ-containing serum increased TRPC6 expression and F-actin content.

CONCLUSIONS

GLEXJ activates CaMKIV-CREB signaling by upregulating TRPC6 in the hippocampus of PTSD rats, leading to the positive modulation of dendritic spine morphology and synaptic remodeling. This mechanism contributes to the attenuation of fear memory generalization. Given the limitations of current PTSD treatments, these findings offer potential avenues for developing more effective therapeutic strategies.

(2R, 6R)-hydroxynorketamine ameliorates PTSD-like behaviors during the reconsolidation phase of fear memory in rats by modulating the VGF/BDNF/GluA1 signaling pathway in the hippocampus

RATIONALE

Fear memory, a fundamental symptom of post-traumatic stress disorder (PTSD), is improved by (2R, 6R)-hydroxynorketamine ((2R, 6R)-HNK) administration. However, the phase of fear memory in which the injected drug is the most effective at mitigating PTSD-like effects remains unknown.

OBJECTIVE

This study aimed to explore the effects of (2 R, 6 R)-HNK administration during three phases [acquisition (AP), reconsolidation (RP), and extinction (EP)] on PTSD-like behaviors in single prolonged stress (SPS) and contextual fear conditioning (CFC) rat models. The effects of VGF-inducible type of nerve growth factor (VGF), brain-derived neurotrophic factor (BDNF), and GluA1 on hippocampus (HIP) expression were also explored.

METHODS

SPS and CFC (SPSC) were used to establish a PTSD rat model. After lateral ventricle injection of 5 μL (2 R, 6 R)-HNK (0.5 nmol). Anxiety-depression-like behaviors were assessed in rats by the open field test (OFT) and elevated plus maze test (EPMT). Situational fear responses were evaluated in rodents by freezing behavior test (FBT) test. In addition, GluA1, VGF, and BDNF were assessed in the hippocampus by Western blot assay (WB) and Immunohistochemistry assay (IF).

RESULTS

SPSC procedure induced PTSD-like behaviors. The SPSC group had decreased spontaneous exploratory behavior and increased fear response. The (2R, 6R)-HNK group showed improved SPSC-induced reduction in GluA1, VGF, and BDNF levels in the HIP. During RP, anxiety and fear avoidance behaviors were alleviated, and the protein levels of GluA1, VGF, and BDNF in the HIP were restored. In contrast, no significant improvement was noted during AP and EP.

CONCLUSIONS

(2R,6R)-HNK modulates the VGF/BDNF/GluA1 signaling pathway in the hippocampus and improves PTSD-like behaviors during the reconsolidation phase of fear memory in rats, which may provide a new target for the clinical treatment and prevention of fear-related disorders such as PTSD.

Advances in synaptic PET imaging and intervention with synapse-targeted small-molecular drugs for dementia diagnosis and therapy

Dementia is characterized by synaptic and neuronal dysfunction in disease-specific brain regions. Repeated failure of dementia clinical trials with therapeutic drugs targeting abnormal protein aggregates has caused researchers to shift their focus to synaptic functions and increased the importance of clinically available imaging for synaptic density and the development of synapse-targeted intervention. Synaptic density imaging with positron emission tomography (PET) tracer enables non-invasive detection of synaptic loss and hence investigates the association with other neuropathological events exemplified by disease-specific abnormal protein accumulation. Many studies have reviewed the progress of synaptic density imaging; however, to our knowledge, there is no article yet that summarizes the research progress of multimodal imaging of synaptic density tracers combined with other dementia biomarkers. Moreover, synaptic function intervention for dementia therapy has not yet been summarized. In this review, first we detail the progress of synaptic density imaging including tracer development and preclinical/clinical application, followed by a discussion of multimodal imaging of synaptic density tracers combined with classic dementia biomarkers in the clinical research stage. Finally, we briefly summarize the synapse-targeted drugs for dementia therapy.

Evaluating the potential for psilocybin as a treatment for post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition that develops following exposure to a traumatic event. Individuals with this condition experience numerous physiological and behavioral alterations, including intrusive memories, avoidance of trauma-related stimuli, heightened anxiety, hypervigilance, impaired cognition, elevated resting heart rate and blood pressure, and altered neuroendocrine function, to name a few. In most patients, currently available pharmacological and psychological treatments are insufficient to alleviate the array of symptoms associated with the disorder. Thus, novel treatment options that can more effectively target the core etiology of PTSD are desperately needed. Recent work demonstrating the psychoplastogenic effects of psychedelics has reinvigorated research to examine their therapeutic potential in psychiatric conditions. Psilocybin, a psychedelic found in the Psilocybe genus of mushrooms, has exhibited promising antidepressant and anxiolytic effects in preclinical and clinical studies. The purpose of this review is to summarize the existing research that has examined the behavioral effects of psilocybin and link it to potential efficacy in treating PTSD-related symptoms. The proposed mechanisms for psilocybin's effects are then explored, as are the benefits and drawbacks for the agent's therapeutic use. Finally, the challenges faced by investigators aiming to study psilocybin as a therapeutic aid in future studies are discussed in order to shed light on this budding area of research. SIGNIFICANCE STATEMENT: Current pharmacotherapy for post-traumatic stress disorder is insufficient. Traditional antidepressants and anxiolytics help reduce symptom severity, but nonresponse rates often reach levels greater than 50%, emphasizing the need for more effective treatment options. The goal of this review is to summarize the existing evidence for and the potential mechanisms of the antidepressant and anxiolytic effects of psilocybin, a psychedelic compound found in the Psilocybe genus of mushrooms. The observed effects are then related to psilocybin's potential use as a treatment for PTSD.

Neuroglia in anxiety disorders

Anxiety disorders are some of the most prevalent in the world and are extraordinarily debilitating to many individuals, costing millions in disability. One of the most disabling is posttraumatic stress disorder (Snijders et al., 2020). Understanding the pathophysiology of these illnesses further and the cell types involved will allow better targeting of treatments. Glial cells, encompassing microglia, astrocytes, and oligodendrocytes, play critical roles in the pathophysiology of PTSD and other anxiety illnesses. Each of these cell types interacts with aspects of neuro-epigenetics, neuroimmune, and neuronal signaling and may contribute to the pathophysiology of anxiety illnesses. This chapter covers the literature on the role of glial cells in the neurobiology and pathology of anxiety disorders, more specifically PTSD. PTSD is one of the most debilitating anxiety disorders and one of the most complicated from a neurobiologic perspective. This chapter also features a discussion surrounding the current state of treatment and some of the hypothesized mechanisms for novel treatments including tetrahydrocannabidiol and 3,4-methylenedioxymethamphetamine. Finally, thoughts on the future directions for precision treatment and pharmacologic development with a focus on neuroglia are undertaken.

H2S improves hippocampal synaptic plasticity in SPS rats via PI3K/AKT signaling pathway

Post-traumatic stress disorder (PTSD) is a severe mental illness that could impose heavy burdens on individuals and society, but effective and precise treatment modalities are unknown. The level of hydrogen sulfide (H2S) in the brain plays an important role in psychiatric diseases. However, it is still unclear whether PTSD exposure could affect the level of H2S and whether there is a correlation between H2S levels and the pathogenesis of PTSD. In this study, we selected single prolonged stress (SPS) as a PTSD model and found that SPS exposure decreased the endogenous H2S content accompanied by abnormal behavioral changes and dysregulation of the hippocampal synaptic plasticity in SPS rats. We further found that the exogenous administration of H2S could alleviate PTSD-like behaviors and improve hippocampal synaptic plasticity in SPS rats. In addition, we further used the phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002 to interfere with the PI3K/AKT/BDNF signaling pathway. It was found that LY294002 significantly blocked the anti-anxiety effect and the improvement in synaptic plasticity derived from the exogenous administration of H2S in SPS rats. These results suggested that the endogenous H2S content was decreased in SPS rats, and that the exogenous administration of H2S could ameliorate abnormal disorders and improve hippocampal synaptic plasticity by mediating the PI3K/AKT pathway.

