When translational neuroscience fails in the clinic: Dexamethasone prior to virtual reality exposure therapy increases drop-out rates

When virtual reality becomes psychoneuroendocrine reality: A stress(or) review

This review article was awarded the Dirk Hellhammer award from ISPNE in 2023. It explores the dynamic relationship between stressors and stress from a historical view as well as a vision towards the future of stress research via virtual reality (VR). We introduce the concept of a "syncytium," a permeable boundary that blurs the distinction between stress and stressor, in order to understand why the field of stress biology continues to inadequately measure stress alone as a proxy for the force of external stressors. Using Virtual Reality (VR) as an illustrative example to explicate the black box of stressors, we examine the distinction between 'immersion' and 'presence' as analogous terms for stressor and stress, respectively. We argue that the conventional psychological approaches to stress measurement and appraisal theory unfortunately fall short in quantifying the force of the stressor, leading to reverse causality fallacies. Further, the concept of affordances is introduced as an ecological or holistic tool to measure and design a stressor's force, bridging the gap between the external environment and an individual's physiological response to stress. Affordances also serve to ameliorate shortcomings in stress appraisal by integrating ecological interdependencies. By combining VR and psychobiological measures, this paper aims to unravel the complexity of the stressor-stress syncytium, highlighting the necessity of assessing both the internal and external facets to gain a holistic understanding of stress physiology and shift away from reverse causality reasoning. We find that the utility of VR extends beyond presence to include affordance-based measures of immersion, which can effectively model stressor force. Future research should prioritize the development of tools that can measure both immersion and presence, thereby providing a more comprehensive understanding of how external stressors interact with individual psychological states.

Impaired learning, memory, and extinction in posttraumatic stress disorder: translational meta-analysis of clinical and preclinical studies

Current evidence-based treatments for post-traumatic stress disorder (PTSD) are efficacious in only part of PTSD patients. Therefore, novel neurobiologically informed approaches are urgently needed. Clinical and translational neuroscience point to altered learning and memory processes as key in (models of) PTSD psychopathology. We extended this notion by clarifying at a meta-level (i) the role of information valence, i.e. neutral versus emotional/fearful, and (ii) comparability, as far as applicable, between clinical and preclinical phenotypes. We hypothesized that cross-species, neutral versus emotional/fearful information processing is, respectively, impaired and enhanced in PTSD. This preregistered meta-analysis involved a literature search on PTSD+Learning/Memory+Behavior, performed in PubMed. First, the effect of information valence was estimated with a random-effects meta-regression. The sources of variation were explored with a random forest-based analysis. The analyses included 92 clinical (N = 6732 humans) and 182 preclinical (N = 6834 animals) studies. A general impairment of learning, memory and extinction processes was observed in PTSD patients, regardless of information valence. Impaired neutral learning/memory and fear extinction were also present in animal models of PTSD. Yet, PTSD models enhanced fear/trauma memory in preclinical studies and PTSD impaired emotional memory in patients. Clinical data on fear/trauma memory was limited. Mnemonic phase and valence explained most variation in rodents but not humans. Impaired neutral learning/memory and fear extinction show stable cross-species PTSD phenotypes. These could be targeted for novel PTSD treatments, using information gained from neurobiological animal studies. We argue that apparent cross-species discrepancies in emotional/fearful memory deserve further in-depth study; until then, animal models targeting this phenotype should be applied with utmost care.

Pharmacological memory modulation to augment trauma-focused psychotherapy for PTSD: a systematic review of randomised controlled trials

