Pharmacological strategies for post-traumatic stress disorder (PTSD): From animal to clinical studies

Behavioral and metabolic effects of escapable electric foot shock stress in male mice

BACKGROUND

The pathophysiology of post-traumatic stress disorder (PTSD) is not fully understood, prompting research using animal models. One of the approaches to induce PTSD-like traits in rodents involves exposure to unavoidable, unpredictable electric foot shocks. This study explored the effects of repeated electric foot shocks on behavior, hematology, and metabolic parameters in male C57BL/6J mice. The mice were subjected to 15 electrical stimuli (each 0.8 mA for 10 s, 10 s interval between sessions) in an electric foot shock apparatus featuring metal floor bars and two insulating bars for two consecutive days.

RESULTS

Stressed mice showed enhanced memory retention of fear, as evidenced by an increased number of freezing events in the aversive context test. In the elevated plus maze test, stressed mice spent significantly less time in the open arms, indicating anxious behavior. However, no significant behavioral differences were observed between the stressed and control groups in the open field test. Stressed mice had a larger hypothalamic mass, elevated liver lipid peroxide levels, and a higher red blood cell count, with no changes in total leukocyte count. Thus, escapable foot shock induces fear response, anxiety-like behavior and minor metabolic changes in mice.

The neuroscientific basis of post-traumatic stress disorder (PTSD): From brain to treatment

Post-traumatic stress disorder (PTSD) is a debilitating mental health condition resulting from exposure to traumatic events, marked by persistent psychological distress and impairment in daily functioning. Risk factors for PTSD include genetic predispositions, neurobiological factors, as well as psychosocial and environmental influences. Specific demographic groups, such as veterans, first responders, and individuals in high-risk environments, are more susceptible to developing the disorder. Despite growing research, there remain gaps in understanding the full pathophysiology of PTSD, and existing diagnostic methods and treatments are not universally effective, contributing to a significant public health burden. This chapter explores the pathophysiology of PTSD, focusing on its underlying mechanisms, associated risk factors, and high-risk populations. Biological biomarkers such as neuroimaging findings, hormonal imbalances, genetic predispositions, and physiological indicators are discussed in the context of their role in PTSD diagnosis and understanding. Both pharmacological treatments and non-pharmacological interventions, including Cognitive Behavioral Therapy (CBT), Eye Movement Desensitization and Reprocessing (EMDR), and mindfulness-based techniques, are reviewed for their effectiveness in symptom management. Further research is essential to advance individualized diagnostic techniques and optimize treatment strategies, ensuring more personalized care for PTSD patients.

Single Intranasal Administration of Ucn3 Affects the Development of PTSD Symptoms in an Animal Model

Post-traumatic stress disorder (PTSD) is a multifactorial psychological disorder that affects different neurotransmitter systems, including the central CRH system. CRH acts via the CRHR1 and CRHR2 receptors, which exert opposite effects, i.e., anxiogenic or anxiolytic. The aim of this work was to investigate how intranasal administration of the CRHR2-specific agonist urocortin 2 (Ucn2) or urocortin 3 (Ucn3) affects manifestations of PTSD in a single prolonged stress (SPS) animal model of PTSD. Elevated plus maze (EPM) and open field (OF) tests were used to assess anxiety-like behavior. Changes in the gene expressions of CRH, CRHR1, CRHR2, glucocorticoid receptor (GR), and FKBP5 were measured in brain regions (BNST, amygdala, and PVN) responsible for modulating the stress response. The SPS animals spent less time in the OF central zone and were less mobile than the controls; however, the Ucn3 treatment reversed this effect. SPS decreased the GR and FKPB5 mRNA levels in the PVN. Ucn3 suppressed the effect of SPS on FKBP5 mRNA expression in the PVN and increased FKBP5 mRNA in the BNST and PVN compared to the stressed animals. We demonstrate that Ucn3 has the potential to ameliorate anxiety-like behavior in SPS animals and also to affect the neuroendocrine system in the BNST and PVN. In addition, we confirm the important role of CRHR2 signaling in mediating the stress response.