Challenges and rewards of in vivo synaptic density imaging, and its application to the study of depression

The development of novel radiotracers for Positron Emission Tomography (PET) imaging agents targeting the synaptic vesicle glycoprotein 2 A (SV2A), an integral glycoprotein present in the membrane of all synaptic vesicles throughout the central nervous system, provides a method for the in vivo quantification of synaptic density. This is of particular interest in neuropsychiatric disorders given that synaptic alterations appear to underlie disease progression and symptom severity. In this review, we briefly describe the development of these SV2A tracers and the evaluation of quantification methods. Next, we discuss application of SV2A PET imaging to the study of depression, including a review of our findings demonstrating lower SV2A synaptic density in people with significant depressive symptoms and the use of a ketamine drug challenge to examine synaptogenesis in vivo. We then highlight the importance of performing translational PET imaging in animal models in conjunction with clinical imaging. We consider the ongoing challenges, possible solutions, and present preliminary findings from our lab demonstrating the translational benefit and potential of in vivo SV2A imaging in animal models of chronic stress. Finally, we discuss methodological improvements and future directions for SV2A imaging, potentially in conjunction with other neural markers.

Microglia-mediated neuroimmune suppression in PTSD is associated with anhedonia

Dynamic brain immune function in individuals with posttraumatic stress disorder is rarely studied, despite evidence of peripheral immune dysfunction. Positron emission tomography brain imaging using the radiotracer [11C]PBR28 was used to measure the 18-kDa translocator protein (TSPO), a microglial marker, at baseline and 3 h after administration of lipopolysaccharide (LPS), a potent immune activator. Data were acquired in 15 individuals with PTSD and 15 age-matched controls. The PTSD group exhibited a significantly lower magnitude LPS-induced increase in TSPO availability in an a priori prefrontal-limbic circuit compared to controls. Greater anhedonic symptoms in the PTSD group were associated with a more suppressed neuroimmune response. In addition, while a reduced granulocyte-macrophage colony-stimulating factor response to LPS was observed in the PTSD group, other measured cytokine responses and self-reported sickness symptoms did not differ between groups; these findings highlight group differences in central-peripheral immune system relationships. The results of this study provide evidence of a suppressed microglia-mediated neuroimmune response to a direct immune system insult in individuals with PTSD that is associated with the severity of symptoms. They also provide further support to an emerging literature challenging traditional concepts of microglial and immune function in psychiatric disease.

Findings of PTSD-specific deficits in default mode network strength following a mild experimental stressor

Reductions in default mode (DMN) connectivity strength have been reported in posttraumatic stress disorder (PTSD). However, the specificity of DMN connectivity deficits in PTSD compared to major depressive disorder (MDD), and the sensitivity of these alterations to acute stressors are not yet known. 52 participants with a primary diagnosis of PTSD (n = 28) or MDD (n = 24) completed resting-state functional magnetic resonance imaging immediately before and after a mild affective stressor. A 2 × 2 design was conducted to determine the effects of group, stress, and group*stress on DMN connectivity strength. Exploratory analyses were completed to identify the brain region(s) underlying the DMN alterations. There was significant group*stress interaction (p = 0.03), reflecting stress-induced reduction in DMN strength in PTSD (p = 0.02), but not MDD (p = 0.50). Nodal exploration of connectivity strength in the DMN identified regions of the ventromedial prefrontal cortex and the precuneus potentially contributing to DMN connectivity deficits. The findings indicate the possibility of distinct, disease-specific, patterns of connectivity strength reduction in the DMN in PTSD, especially following an experimental stressor. The identified dynamic shift in functional connectivity, which was perhaps induced by the stressor task, underscores the potential utility of the DMN connectivity and raises the question whether these disruptions may be inversely affected by antidepressants known to treat both MDD and PTSD psychopathology.

Maternal deprivation causes CaMKII downregulation and modulates glutamate, norepinephrine and serotonin in limbic brain areas in a rat model of single prolonged stress

BACKGROUND

Early life stress is a major risk factor for later development of psychiatric disorders, including post-traumatic stress disorder (PTSD). An intricate relationship exists between various neurotransmitters (such as glutamate, norepinephrine or serotonin), calcium/calmodulin-dependent protein kinase II (CaMKII), as an important regulator of glutamatergic synaptic function, and PTSD. Here, we developed a double-hit model to investigate the interaction of maternal deprivation (MD) as an early life stress model and single prolonged stress (SPS) as a PTSD model at the behavioral and molecular levels.

METHODS

Male Wistar rats exposed to these stress paradigms were subjected to a comprehensive behavioral analysis. In hippocampal synaptosomes we investigated neurotransmitter release and glutamate concentration. The expression of CaMKII and the content of monoamines were determined in selected brain regions. Brain-derived neurotrophic factor (BDNF) mRNA was quantified by radioactive in situ hybridization.

RESULTS

We report a distinct behavioral phenotype in the double-hit group. Double-hit and SPS groups had decreased hippocampal presynaptic glutamatergic function. In hippocampus, double-hit stress caused a decrease in autophosphorylation of CaMKII. In prefrontal cortex, both SPS and double-hit stress had a similar effect on CaMKII autophosphorylation. Double-hit stress, rather than SPS, affected the norepinephrine and serotonin levels in prefrontal cortex, and suppressed BDNF gene expression in prefrontal cortex and hippocampus.

LIMITATIONS

The study was conducted in male rats only. The affected brain regions cannot be restricted to hippocampus, prefrontal cortex and amygdala.

CONCLUSION

Double-hit stress caused more pronounced and distinct behavioral, molecular and functional changes, compared to MD or SPS alone.

Psychedelic Therapy: A Primer for Primary Care Clinicians-Ketamine

BACKGROUND

Ketamine, an arylcyclohexylamine dissociative anesthetic agent, has evolved into a versatile therapeutic. It has a rapid-onset, well-understood cardiovascular effects and a favorable safety profile in clinical use. Its enantiomeric compound, esketamine, was approved by the Food and Drug Administration in 2019 for both treatment-resistant depression and major depressive disorder with suicidal ideation.

AREAS OF UNCERTAINTY

Research indicates dose-dependent impacts on cognition, particularly affecting episodic and working memory following both acute administration and chronic use, albeit temporarily for the former and potentially persistent for the latter. Alongside acute risks to cardiovascular stability, ketamine use poses potential liver toxicity concerns, especially with prolonged or repeated exposure within short time frames. The drug's association with "ketamine cystitis," characterized by bladder inflammation, adds to its profile of physiological risks.

THERAPEUTIC ADVANCES

Data demonstrate a single intravenous infusion of ketamine exhibits antidepressant effects within hours (weighted effect size averages of depression scores (N = 518) following a single 0.5 mg/kg infusion of ketamine is d = 0.96 at 24 hours). Ketamine is also effective at reducing posttraumatic stress disorder (PTSD) symptom severity following repeated infusions (Clinician-Administered PTSD Scale scores: -11.88 points compared with midazolam control). Ketamine also decreased suicidal ideation in emergency settings (Scale for Suicidal Ideation scores: -4.96 compared with midazolam control). Through its opioid-sparing effect, ketamine has revolutionized postoperative pain management by reducing analgesic consumption and enhancing recovery.

LIMITATIONS

Many studies indicate that ketamine's therapeutic effects may subside within weeks. Repeated administrations, given multiple times per week, are often required to sustain decreases in suicidality and depressive symptoms.

CONCLUSIONS

Ketamine's comprehensive clinical profile, combined with its robust effects on depression, suicidal ideation, PTSD, chronic pain, and other psychiatric conditions, positions it as a substantial contender for transformative therapeutic application.

BLA DBS improves anxiety and fear by correcting weakened synaptic transmission from BLA to adBNST and CeL in a mouse model of foot shock

Deep brain stimulation (DBS) in the basal lateral amygdala (BLA) has been established to correct symptoms of refractory post-traumatic stress disorder (PTSD). However, how BLA DBS operates in correcting PTSD symptoms and how the BLA elicits pathological fear and anxiety in PTSD remain unclear. Here, we discover that excitatory synaptic transmission from the BLA projection neurons (PNs) to the adBNST, and lateral central amygdala (CeL) is greatly suppressed in a mouse PTSD model induced by foot shock (FS). BLA DBS revises the weakened inputs from the BLA to these two areas to improve fear and anxiety. Optogenetic manipulation of the BLA-adBNST and BLA-CeL circuits shows that both circuits are responsible for anxiety but the BLA-CeL for fear in FS mice. Our results reveal that synaptic transmission dysregulation of the BLA-adBNST or BLA-CeL circuits is reversed by BLA DBS, which improves anxiety and fear in the FS mouse model.

