Pharmacological enhancement of exposure-based treatment in PTSD: a qualitative review

Functional brain changes after alternative pharmacological interventions in posttraumatic stress disorder: A systematic review of clinical trials

BACKGROUND

Posttraumatic stress disorder (PTSD) is a complex and heterogeneous mental health condition that can develop after exposure to a traumatic event. Clinical trials have used alternative pharmacological agents to treat PTSD, but their associated neural correlates remain unclear. The present systematic review aims to summarize the changes in brain function associated with the use of these alternative pharmacological agents in PTSD.

METHODS

Clinical trials using functional magnetic resonance imaging, either at rest or during the performance of tasks, were included if they compared the effects of alternative pharmacological agents between PTSD patients and either trauma-exposed controls or never-exposed healthy controls.

RESULTS

Sixteen studies were included, of which 11 used intranasal oxytocin, 2 used hydrocortisone, and 3 used delta-9-tetrahydrocannabinol (THC). Oxytocin administration was associated with the normalization of functional connectivity between the ventromedial prefrontal cortex and amygdala as well as enhanced the function of brain regions specifically involved in emotion processing (e.g., amygdala), working memory (e.g., dorsolateral prefrontal cortex), and reward (e.g., putamen). Hydrocortisone did not influence brain function at rest or during the performance of an autobiographical memory task, whereas THC was associated with the reduction of the amygdala and increased medial prefrontal cortex activation.

CONCLUSIONS

This systematic review identified preliminary evidence for normalizing brain function after the use of alternative pharmacological agents. Importantly, sex-specific differences were noted, in particular when using oxytocin, that will require further investigation.

Ventral Hippocampal Input to Infralimbic Cortex Is Necessary for the Therapeutic-Like Effects of Extinction in Stressed Rats

BACKGROUND

Posttraumatic stress disorder is characterized by deficits in cognitive flexibility related to dysfunction of the medial prefrontal cortex (mPFC). Exposure therapy can effectively reverse these deficits. Fear extinction in rodents bears similarity to exposure therapy. Extinction reverses chronic stress-induced deficits in cognitive flexibility on the attentional set-shifting test (AST), an mPFC-mediated process. This therapeutic effect requires activity of pyramidal neurons and brain derived neurotrophic factor (BDNF) signaling in infralimbic cortex (IL). However, the circuit mechanisms governing BDNF-mediated plasticity initiated by extinction in IL are unknown. The ventral hippocampus (vHipp) plays a role in regulating IL activity during extinction, and plasticity in vHipp is necessary for extinction memory consolidation. Therefore, we investigated the role of vHipp input to IL in the effects of extinction in reversing stress-induced cognitive deficits.

METHODS

vHipp input to IL was silenced using a Gi-Designer Receptors Exclusively Activated by Designer Drugs (DREADD) via local infusion of clozapine-N-oxide (CNO) into IL before extinction. A day later, rats were tested on AST. In a separate experiment, we tested whether vHipp input to the IL induces BDNF signaling to exert therapeutic effects. We activated the vHipp using a Gq-DREADD, and injected an anti-BDNF neutralizing antibody into IL. Rats were tested on the AST 24 hours later.

RESULTS

Silencing the vHipp input to IL prevented the beneficial effects of extinction in reversing stress-induced cognitive deficits. Activating vHipp input to IL in the absence of extinction was sufficient to reverse stress-induced deficits in set-shifting. The beneficial effects were blocked by local infusion of a neutralizing anti-BDNF antibody into IL.

CONCLUSIONS

vHipp-driven BDNF signaling in IL is critical for extinction to counteract the deleterious cognitive effects of chronic stress.

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.

Infralimbic BDNF signaling is necessary for the beneficial effects of extinction on set shifting in stressed rats

Current pharmacotherapies for posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are ineffective for many patients, and often do not restore cognitive dysfunction associated with these disorders. Behavioral therapies, such as exposure therapy, can be effective for treatment-resistant patients. The mechanisms underlying exposure therapy are not well-understood. Fear extinction as an intervention after chronic stress can model the beneficial effects of exposure therapy in rats. Extinction requires neuronal activity and protein synthesis in the infralimbic (IL) cortex for its beneficial effects. We hypothesized that extinction requires Brain-Derived Neurotrophic Factor (BDNF) activity in the IL cortex to reverse stress-induced cognitive flexibility impairments. Extinction learning reversed set-shifting deficits induced by Chronic Unpredictable Stress (CUS), tested 24 h after extinction. Blocking BDNF signaling in the IL cortex during extinction by local administration of a neutralizing antibody prevented the beneficial effects of extinction on set shifting after stress. Extinction induced activation of the BDNF TrkB receptor, and signaling pathways associated with BDNF (Akt and Erk). Administration of exogenous BDNF into IL cortex in the absence of extinction was sufficient to reverse the effects of stress on set shifting. The effects of extinction were prevented by blocking either Erk or Akt signaling in the IL cortex, whereas the effects of exogenous BDNF were dependent on Erk, but not Akt, signaling. Our observations suggest that BDNF-Erk signaling induced by extinction underlies plastic changes that can reverse or counteract the effects of chronic stress in the IL cortex.

A randomized, double-blind, placebo-controlled trial of hydrocortisone augmentation of Prolonged Exposure for PTSD in U.S. combat veterans

OBJECTIVE

Cognitive behavioral therapies such as Prolonged Exposure (PE) are considered first line treatments for posttraumatic stress disorder (PTSD). Nonetheless, many continue to experience significant symptoms following treatment and there is interest in enhancing treatment effectiveness. Glucocorticoid alterations in PTSD are well documented, and these steroids have been shown to enhance extinction learning.

METHODS

Augmentation of PE with the synthetic glucocorticoid hydrocortisone (HCORT) was tested in a randomized, double-blind, placebo-controlled trial in 60 veterans of wars in Iraq or Afghanistan with PTSD (NCT01525680). Participants ingested 30 mg oral HCORT or placebo 30 min prior to exposure sessions.

PRIMARY OUTCOME MEASURE

PTSD severity assessed by the CAPS; secondary outcome measures: self reported PTSD symptoms assessed by the PDS and depression assessed by the BDI; all administered at pretreatment, posttreatment, and 3-month follow up.

RESULTS

Across conditions, there was a robust effect of PE over time. An intent-to-treat analysis showed that HCORT did not measurably improve PTSD symptoms or secondary outcomes. However, exploratory analyses indicated that veterans with mild TBI exposure and current postconcussive symptoms showed a greater reduction in hyperarousal symptoms following PE treatment with HCORT augmentation. Additionally, veterans with higher baseline glucocorticoid sensitivity showed a greater reduction in avoidance symptoms with HCORT augmentation.

CONCLUSIONS

Treatment matching based on cognitive or biological vulnerabilities might lead to greater efficacy of PE with glucocorticoid augmentation.