Trauma-focused psychotherapy (tf-PT) is the first-line treatment for posttraumatic stress disorder (PTSD). Tf-PT focuses on processing and modulating trauma memories. Not all patients benefit, however, and there is room for improvement of efficacy. Pharmacologically augmenting trauma memory modulation in the context of tf-PT may help optimise treatment outcome. To systematically review effects of pharmacologically augmented memory modulation in the context of tf-PT for PTSD (PROSPERO preregistration ID: CRD42021230623). We conducted a systematic review of randomised controlled trials of psychotherapy treatment for PTSD. We included placebo-controlled studies that augmented at least one treatment session pharmacologically targeting memory extinction or reconsolidation. We calculated post-treatment between group (pharmacological augmentation vs placebo control) effect sizes of PTSD symptom severity. We included 13 RCTs. There was large heterogeneity in augmentation procedure and methodological quality. Four studies showed significantly greater PTSD symptom reduction in the pharmacological augmentation group (propranolol, hydrocortisone, dexamethasone, D-cycloserine) compared to placebo. Seven studies showed no significant effect of pharmacological augmentation compared to placebo (D-cycloserine, rapamycin, mifepristone, propranolol, mifepristone combined with D-cycloserine, methylene blue). Two studies showed significantly smaller PTSD symptom reduction in the pharmacological augmentation group (D-cycloserine, dexamethasone) compared to placebo. Results of pharmacological augmentation were mixed overall and heterogenous for the pharmacological agents tested in more than one study. Additional studies and replications are needed to identify which pharmacological agents work, in which combination and to identify patient groups that benefit most to tailor PTSD treatment.

Virtual Reality Exposure Therapy as a Treatment Method Against Anxiety Disorders and Depression-A Structured Literature Review

Mental illness is a growing global health problem affecting individuals and society. In Sweden, the number of people suffering from mental health illnesses, such as anxiety and depression, is increasing and is expected to be one of the largest public health challenges in 2030. As mental illness increases, the area also needs effective forms of treatment. This study aims to investigate if Virtual Reality Exposure Therapy (VRET) works as a treatment method for adults suffering from anxiety disorders and depression. A structured literature review based on 24 articles found in the databases PubMed, MEDLINE, CINAHL and PsycInfo. Two reviewers independently reviewed and collectively extracted data from the included articles. The articles have been analyzed by using thematic analysis. The results suggest that Virtual reality exposure therapy can work as an effective treatment method for adults with anxiety disorders. It also indicates that VRET may act as a health-promoting intervention to reduce anxiety disorders, phobias, and depression symptoms. Virtual reality exposure therapy can be an effective treatment method and health-promoting effort against anxiety disorders in adults. An essential factor for the patients who accept VRET as a treatment is the initial information therapists give.

Extinction-Based Exposure Therapies Using Virtual Reality

The focus of this chapter is an overview of integrating virtual reality (VR) technology within the context of exposure therapy for anxiety disorders, a gold standard treatment, with a focus on how VR can help facilitate extinction learning processes integral to these interventions. The chapter will include an overview of advantages of incorporating VR within exposure therapy, and benefits specifically within an inhibitory learning approach for extinction training. A review of the empirical literature on the effectiveness of VR exposure therapy for specific phobia and PTSD will be provided, as well as practical overview of how to effectively incorporate VR within exposure therapy.

Enhancing Fear Extinction: Pharmacological Approaches

Extinction is the process by which the memory of a learned conditioned association decreases over time and with introduction of new associations. It is a vital part of fear learning, and it is critical to recovery in multiple fear-related disorders, including Specific and Social Phobias, Panic Disorder, Obsessive Compulsive Disorder (OCD), and Posttraumatic Stress Disorder (PTSD). The process of extinction is also the underlying mechanism for recovery in gold-standard therapies for PTSD, including prolonged exposure, cognitive processing therapy, eye movement desensitization and procession, as well as other empirically-based paradigms. Pharmacological modulators of extinction are thus promising targets for treatment of fear-related disorders. We focus here on emerging psychopharmacological treatments to facilitate extinction: D-cycloserine, scopolamine, losartan, ketamine, and 3,4-methylenedioxymethamphetamine. We also provide an overview of recent advances in molecular pathways that show promise as targets for extincion and inhibitory learning, including pathways related to cannabinoid, brain-derived neurotrophic factor, hypothalamic-pituitary-adrenal signaling, and promising work in neurosteroid compounds.