Ketamine-assisted psychotherapy, psychedelic methodologies, and the impregnable value of the subjective-a new and evolving approach

Psychiatry is in a growth phase in which several psychedelic medicines have entered its arena with great promise. Of these, presently, ketamine is the only medicine that may be legally prescribed. We hypothesize that at subanesthetic doses, ketamine produces a unique spectrum of altered states, ranging from psychoactive to deep ego-dissolving experiences, that are intrinsic to ketamine's therapeutic effects. When these experiences are embedded in a therapeutic relationship-a setting-that fosters an amplification of the recipient's subjective consciousness, personal growth, inner healing, greater clarity, and better relationships may well ensue. While much of the literature on ketamine labels its dissociative effects as 'side effects', alteration of consciousness is a component and unavoidable 'effect' of its therapeutic impact. From its inception in the clinical trials of the 1960s, ketamine was recognized for producing dissociative, psychedelic effects on consciousness in subjects as they emerged from ketamine-induced anesthesia. Unanticipated and unintegrated, these experiences of 'emergence phenomena' were felt to be disturbing. Accordingly, such experiences have been typically labeled as dissociative side effects. However, in a conducive set and settings, these experiences have been demonstrated to be of positive use in psychiatry and psychotherapy, providing a time-out from usual states of mind to facilitate a reshaping of self-experience along with symptomatic relief. In this way, ketamine-assisted psychotherapy (KAP) offers a new potential in psychiatry and psychotherapy that is powerfully valanced toward recognizing experience, individuality, and imagination. Essential to a successful therapeutic experience and outcome with KAP is close attention to the subjective experience, its expression by the recipient and integration of the ketamine experience as a healing opportunity.

Effectiveness of Ketamine for the Treatment of Post-Traumatic Stress Disorder - A Systematic Review and Meta-Analysis

Objective

Post-traumatic stress disorder (PTSD) is an enduring condition characterized by a chronic course and impairments across several areas. Despite its significance, treatment options remain limited, and remission rates are often low. Ketamine has demonstrated antidepressant properties and appears to be a promising agent in the management of PTSD.

Method

A systematic review was conducted in PubMed/MEDLINE, Cochrane Library, Clinicaltrials.gov, Lilacs, Scopus, and Embase, covering studies published between 2012 and December 2022 to assess the effectiveness of ketamine in the treatment of PTSD. Ten studies, consisting of five RCTs, two crossover trials, and three non-randomized trials, were included in the meta-analysis.

Results

Ketamine demonstrated significant improvements in PCL-5 scores, both 24 hours after the initial infusion and at the endpoint of the treatment course, which varied between 1 to 4 weeks in each study. Notably, the significance of these differences was assessed using the Two Sample T-test with pooled variance and the Two Sample Welch's T-test, revealing a statistically significant effect for ketamine solely at the endpoint of the treatment course (standardized effect size= 0.25; test power 0.9916; 95% CI = 0.57 to 17.02, p=0.0363). It is important to note that high heterogeneity was observed across all analyses.

Conclusions

Our findings suggest that ketamine holds promise as an effective treatment option for PTSD. However, further trials are imperative to establish robust data for this intervention.

So how special is special K? A systematic review and meta-analysis of ketamine for PTSD RCTs

Background: PTSD is a significant mental health problem worldwide. Current evidence-based interventions suffer various limitations. Ketamine is a novel agent that is hoped to be incrementally better than extant interventions.Objective: Several randomized control trials (RCTs) of ketamine interventions for PTSD have now been published. We sought to systematically review and meta-analyse results from these trials to evaluate preliminary evidence for ketamine's incremental benefit above-and-beyond control interventions in PTSD treatment.Results: Omnibus findings from 52 effect sizes extracted across six studies (n = 221) yielded a small advantage for ketamine over control conditions at reducing PTSD symptoms (g = 0.27, 95% CI = 0.03, 0.51). However, bias-correction estimates attenuated this effect (adjusted g = 0.20, 95%, CI = -0.08, 0.48). Bias estimates indicated smaller studies reported larger effect sizes favouring ketamine. The only consistent timepoint assessed across RCTs was 24-hours post-initial infusion. Effects at 24-hours post-initial infusion suggest ketamine has a small relative advantage over controls (g = 0.35, 95% CI = 0.06, 0.64). Post-hoc analyses at 24-hours post-initial infusion indicated that ketamine was significantly better than passive controls (g = 0.44, 95% CI = 0.03, 0.85), but not active controls (g = 0.24, 95% CI = -0.30, 0.78). Comparisons one-week into intervention suggested no meaningful group differences (g = 0.24, 95% CI = 0.00, 0.48). No significant differences were evident for RCTs that examined effects two-weeks post initial infusion (g = 0.17, 95% CI = -0.10, 0.44).Conclusions: Altogether, ketamine-for-PTSD RCTs reveal a nominal initial therapeutic advantage relative to controls. However, bias and heterogeneity appear problematic. While rapid acting effects were observed, all control agents (including saline) also evidenced rapid acting effects. We argue blind penetration to be a serious concern, and that placebo is the likely mechanism behind reported therapeutic effects.

Microglia are necessary for probiotics supplementation to improve impaired fear extinction caused by pregnancy stress in adult offspring of rats

The prevention and treatment of fear-related disorders in offspring affected by pregnancy stress remains challenging at clinic. Here, we examined the effects of gut microbiota of stressed pregnant rats on the fear extinction of their offsprings, and the potential mechanisms. We found that gut microbiota transplantation from rats with pregnancy stress to normal pregnant rats impaired fear extinction, induced microglial activation and synaptic phagocytosis, increased synapse loss in offsprings. Probiotics supplement during pregnancy stress partly normalized pregnancy stress-induced gut microbiota dysbiosis of pregnant rats, and promoted fear memory extinction, inhibited fear memory reappearance, and limited microglial activation and synaptic phagocytosis in offsprings. These data revealed that gut microbiota of stressed pregnant mother improved the development of fear-related disorders of offspring, which may be associated with microglial synaptic pruning.

The Psychedelic Future of Post-Traumatic Stress Disorder Treatment

Post-traumatic stress disorder (PTSD) is a mental health condition that can occur following exposure to a traumatic experience. An estimated 12 million U.S. adults are presently affected by this disorder. Current treatments include psychological therapies (e.g., exposure-based interventions) and pharmacological treatments (e.g., selective serotonin reuptake inhibitors (SSRIs)). However, a significant proportion of patients receiving standard-of-care therapies for PTSD remain symptomatic, and new approaches for this and other trauma-related mental health conditions are greatly needed. Psychedelic compounds that alter cognition, perception, and mood are currently being examined for their efficacy in treating PTSD despite their current status as Drug Enforcement Administration (DEA)- scheduled substances. Initial clinical trials have demonstrated the potential value of psychedelicassisted therapy to treat PTSD and other psychiatric disorders. In this comprehensive review, we summarize the state of the science of PTSD clinical care, including current treatments and their shortcomings. We review clinical studies of psychedelic interventions to treat PTSD, trauma-related disorders, and common comorbidities. The classic psychedelics psilocybin, lysergic acid diethylamide (LSD), and N,N-dimethyltryptamine (DMT) and DMT-containing ayahuasca, as well as the entactogen 3,4-methylenedioxymethamphetamine (MDMA) and the dissociative anesthetic ketamine, are reviewed. For each drug, we present the history of use, psychological and somatic effects, pharmacology, and safety profile. The rationale and proposed mechanisms for use in treating PTSD and traumarelated disorders are discussed. This review concludes with an in-depth consideration of future directions for the psychiatric applications of psychedelics to maximize therapeutic benefit and minimize risk in individuals and communities impacted by trauma-related conditions.