Medial prefrontal cortex neurotransmitter abnormalities in posttraumatic stress disorder with and without comorbidity to major depression

Posttraumatic stress disorder (PTSD) is a chronic psychiatric condition that follows exposure to a traumatic stressor. Though previous in vivo proton (1H) MRS) research conducted at 4 T or lower has identified alterations in glutamate metabolism associated with PTSD predisposition and/or progression, no prior investigations have been conducted at higher field strength. In addition, earlier studies have not extensively addressed the impact of psychiatric comorbidities such as major depressive disorder (MDD) on PTSD-associated 1H-MRS-visible brain metabolite abnormalities. Here we employ 7 T 1H MRS to examine concentrations of glutamate, glutamine, GABA, and glutathione in the medial prefrontal cortex (mPFC) of PTSD patients with MDD (PTSD+MDD+; N = 6) or without MDD (PTSD+MDD-; N = 5), as well as trauma-unmatched controls without PTSD but with MDD (PTSD-MDD+; N = 9) or without MDD (PTSD-MDD-; N = 18). Participants with PTSD demonstrated decreased ratios of GABA to glutamine relative to healthy PTSD-MDD- controls but no single-metabolite abnormalities. When comorbid MDD was considered, however, MDD but not PTSD diagnosis was significantly associated with increased mPFC glutamine concentration and decreased glutamate:glutamine ratio. In addition, all participants with PTSD and/or MDD collectively demonstrated decreased glutathione relative to healthy PTSD-MDD- controls. Despite limited findings in single metabolites, patterns of abnormality in prefrontal metabolite concentrations among individuals with PTSD and/or MDD enabled supervised classification to separate them from healthy controls with 80+% sensitivity and specificity, with glutathione, glutamine, and myoinositol consistently among the most informative metabolites for this classification. Our findings indicate that MDD can be an important factor in mPFC glutamate metabolism abnormalities observed using 1H MRS in cohorts with PTSD.

Central innate immunization induces tolerance against post-traumatic stress disorder-like behavior and neuroinflammatory responses in male mice

Post-traumatic stress disorder (PTSD) is a severe psychiatric disorder associated with abnormally elevated neuroinflammatory responses. Suppression of neuroinflammation is considered to be effective in ameliorating PTSD-like behaviors in rodents. Since pre-stimulation of microglia prior to stress exposure can prevent neuroinflammation, we hypothesized that pre-stimulation of microglia may prevent PTSD in animals. The results show that a single injection of a classical immune stimulant, lipopolysaccharide (LPS), at 50, 100 or 500, but not 10 μg/kg, one day before stress exposure, prevented the anxiety- and fear-like behaviors induced by modified single prolonged stress (mSPS). The time-dependent analysis shows that a single injection of LPS (100 μg/kg) either one or five, but not ten, days before stress prevented mSPS-induced anxiety- and fear-like behaviors. A second low-dose LPS injection 10 days after the first injection or a repeated LPS injection (4 × ) 10 days before stress induced tolerance to mSPS. Mechanistic studies show that a single injection of LPS one day before stress stimulation prevented mSPS-induced increases in levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-6 mRNA in the hippocampus and medial prefrontal cortex. Inhibition of microglia by pretreatment with minocycline or depletion of microglia by PLX3397 abolished the preventive effect of low-dose LPS pre-injection on mSPS-induced anxiety- and fear-like behavior and neuroinflammatory responses. These results suggest that pre-stimulation of microglia may prevent the development of PTSD-like behaviors by attenuating the development of neuroinflammatory responses. This could help to develop new strategies to prevent the damaging effects of harmful stress on the brain.

Similarities and differences between post-traumatic stress disorder and major depressive disorder: Evidence from task-evoked functional magnetic resonance imaging meta-analysis

BACKGROUND

Post-traumatic stress disorder (PTSD) and major depressive disorder (MDD) are psychiatric disorders that can present with overlapping symptoms and shared risk factors. However, the extent to which these disorders share common underlying neuropathological mechanisms remains unclear. To investigate the similarities and differences in task-evoked brain activation patterns between patients with PTSD and MDD.

METHODS

A coordinate-based meta-analysis was conducted across 35 PTSD studies (564 patients and 543 healthy controls) and 125 MDD studies (4049 patients and 4170 healthy controls) using anisotropic effect-size signed differential mapping software.

RESULTS

Both PTSD and MDD patients exhibited increased neural activation in the bilateral inferior frontal gyrus. However, PTSD patients showed increased neural activation in the right insula, left supplementary motor area extending to median cingulate gyrus and superior frontal gyrus (SFG), and left fusiform gyrus, and decreased neural activation in the right posterior cingulate gyrus, right middle temporal gyrus, right paracentral lobule, and right inferior parietal gyrus relative to MDD patients.