Randomized controlled experimental study of hydrocortisone and D-cycloserine effects on fear extinction in PTSD

Fear extinction underlies prolonged exposure, one of the most well-studied treatments for posttraumatic stress disorder (PTSD). There has been increased interest in exploring pharmacological agents to enhance fear extinction learning in humans and their potential as adjuncts to PE. The objective of such adjuncts is to augment the clinical impact of PE on the durability and magnitude of symptom reduction. In this study, we examined whether hydrocortisone (HC), a corticosteroid, and D-Cycloserine (DCS), an N-methyl-D-aspartate receptor partial agonist, enhance fear extinction learning and consolidation in individuals with PTSD. In a double-blind placebo-controlled 3-group experimental design, 90 individuals with full or subsyndromal PTSD underwent fear conditioning with stimuli that were paired (CS+) or unpaired (CS-) with shock. Extinction learning occurred 72 h later and extinction retention was tested one week after extinction. HC 25 mg, DCS 50 mg or placebo was administered one hour prior to extinction learning. During extinction learning, the DCS and HC groups showed a reduced differential CS+/CS- skin conductance response (SCR) compared to placebo (b = -0.19, CI = -0.01 to -37, p = 0.042 and b = -0.25, CI = -08 to -0.43, p = 0.005, respectively). A nonsignificant trend for a lower differential CS+/CS- SCR in the DCS group, compared to placebo, (b = -0.25, CI = 0.04 to -0.55, p = 0.089) was observed at retention testing, one week later. A single dose of HC and DCS facilitated fear extinction learning in participants with PTSD symptoms. While clinical implications have yet to be determined, our findings suggest that glucocorticoids and NMDA agonists hold promise for facilitating extinction learning in PTSD.

Invisible wounds: Suturing the gap between the neurobiology, conventional and emerging therapies for posttraumatic stress disorder

A sharp increase in the prevalence of neuropsychiatric disorders, including major depression, anxiety, substance use disorders and posttraumatic stress disorder (PTSD) has occurred due to the traumatic nature of the persisting COVID-19 global pandemic. PTSD is estimated to occur in up to 25% of individuals following exposure to acute or chronic trauma, and the pandemic has inflicted both forms of trauma on much of the population through both direct physiological attack as well as an inherent upheaval to our sense of safety. However, despite significant advances in our ability to define and apprehend the effects of traumatic events, the neurobiology and neuroanatomical circuitry of PTSD, one of the most severe consequences of traumatic exposure, remains poorly understood. Furthermore, the current psychotherapies or pharmacological options for treatment have limited efficacy, durability, and low adherence rates. Consequently, there is a great need to better understand the neurobiology and neuroanatomy of PTSD and develop novel therapies that extend beyond the current limited treatments. This review summarizes the neurobiological and neuroanatomical underpinnings of PTSD and discusses the conventional and emerging psychotherapies, pharmacological and combined psychopharmacological therapies, including the use of psychedelic-assisted psychotherapies and neuromodulatory interventions, for the improved treatment of PTSD and the potential for their wider applications in other neuropsychiatric disorders resulting from traumatic exposure.

A Case for Translation From the Clinic to the Laboratory

Laboratory procedures have been used for decades as analogues for clinical processes with the goal of improving our understanding of psychological treatments for emotional disorders and identifying strategies to make treatments more effective. This research has often focused on translation from the laboratory to the clinic. Although this approach has notable successes, it has not been seamless. There are many examples of strategies that work in the laboratory that fail to lead to improved outcomes when applied clinically. One possible reason for this gap between experimental and clinical research is a failure to focus on translation from the clinic to the laboratory. Here, we discuss potential benefits of translation from the clinic to the laboratory and provide examples of how this might be implemented. We first consider two well-established laboratory analogues (extinction and cognitive reappraisal), identify critical aspects of the related clinical procedures (exposure and cognitive restructuring) that are missing from these analogues, and propose variations to better capture the clinical process. Second, we discuss two clinical procedures that have more recently been brought into the laboratory (eye-movement desensitization and reprocessing and imagery rescripting). We conclude by highlighting potential implications of this proposed shift in focus for translational research.

Augmentation of Psychotherapy with Neurobiological Methods: Current State and Future Directions

BACKGROUND

Psychotherapy and pharmacotherapy are first-line treatments for mental disorders. Despite recent improvements, only approximately 50% of the patients reach sustained remission, indicating a need for novel developments. The main concept put forward in this systematic review and hypothesis article is the targeted co-administration of defined neurobiological interventions and specific psychotherapeutic techniques.