The efficacy of memantine in the treatment of civilian posttraumatic stress disorder: an open-label trial

Background: Currently, there is a paucity of pharmacological treatment options for posttraumatic stress disorder (PTSD), and the development of a novel pharmacotherapeutic approach has become a matter of great interest. Objective: We conducted a 12-week open-label clinical trial to examine the efficacy and safety of memantine, an N-methyl-D-aspartate receptor antagonist, in the treatment of civilian PTSD. Method: Thirteen adult patients with DSM-IV PTSD, all civilian women, were enrolled. They were monitored at an ambulatory care facility every week until 4 weeks and then every 4 weeks until 12 weeks. Memantine was added to each patient's current medication, with the initial dosage of 5 mg/day and then titrated. Concomitant medications were essentially kept unchanged during the trial. The primary outcome was PTSD diagnosis and severity assessed with the Posttraumatic Diagnostic Scale (PDS). Results: Of the 13 cases, one dropped out and two were discarded due to the protocol deviation, and the analysis was done for the remaining 10. Mean PDS total scores decreased from 32.3 ± 9.7 at baseline to 12.2 ± 7.9 at endpoint, which was statistically significant with a large effect (paired t-test: p = .002, d = 1.35); intrusion, avoidance, hyperarousal symptoms were all significantly improved from baseline to endpoint. Six patients no longer fulfilled the diagnostic criteria of PTSD at endpoint. Some adverse, but not serious, effects possibly related to memantine were observed, including sleep problems, sleepiness, sedation, weight change and hypotension. Conclusions: Memantine significantly reduced PTSD symptoms in civilian female PTSD patients and the drug was well tolerated. Future randomized controlled trials are necessary to verify the efficacy and safety of memantine in the treatment of PTSD.

The reconsolidation using rewind study (RETURN): trial protocol

Background: An increasing body of research highlights reconsolidation-based therapies as emerging treatments for post-traumatic stress disorder (PTSD). The Rewind Technique is a non-pharmacological reconsolidation-based therapy with promising early results, which now requires evaluation through an RCT. Objectives: This is a preliminary efficacy RCT to determine if the Rewind Technique is likely to be a good candidate to test against usual care in a future pragmatic efficacy RCT. Methods: 40 participants will be randomised to receive either the Rewind Technique immediately, or after an 8 week wait. The primary outcome will be PTSD symptom severity as measured by the Clinician-Administered PTSD Scale for DSM5 (CAPS-5) at 8 and 16 weeks post-randomisation. Secondary outcome measures include the PTSD Checklist (PCL-5), International Trauma Questionnaire (ITQ), Patient Health Questionnaire (PHQ-9), the General Anxiety Disorder-7 (GAD-7), Insomnia Severity Index, the Euro-Qol-5D (EQ5D-5 L), the prominence of re-experiencing specific symptoms (CAPS-5) and an intervention acceptability questionnaire to measure tolerability of the intervention. Conclusions: This study will be the first RCT to assess the Rewind Technique. Using a cross-over methodology we hope to rigorously assess the efficacy and tolerability of Rewind using pragmatic inclusion criteria. Potential challenges include participant recruitment and retention. Trial registration: ISRCTN91345822.

The Paradoxical Effect of Deep Brain Stimulation on Memory

Deep brain stimulation (DBS) is a promising treatment for many memory-related disorders including dementia, anxiety, and addiction. However, the use of DBS can be a paradoxical conundrum-dementia treatments aim to improve memory, whereas anxiety or addiction treatments aim to suppress maladaptive memory. In this review, the key hypotheses on how DBS affects memory are highlighted. We consolidate the findings and conclusions from the current research on the effects of DBS on memory in attempt to make sense of the bidirectional nature of DBS in disrupting and enhancing memory. Based on the current literature, we hypothesize that the timing of DBS plays a key role in its contradictory effects, and therefore, we propose a consolidated model of how DBS can both disrupt and enhance memory.

MDMA-assisted psychotherapy for people diagnosed with treatment-resistant PTSD: what it is and what it isn't

BACKGROUND

PTSD is a chronic condition with high rates of comorbidity, but current treatment options are limited and not always effective. One novel approach is MDMA-assisted psychotherapy for people diagnosed with treatment-resistant PTSD, where MDMA is used as a catalyst to facilitate trauma processing during psychotherapy. The aim was to review all current research into MDMA-assisted psychotherapy for PTSD.

METHODS

Articles were identified through PubMed and Science Direct for items published up to 31st March 2019 using terms "treatments for PTSD", "drug treatments for PTSD", "MDMA", "MDMA pathway", "MDMA-assisted psychotherapy" and "MDMA-assisted psychotherapy for PTSD". Articles were identified through Google Scholar and subject-specific websites. Articles and relevant references cited in those articles were reviewed.

RESULTS

Small-scale studies have shown reduced psychological trauma, however there has been widespread misunderstanding of the aims and implications of this work, most commonly the notion that MDMA is a 'treatment for PTSD', which to date has not been researched. This has harmful consequences, namely dangerous media reporting and impeding research progression in an already controversial field.

CONCLUSIONS

MDMA-assisted psychotherapy may help people who have experienced psychological trauma and who have not been able to resolve their problems through existing treatments, however more research is needed. If this is to get appropriate research attention, we must report this accurately and objectively.

Pharmacotherapy of anxiety disorders in the 21st century: A call for novel approaches

While limited advances have occurred in the past 30 years in the pharmacological management of anxiety and stress-related disorders, novel molecular pathways both within and without the monoamine systems are currently under investigation and offer promising new avenues for more effective future treatments. Enhancing psychotherapy approaches with pharmacological compounds offers the potential to not only transform the standard of care of these conditions, but more broadly would introduce a paradigm shift in the way medications and their role in psychiatric care are conceptualised. Although further human trials and more translational research are sorely needed, continuing to pursue innovative mechanisms and treatments is hoped to yield substantial results in the coming decades and a departure from the reliance on chemical agents of the 20th century.

A decennial review of psychotraumatology: what did we learn and where are we going?

On 6 December 2019 we start the 10th year of the European Journal of Psychotraumatogy (EJPT), a full Open Access journal on psychotrauma. This editorial is part of a special issue/collection celebrating the 10 years anniversary of the journal where we will acknowledge some of our most impactful articles of the past decade (also discussed below and marked with * in the reference list). In this editorial the editors present a decennial review of the field addressing a range of topics that are core to both the journal and to psychotraumatology as a discipline. These include neurobiological developments (genomics, neuroimaging and neuroendocrine research), forms of trauma exposure and impact across the lifespan, mass trauma and early interventions, work-related trauma, trauma in refugee populations, and the potential consequences of trauma such as PTSD or Complex PTSD, but also resilience. We address innovations in psychological, medication (enhanced) and technology-assisted treatments, mediators and moderators like social support and finally how new research methods help us to gain insights in symptom structures or to better predict symptom development or treatment success. We aimed to answer three questions 1. Where did we stand in 2010? 2. What did we learn in the past 10 years? 3. What are our knowledge gaps? We conclude with a number of recommendations concerning top priorities for the future direction of the field of psychotraumatology and correspondingly the journal.

Eternal sunshine of the neuromodulated mind: Altering fear memories through neuromodulation

Anxiety disorders pose one of the greatest threats to mental health. Modern treatment methods exist but are hindered by relapse, toxicity, and low efficacy. The use of neuromodulation to treat anxiety disorders has shown promising results, yet its underpinning mechanisms remain poorly understood. In this review, we make the case for further development of neuromodulation techniques to alter fear memories, with particular regard to future clinical applications in treating anxiety disorders. We start by briefly summarizing the neural circuitry of fear while identifying the pros and cons of possible neuromodulation targets. We then highlight recent advances in neuromodulation techniques that have been used to alter fear memories. Next, we apply a novel network-based approach to elucidate possible mechanisms of neuromodulation which may disrupt the consolidation of fear memory. Finally, we emphasize the need for more systematic neuromodulation studies on animal models and the developing brain. Overall, we aim to provide an integrated framework for future action, identifying key research priorities that must be addressed before effective neuromodulation-based treatments can be developed for practical use.