Bedside to bench: the outlook for psychedelic research

There has recently been a resurgence of interest in psychedelic compounds based on studies demonstrating their potential therapeutic applications in treating post-traumatic stress disorder, substance abuse disorders, and treatment-resistant depression. Despite promising efficacy observed in some clinical trials, the full range of biological effects and mechanism(s) of action of these compounds have yet to be fully established. Indeed, most studies to date have focused on assessing the psychological mechanisms of psychedelics, often neglecting the non-psychological modes of action. However, it is important to understand that psychedelics may mediate their therapeutic effects through multi-faceted mechanisms, such as the modulation of brain network activity, neuronal plasticity, neuroendocrine function, glial cell regulation, epigenetic processes, and the gut-brain axis. This review provides a framework supporting the implementation of a multi-faceted approach, incorporating in silico, in vitro and in vivo modeling, to aid in the comprehensive understanding of the physiological effects of psychedelics and their potential for clinical application beyond the treatment of psychiatric disorders. We also provide an overview of the literature supporting the potential utility of psychedelics for the treatment of brain injury (e.g., stroke and traumatic brain injury), neurodegenerative diseases (e.g., Parkinson's and Alzheimer's diseases), and gut-brain axis dysfunction associated with psychiatric disorders (e.g., generalized anxiety disorder and major depressive disorder). To move the field forward, we outline advantageous experimental frameworks to explore these and other novel applications for psychedelics.

Novel Pharmacological Targets of Post-Traumatic Stress Disorders

Post-traumatic stress disorder (PTSD) is a psychopathological condition with a heterogeneous clinical picture that is complex and challenging to treat. Its multifaceted pathophysiology still remains an unresolved question and certainly contributes to this issue. The pharmacological treatment of PTSD is mainly empirical and centered on the serotonergic system. Since the therapeutic response to prescribed drugs targeting single symptoms is generally inconsistent, there is an urgent need for novel pathogenetic hypotheses, including different mediators and pathways. This paper was conceived as a narrative review with the aim of debating the current pharmacological treatment of PTSD and further highlighting prospective targets for future drugs. The authors accessed some of the main databases of scientific literature available and selected all the papers that fulfilled the purpose of the present work. The results showed that most of the current pharmacological treatments for PTSD are symptom-based and show only partial benefits; this largely reflects the limited knowledge of its neurobiology. Growing, albeit limited, data suggests that the hypothalamic-pituitary-adrenal axis, opioids, glutamate, cannabinoids, oxytocin, neuropeptide Y, and microRNA may play a role in the development of PTSD and could be targeted for novel treatments. Indeed, recent research indicates that examining different pathways might result in the development of novel and more efficient drugs.

Assessing and Modelling of Post-Traumatic Stress Disorder Using Molecular and Functional Biomarkers

Post-traumatic stress disorder (PTSD) is a complex psychological disorder that develops following exposure to traumatic events. PTSD is influenced by catalytic factors such as dysregulated hypothalamic-pituitary-adrenal (HPA) axis, neurotransmitter imbalances, and oxidative stress. Genetic variations may act as important catalysts, impacting neurochemical signaling, synaptic plasticity, and stress response systems. Understanding the intricate gene networks and their interactions is vital for comprehending the underlying mechanisms of PTSD. Focusing on the catalytic factors of PTSD is essential because they provide valuable insights into the underlying mechanisms of the disorder. By understanding these factors and their interplay, researchers may uncover potential targets for interventions and therapies, leading to more effective and personalized treatments for individuals with PTSD. The aforementioned gene networks, composed of specific genes associated with the disorder, provide a comprehensive view of the molecular pathways and regulatory mechanisms involved in PTSD. Through this study valuable insights into the disorder's underlying mechanisms and opening avenues for effective treatments, personalized interventions, and the development of biomarkers for early detection and monitoring are provided.

A Randomized Controlled Trial of Repeated Ketamine Administration for Chronic Posttraumatic Stress Disorder

Objective

Posttraumatic stress disorder (PTSD) is a chronic and disabling disorder, for which available pharmacotherapies have limited efficacy. The authors' previous proof-of-concept randomized controlled trial of single-dose intravenous ketamine infusion in individuals with PTSD showed significant and rapid PTSD symptom reduction 24 hours postinfusion. The present study is the first randomized controlled trial to test the efficacy and safety of repeated intravenous ketamine infusions for the treatment of chronic PTSD.

Methods

Individuals with chronic PTSD (N=30) were randomly assigned (1:1) to receive six infusions of ketamine (0.5 mg/kg) or midazolam (0.045 mg/kg) (psychoactive placebo control) over 2 consecutive weeks. Clinician-rated and self-report assessments were administered 24 hours after the first infusion and at weekly visits. The primary outcome measure was change in PTSD symptom severity, as assessed with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), from baseline to 2 weeks (after completion of all infusions). Secondary outcome measures included the Impact of Event Scale-Revised, the Montgomery-Åsberg Depression Rating Scale (MADRS), and side effect measures.

Results

The ketamine group showed a significantly greater improvement in CAPS-5 and MADRS total scores than the midazolam group from baseline to week 2. At week 2, the mean CAPS-5 total score was 11.88 points (SE=3.96) lower in the ketamine group than in the midazolam group (d=1.13, 95% CI=0.36, 1.91). Sixty-seven percent of participants in the ketamine group were treatment responders, compared with 20% in the midazolam group. Among ketamine responders, the median time to loss of response was 27.5 days following the 2-week course of infusions. Ketamine infusions were well tolerated overall, without serious adverse events.

Conclusions

This randomized controlled trial provides the first evidence of efficacy of repeated ketamine infusions in reducing symptom severity in individuals with chronic PTSD. Further studies are warranted to understand ketamine's full potential as a treatment for chronic PTSD.Reprinted from Am J Psychiatry 2021; 178:193-202, with permission from American Psychiatric Association Publishing. Copyright © 2021.

Recent advances in the role of miRNAs in post-traumatic stress disorder and traumatic brain injury

Post-traumatic stress disorder (PTSD) is usually considered a psychiatric disorder upon emotional trauma. However, with the rising number of conflicts and traffic accidents around the world, the incidence of PTSD has skyrocketed along with traumatic brain injury (TBI), a complex neuropathological disease due to external physical force and is also the most common concurrent disease of PTSD. Recently, the overlap between PTSD and TBI is increasingly attracting attention, as it has the potential to stimulate the emergence of novel treatments for both conditions. Of note, treatments exploiting the microRNAs (miRNAs), a well-known class of small non-coding RNAs (ncRNAs), have rapidly gained momentum in many nervous system disorders, given the miRNAs' multitudinous and key regulatory role in various biological processes, including neural development and normal functioning of the nervous system. Currently, a wealth of studies has elucidated the similarities of PTSD and TBI in pathophysiology and symptoms; however, there is a dearth of discussion with respect to miRNAs in both PTSD and TBI. In this review, we summarize the recent available studies of miRNAs in PTSD and TBI and discuss and highlight promising miRNAs therapeutics for both conditions in the future.

White Matter Microstructure Is Associated with Serum Neuroactive Steroids and Psychological Functioning

Military service members are at increased risk for mental health issues, and comorbidity with mild traumatic brain injury (mTBI) is common. Largely overlapping symptoms between conditions suggest a shared pathophysiology. The present work investigates the associations among white matter microstructure, psychological functioning, and serum neuroactive steroids that are part of the stress-response system. Diffusion-weighted brain imaging was acquired from 163 participants (with and without military affiliation) and free-water-corrected fractional anisotropy (FAT) was extracted. Associations between serum neurosteroid levels of allopregnanolone (ALLO) and pregnenolone (PREGNE), psychological functioning, and whole-brain white matter microstructure were assessed using regression models. Moderation models tested the effect of mTBI and comorbid post-traumatic stress disorder (PTSD) and mTBI on these associations. ALLO is associated with whole-brain white matter FAT (β = 0.24, t = 3.05, p = 0.006). This association is significantly modulated by PTSD+mTBI comorbidity (β = 0.00, t = 2.50, p = 0.027), although an mTBI diagnosis alone did not significantly impact this association (p = 0.088). There was no significant association between PREGNE and FAT (p = 0.380). Importantly, lower FAT is associated with poor psychological functioning (β = -0.19, t = -2.35, p = 0.020). This study provides novel insight into a potential common pathophysiological mechanism of neurosteroid dysregulation underlying the high risk for mental health issues in military service members. Further, comorbidity of PTSD and mTBI may bring the compensatory effects of the brain's stress response to their limit. Future research is needed to investigate whether neurosteroid regulation may be a promising tool for restoring brain health and improving psychological functioning.