METHODS

We conducted a systematic literature search for randomized controlled trials comparing the efficacy of augmented psychotherapy to psychotherapy alone.

RESULTS

Thirty-five trials fulfilled the inclusion criteria. The majority (29 trials) used augmentation strategies such as D-cycloserine, yohimbine, or sleep to enhance the effects of exposure therapy for anxiety disorders. Fewer studies investigated noninvasive brain stimulation with the aim of improving cognitive control, psychedelic compounds with the aim of enhancing existentially oriented psychotherapy, and oxytocin to improve social communication during psychotherapy. Results demonstrate small augmentation effects for the enhancement of exposure therapy - however, some of the studies found negative results. Other methods are less thoroughly researched, and results are mixed.

CONCLUSIONS

This approach provides an open matrix for further research and has the potential to systematically guide future studies.

Corrigendum: Implementation of Therapeutic Virtual Reality Into Psychiatric Care: Clinicians' and Service Managers' Perspectives

[This corrects the article DOI: 10.3389/fpsyt.2021.791123.].

Virtual Reality Exposure Therapy for Armed Forces Veterans with Post-Traumatic Stress Disorder: A Systematic Review and Focus Group

Virtual reality exposure therapy (VRET) is an emerging treatment for people diagnosed with Post-Traumatic Stress Disorder (PTSD) due to the limited accessibility of psychotherapies. This research aims to determine the guidelines for developing a Virtual Reality–War Scenario program for Armed Forces veterans with PTSD and encompasses two studies: Study 1, a systematic electronic database review; Study 2, a focus group of twenty-two Portuguese Armed Forces veterans. Results showed a positive impact of VRET on PTSD; however, there were no group differences in most of the studies. Further, according to veterans, new VRET programs should be combined with the traditional therapy and must consider as requirements the sense of presence, dynamic scenarios, realistic feeling, and multisensorial experience. Regardless, these findings suggest VRET as a co-creation process, which requires more controlled, personalized, and in-depth research on its clinical applicability.

Translation of animal endocannabinoid models of PTSD mechanisms to humans: Where to next?

The endocannabinoid system is known to be involved in mechanisms relevant to PTSD aetiology and maintenance, though this understanding is mostly based on animal models of the disorder. Here we review how human paradigms can successfully translate animal findings to human subjects, with the view that substantially increased insight into the effect of endocannabinoid signalling on stress responding, emotional and intrusive memories, and fear extinction can be gained using modern paradigms and methods for assessing the state of the endocannabinoid system in PTSD.

Virtual Reality Therapy in Mental Health

Initially designed for the treatment of phobias, the use of virtual reality in phobic disorders has expanded to other mental health disorders such as posttraumatic stress disorder, substance-related disorders, eating disorders, psychosis, and autism spectrum disorder. The goal of this review is to provide an accessible understanding of why this approach is important for future practice, given its potential to provide clinically relevant information associated with the assessment and treatment of people suffering from mental illness. Most of the evidence is available for the use of virtual reality exposure therapy in anxiety disorders and posttraumatic stress disorder. There is hardly any evidence that virtual reality therapy is effective in generalized anxiety disorder and obsessive-compulsive disorder. There is increasing evidence that cue exposure therapy is effective in addiction and eating disorders. Studies into the use of virtual reality therapy in psychosis, autism spectrum disorder, and attention deficit hyperactivity disorder (ADHD) are promising.

Implementation of Therapeutic Virtual Reality Into Psychiatric Care: Clinicians' and Service Managers' Perspectives