Modulation of naturalistic maladaptive memories using behavioural and pharmacological reconsolidation-interfering strategies: a systematic review and meta-analysis of clinical and 'sub-clinical' studies

BACKGROUND

Consolidated memories can undergo enduring modification through retrieval-dependent treatments that modulate reconsolidation. This represents a potentially transformative strategy for weakening or overwriting the maladaptive memories that underlie substance use and anxiety/trauma-related disorders. However, modulation of naturalistic maladaptive memories may be limited by 'boundary conditions' imposed on the reconsolidation process by the nature of these memories.

METHODS

We conducted a systematic review and meta-analyses of behavioural and pharmacological studies examining retrieval-dependent modulation of reward- and threat-related memories in (sub) clinical substance use and anxiety/trauma, respectively.

RESULTS

Of 4938 publications assessed for eligibility, 8 studies of substance use and 10 of anxiety (phobia)- and trauma-related symptoms were included in the meta-analyses. Overall, the findings were in the predicted direction, with most studies favouring the 'retrieval + treatment' condition. However, the magnitude of effects was dependent upon the nature of treatment, with pharmacological interventions showing a medium-sized effect (g = 0.59, p = 0.03) and behavioural treatments, a relatively small effect (g = 0.32, p = 0.10) in studies of phobia/trauma. Among studies of substance use, post-retrieval behavioural interventions yielded a larger effect (g = 0.60, p < 0.001) relative to pharmacological treatments (g = - 0.03, p = 0.91), with treatment type being a statistically significant moderator (χ2(1) = 4.20, p = 0.04).

CONCLUSION

Modification of naturalistic maladaptive memories during reconsolidation appears to be a viable treatment strategy for substance use and phobias/trauma disorders. However, high levels of heterogeneity and methodological variation limit the strength of conclusions that can be drawn from the reviewed studies at this stage.

Acute effects of 3,4-methylenedioxymethamphetamine (MDMA) and R(-) MDMA on actigraphy-based daytime activity and sleep parameters in rhesus monkeys

3,4-Methylenedioxymethamphetamine (MDMA) affects monoaminergic pathways that play a critical role in sleep-wake cycles. Dopaminergic mechanisms are thought to mediate the sleep-disrupting effects of stimulant drugs. However, the mechanisms underlying the effects of MDMA on sleep-wake cycles and the effects of R(-) MDMA, a stereoisomer that lacks dopaminergic activity, on sleep remain unknown. The aim of the present study was to investigate the effects of racemic MDMA and R(-) MDMA on daytime activity and sleep-like parameters evaluated with actigraphy in adult rhesus macaques (Macaca mulatta, n = 6). Actiwatch monitors were attached to the monkeys' collars and actigraphy recording was conducted during baseline conditions and after the administration of acute intramuscular injections of saline (vehicle), racemic MDMA (0.3, 1.0, or 1.7 mg/kg), or R(-) MDMA (0.3, 1.0, or 1.7 mg/kg) at 9 or 16 h (3 h before "lights off"). Morning treatments had no effects on sleep-like parameters. Racemic MDMA decreased general daytime activity during the first hour after injection and increased daytime activity at 3 hr posttreatment. Although afternoon administration of racemic MDMA increased sleep latency, it improved other sleep parameters, decreasing wake time after sleep onset (WASO) and increasing sleep efficiency for subjects with low baseline sleep efficiency. Afternoon treatment with R(-) MDMA improved sleep measures, increasing sleep efficiency and decreasing sleep latency and WASO, while having no effects on daytime activity. The stimulant and sleep-disrupting effects of racemic MDMA are likely mediated by dopaminergic and noradrenergic mechanisms, while serotonergic pathways appear to be involved in the sleep-promoting effects of MDMA. (PsycINFO Database Record

d-Serine is a potential biomarker for clinical response in treatment of post-traumatic stress disorder using (R,S)-ketamine infusion and TIMBER psychotherapy: A pilot study

Post-traumatic stress disorder (PTSD) is a chronic and debilitating condition that is often refractory to standard frontline antidepressant therapy. A promising new approach to PTSD therapy is administration of a single sub-anesthetic dose of (R,S)-ketamine (Ket). The treatment produces rapid and significant therapeutic response, which lasts for only 4-7 days. In one of our studies, the mean duration of response was increased to 33 days when Ket administration was combined with a mindfulness-based cognitive therapy, Trauma Interventions using Mindfulness Based Extinction and Reconsolidation (TIMBER). We now report the results from a 20-patient study, which examined the duration of sustained response with combined TIMBER-Ket therapy, TIMBER-K arm, relative to the response observed in a placebo-controlled arm, TIMBER-P. A significant difference in the duration of response was observed between TIMBER-K and TIMBER-P arms: 34.44 ± 19.12 days and 16.50 ± 11.39 days, respectively (p = 0.022). Previous studies identified a negative correlation between antidepressant response to Ket and basal plasma concentrations of d-serine (DSR). In this study, the basal DSR levels positively correlated with the pre-treatment severity of PTSD symptoms (Pearson's r = 0.42, p = 0.07) and patients with basal DSR level ≥ 3.5 μM displayed not only higher PTSD severity but also shorter duration of response. The data indicate that basal DSR levels may serve as a biomarker of the severity of PTSD symptoms and as a predictor of clinical response. This article is part of a Special Issue entitled: d-Amino acids: biology in the mirror, edited by Dr. Loredano Pollegioni, Dr. Jean-Pierre Mothet and Dr. Molla Gianluca.

A Novel Retrieval-Dependent Memory Process Revealed by the Arrest of ERK1/2 Activation in the Basolateral Amygdala

Fully consolidated fear memories can be maintained or inhibited by retrieval-dependent mechanisms depending on the degree of re-exposure to fear cues. Short exposures promote memory maintenance through reconsolidation, and long exposures promote inhibition through extinction. Little is known about the neural mechanisms by which increasing cue exposure overrides reconsolidation and instead triggers extinction. Using auditory fear conditioning in male rats, we analyzed the role of a molecular mechanism common to reconsolidation and extinction of fear, ERK1/2 activation within the basolateral amygdala (BLA), after intermediate conditioned stimulus (CS) exposure events. We show that an intermediate re-exposure (four CS presentations) failed to activate ERK1/2 in the BLA, suggesting the absence of reconsolidation or extinction mechanisms. Supporting this hypothesis, pharmacologically inhibiting the BLA ERK1/2-dependent signaling pathway in conjunction with four CS presentations had no effect on fear expression, and the NMDA receptor partial agonist d-cycloserine, which enhanced extinction and ERK1/2 activation in partial extinction protocols (seven CSs), had no behavioral or molecular effect when given in association with four CS presentations. These molecular and behavioral data reveal a novel retrieval-dependent memory phase occurring along the transition between conditioned fear maintenance and inhibition. CS-dependent molecular events in the BLA may arrest reconsolidation intracellular signaling mechanism in an extinction-independent manner. These findings are critical for understanding the molecular underpinnings of fear memory persistence after retrieval both in health and disease.SIGNIFICANCE STATEMENT Consolidated fear memories can be altered by retrieval-dependent mechanisms. Whereas a brief conditioned stimulus (CS) exposure promotes fear memory maintenance through reconsolidation, a prolonged exposure engages extinction and fear inhibition. The nature of this transition and whether an intermediate degree of CS exposure engages reconsolidation or extinction is unknown. We show that an intermediate cue exposure session (four CSs) produces the arrest of ERK1/2 activation in the basolateral amygdala, a common mechanism for reconsolidation and extinction. Amnestic or hypermnestic treatments given in association with four CSs had no behavioral or molecular effects, respectively. This evidence reveals a novel retrieval-dependent memory phase. Intermediate degrees of CS exposure fail to trigger reconsolidation or extinction, leaving the original memory in an insensitive state.