Ketamine as a therapeutic agent in major depressive disorder and posttraumatic stress disorder: Potential medicinal and deleterious effects

Major depressive disorder (MDD) and posttraumatic stress disorder (PTSD) are the most common causes of emotional distress that impair an individual's quality of life. MDD is a chronic mental illness that affects 300 million people across the world. Clinical manifestations of MDD include fatigue, loss of interest in routine tasks, psychomotor agitation, impaired ability to focus, suicidal ideation, hypersomnolence, altered psychosocial functioning, and appetite loss. Individuals with depression also demonstrate a reduced behavioral response while experiencing pleasure, a symptom known as anhedonia. Like MDD, PTSD is a prevalent and debilitating psychiatric disorder resulting from a traumatic incident such as sexual assault, war, severe accident, or natural disaster. Symptoms such as recalling event phases, hypervigilance, irritability, and anhedonia are common in PTSD. Both MDD and PTSD pose enormous socioeconomic burdens across the globe. The search for effective treatment with minimal side effects is still ongoing. Ketamine is known for its anesthetic and analgesic properties. Psychedelic and psychotropic effects of ketamine have been found on the nervous system, which highlights its toxicity. In this article, the effectiveness of ketamine as a potential therapeutic for PTSD and MDD along with its mechanisms of action, clinical trials, and possible side effects have been discussed.

Immune-metabolic mechanisms of post-traumatic stress disorder and atherosclerosis

The interaction of post-traumatic stress disorder (PTSD) and atherosclerosis (AS) increase the risk of mortality. Metabolism and immunity play important roles in the comorbidity associated with PTSD and AS. The adenosine monophosphate-activated protein kinase/mammalian target of rapamycin and phosphatidylinositol 3-kinase/Akt pathways are attractive research topics in the fields of metabolism, immunity, and autophagy. They may be effective intervention targets in the prevention and treatment of PTSD comorbidity with AS. Herein, we comprehensively review metabolic factors, including glutamate and lipid alterations, in PTSD comorbidity with AS and discuss the possible implications in the pathophysiology of the diseases.

Toward staging differentiation for posttraumatic stress disorder treatment

OBJECTIVES

Several medical and psychiatric disorders have stage-based treatment decision-making methods. However, international treatment guidelines for posttraumatic stress disorder (PTSD) fail to give specific treatment recommendations based on chronicity or stage of the disorder. There is convincing evidence of a finite range of PTSD symptom trajectories, implying that different phenotypes of the disorder can be distinguished, which are highly relevant for a staging typology of PTSD.

METHODS

State-of-the-art review building on prior work on staging models in other disorders as a mapping tool to identify and synthesize toward PTSD.

RESULTS

We propose a four-stage model of PTSD ranging from stage 0: trauma-exposed asymptomatic but at risk to stage 4: severe unremitting illness of increasing chronicity. We favor a symptom description in various chronological characteristics based on neurobiological markers, information processing systems, stress reactivity, and consciousness dimensions. We also advocate for a separate phenomenology of treatment resistance since this can yield treatment recommendations.

CONCLUSION

A staging perspective in the field of PTSD is highly needed. This can facilitate the selection of interventions that are proportionate to patients' current needs and risk of illness progression and can also contribute to an efficient framework to organize biomarker data and guide service delivery. Therefore, we propose that a neurobiologically driven trajectory-based typology of PTSD can help deduct several treatment recommendations leading to a more personalized and refined grid to strategize, plan and evaluate treatment interventions.

The potential of ketamine for posttraumatic stress disorder: a review of clinical evidence

Posttraumatic stress disorder (PTSD) is a devastating condition, for which there are few pharmacological agents, often with a delayed onset of action and poor efficacy. Trauma-focused psychotherapies are further limited by few trained providers and low patient engagement. This frequently results in disease chronicity as well as psychiatric and medical comorbidity, with considerable negative impact on quality of life. As such, off-label interventions are commonly used for PTSD, particularly in chronic refractory cases. Ketamine, an N-methyl-D-aspartate (NDMA) receptor antagonist, has recently been indicated for major depression, exhibiting rapid and robust antidepressant effects. It also shows transdiagnostic potential for an array of psychiatric disorders. Here, we synthesize clinical evidence on ketamine in PTSD, spanning case reports, chart reviews, open-label studies, and randomized trials. Overall, there is high heterogeneity in clinical presentation and pharmacological approach, yet encouraging signals of therapeutic safety, efficacy, and durability. Avenues for future research are discussed.

Individual behavioral profiling as a translational approach to assess treatment efficacy in an animal model of post-traumatic stress disorder

A major challenge in treating post-traumatic stress disorder (PTSD) continues to be the large variability in responsiveness to pharmacotherapy. Only 20-30% of patients experience total remission to a specific treatment, while others demonstrate either partial remission or no response. However, this heterogeneity in response to pharmacotherapy has not been adequately addressed in animal models, since these analyze the averaged group effects, ignoring the individual variability to treatment response, which seriously compromises the translation power of such models. Here we examined the possibility of employing an "individual behavioral profiling" approach, originally developed to differentiate between "affected" and "exposed-unaffected" individuals in an animal model of PTSD, to also enable dissociating "responders" or "non-responders" after SSRI (fluoxetine) treatment. Importantly, this approach does not rely on a group averaged response to a single behavioral parameter, but considers a cluster of behavioral parameters, to individually characterize an animal as either "responder" or "non-responder" to the treatment. The main variable to assess drug efficacy thus being the proportion of "responders" following treatment. Alteration in excitatory/inhibitory (E/I) balance has been proposed as being associated with stress-related psychopathology. Toward a functional proof of concept for our behaviorally-based characterization approach, we examined the expression patterns of α1 and α2 subunits of GABA_A receptor, and GluN1 and GluN2A subunits of the NMDAR receptor in the ventral hippocampus, as well as electrophysiologically local circuit activity in the dorsal dentate gyrus (DG). We demonstrate that with both parameters, treatment "responders" differed from treatment "non-responders," confirming the functional validity of the behavior-based categorization. The results suggest that the ability to respond to fluoxetine treatment may be linked to the ability to modulate excitation-inhibition balance in the hippocampus. We propose that employing the "individual behavioral profiling" approach, and the resultant novel variable of the proportion of "recovered" individuals following treatment, offers an effective translational tool to assess pharmacotherapy treatment efficacy in animal models of stress and trauma-related psychopathology.

Stress, mental disorder and ketamine as a novel, rapid acting treatment

The experience of stress is often utilised in models of emerging mental illness and neurobiological systems are implicated as the intermediary link between the experience of psychological stress and the development of a mental disorder. Chronic stress and prolonged glucocorticoid exposure have potent effects on neuronal architecture particularly in regions that modulate the hypothalamic-pituitary-adrenal (HPA) axis and are commonly associated with psychiatric disorders. This review provides an overview of stress modulating neurobiological and neurochemical systems which underpin stress-related structural and functional brain changes. These changes are thought to contribute not only to the development of disorders, but also to the treatment resistance and chronicity seen in some of our most challenging mental disorders. Reports to date suggest that stress-related psychopathology is the aetiological mechanism of these disorders and thus we review the rapid acting antidepressant ketamine as an effective emerging treatment. Ketamine, an N-methyl D-aspartate (NMDA) receptor antagonist, is shown to induce a robust treatment effect in mental disorders via enhanced synaptic strength and connectivity in key brain regions. Whilst ketamine's glutamatergic effect has been previously examined, we further consider ketamine's capacity to modulate the HPA axis and associated pathways.