Objectives: Virtual reality (VR) has emerged as a highly promising tool for assessing and treating a range of mental illnesses. However, little is known about the perspectives of key stakeholders in mental healthcare, whose support will be critical for its successful implementation into routine clinical practise. This study aimed to explore the perspectives of staff working in the private mental health sector around the use of therapeutic VR, including potential implementation barriers and facilitators. Methods: Semi-structured qualitative interviews were conducted with cross-disciplinary clinicians (n = 14) and service managers (n = 5), aged 28-70 years working in a major private mental health hospital in Victoria, Australia. Transcripts were analysed using general inductive coding to allow themes to naturally emerge. Results: Three major themes were identified: clinical factors (four subthemes), organisational factors (five subthemes), and professional factors (three subthemes). The themes encompassed enabling factors and potential barriers that need to be addressed for successful implementation of VR. Clinical factors highlighted the influence of knowledge or perceptions about appropriate clinical applications, therapeutic efficacy, safety and ethical concerns, and patient engagement. Organisational factors emphasised the importance of service contexts, including having a strong business case, stakeholder planning, recruitment of local opinion leaders to champion change, and an understanding of resourcing challenges. Professional factors highlighted the need for education and training for staff, and the influence of staff attitudes towards technology and perceived usability of VR. Conclusions: In addition to enabling factors, potential implementation barriers of therapeutic VR were identified, including resourcing constraints, safety and ethical concerns, negative staff attitudes towards technology and VR system limitations. Future dissemination should focus on addressing knowledge and skills gaps and attitudinal barriers through development of clinical guidelines, training programs, and implementation resources (e.g., adoption decision tools, consultation opportunities).

A Review of PTSD Augmentation Strategies for Older Adults and Case of rTMS-Augmented Prolonged Exposure

Evidence-based psychotherapies such as prolonged exposure therapy (PE) are recommended by clinical practice guidelines as first-line treatments for post-traumatic stress disorder (PTSD) and are safe and acceptable for use with older adults. One third to one half of all patients do not achieve a clinically meaningful response to standard outpatient PE and recent research suggests that older adults in particular may experience barriers to full engagement and response. Standard treatment may be challenging in older adults due to cognitive, medical, and psychosocial barriers. This article reviews the current state of the evidence on adjunctive and second-tier interventions that show promise for increasing response and/or engagement in evidence-based psychotherapy for PTSD, including medications such as d-cycloserine and 3,4-methylenedioxy-methamphetamine, neuromodulation techniques such as repetitive transcranial magnetic stimulation, and augmentations to the structure and content of psychotherapy, such as intensive outpatient formats. A case illustration of successful application of multiple augmentations to PE with an initially nonresponsive older adult patient is presented. A creative interdisciplinary approach based in available research may be beneficial for older adults who do not respond to first-line treatments.

Virtual Trauma Interventions for the Treatment of Post-traumatic Stress Disorders: A Scoping Review

Some post-traumatic stress disorder (PTSD) patients do not benefit from imaginal exposure therapy. One possible approach to reach such patients are virtual trauma interventions. Herein, a qualitative scoping review was conducted. Different types of virtual trauma exposure interventions were identified. For each type of virtual trauma exposure interventions it was examined in detail: (1) which in sensu trauma exposure approach serves as therapeutic framework, how it was transferred into virtual reality, and if it was manualized; (2) which hardware and software were used; (3) whether the influence of spatial and social presence on the efficacy of virtual trauma interventions have been measured, and (4) whether the efficacy of virtual trauma interventions for PTSD patients having imagination difficulties was evaluated. These research questions were analyzed qualitatively. Accordingly, an extensive literature search was conducted using the databases Web of Science, PsycINFO, LIVIVO, PTSDpubs, and PubMed for scientific articles published between January 2013 and July 2020. Only studies aimed to reduce PTSD symptoms using virtual trauma interventions were included. The literature search was not limited to a specific study design, treatment/intervention method, or a minimum sample size. Eighteen studies were identified, which reported three different virtual trauma intervention approaches, namely, virtual reality exposure therapy (VRET), multi-modular motion-assisted memory desensitization and reconsolidation (3MDR), and action-centered exposure therapy (ACET). Seven randomized controlled trials (RCTs), two pilot studies, and one case study were focused on VRET; while two RCTs, one pilot study, and three case studies focused on 3MDR, and two case studies on ACET. Regarding the first research question (1), the results show that VRET is based on prolonged exposure, aiming for a virtual re-creation of the patient's traumatic recounting. Several treatment protocols exist for VRET. 3MDR is based on eye movement desensitization and reprocessing, aiming to reduce the patient's avoidance behavior. In 3MDR patients walk toward individualized trauma-related symbolic images in a cave automatic virtual environment (CAVE). One treatment protocol exists for 3MDR. ACET is based on the inhibitory learning theory, aiming for active interactions with a virtual trauma-associated environment to alter the anxiety structure through new secondary inhibitory learning. One treatment protocol exists for ACET. For the second research question (2), the results indicate that all VRET studies used head-mounted displays (HMDs) with a virtual version of the Iraq/Afghanistan or the World Trade Center attacks, while 3MDR studies utilized two different versions of a CAVE with personalized trauma-related images, and the ACET studies used HMDs with virtual street scenarios. For the third research question (3), the results demonstrate that the influence of spatial or social presence on the efficacy of virtual trauma interventions was not examined in any of the included studies. Similarly, for the fourth research question (4), the results show that empirical evidence for the efficacy of virtual trauma interventions on PTSD patients having imagination difficulties was lacking. Therefore, such empirical studies are needed to fill these research gaps.