Augmenting Prolonged Exposure therapy for PTSD with intranasal oxytocin: A randomized, placebo-controlled pilot trial

Posttraumatic stress disorder (PTSD) is a chronic, debilitating condition for which Prolonged Exposure (PE) therapy is highly efficacious. However, for some individuals, premature dropout and residual PTSD symptoms remain obstacles. The neuropeptide oxytocin is a promising candidate to enhance PE due to its ability to enhance 1) prosocial cognition and behavior, which are theorized to promote positive working alliance, and 2) extinction learning, which is the central mechanism of action underlying successful PE treatment. Despite a robust theoretical rationale, no studies to date have combined evidence-based psychotherapy for PTSD with oxytocin. This randomized, placebo-controlled, double-blind pilot trial examined the feasibility, safety, and preliminary efficacy of augmenting PE with oxytocin. Participants were 17 individuals with diverse index traumas. Participants self-administered intranasal oxytocin (40 IU) or matching placebo 45 min prior to each weekly PE therapy session. One adverse event occurred in the placebo group and three individuals dropped out (17.6%; 2 oxytocin group and 1 placebo group). The oxytocin group demonstrated lower PTSD and depression symptoms during PE, and had higher working alliance scores, although these differences did not reach statistical significance. Although preliminary, the findings support the feasibility of oxytocin combined with PE. Adequately powered studies are necessary to determine whether oxytocin enhances PE treatment outcomes and to examine potential mechanisms, such as accelerating extinction learning, enhancing early response, and preventing premature dropout. NCT03238924.

Activity in the Ventral Medial Prefrontal Cortex Is Necessary for the Therapeutic Effects of Extinction in Rats

Poor response and high relapse rates remain problematic in the treatment of stress-related psychiatric disorders such as depression and post-traumatic stress disorder. Although mechanisms of pharmacotherapies are intensely studied, little is known about mechanisms of behavioral therapy that could inform improved treatments. We have previously demonstrated the therapeutic effects of extinction learning as a behavioral intervention modeling exposure therapy in rats. In the present study, we tested the hypothesis that activity in the ventral medial prefrontal cortex (vmPFC) during extinction is necessary for its therapeutic effects. The inhibitory Gi-coupled designer receptor exclusively activated by designer drug CaMKIIα-hM4Di was expressed in vmPFC before administering chronic unpredictable stress (CUS). vmPFC projection neurons were then inhibited during extinction treatment by administering clozapine-N-oxide. Coping behavior and cognitive flexibility were assessed 24 h later on the shock-probe defensive burying test and attentional set-shifting test, respectively. Replicating previous results, extinction reversed the CUS-induced deficits in coping behavior and cognitive flexibility. Inhibiting vmPFC during extinction blocked these therapeutic effects. Further, increasing vmPFC activity with the excitatory Gq-coupled designer receptor exclusively activated by designer drug hM3Dq 24 h before testing was sufficient to reverse the CUS-induced deficits. CUS reduced mPFC responsivity, assessed by measuring afferent-evoked field potentials in the mPFC, and this reduction was reversed by extinction treatment 24 h before testing. These results demonstrate the necessity of vmPFC activity in the therapeutic effects of extinction as a model of exposure therapy, and suggest that increased vmPFC activity induced by extinction is sufficient to produce lasting plastic changes that underlie its beneficial effects.SIGNIFICANCE STATEMENT Stress-related psychiatric disorders remain poorly treated. Psychotherapies can be effective, but their mechanisms remain unknown, hindering progress toward improved treatment. We used a rat model of behavioral therapy to identify potential targets for enhancing treatment. Fear extinction as a therapeutic behavioral intervention reversed stress-induced cognitive dysfunction and passive coping in rats, modeling components of stress-related psychiatric disease. Extinction also reversed stress-induced attenuation of mPFC responsivity. The therapeutic effects were prevented by blocking activity of glutamatergic neurons in the mPFC during extinction, and were mimicked by inducing activity in lieu of extinction. Thus, activity and plasticity in the mPFC underlie the beneficial effects of extinction on cognitive flexibility and coping behavior compromised by stress, and could be targets to enhance behavioral therapy.

Intensive prolonged exposure therapy for chronic PTSD patients following multiple trauma and multiple treatment attempts

Background: Suboptimal response and high dropout rates leave room for improvement of trauma-focused treatment (TFT) effectiveness in ameliorating posttraumatic stress disorder (PTSD) symptoms. Objective: To explore the effectiveness and safety of intensive prolonged exposure (iPE) targeting chronic PTSD patients with a likely diagnosis of ICD-11 Complex PTSD following multiple interpersonal trauma and a history of multiple treatment attempts. Method: Participants (N = 73) received iPE in 12 × 90-minute sessions over four days (intensive phase) followed by four weekly 90-minute booster prolonged exposure (PE) sessions (booster phase). The primary outcomes, clinician-rated severity of PTSD symptoms, and diagnostic status (Clinician-Administered PTSD Scale; CAPS-IV) were assessed at baseline, post-treatment, and at three and six months. Treatment response trajectories were identified and predictors of these trajectories explored. Results: Mixed model repeated measures analysis of CAPS-IV scores showed a baseline-to-posttreatment decrease in PTSD symptom severity (p < .001) that persisted during the three- and six-month follow-ups with large effect sizes (Cohen's d > 1.2); 71% of the participants responded. None of the participants dropped out during the intensive phase and only 5% during the booster phase. Adverse events were extremely low and only a minority showed symptom exacerbation. Cluster analysis demonstrated four treatment response trajectories: Fast responders (13%), Slow responders (26%), Partial responders (32%), and Non-responders (29%). Living condition and between-session fear habituation were found to predict outcome. Participants living alone were more likely to belong to the Partial responders than to the Non-responders cluster, and participants showing more between-session fear habituation were more likely to belong to the Fast responders than to the Non-responders cluster. Conclusions: The results of this open study suggest that iPE can be effective in PTSD patients with multiple interpersonal trauma and after multiple previous treatment attempts. In addition, in this chronic PTSD population iPE was safe.

Inhibition of serotonin transporters disrupts the enhancement of fear memory extinction by 3,4-methylenedioxymethamphetamine (MDMA)

RATIONALE

3,4-Methylenedioxymethamphetamine (MDMA) persistently improves symptoms of post-traumatic stress disorder (PTSD) when combined with psychotherapy. Studies in rodents suggest that these effects can be attributed to enhancement of fear memory extinction. Therefore, MDMA may improve the effects of exposure-based therapy for PTSD, particularly in treatment-resistant patients. However, given MDMA's broad pharmacological profile, further investigation is warranted before moving to a complex clinical population.