(2R,6R)-hydroxynorketamine acts through GluA1-induced synaptic plasticity to alleviate PTSD-like effects in rat models

Post-traumatic stress disorder (PTSD) is a debilitating mental disorder with high morbidity and great social and economic relevance. However, extant pharmacotherapies of PTSD require long-term use to maintain effectiveness and have enormous side effects. The glutamatergic system, especially the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), is an important target of current research on the mechanism of PTSD. Postsynaptic AMPAR function and expression are known to be increased by (2R, 6R)-hydronorketamine (HNK), the primary metabolite of ketamine. However, whether (2R,6R)-HNK alleviates PTSD-like effects via AMPAR upregulation is yet to be known. In the present study, rats were exposed to single prolonged stress and electric foot shock (SPS&S). Afterwards, gradient concentrations of (2R,6R)-HNK (20, 50, and 100 μM) were administered by intracerebroventricular (i.c.v.) injection. Open field, elevated plus maze, freezing behavior, and forced swimming tests were used to examine PTSD-like symptoms. In addition, the protein levels of GluA1, BDNF and PSD-95 were analyzed using western blotting and immunofluorescence, and the synaptic ultrastructure of the prefrontal cortex (PFC) was observed by transmission electron microscopy. We found that (2R,6R)-HNK changed SPS&S-induced behavioral expression, such as increasing autonomous activity and residence time in the open arm and decreasing immobility time. Likewise, (2R,6R)-HNK (50 μM) increased GluA1, BDNF, and PSD-95 protein expression in the PFC. Changes in synaptic ultrastructure induced by SPS&S were reversed by administration of (2R,6R)-HNK. Overall, we find that (2R,6R)-HNK can ameliorate SPS&S-induced fear avoidance in rats, as well as rat cognates of anxiety and depression. This may be related to GluA1-mediated synaptic plasticity in the PFC.

The Efficacy of Psychedelic-Assisted Therapy in Managing Post-traumatic Stress Disorder (PTSD): A New Frontier?

Post-traumatic stress disorder (PTSD) is a significant public health concern for which existing therapies are only marginally effective. Indisputably, the primary line of treatment for PTSD is psychotherapy, according to current treatment guidelines. However, PTSD continues to be a chronic condition even after psychotherapy, with high psychiatric and medical illness rates. There is a dire need to search for new compounds and approaches for managing PTSD. The usage of psychedelic substances is a potential new method. This article reviews the efficacy of psychedelic-assisted therapy in treating PTSD and improving patient outcomes. It will examine current research on the topic and evaluate the benefits and drawbacks of different therapies. The current evidence for the use of four different types of psychedelics (3,4-methylenedioxymethamphetamine, ketamine, classical psychedelics, and cannabis) in the treatment of PTSD will be reviewed. It will also include an overview of the therapeutic justification, context of use, and level of evidence available for each drug. Several questions are formulated that could be studied in future research in order to gain a better understanding of the topic.

Intra-mPFC injection of sodium butyrate promotes BDNF expression and ameliorates extinction recall impairment in an experimental paradigm of post-traumatic stress disorder

Objectives

Therapeutic strategies that facilitate extinction are promising in the treatment of post-traumatic stress disorder (PTSD). Brain-derived neurotrophic factor (BDNF) has a crucial role in neural plasticity, a process needed for the retention of fear extinction. In this study, we investigated the effects of local administration of a histone deacetylase (HDAC) inhibitor, sodium butyrate (NaBu), on BDNF transcription and behavioral markers of extinction in the single prolonged stress (SPS) model of PTSD.

Materials and Methods

NaBu was infused into the infralimbic (IL) subregion of the medial prefrontal cortex (mPFC) of male rats. The freezing response was recorded as the criterion to assess fear strength on the day of extinction as well as 24 hr later in the retention test. Other behavioral tests were also measured to evaluate the anxiety level, locomotor activity, and working memory on the retention day. HDAC activity and BDNF mRNA expression were evaluated after the behavioral experiments.

Results

NaBu facilitated the recall of fear extinction in SPS rats (P<0.0001). SPS rats had higher HDAC activity (P<0.0001) and lower BDNF expression (P<0.05) than non-SPS animals. Also, anxiety was higher in the SPS group (P<0.0001), but locomotor activity (P=0.61) and working memory (P=0.36) were not different between SPS and Non-SPS groups.

Conclusion

Our findings provide evidence that the mechanism of action of NaBu in the improvement of extinction recall is mediated, in part, by enhancing histone acetylation and reviving BDNF expression in IL.

Progress in Personalized Psychiatric Therapy with the Example of Using Intranasal Oxytocin in PTSD Treatment

Post-traumatic stress disorder (PTSD) is a severe mental disorder that results in the frequent coexistence of other diseases, lowers patients' quality of life, and has a high annual cost of treatment. However, despite the variety of therapeutic approaches that exist, some patients still do not achieve the desired results. In addition, we may soon face an increase in the number of new PTSD cases because of the current global situation-both the COVID-19 pandemic and the ongoing armed conflicts. Hence, in recent years, many publications have sought a new, more personalized treatment approach. One such approach is the administration of intranasal oxytocin (INOXT), which, due to its pleiotropic effects, seems to be a promising therapeutic option. However, the current findings suggest that it might only be helpful for a limited, strictly selected group of patients.

Involvement of Nuclear Factor-κB in Inflammation and Neuronal Plasticity Associated with Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition which develops either due to stress or witnessing a traumatic situation. PTSD is characterized by acute and chronic stress response exhibit anxiety, fear, and an increased inflammatory etiology. Inflammation contributes a critical role in several parts of the brain that control fear and flashback cognatic function. It is known that impairment of the neurological circuit leads to the development of PTSD. Evidence has suggested that dysregulation of the sympathetic nervous system and hypothalamic-pituitary adrenal (HPA) axis and inflammatory responsiveness are pivotal and a greater risk in PTSD. NF-κB, a master regulator for inflammation, has been showed to modulate memory reconsolidation and synaptic plasticity; however, NF-κB’s association with PTSD remain elusive. In this review, we provide relevant findings regarding NF-κB activity in various components of brain and describe a potential mechanism linking PTSD using preclinical and clinical models. We envisage NF-κB signaling as a crucial mediator for inflammation, cognitive function, memory restoration and behavioral actions of stress and suggest that it could be used for therapeutic intervention in PTSD.

Psychoactive Drugs in the Management of Post Traumatic Stress Disorder: A Promising New Horizon

Post-traumatic stress disorder (PTSD) is an anxiety disorder that often presents after exposure to a traumatic, life-threatening event. Experiencing a traumatic event is not rare, with inciting incidents ranging from being burglarized to politically motivated genocide. While traditional psychopharmacology and psychotherapy are the mainstays of the treatment of PTSD currently, psychoactive drugs (otherwise known as psychedelics) are being explored for their novel role in the treatment of PTSD patients. Psychoactive drugs such as MDMA, ketamine, and psilocybin have been shown to specifically target and decrease fear and anxiety pathways in the brain. These unique properties hold the potential to be utilized in addressing symptoms of trauma in those with refractory or treatment-resistant PTSD. Historically, federal and state laws have restricted research into how psychoactive drugs can be used to treat mental illness due to the widespread belief that these drugs present more harm than benefit. However, the current shift in public opinion on psychedelics has propelled research to look into the benefits of these drugs for patients with mental illness. This article aims to discuss the mechanisms of how MDMA, ketamine, and psilocybin work in the PTSD brain, as well as their beneficial role in treatment.

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.

Prefrontal Glutamate Neurotransmission in PTSD: A Novel Approach to Estimate Synaptic Strength in Vivo in Humans

Background

Trauma and chronic stress are believed to induce and exacerbate psychopathology by disrupting glutamate synaptic strength. However, in vivo in human methods to estimate synaptic strength are limited. In this study, we established a novel putative biomarker of glutamatergic synaptic strength, termed energy-per-cycle (EPC). Then, we used EPC to investigate the role of prefrontal neurotransmission in trauma-related psychopathology.

Methods

Healthy controls (n = 18) and patients with posttraumatic stress (PTSD; n = 16) completed ¹³C-acetate magnetic resonance spectroscopy (MRS) scans to estimate prefrontal EPC, which is the ratio of neuronal energetic needs per glutamate neurotransmission cycle (V_TCA/V_Cycle).

Results

Patients with PTSD were found to have 28% reduction in prefrontal EPC (t = 3.0; df = 32, P = .005). There was no effect of sex on EPC, but age was negatively associated with prefrontal EPC across groups (r = -0.46, n = 34, P = .006). Controlling for age did not affect the study results.

Conclusion

The feasibility and utility of estimating prefrontal EPC using ¹³C-acetate MRS were established. Patients with PTSD were found to have reduced prefrontal glutamatergic synaptic strength. These findings suggest that reduced glutamatergic synaptic strength may contribute to the pathophysiology of PTSD and could be targeted by new treatments.