Neuroendocrine biomarkers of prolonged exposure treatment response in military-related PTSD

Posttraumatic stress disorder (PTSD) is associated with dysregulation of the neuroendocrine system, including cortisol, allopregnanolone, and pregnanolone. Preliminary evidence from animal models suggests that baseline levels of these biomarkers may predict response to PTSD treatment. We report the change in biomarkers over the course of PTSD treatment. Biomarkers were sampled from individuals participating in (1) a randomized controlled trial comparing a web-version of Prolonged Exposure (Web-PE) therapy to in-person Present-Centered Therapy (PCT) and (2) from individuals participating in a nonrandomized effectiveness study testing PE delivered in-person as part of an intensive outpatient PTSD program. We found that higher cortisol reactivity during script-driven imagery was associated with higher baseline PTSD severity and that baseline allopregnanolone, pregnanolone, and cortisol reactivity were associated with PTSD treatment responder status over the course of intensive outpatient treatment. These findings demonstrate that peripherally assessed biomarkers are associated with PTSD severity and likelihood of successful treatment outcome of PE delivered daily over two weeks. These assessments could be used to determine which patients are likely to respond to treatment and which patients require augmentation to increase the likelihood of optimal response to PTSD treatment.

Cortisol awakening response in PTSD treatment: Predictor or mechanism of change

PTSD is associated with abnormalities in hypothalamic-pituitary-adrenal (HPA) axis activity. This includes enhanced HPA axis negative feedback, attenuated cortisol awakening response, and attenuated cortisol response to personal trauma script. Whether HPA axis function predicts treatment response or treatment related symptom reduction in PTSD remains unclear. In addition, the relative effects of different treatment modalities (i.e., medication and psychotherapy) on HPA axis is unclear. To address this gap in knowledge, the PROGrESS study examined cortisol awakening response across treatment in Veterans with chronic PTSD randomized to receive Prolonged Exposure + Placebo (PE + PLB), Sertraline + PE (SERT + PE) or Sertraline + Enhanced Medication Management (SERT + EMM). Salivary cortisol awakening response (CAR) was assessed at baseline, mid-treatment (week 6 and 12), post-treatment (week 24) and follow-up (week 36 and 52). Among males at baseline, combat veterans with PTSD showed lower CAR Area Under the Curve Increase (AUCi; M = 3.15, SD = 9.57) than Combat controls (M = 7.63, SD = 9.07; p = .02), demonstrating combat veterans with PTSD have a less responsive system than combat controls. Higher PTSD severity was also related to lower CAR AUCi (r = -0.52, p = .03). When controlling for PTSD severity, higher baseline CAR AUCi was related to attenuated reduction in PTSD and lower likelihood of high treatment response over treatment (z = -2.06, p = .04).