OBJECTIVES

We aimed to inform clinical research by providing a translational model of MDMA's effect, and elucidating monoaminergic mechanisms through which MDMA enhances fear extinction.

METHODS

We explored the importance of monoamine transporters targeted by MDMA to fear memory extinction, as measured by reductions in conditioned freezing and fear-potentiated startle (FPS) in mice. Mice were treated with selective inhibitors of individual monoamine transporters prior to combined MDMA treatment and fear extinction training.

RESULTS

MDMA enhanced the lasting extinction of FPS. Acute and chronic treatment with a 5-HT transporter (5-HTT) inhibitor blocked MDMA's effect on fear memory extinction. Acute inhibition of dopamine (DA) and norepinephrine (NE) transporters had no effect. 5-HT release alone did not enhance extinction. Blockade of MDMA's effect by 5-HTT inhibition also downregulated 5-HT2A-mediated behavior, and 5-HT2A antagonism disrupted MDMA's effect on extinction.

CONCLUSIONS

We validate enhancement of fear memory extinction by MDMA in a translational behavioral model, and reveal the importance of 5-HTT and 5-HT2A receptors to this effect. These observations support future clinical research of MDMA as an adjunct to exposure therapy, and provide important pharmacological considerations for clinical use in a population frequently treated with 5-HTT inhibitors.

D-cycloserine augmentation of behavior therapy for anxiety and obsessive-compulsive disorders: A meta-analysis

OBJECTIVE

The present meta-analysis investigates whether the antibiotic D-cycloserine (DCS), a partial agonist at the glutamatergic N-methyl-D-aspartate receptor, can augment the effect of behavior therapy in humans with anxiety and obsessive-compulsive disorders.

METHOD

A keyword-based computer search was conducted using common electronic databases. Only studies investigating the effect of DCS in humans with anxiety and obsessive-compulsive disorders were included, resulting in 23 studies with a combined sample size of 1314 patients. Effect sizes were coded as Hedges' g and SMCC, the latter also incorporating differences in pre-treatment values. Bayesian multilevel meta-analysis was applied to take dependencies of effect sizes obtained from the same study into account.

RESULTS

While previous meta-analyses found small to moderate improvements, the current results including the most recent research indicate that the overall effect of DCS is very small and almost indistinguishable from zero (g = -0.12, CI = [-0.27, 0.02]; SMCC = -0.10, CI = [-0.29, 0.07]). Slightly larger effects were found for social anxious patients. Further, study quality and year of publication were relevant moderators, with higher quality / more recent studies reported smaller effects of DCS.

CONCLUSIONS

These findings raise the question of the usefulness of DCS as an augmentation of exposure therapy for anxiety and obsessive-compulsive disorders. At least, it seems to be less promising than initially thought. The fact that study quality was inversely related to the reported effect sizes underlines the importance of high quality primary research in order to avoid over-estimation of treatment effects in clinical psychology.

Fear extinction and memory reconsolidation as critical components in behavioral treatment for posttraumatic stress disorder and potential augmentation of these processes

Posttraumatic stress disorder (PTSD) is associated with alterations in critical brain regions such as the amygdala, hippocampus, and prefrontal cortex. This brief review has two objectives: (1) to discuss research examining extinction and reconsolidation processes as mechanisms in PTSD psychotherapy, and (2) present possibilities for augmenting extinction and reconsolidation within treatment through alterations to therapeutic interventions and novel approaches. A key component of many effective PTSD therapies is exposure, which involves intentional confrontation and processing of the traumatic memory. Our review suggests that extinction and reconsolidation processes underlie effective exposure-based treatment, but the neurobiological mechanisms of these processes in behavioral treatments for PTSD remains unclear. We argue that enhancing extinction and/or disrupting reconsolidation of a feared memory may improve the efficacy of existing treatments (e.g., increased change for limited/non-responders, faster/greater changes for responders), which can be done through multiple channels. Potential avenues for augmentation of the processes of extinction and reconsolidation in PTSD psychotherapies are reviewed, including behavioral modifications, pharmacotherapy agents, and the use of devices during therapy. We further suggest that investigations towards understanding the extent to which extinction and reconsolidation processes are necessary in effective PTSD psychotherapy is an important future direction for enhancing clinical care among PTSD populations.

Therapeutic Effects of Extinction Learning as a Model of Exposure Therapy in Rats

Current treatments for stress-related psychiatric disorders, such as depression and posttraumatic stress disorder (PTSD), are inadequate. Cognitive behavioral psychotherapies, including exposure therapy, are an alternative to pharmacotherapy, but the neurobiological mechanisms are unknown. Preclinical models demonstrating therapeutic effects of behavioral interventions are required to investigate such mechanisms. Exposure therapy bears similarity to extinction learning. Thus, we investigated the therapeutic effects of extinction learning as a behavioral intervention to model exposure therapy in rats, testing its effectiveness in reversing chronic stress-induced deficits in cognitive flexibility and coping behavior that resemble dimensions of depression and PTSD. Rats were fear-conditioned by pairing a tone with footshock, and then exposed to chronic unpredictable stress (CUS) that induces deficits in cognitive set-shifting and active coping behavior. They then received an extinction learning session as a therapeutic intervention by repeated exposure to the tone with no shock. Effects on cognitive flexibility and coping behavior were assessed 24 h later on the attentional set-shifting test or shock-probe defensive burying test, respectively. Extinction reversed the CUS-induced deficits in cognitive flexibility and coping behavior, and increased phosphorylation of ribosomal protein S6 in the medial prefrontal cortex (mPFC) of stress-compromised rats, suggesting a role for activity-dependent protein synthesis in the therapeutic effect. Inhibiting protein synthesis by microinjecting anisomycin into mPFC blocked the therapeutic effect of extinction on cognitive flexibility. These results demonstrate the utility of extinction as a model by which to study mechanisms underlying exposure therapy, and suggest these mechanisms involve protein synthesis in the mPFC, the further study of which may identify novel therapeutic targets.

Intranasal Oxytocin Normalizes Amygdala Functional Connectivity in Posttraumatic Stress Disorder

The neuropeptide oxytocin (OT) has been suggested as a promising pharmacological agent for medication-enhanced psychotherapy in posttraumatic stress disorder (PTSD) because of its anxiolytic and prosocial properties. We therefore investigated the behavioral and neurobiological effects of a single intranasal OT administration (40 IU) in PTSD patients. We conducted a randomized, placebo-controlled, cross-over resting-state fMRI study in male and female police officers with (n=37, 21 males) and without PTSD (n=40, 20 males). We investigated OT administration effects on subjective anxiety and functional connectivity of basolateral (BLA) and centromedial (CeM) amygdala subregions with prefrontal and salience processing areas. In PTSD patients, OT administration resulted in decreased subjective anxiety and nervousness. Under placebo, male PTSD patients showed diminished right CeM to left ventromedial prefrontal cortex (vmPFC) connectivity compared with male trauma-exposed controls, which was reinstated after OT administration. Additionally, female PTSD patients showed enhanced right BLA to bilateral dorsal anterior cingulate cortex (dACC) connectivity compared with female trauma-exposed controls, which was dampened after OT administration. Although caution is warranted, our findings tentatively suggest that OT has the potential to diminish anxiety and fear expression of the amygdala in PTSD, either via increased control of the vmPFC over the CeM (males) or via decreased salience processing of the dACC and BLA (females). Our findings add to accumulating evidence that OT administration could potentially enhance treatment response in PTSD.