Acute Ketamine Facilitates Fear Memory Extinction in a Rat Model of PTSD Along With Restoring Glutamatergic Alterations and Dendritic Atrophy in the Prefrontal Cortex

Stress represents a major risk factor for psychiatric disorders, including post-traumatic stress disorder (PTSD). Recently, we dissected the destabilizing effects of acute stress on the excitatory glutamate system in the prefrontal cortex (PFC). Here, we assessed the effects of single subanesthetic administration of ketamine (10 mg/kg) on glutamate transmission and dendritic arborization in the PFC of footshock (FS)-stressed rats, along with changes in depressive, anxious, and fear extinction behaviors. We found that ketamine, while inducing a mild increase of glutamate release in the PFC of naïve rats, blocked the acute stress-induced enhancement of glutamate release when administered 24 or 72 h before or 6 h after FS. Accordingly, the treatment with ketamine 6 h after FS also reduced the stress-dependent increase of spontaneous excitatory postsynaptic current (sEPSC) amplitude in prelimbic (PL)-PFC. At the same time, ketamine injection 6 h after FS was found to rescue apical dendritic retraction of pyramidal neurons induced by acute stress in PL-PFC and facilitated contextual fear extinction. These results show rapid effects of ketamine in animals subjected to acute FS, in line with previous studies suggesting a therapeutic action of the drug in PTSD models. Our data are consistent with a mechanism of ketamine involving re-establishment of synaptic homeostasis, through restoration of glutamate release, and structural remodeling of dendrites.

Imaging the effect of ketamine on synaptic density (SV2A) in the living brain

The discovery of ketamine as a rapid and robust antidepressant marks the beginning of a new era in the treatment of psychiatric disorders. Ketamine is thought to produce rapid and sustained antidepressant effects through restoration of lost synaptic connections. We investigated this hypothesis in humans for the first time using positron emission tomography (PET) and [¹¹C]UCB-J-a radioligand that binds to the synaptic vesicle protein 2A (SV2A) and provides an index of axon terminal density. Overall, we did not find evidence of a measurable effect on SV2A density 24 h after a single administration of ketamine in non-human primates, healthy controls (HCs), or individuals with major depressive disorder (MDD) and/or posttraumatic stress disorder (PTSD), despite a robust reduction in symptoms. A post-hoc, exploratory analysis suggests that patients with lower SV2A density at baseline may exhibit increased SV2A density 24 h after ketamine. This increase in SV2A was associated with a reduction in depression severity, as well as an increase in dissociative symptoms. These initial findings suggest that a restoration of synaptic connections in patients with lower SV2A at baseline may underlie ketamine's therapeutic effects, however, this needs replication in a larger sample. Further work is needed to build on these initial findings and further establish the nuanced pre- and post-synaptic mechanisms underpinning ketamine's therapeutic effects.

Oral ketamine reduces the experience of stress in people with chronic suicidality

BACKGROUND

Stress is prevalent in people experiencing suicidality and is a major contributor to the development of mental disorders. Evidence suggests ketamine shows capacity to reverse stress-induced brain changes. Though stress and ketamine have been explored individually for suicidality, this study is the first to examine ketamine treatment for self-reported stress in adults with chronic suicidality, building on pre-clinical evidence of ketamine's capacity to normalize stress-induced responses and contributing to our understanding of oral ketamine in clinical populations.

METHODS

Thirty two adult participants (22-72 years; 17 female) with chronic suicidality completed 6 weeks of active treatment, receiving low (0.5 mg/kg - 3.0 mg/kg) doses of oral ketamine once per week, with a 4-week follow-up phase, to assess the effect of ketamine on their perceived stress. Stress was measured via self-report utilizing the Depression Anxiety Stress Scale-21(DASS-21), and analysed at pre-treatment (week 0), post-treatment (week 6) and at follow-up (week 10).

RESULTS

Repeated measures ANOVA showed a significant reduction in stress (p<.001) post-treatment and Reliable Change Index calculations confirmed this to be clinically significant. Furthermore, those classified as 'prolonged responders' demonstrated a sustained reduction in stress at follow-up (i.e. after 4 weeks of nil ketamine).

LIMITATIONS

Small sample size, open label design, expectancy, secondary analysis CONCLUSIONS: Ketamine showed the capacity to produce a robust and sustained improvement in stress symptoms, in people with chronic suicidality. Future larger, controlled studies examining treatment suitability in a range of stress related disorders are warranted.

Utility of 7,8-dihydroxyflavone in preventing astrocytic and synaptic deficits in the hippocampus elicited by PTSD

Astrocytic functions and brain-derived neurotrophic factor (BDNF)-tyrosine kinase receptor B (TrkB) signaling pathways are impaired in stress-related neuropsychiatric diseases. Previous studies have reported neuroprotective effects of 7,8-dihydroxyflavone (7,8-DHF), a TrkB activator. Here, we investigated the molecular mechanisms underlying pathogenesis of post-traumatic stress disorder (PTSD) using a modified single-prolonged stress (SPS&S) model and the potential beneficial effects of 7,8-DHF. SPS&S reduced the hippocampal expression of glial fibrillary acidic protein (GFAP), a marker of astrocytes, and induced morphological changes in astrocytes. From the perspective of synaptic function, the SPS&S model displayed reduced expression of BDNF, p-TrkB, postsynaptic density protein 95 (PSD95), AMPA receptor subunit GluR1 (GluA1), NMDA receptor subunit N2A/N2B ratio, calpain-1, phosphorylated protein kinase B (Akt) and phosphorylated mammalian target of rapamycin (mTOR) and conversely, higher phosphatase and tension homolog (PTEN) expression in the hippocampus. Acute or continuous intraperitoneal administration of 7,8-DHF (5 mg/kg) after SPS&S procedures prevented SPS&S-induced fear memory generalization and anxiety-like behaviors as well as abnormalities of hippocampal oscillations. Most importantly, 7,8-DHF attenuated SPS&S-induced abnormal BDNF-TrkB signaling and calpain-1-dependent cascade of synaptic deficits. Furthermore, treatment with a TrkB inhibitor completely blocked while an mTOR inhibitor partially blocked the effects of 7,8-DHF on behavioral changes of SPS&S model mice. Our collective findings suggest that 7,8-DHF effectively alleviates PTSD-like symptoms, including fear generalization and anxiety-like behavior, potentially by preventing astrocytic and synaptic deficits in the hippocampus through targeting of TrkB.

Is Prehospital Ketamine Associated With a Change in the Prognosis of PTSD?

INTRODUCTION

Ketamine is an alternative to opioids for prehospital analgesia following serious combat injury. Limited research has examined prehospital ketamine use, associated injuries including traumatic brain injury (TBI) and PTSD outcomes following serious combat injury.

MATERIALS AND METHODS

We randomly selected 398 U.S. service members from the Expeditionary Medical Encounter Database who sustained serious combat injuries in Iraq and Afghanistan, 2010-2013. Of these 398 patients, 213 individuals had charted prehospital medications. Clinicians reviewed casualty records to identify injuries and all medications administered. Outcomes were PTSD diagnoses during the first year and during the first 2 years postinjury extracted from military health databases. We compared PTSD outcomes for patients treated with either (a) prehospital ketamine (with or without opioids) or (b) prehospital opioids (without ketamine).

RESULTS

Fewer patients received prehospital ketamine (26%, 56 of 213) than only prehospital opioids (69%, 146 of 213) (5%, 11 of 213 received neither ketamine nor opioids). The ketamine group averaged significantly more moderate-to-serious injuries, particularly lower limb amputations and open wounds, compared with the opioid group (Ps < .05). Multivariable regressions showed a significant interaction between prehospital ketamine (versus opioids) and TBI on first-year PTSD (P = .027). In subsequent comparisons, the prehospital ketamine group had significantly lower odds of first-year PTSD (OR = 0.08, 95% CI [0.01, 0.71], P = .023) versus prehospital opioids only among patients who did not sustain TBI. We also report results from separate analyses of PTSD outcomes among patients treated with different prehospital opioids only (without ketamine), either morphine or fentanyl.