CONCLUSION

Our meta-analysis suggests that PTSD and MDD share some similar patterns of brain activation, but also have distinct neural signatures. These findings contribute to our understanding of the potential neuropathology underlying these disorders and may inform the development of more targeted and effective treatment and intervention strategies. Moreover, these results may provide useful neuroimaging targets for the differential diagnosis of MDD and PTSD.

Sex difference affects fear extinction but not lithium efficacy in rats following fear-conditioning with respect to the hippocampal level of BDNF

In rodents, exposure to electrical shock and creating a strong fear memory using fear-conditioning model can induce PTSD-like behavior. In this study, we induced a fear-conditioning model in rats and investigated freezing (PTSD-like) behavior, 21 days after three shocks exposure (0.6 mA, 3 s, 30 seconds interval) in both male and female rats. Lithium was injected intraperitoneally (100 mg/kg) in three protocols: (1) 1 h after fear-conditioning (2) 1 h, 24 h, and 48 h after fear-conditioning (3), 1 h, 24 h, 48 h, 72 h, and 96 h after fear-conditioning. Extinction training (20 sounds without shocks, 75 dB, 3 s, 30 seconds interval) was performed in three protocols: (1) 1 h after fear-conditioning (one session), (2) 1 h, 24 h, and 48 h after fear-conditioning (three sessions), (3), 1 h, 24 h, 48 h, 72 h, and 96 h after fear-conditioning (five sessions). Forced swim test (FST) and hot plate were used to assess behavior. Results showed that lithium in all protocols had no effect on freezing behavior, FST, and pain subthreshold in all rats. Extinction training decreased freezing behavior, with more efficacy in females. In males, only 5-session training was effective, while in females all protocols were effective. Extinction training also altered pain perception and the results of FST, depending on the sessions and was different in males and females. Brain-derived neurotrophic factor (BDNF) mRNA level was increased in females following 3 and 5 sessions, and in males following 5 sessions extinction training. In conclusion, we suggested that there is a sex difference for the effect of extinction training on freezing behavior and BDNF mRNA level in a rat model of fear-conditioning.

MDMA-Based Psychotherapy in Treatment-Resistant Post-Traumatic Stress Disorder (PTSD): A Brief Narrative Overview of Current Evidence

Post-traumatic stress disorder (PTSD) is a debilitating mental health disorder that causes significant dysfunction in individuals. Currently, there are many approved pharmacotherapy and psychotherapy treatment options for PTSD, but unfortunately, half of the patients do not respond to traditional therapies. In this article, we review clinical trials and research on 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy in PTSD patients, its pharmacokinetics, and current treatment guidelines for PTSD. Our findings are based on the results of the efficacy of MDMA-assisted psychotherapy from six phase II randomized controlled trials. MDMA-assisted psychotherapy for PTSD has received the "breakthrough therapy" designation from the FDA. MDMA can reduce PTSD symptoms even in treatment-resistant cases by increasing certain neurohormones, i.e., dopamine, serotonin, norepinephrine, and oxytocin. It also modulates activities in the brain regions involved in fear and anxiety. Future research is needed to show whether the advantages outweigh the disadvantages and whether its use can be integrated into available treatment options for PTSD.

Update on neurobiological mechanisms of fear: illuminating the direction of mechanism exploration and treatment development of trauma and fear-related disorders

Fear refers to an adaptive response in the face of danger, and the formed fear memory acts as a warning when the individual faces a dangerous situation again, which is of great significance to the survival of humans and animals. Excessive fear response caused by abnormal fear memory can lead to neuropsychiatric disorders. Fear memory has been studied for a long time, which is of a certain guiding effect on the treatment of fear-related disorders. With continuous technological innovations, the study of fear has gradually shifted from the level of brain regions to deeper neural (micro) circuits between brain regions and even within single brain regions, as well as molecular mechanisms. This article briefly outlines the basic knowledge of fear memory and reviews the neurobiological mechanisms of fear extinction and relapse, which aims to provide new insights for future basic research on fear emotions and new ideas for treating trauma and fear-related disorders.