Intranasal Oxytocin Administration Dampens Amygdala Reactivity towards Emotional Faces in Male and Female PTSD Patients

Post-traumatic stress disorder (PTSD) is a disabling psychiatric disorder. As a substantial part of PTSD patients responds poorly to currently available psychotherapies, pharmacological interventions boosting treatment response are needed. Because of its anxiolytic and pro-social properties, the neuropeptide oxytocin (OT) has been proposed as promising strategy for treatment augmentation in PTSD. As a first step to investigate the therapeutic potential of OT in PTSD, we conducted a double-blind, placebo-controlled, cross-over functional MRI study examining OT administration effects (40 IU) on amygdala reactivity toward emotional faces in unmedicated male and female police officers with (n=37, 21 males) and without (n=40, 20 males) PTSD. Trauma-exposed controls were matched to PTSD patients based on age, sex, years of service and educational level. Under placebo, the expected valence-dependent amygdala reactivity (ie, greater activity toward fearful-angry faces compared with happy-neutral faces) was absent in PTSD patients. OT administration dampened amygdala reactivity toward all emotional faces in male and female PTSD patients, but enhanced amygdala reactivity in healthy male and female trauma-exposed controls, independent of sex and stimulus valence. In PTSD patients, greater anxiety prior to scanning and amygdala reactivity during the placebo session were associated with greater reduction of amygdala reactivity after OT administration. Taken together, our results indicate presumably beneficial neurobiological effects of OT administration in male and female PTSD patients. Future studies should investigate OT administration in clinical settings to fully appreciate its therapeutic potential.

Revisiting propranolol and PTSD: Memory erasure or extinction enhancement?

Posttraumatic stress disorder (PTSD) has been described as the only neuropsychiatric disorder with a known cause, yet effective behavioral and pharmacotherapies remain elusive for many afflicted individuals. PTSD is characterized by heightened noradrenergic signaling, as well as a resistance to extinction learning. Research aimed at promoting more effective treatment of PTSD has focused on memory erasure (disrupting reconsolidation) and/or enhancing extinction retention through pharmacological manipulations. Propranolol, a β-adrenoceptor antagonist, has received considerable attention for its therapeutic potential in PTSD, although its impact on patients is not always effective. In this review, we briefly examine the consequences of β-noradrenergic manipulations on both reconsolidation and extinction learning in rodents and in humans. We suggest that propranolol is effective as a fear-reducing agent when paired with behavioral therapy soon after trauma when psychological stress is high, possibly preventing or dampening the later development of PTSD. In individuals who have already suffered from PTSD for a significant period of time, propranolol may be less effective at disrupting reconsolidation of strong fear memories. Also, when PTSD has already developed, chronic treatment with propranolol may be more effective than acute intervention, given that individuals with PTSD tend to experience long-term, elevated noradrenergic hyperarousal.

Rapid stress-induced transcriptomic changes in the brain depend on beta-adrenergic signaling

Acute exposure to stressful experiences can rapidly increase anxiety and cause neuropsychiatric disorders. The effects of stress result in part from the release of neurotransmitters and hormones, which regulate gene expression in different brain regions. The fast neuroendocrine response to stress is largely mediated by norepinephrine (NE) and corticotropin releasing hormone (CRH), followed by a slower and more sustained release of corticosterone. While corticosterone is an important regulator of gene expression, it is not clear which stress-signals contribute to the rapid regulation of gene expression observed immediately after stress exposure. Here, we demonstrate in mice that 45 min after an acute swim stress challenge, large changes in gene expression occur across the transcriptome in the hippocampus, a region sensitive to the effects of stress. We identify multiple candidate genes that are rapidly and transiently altered in both males and females. Using a pharmacological approach, we show that most of these rapidly induced genes are regulated by NE through β-adrenergic receptor signaling. We find that CRH and corticosterone can also contribute to rapid changes in gene expression, although these effects appear to be restricted to fewer genes. These results newly reveal a widespread impact of NE on the transcriptome and identify novel genes associated with stress and adrenergic signaling.

Investigating biological traces of traumatic stress in changing societies: challenges and directions from the ESTSS Task Force on Neurobiology

Traumatic stress can have severe consequences for both mental and physical health. Furthermore, both psychological and biological traces of trauma increase as a function of accumulating traumatic experiences. Neurobiological research may aid in limiting the impact of traumatic stress, by leading to advances in preventive and treatment interventions. To promote the possibility for clinical implementation of novel research findings, this brief review describes timely conceptual and methodological challenges and directions in neurobiological trauma research on behalf of the Task Force "Neurobiology of Traumatic Stress" of the European Society for Traumatic Stress Studies (ESTSS). The most important conceptual challenges are the heterogeneity of disorders and existence of subtypes across diagnostic categories: differential latent profiles and trajectories regarding symptom expression and neural correlates are being unraveled; however, similar latent classes' approaches for treatment response and neurobiological data remain scarce thus far. The key to improving the efficacy of currently available preventive interventions and treatments for trauma-related disorders lies in a better understanding and characterization of individual differences in response to trauma and interventions. This could lead to personalized treatment strategies for trauma-related disorders, based on objective information indicating whether individuals are expected to benefit from them. The most important methodological challenge identified here is the need for large consortia and meta-analyses or, rather, mega-analyses on existent data as a first step. In addition, large multicenter studies, combining novel methods for repeated sampling with more advanced statistical modeling techniques, such as machine learning, should aim to translate identified disease mechanisms into molecular blood-based biomarker combinations to predict disorder vulnerability and treatment responses.

Posttraumatic stress disorder under ongoing threat: a review of neurobiological and neuroendocrine findings

BACKGROUND

Although numerous studies have investigated the neurobiology and neuroendocrinology of posttraumatic stress disorder (PTSD) after single finished trauma, studies on PTSD under ongoing threat are scarce and it is still unclear whether these individuals present similar abnormalities.

OBJECTIVE

The purpose of this review is to present the neurobiological and neuroendocrine findings on PTSD under ongoing threat. Ongoing threat considerably affects PTSD severity and treatment response and thus disentangling its neurobiological and neuroendocrine differences from PTSD after finished trauma could provide useful information for treatment.

METHOD

Eighteen studies that examined brain functioning and cortisol levels in relation to PTSD in individuals exposed to intimate partner violence, police officers, and fire fighters were included.

RESULTS

Hippocampal volume was decreased in PTSD under ongoing threat, although not consistently associated with symptom severity. The neuroimaging studies revealed that PTSD under ongoing threat was not characterized by reduced volume of amygdala or parahippocampal gyrus. The neurocircuitry model of PTSD after finished trauma with hyperactivation of amygdala and hypoactivation of prefrontal cortex and hippocampus was also confirmed in PTSD under ongoing threat. The neuroendocrine findings were inconsistent, revealing increased, decreased, or no association between cortisol levels and PTSD under ongoing threat.