CONCLUSIONS

The present results showed that patients treated with prehospital ketamine had significantly lower odds of PTSD during the first year postinjury only among patients who did not sustain TBI. These findings can inform combat casualty care guidelines for use of prehospital ketamine and opioid analgesics following serious combat injury.

mTORC1 Signaling Pathway Mediates Chronic Stress-Induced Synapse Loss in the Hippocampus

Background: The mechanistic target of rapamycin complex 1 (mTORC1) signaling has served as a promising target for therapeutic intervention of major depressive disorder (MDD), but the mTORC1 signaling underlying MDD has not been well elucidated. In the present study, we investigated whether mTORC1 signaling pathway mediates synapse loss induced by chronic stress in the hippocampus. Methods: Chronic restraint stress-induced depression-like behaviors were tested by behavior tests (sucrose preference test, forced swim test and tail suspension test). Synaptic proteins and alternations of phosphorylation levels of mTORC1 signaling-associated molecules were measured using Western blotting. In addition, mRNA changes of immediate early genes (IEGs) and glutamate receptors were measured by RT-PCR. Rapamycin was used to explore the role of mTORC1 signaling in the antidepressant effects of fluoxetine. Results: After successfully establishing the chronic restraint stress paradigm, we observed that the mRNA levels of some IEGs were significantly changed, indicating the activation of neurons and protein synthesis alterations. Then, there was a significant downregulation of glutamate receptors and postsynaptic density protein 95 at protein and mRNA levels. Additionally, synaptic fractionation assay revealed that chronic stress induced synapse loss in the dorsal and ventral hippocampus. Furthermore, these effects were associated with the mTORC1 signaling pathway-mediated protein synthesis, and subsequently the phosphorylation of associated downstream signaling targets was reduced after chronic stress. Finally, we found that intracerebroventricular infusion of rapamycin simulated depression-like behavior and also blocked the antidepressant effects of fluoxetine. Conclusion: Overall, our study suggests that mTORC1 signaling pathway plays a critical role in mediating synapse loss induced by chronic stress, and has part in the behavioral effects of antidepressant treatment.

A Systematic Review and Meta-Analysis of Lipid Signatures in Post-traumatic Stress Disorder

BACKGROUND

Research assessing lipid levels in individuals diagnosed with post-traumatic stress disorder (PTSD) has yielded mixed results. This study aimed to employ meta-analytic techniques to characterize the relationship between the levels of lipid profiles and PTSD.

METHODS

We performed meta-analyses of studies comparing profiles and levels of lipids between PTSD patients and healthy individuals by searching Embase, Ovid Medline, Scopus, PsycINFO, and Cochrane databases for the studies until March 2021. Meta-analyses were performed using random-effects models with the restricted maximum-likelihood estimator to synthesize the effect size assessed by standardized mean difference (SMD) across studies.

FINDINGS

A total of 8,657 abstracts were identified, and 17 studies were included. Levels of total cholesterol (TC) (SMD = 0.57 95% CI, 0.27-0.87, p = 0.003), low-density lipoprotein (LDL) (SMD = 0.48, 95% CI, 0.19-0.76, p = 0.004), and triglyceride (TG) (SMD = 0.46, 95% CI, 0.22-0.70, p = 0.001) were found to be higher, while levels of high-density lipoprotein (HDL) (SMD = -0.47, -0.88 to -0.07, p = 0.026) were found to be lower in PTSD patients compared to healthy controls. Subgroup analysis showed that TG levels were higher in PTSD patients who were on or off of psychotropic medications, both < 40 and ≥ 40 years of age, and having body mass index of < 30 and ≥ 30 compared to healthy controls.

INTERPRETATION

This work suggested dysregulation of lipids in PTSD that may serve as biomarker to predict the risk. The study will be useful for physicians considering lipid profiles in PTSD patients to reduce cardiovascular morbidity and mortality.

Psilocybin for Trauma-Related Disorders

Posttraumatic stress disorder (PTSD) is a debilitating, chronic disorder and efficacy rates of current PTSD treatments are underwhelming. There is a critical need for innovative approaches. We provide an overview of trauma and PTSD and cite literature providing converging evidence of the therapeutic potential of psilocybin for PTSD. No study to date has investigated psilocybin or psilocybin-assisted psychotherapy (PAP) as treatments for PTSD. An open-label study in traumatized AIDS survivors found that PAP reduced PTSD symptoms, attachment anxiety, and demoralization. Several PAP trials show preliminary efficacy in facilitating confronting traumatic memories, decreasing emotional avoidance, depression, anxiety, pessimism, and disconnection from others, and increasing acceptance, self-compassion, and forgiveness of abusers, all of which are relevant to PTSD recovery. There is also early evidence that other classic psychedelics may produce large reductions in PTSD symptoms in combat veterans. However, this body of literature is small, mechanisms are not yet well understood, and the risks of using psychedelic compounds for trauma-related disorders need further study. In sum, evidence supports further investigation of PAP as a radically new approach for treating PTSD.

A proposed mechanism for the MDMA-mediated extinction of traumatic memories in PTSD patients treated with MDMA-assisted therapy

Post-traumatic stress disorder (PTSD) is a devastating psychiatric disorder afflicting millions of people around the world. Characterized by severe anxiety, intrusive thoughts, pervasive nightmares, an assortment of somatic symptoms, associations with severe long-term health problems, and an elevated risk of suicide, as much as 40-70% of patients suffer from refractory disease. 3,4-Methylenedioxy-methamphetamine (MDMA), like classic psychedelics such as psilocybin, have been used to enhance the efficacy of psychotherapy almost since their discovery, but due to their perceived potential for abuse and inclusion on USFDA (United States Food and Drug Administration) schedule 1, research into the mechanism by which they produce improvements in PTSD symptomology has been limited. Nevertheless, several compelling rationales have been explored, with the pro-social effects of MDMA thought to enhance therapeutic alliance and thus facilitate therapist-assisted trauma processing. This may be insufficient to fully explain the efficacy of MDMA in the treatment of psychiatric illness. Molecular mechanisms such as the MDMA mediated increase of brain-derived neurotrophic factor (BDNF) availability in the fear memory learning pathways combined with MDMA's pro-social effects may provide a more nuanced explanation for the therapeutic actions of MDMA.

Effects of traumatic stress in adolescence on PTSD-like behaviors, dendrite development, and H3K9me2/BDNF expression in the amygdala of male rats

Early detrimental experiences increase the risk of psychiatric disorders, including posttraumatic stress disorder (PTSD). In a previous experiment, we demonstrated that traumatic stress in adolescence triggers changes in the expression of the epigenetic marker H3K9me2 in the hippocampus and prefrontal cortex of adolescent and adult rats, which suppresses transcription of the brain-derived neurotrophic factor (Bdnf) gene that promotes dendrite development and synaptic growth. However, corresponding changes in the amygdala in response to traumatic stress in early life have not yet been fully elucidated. In the current study, we used the inescapable foot shock (IFS) procedure to establish a PTSD model. Half an hour after the end of electric shocks, intraperitoneal injection of the G9a enzyme inhibitor Unc0642, a small molecule inhibitor of EHMT2 that can decrease H3K9me2 expression, was applied to reverse the corresponding epigenetic changes. Exploratory behaviors, anxiety-like behavior, social communication ability, spatial exploration and memory were determined using the open field test (OFT), elevated plus maze (EPM) test, three-chamber sociability test (SIT), Morris water maze (MWM) test, and Y maze test (YMZ), respectively. Additionally, the levels of H3K9me2 and BDNF were measured by quantitative reverse transcription-polymerase chain reaction (qPCR) and Western blotting. Furthermore, neuronal development was examined using Golgi staining. The results showed that the IFS procedure induced anxiety-like and depression-like behaviors, social skills dysfunction, and spatial exploration and memory disorders. It also decreased the mRNA expression of BDNF and BDNF and increased the expression of H3K9me2 in the amygdala. More importantly, compared to unstressed animals, traumatic stress during adolescence induced dendrite maldevelopment in adolescent and adult rats. In summary, the present study indicates that early-life stress alters the epigenetic marker expression of H3K9me2 and decreases levels of BDNF in the amygdala, resulting in dendrite maldevelopment and a higher risk of mental disorders.