From recent advances in underlying neurocircuitry of fear and anxiety to promising pharmacotherapies for PTSD: The saga of heart, sex and the developing brain

Available pharmacotherapies for anxiety disorders and post-traumatic stress-disorder (PTSD) have limited efficacy, but no new anxiolytic drug has been approved for treatment since the 1980s. In this issue of Neuropharmacology on "Fear, anxiety and PTSD: from cellular mechanisms to translational approaches", we review the currently recommended pharmacotherapy for PTSD and discuss promising pharmacotherapies being revisited or newly developed. Novel strategies for pharmaceuticals in PTSD treatment include the use of serotonergic psychedelics as low-dose adjunct therapies combined with psychotherapy. We also discuss the use of glucocorticoids targeting the temporal window shortly following trauma exposure to interfere with fear memory consolidation. Although many factors have impeded progress in pharmacotherapy development for anxiety disorders and PTSD, we highlight three: (1) the sparsity of preclinical studies investigating the neurobiology of fear processing in female animal models despite the higher prevalence of anxiety disorders in women, (2) the poor implementation of the knowledge of how stress affects fear circuitry development across the lifetime into clinical practice, and (3) our paucity of knowledge of canonical fear circuitry in adaptive vs. maladaptive fear processing. Finally, we emphasize the functional link between interoceptive signals and emotion regulation and discuss how these interoceptive signals may be an inroad into PTSD treatment, which is often accompanied by cardiovascular dysregulation. A better understanding of the neurobiological underpinnings of adaptive and maladaptive fear processing is critical for identifying risk factors that will spur the development of sex- and developmental trauma-specific interventions, ushering in a new era of precision medicine for anxiety disorders and PTSD.

Clinical outcomes of recommended active pharmacotherapy agents from NICE guideline for post-traumatic stress disorder: Network meta-analysis

BACKGROUND

Post-traumatic stress disorder (PTSD) is a mental disorder that can emerge after an individual experiences a traumatic event such as physical abuse, sexual/relationship violence, combat exposure, witnessing death, or serious injury. This study aimed to identify the most suitable drugs for the management of PTSD based on a network meta-analysis (NMA).

METHODS

Six databases (Ovid Medline, EMBase, CENTRAL, PsycINFO, Ovid Health and Psychosocial Instruments, and Web of Science) were searched from inception to September 6, 2022.

RESULTS

Thirty articles with a total of 5170 participants were included. Compared with placebo, active drugs including olanzapine (SMD = -0.66, 95% CI: -1.19 to -0.13), risperidone (SMD = -0.23, 95% CI: -0.42 to -0.03), quetiapine (SMD = -0.49, 95% CI: -0.93 to -0.04), venlafaxine (SMD = -0.29, 95% CI: -0.42 to -0.16), sertraline (SMD = -0.23, 95% CI: -0.34 to -0.11), paroxetine (SMD = -0.48, 95% CI: -0.60 to -0.36) and fluoxetine (SMD = -0.27, 95% CI: -0.42 to -0.12), significantly reduced the total clinician-administered PTSD scale score.

CONCLUSION

The results of this study support the use of paroxetine, venlafaxine, and quetiapine as first-line treatment for PTSD. In addition, quetiapine is recommended for patients with PTSD affected by symptoms of hyperarousal and re-experience disorder. Clinicians should prescribe medications based on the severity of PTSD symptoms and other conditions to develop the best treatment strategy for this patient population.

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.

Perspectives on the therapeutic potential of MDMA: A nation-wide exploratory survey among substance users

Background

Alcohol and other substance use disorders are commonly associated with post-traumatic stress disorder (PTSD), and the presence of these comorbidities is associated with worse treatment outcomes. Additionally, disparities in substance and PTSD prevalence have been associated with minority races and ethnicities, and minorities have been shown to be less likely to engage in treatment. Psychedelic-assisted treatments, including 3,4-methylenedioxymethamphetamine (MDMA), have shown preliminary trans-diagnostic effectiveness, however it is unknown how individuals with substance use disorders view the therapeutic potential of MDMA therapy. Previous studies have also shown that minority races and ethnicities are under-represented in the MDMA trials, leading to concerns about inequitable access to clinical treatment.

Methods

To explore demographic characteristics related to patient-level perspectives on the therapeutic potential of MDMA-assisted therapy, this study describes data from a nationwide, cross-sectional survey of 918 individuals self-reporting criteria consistent with alcohol or substance use disorders.

Results

Overall, a majority of individuals reported support for medical research of MDMA (68.1%), belief that MDMA-assisted therapy might be a useful treatment (70.1%), and willingness to try MDMA-assisted therapy if it were determined to be an appropriate treatment for them (58.8%). No race or ethnicity differences were found in support for further research or belief in effectiveness, however there were small disparities in terms of willingness to try MDMA-assisted therapy and concerns related to use of this treatment approach.