CONCLUSIONS

Although PTSD under ongoing threat is characterized by abnormal neurocircuitry patterns similar to those previously found in PTSD after finished trauma, this is less so for other neurobiological and in particular neuroendocrine findings. Direct comparisons between samples with ongoing versus finished trauma are needed in future research to draw more solid conclusions before administering cortisol to patients with PTSD under ongoing threat who may already exhibit increased endogenous cortisol levels.

Cognitive disruptions in stress-related psychiatric disorders: A role for corticotropin releasing factor (CRF)

This article is part of a Special Issue "SBN 2014". Stress is a potential etiology contributor to both post-traumatic stress disorders (PTSD) and major depression. One stress-related neuropeptide that is hypersecreted in these disorders is corticotropin releasing factor (CRF). Dysregulation of CRF has long been linked to the emotion and mood symptoms that characterize PTSD and depression. However, the idea that CRF also mediates the cognitive disruptions observed in patients with these disorders has received less attention. Here we review literature indicating that CRF can alter cognitive functions. Detailed are anatomical studies revealing that CRF is poised to modulate regions required for learning and memory. We also describe preclinical behavioral studies that demonstrate CRF's ability to alter fear conditioning, impair memory consolidation, and alter a number of executive functions, including attention and cognitive flexibility. The implications of these findings for the etiology and treatment of the cognitive impairments observed in stress-related psychiatric disorders are described.

Post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) occurs in 5-10% of the population and is twice as common in women as in men. Although trauma exposure is the precipitating event for PTSD to develop, biological and psychosocial risk factors are increasingly viewed as predictors of symptom onset, severity and chronicity. PTSD affects multiple biological systems, such as brain circuitry and neurochemistry, and cellular, immune, endocrine and metabolic function. Treatment approaches involve a combination of medications and psychotherapy, with psychotherapy overall showing greatest efficacy. Studies of PTSD pathophysiology initially focused on the psychophysiology and neurobiology of stress responses, and the acquisition and the extinction of fear memories. However, increasing emphasis is being placed on identifying factors that explain individual differences in responses to trauma and promotion of resilience, such as genetic and social factors, brain developmental processes, cumulative biological and psychological effects of early childhood and other stressful lifetime events. The field of PTSD is currently challenged by fluctuations in diagnostic criteria, which have implications for epidemiological, biological, genetic and treatment studies. However, the advent of new biological methodologies offers the possibility of large-scale approaches to heterogeneous and genetically complex brain disorders, and provides optimism that individualized approaches to diagnosis and treatment will be discovered.

Identification and characterization of HPA-axis reactivity endophenotypes in a cohort of female PTSD patients

Analysis of the function of the hypothalamic-pituitary-adrenal (HPA)-axis in patients suffering from posttraumatic stress disorder (PTSD) has hitherto produced inconsistent findings, inter alia in the Trier Social Stress Test (TSST). To address these inconsistencies, we compared a sample of 23 female PTSD patients with either early life trauma (ELT) or adult trauma (AT) or combined ELT and AT to 18 age-matched non-traumatized female healthy controls in the TSST which was preceded by intensive baseline assessments. During the TSST, we determined a variety of clinical, psychological, endocrine and cardiovascular parameters as well as expression levels of four HPA-axis related genes. Using a previously reported definition of HPA-axis responsive versus non-responsive phenotypes, we identified for the first time two clinically and biologically distinct HPA-axis reactivity subgroups of PTSD. One subgroup ("non-responders") showed a blunted HPA-axis response and distinct clinical and biological characteristics such as a higher prevalence of trauma-related dissociative symptoms and of combined AT and ELT as well as alterations in the expression kinetics of the genes encoding for the mineralocorticoid receptor (MR) and for FK506 binding protein 51 (FKBP51). Interestingly, this non-responder subgroup largely drove the relatively diminished HPA axis response of the total cohort of PTSD patients. These findings are limited by the facts that the majority of patients was medicated, by the lack of traumatized controls and by the relatively small sample size. The here for the first time identified and characterized HPA-axis reactivity endophenotypes offer an explanation for the inconsistent reports on HPA-axis function in PTSD and, moreover, suggest that most likely other factors than HPA-axis reactivity play a decisive role in determination of PTSD core symptom severity.

Posttraumatic Stress Disorder: Developments in Assessment and Treatment

Diagnostic discordance between posttraumatic stress disorder definitions, treatment dropout rates, comorbidities, and varying policy approaches leave VA and DoD clinicians with unique concerns in providing effective treatment for many postwar health problems.

Positive effects of the traditional Chinese medicine MLC901 in cognitive tasks

MLC901 (NurAiDII) is used as a treatment for stroke patients. It has been shown that MLC901 improves motor and cognitive recovery in ischemic and traumatic brain‐injured rodents. The present study seeks to delineate cognitive effects induced by MLC901 in normal, noninjured mice. To this end, the behaviors of vehicle‐ and MLC901‐treated C57BL/6 mice in hippocampus‐dependent (passive avoidance, Morris water maze) and hippocampus‐independent (novel object recognition) cognitive tasks are compared. The potential influence of the compound on the anxiety level and nycthemeral rhythm of mice is also assessed. In addition, the long‐term effects of MLC901 on hippocampal neurogenesis are measured. The results clearly demonstrate that MLC901 promotes extinction in passive avoidance and reversal learning in the Morris water maze and improves the performance of mice in novel object recognition. In parallel, this study shows the long‐term proneurogenesis effects of MLC901 that result in the increase in the number of mature neurons in the hippocampus. If these observations can be extended to humans, then MLC901 could represent a promising therapeutic strategy. © 2015 The Authors. Journal of Neuroscience Research Published by Wiley Periodicals, Inc.

Cortisol augmentation of a psychological treatment for warfighters with posttraumatic stress disorder: Randomized trial showing improved treatment retention and outcome

BACKGROUND

Prolonged exposure (PE) therapy for post-traumatic stress disorder (PTSD) in military veterans has established efficacy, but is ineffective for a substantial number of patients. PE is also associated with high dropout rates. We hypothesized that hydrocortisone augmentation would enhance symptom improvement and reduce drop-out rates by diminishing the distressing effects of traumatic memories retrieved during imaginal exposure. We also hypothesized that in responders, hydrocortisone augmentation would be more effective in reversing glucocorticoid indices associated with PTSD than placebo augmentation.

METHOD

Twenty-four veterans were randomized to receive either 30 mg oral hydrocortisone or placebo prior to PE sessions 3-10 in a double-blind protocol. Glucocorticoid receptor sensitivity was assessed in cultured peripheral blood mononuclear cells (PBMC) using the in vitro lysozyme inhibition test and was determined before and after treatment. Intent-to-treat analysis was performed using latent growth curve modeling of treatment effects on change in PTSD severity over time. Veterans who no longer met diagnostic criteria for PTSD at post-treatment were designated as responders.

RESULTS

Veterans randomized to hydrocortisone or placebo augmentation did not differ significantly in clinical severity or glucocorticoid sensitivity at pre-treatment. Hydrocortisone augmentation was associated with greater reduction in total PTSD symptoms compared to placebo, a finding that was explained by significantly greater patient retention in the hydrocortisone augmentation condition. A significant treatment condition by responder status interaction for glucocorticoid sensitivity indicated that responders to hydrocortisone augmentation had the highest pre-treatment glucocorticoid sensitivity (lowest lysozyme IC50-DEX) that diminished over the course of treatment. There was a significant association between decline in glucocorticoid responsiveness and improvement in PTSD symptoms among hydrocortisone recipients.