Virtual Reality for Anxiety Disorders: Rethinking a Field in Expansion

The principal aim to this chapter is to present the latest ideas in virtual reality (VR), some of which have already been applied to the field of anxiety disorders, and others are still pending to be materialized. More than 20 years ago, VR emerged as an exposure tool in order to provide patients and therapists with more appealing ways of delivering a technique that was undoubtedly effective but also rejected and thus underused. Throughout these years, many improvements were achieved. The first section of the chapter describes those improvements, both considering the research progresses and the applications in the real world. In a second part, our main interest is to expand the discussion of the new applications of VR beyond its already known role as an exposure tool. In particular, VR is enabling the materialization of numerous ideas that were previously confined to a merely philosophical discussion in the field of cognitive sciences. That is, VR has the enormous potential of providing feasible ways to explore nonclassical ways of cognition, such as embodied and situated information processing. Despite the fact that many of these developments are not fully developed, and not specifically designed for anxiety disorders, we want to introduce these new ideas in a context in which VR is experiencing an enormous transformation.

Translating Molecular and Neuroendocrine Findings in Posttraumatic Stress Disorder and Resilience to Novel Therapies

Many biological systems are altered in association with posttraumatic stress disorder (PTSD) and resilience. However, there are only few approved pharmacological treatments for PTSD, and no approved medications to enhance resilience. This article provides a critical review of select neurobiological findings in PTSD and resilience, and also of pharmacologic approaches that have emerged from this work. The medications summarized involve engagement with targets in the adrenergic, hypothalamic-pituitary-adrenal axis, and neuropeptide Y systems. Other highlighted approaches involve the use of ketamine and 3,4-methylenedioxymethamphetamine-assisted psychotherapy, which recently surfaced as promising strategies for PTSD, though the neurobiological mechanisms underlying their actions, including for promoting resilience, are not yet fully understood. The former approaches fall within the broad concept of "rational pharmacotherapy," in that they attempt to directly target dysregulated systems known to be associated with posttraumatic symptoms. To the extent that use of ketamine and 3,4-methylenedioxymethamphetamine promotes symptom improvement and resilience in PTSD, this provides an opportunity for reverse translation and identification of relevant targets and mechanisms of action through careful study of biological changes resulting from these interventions. Promoting resilience in trauma-exposed individuals may involve more than pharmacologically manipulating dysregulated molecules and pathways associated with developing and sustaining PTSD symptom severity, but also producing a substantial change in mental state that increases the ability to engage with traumatic material in psychotherapy. Neurobiological examination in the context of treatment studies may yield novel targets and promote a greater understanding of mechanisms of recovery from trauma.

Making translation work: Harmonizing cross-species methodology in the behavioural neuroscience of Pavlovian fear conditioning

Translational neuroscience bridges insights from specific mechanisms in rodents to complex functions in humans and is key to advance our general understanding of central nervous function. A prime example of translational research is the study of cross-species mechanisms that underlie responding to learned threats, by employing Pavlovian fear conditioning protocols in rodents and humans. Hitherto, evidence for (and critique of) these cross-species comparisons in fear conditioning research was based on theoretical viewpoints. Here, we provide a perspective to substantiate these theoretical concepts with empirical considerations of cross-species methodology. This meta-research perspective is expected to foster cross-species comparability and reproducibility to ultimately facilitate successful transfer of results from basic science into clinical applications.

Augmenting Treatment for Posttraumatic Stress Disorder and Co-Occurring Conditions with Oxytocin

Purpose of review

The goal of this manuscript is to review the extant literature examining the neurobiological and behavioral mechanisms underlying the potential utility of intranasal oxytocin as a novel pharmacologic intervention for the treatment of posttraumatic stress disorder (PTSD), and for the treatment of co-morbid PTSD and alcohol and substance use disorders.

Recent findings

Research indicates that intranasal oxytocin is a low-cost and easily accessible medication with an excellent safety profile. Oxytocin holds promise for facilitating more effective PTSD treatment, particularly when used in combination with evidence-supported psychotherapy interventions. There is still a significant need to identify the mechanisms of action underlying oxytocin treatment of PTSD, and to maximize methods of nasal spray delivery, examine dose-response outcomes, and clarify the characteristics of individuals and populations that are most likely to benefit from adjunctive oxytocin treatment.

Summary

Collectively, preclinical and human laboratory research suggest that oxytocin may be an effective mechanism by which treatment outcomes for PTSD and common comorbidities can be enhanced. Adequately powered randomized controlled trials are needed to address efficacy, identify predictors of treatment outcome, and to assess the use of intranasal oxytocin within appropriate PTSD populations.