Conclusion

These results provide insights and future directions as the field of psychedelic-assisted therapy seeks to provide equitable access to clinical care and to diversify research participation.

Assessing the quality of publicly available videos on MDMA-assisted psychotherapy for PTSD

BACKGROUND AND OBJECTIVES

Patients increasingly rely on the Internet for healthcare information. This study aimed to evaluate the quality of videos on 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for posttraumatic stress disorder (PTSD) on YouTube™.

METHODS

YouTube™ was searched for the terms "MDMA" and "PTSD." The 100 most viewed videos were analyzed using three standard quality measures: Global Quality Scores (GQS), JAMA benchmark, and DISCERN. Viewer engagement features and source of upload, video duration, inclusion of patient narrative and/or MD/DO/PhD, the mention of lack of Food and Drug Administration (FDA) approval, side effects, potential for abuse, and use in conjunction with psychotherapy were recorded.

RESULTS

The videos were of poor quality (mean GQS: 2.26 ± 0.94/5, JAMA: 1.96 ± 0.45/4, and DISCERN: 29.5 ± 8.2/80). A significant positive association was found between video quality and duration (GQS: r = .5857, p < .0001, JAMA: r = .279, p = .0409, DISCERN: r = .5783, p < .0001). Videos including an MD/DO/PhD had the highest scores (GQS: 2.87/5 [1.22], p = .006, DISCERN: 38.35/80 [13.32], p < .0003). A minority of videos were uploaded by academic institutions (1%); most were from professional organizations (29%). No correlation was found between quality and viewer engagement features-number of views, subscribers, likes/dislikes, or comments. A majority mentioned that MDMA must be used in conjunction with psychotherapy (85%) and is not FDA-approved (82%) for PTSD. Only 32% of videos mentioned risks or potential for abuse.

CONCLUSIONS

These findings highlight the need for better quality of online health material and an opportunity for involvement of healthcare professionals in the dissemination of accurate health information via content creation.

SCIENTIFIC SIGNIFICANCE

This is the first study to examine publicly available information on the use of MDMA for PTSD.

Methylone, a rapid acting entactogen with robust anxiolytic and antidepressant-like activity

INTRODUCTION

Selective serotonin reuptake inhibitor (SSRI) antidepressants represent first-line pharmacological treatment for a variety of neuropsychiatric illnesses, including major depressive disorder (MDD), anxiety, and post-traumatic stress disorder (PTSD), which show high rates of comorbidity. SSRIs have a delayed onset of action. Most patients do not show significant effects until 4-8 weeks of continuous treatment, have impairing side effects and as many as 40% of patients do not respond. Methylone (3,4-methylenedioxy-N-methylcathinone; MDMC, βk-MDMA, M1) is a rapid-acting entactogen that showed significant benefit in a clinical case series of PTSD patients and was well-tolerated in two Phase 1 studies of healthy volunteers. Based on these early observations in humans, in the current study we tested the hypothesis that methylone has antidepressant-like and anxiolytic effects in preclinical tests.

METHODS

For all studies, 6-8-week-old male Sprague Dawley rats (N = 6-16) were used. We employed the Forced Swim Test (FST), a classic and widely used screen for antidepressants, to explore the effects of methylone and to probe dose-response relationships, durability of effect, and potential interactions with combined SSRI treatment. We compared the effect of methylone with the prototypical SSRI fluoxetine.

RESULTS

Three doses of fluoxetine (10 mg/kg) given within 24 h before FST testing caused a 50% reduction in immobility compared with controls that lasted less than 24 h. In contrast, a single dose of methylone (5-30 mg/kg) administered 30 min prior to testing produced a rapid, robust, and durable antidepressant-like response in the FST, greater in magnitude than fluoxetine. Immobility was reduced by nearly 95% vs. controls and effects persisted for at least 72 h after a single dose (15 mg/kg). Effects on swimming and climbing behavior in the FST, which reflect serotonergic and noradrenergic activity, respectively, were consistent with studies showing that methylone is less serotoninergic than MDMA. Fluoxetine pretreatment did not change methylone's antidepressant-like effect in the FST, suggesting the possibility that the two may be co-administered. In addition, methylone (5-30 mg/kg) exhibited anxiolytic effects measured as increased time spent in the center of an open field.

DISCUSSION

Taken together, and consistent with initial clinical findings, our study suggests that methylone may have potential for treating depression and anxiety.