CONCLUSIONS

The results of this pilot study suggest that hydrocortisone augmentation of PE may result in greater retention in treatment and thereby promote PTSD symptom improvement. Further, the results suggest that particularly elevated glucocorticoid responsiveness at pre-treatment may identify veterans likely to respond to PE combined with an intervention that targets glucocorticoid sensitivity. Confirmation of these findings will suggest that pharmacologic interventions that target PTSD-associated glucocorticoid dysregulation may be particularly helpful in promoting a positive clinical response to PTSD psychotherapy.

Xenon impairs reconsolidation of fear memories in a rat model of post-traumatic stress disorder (PTSD)

Xenon (Xe) is a noble gas that has been developed for use in people as an inhalational anesthestic and a diagnostic imaging agent. Xe inhibits glutamatergic N-methyl-D-aspartate (NMDA) receptors involved in learning and memory and can affect synaptic plasticity in the amygdala and hippocampus, two brain areas known to play a role in fear conditioning models of post-traumatic stress disorder (PTSD). Because glutamate receptors also have been shown to play a role in fear memory reconsolidation--a state in which recalled memories become susceptible to modification--we examined whether Xe administered after fear memory reactivation could affect subsequent expression of fear-like behavior (freezing) in rats. Male Sprague-Dawley rats were trained for contextual and cued fear conditioning and the effects of inhaled Xe (25%, 1 hr) on fear memory reconsolidation were tested using conditioned freezing measured days or weeks after reactivation/Xe administration. Xe administration immediately after fear memory reactivation significantly reduced conditioned freezing when tested 48 h, 96 h or 18 d after reactivation/Xe administration. Xe did not affect freezing when treatment was delayed until 2 h after reactivation or when administered in the absence of fear memory reactivation. These data suggest that Xe substantially and persistently inhibits memory reconsolidation in a reactivation and time-dependent manner, that it could be used as a new research tool to characterize reconsolidation and other memory processes, and that it could be developed to treat people with PTSD and other disorders related to emotional memory.

Pharmacotherapy in the aftermath of trauma; opportunities in the 'golden hours'

Several lines of research have demonstrated that memories for fearful events become transiently labile upon re-exposure. Activation of molecular mechanisms is required in order to maintain retrieved information. This process is called reconsolidation. Targeting reconsolidation - as in exposure-based psychotherapy - offers therefore a potentially interesting tool to manipulate fear memories, and subsequently to treat disorders such as post-traumatic stress disorder (PTSD). In this paper we discuss the evidence for reconsolidation in rodents and humans and highlight recent studies in which clinical research on normal and abnormal fear extinction reduction of the expression of fear was obtained by targeting the process of reconsolidation. We conclude that reconsolidation presents an interesting opportunity to modify or alter fear and fear-related memories. More clinical research on normal and abnormal fear extinction is required.

Enhancing exposure therapy for anxiety disorders, obsessive-compulsive disorder and post-traumatic stress disorder

Translating findings from basic science, several compounds have been identified that may enhance therapeutic outcomes and/or expedite treatment gains when administered alongside exposure-based treatments. Four of these compounds (referred to as cognitive enhancers) have been evaluated in the context of randomized controlled trials for anxiety disorders (e.g., specific phobias, panic disorder, social anxiety disorder), obsessive-compulsive disorder and post-traumatic stress disorder. These cognitive enhancers include D-cycloserine, yohimbine hydrochloride, glucocorticoids and cortisol and brain-derived neurotrophic factor. There is consistent evidence that cognitive enhancers can enhance therapeutic outcomes and/or expedite treatment gains across anxiety disorders, obsessive-compulsive disorder and post-traumatic stress disorder. Emerging evidence has highlighted the importance of within-session fear habituation and between-session fear learning, which can either enhance fear extinction or reconsolidate of fear responses. Although findings from these trials are promising, there are several considerations that warrant further evaluation prior to widespread use of cognitive enhancers in exposure-based treatments. Consistent trial design and large sample sizes are important in future studies of cognitive enhancers.

MDMA is certainly damaging after 25 years of empirical research: a reply and refutation of Doblin et al. (2014)

Human Psychopharmacology recently published my review into the increase in empirical knowledge about the human psychobiology of MDMA over the past 25 years (Parrott, 2013a). Deficits have been demonstrated in retrospective memory, prospective memory, higher cognition, complex visual processing, sleep architecture, sleep apnoea, pain, neurohormonal activity, and psychiatric status. Neuroimaging studies have shown serotonergic deficits, which are associated with lifetime Ecstasy/MDMA usage, and degree of neurocognitive impairment. Basic psychological skills remain intact. Ecstasy/MDMA use by pregnant mothers leads to psychomotor impairments in the children. Hence, the damaging effects of Ecstasy/MDMA were far more widespread than was realized a few years ago. In their critique of my review, Doblin et al. (2014) argued that my review contained misstatements, omitted contrary findings, and recited dated misconceptions. In this reply, I have answered all the points they raised. I have been able to refute each of their criticisms by citing the relevant empirical data, since many of their points were based on inaccurate summaries of the actual research findings. Doblin and colleagues are proponents of the use of MDMA for drug-assisted psychotherapy, and their strongest criticisms were focused on my concerns about this proposal. However, again all the issues I raised were based on sound empirical evidence or theoretical understanding. Indeed I would recommend potentially far safer co-drugs such as D-cycloserine or oxytocin. In summary, MDMA can induce a wide range of neuropsychobiological changes, many of which are damaging to humans.

Enhance, delete, incept: manipulating hippocampus-dependent memories

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Newly developed methods allow manipulation of hippocampus-dependent memories.

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Cued reactivation during sleep and transcranial stimulation can enhance memories.

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Pharmacological agents can delete memories.

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Optogenetics and DREADDs can be used to incept memories.

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Electrophysiology and fMRI have been used to investigate the underlying mechanisms.

Here we provide a brief overview of recent research on memory manipulation. We focus primarily on memories for which the hippocampus is thought to be required due to its central importance in the study of memory. The repertoire of methods employed is expanding and includes optogenetics, transcranial stimulation, deep brain stimulation, cued reactivation during sleep and the use of pharmacological agents. In addition, the possible mechanisms underlying these memory changes have been investigated using techniques such as single unit recording and functional magnetic resonance imaging (fMRI).

This article is part of a Special Issue entitled ‘Memory enhancement’.

Animal models of fear relapse

Whereas fear memories are rapidly acquired and enduring over time, extinction memories are slow to form and are susceptible to disruption. Consequently, behavioral therapies that involve extinction learning (e.g., exposure therapy) often produce only temporary suppression of fear and anxiety. This review focuses on the factors that are known to influence the relapse of extinguished fear. Several phenomena associated with the return of fear after extinction are discussed, including renewal, spontaneous recovery, reacquisition, and reinstatement. Additionally, this review describes recent work, which has focused on the role of psychological stress in the relapse of extinguished fear. Recent developments in behavioral and pharmacological research are examined in light of treatment of pathological fear in humans.