Pharmacotherapy of post-traumatic stress disorder

Correlation between 5-HTTLPR gene polymorphism and cognitive function of traumatic stress in Chinese Han children

BACKGROUND

Post-traumatic stress disorder (PTSD) is a trauma-related psychological disorder with serious social and familial impacts. The involvement of 5-hydroxytryptamine transporter gene-linked polymorphic region (5-HTTLPR) in numerous mental disorders has been documented. This study explored the correlation between 5-HTTLPR gene polymorphism and cognitive function in Chinese Han children with PTSD.

METHODS

A total of 60 PTSD children treated from December 2019 to December 2021 were selected as study participants, with another 60 healthy children selected as controls. We assessed the cognitive function of participants using the Mini-Mental State Examination (MMSE). Additionally, the PTSD level was estimated by the Children's Revised Impact of Event Scale (CRIES). The 5-HTTLPR gene polymorphism was detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The genotype and allele frequency were evaluated via case-control association analysis.

RESULTS

Children in the PTSD group showed low MMSE scores and high CRIES scores. In terms of genotype, cases of LL, LS, and SS in PTSD children were 4 (6.67%), 20 (33.3%), and 36 (60.00%), and 18 (30.00%), 28 (46.67%), and 14 (23.33%) cases in healthy controls. In terms of allele gene frequency, incidences of L and S were 23.33% and 76.67% in PTSD children, respectively, and were 53.33% and 46.67% in healthy controls, respectively. Moreover, the CRIES and MMSE scores of LS and SS genotypes were evidently different from those of LL genotype in PTSD children.

CONCLUSIONS

Polymorphism of the 5-HTTLPR gene is correlated with cognitive dysfunction in Chinese Han children with PTSD.

Inflammation-driven brain and gut barrier dysfunction in stress and mood disorders

Regulation of emotions is generally associated exclusively with the brain. However, there is evidence that peripheral systems are also involved in mood, stress vulnerability vs. resilience, and emotion‐related memory encoding. Prevalence of stress and mood disorders such as major depression, bipolar disorder, and post‐traumatic stress disorder is increasing in our modern societies. Unfortunately, 30%–50% of individuals respond poorly to currently available treatments highlighting the need to further investigate emotion‐related biology to gain mechanistic insights that could lead to innovative therapies. Here, we provide an overview of inflammation‐related mechanisms involved in mood regulation and stress responses discovered using animal models. If clinical studies are available, we discuss translational value of these findings including limitations. Neuroimmune mechanisms of depression and maladaptive stress responses have been receiving increasing attention, and thus, the first part is centered on inflammation and dysregulation of brain and circulating cytokines in stress and mood disorders. Next, recent studies supporting a role for inflammation‐driven leakiness of the blood–brain and gut barriers in emotion regulation and mood are highlighted. Stress‐induced exacerbated inflammation fragilizes these barriers which become hyperpermeable through loss of integrity and altered biology. At the gut level, this could be associated with dysbiosis, an imbalance in microbial communities, and alteration of the gut–brain axis which is central to production of mood‐related neurotransmitter serotonin. Novel therapeutic approaches such as anti‐inflammatory drugs, the fast‐acting antidepressant ketamine, and probiotics could directly act on the mechanisms described here improving mood disorder‐associated symptomatology. Discovery of biomarkers has been a challenging quest in psychiatry, and we end by listing promising targets worth further investigation.

Korean Red Ginseng prevents posttraumatic stress disorder-triggered depression-like behaviors in rats via activation of the serotonergic system

Background

Posttraumatic stress disorder (PTSD), a mental disorder induced by traumatic stress and often accompanied by depression and/or anxiety, may involve an imbalance in the neurotransmitters associated with the fear response. Korean Red Ginseng (KRG) has long been used as a traditional medicine and is known to be involved in a variety of pharmacological activities. We used the open field test and forced swimming test to examine the effects of KRG on the depression-like response of rats after exposure to single prolonged stress (SPS), leading to activation of the serotonergic system.

Methods

Male rats received KRG (30, 50, and 100 mg/kg, intraperitoneal injection) once daily for 14 days after exposure to SPS.

Results

Daily KRG administration significantly improved depression-like behaviors in the forced swimming test, increased the number of lines crossed and time spent in the central zone in the open field test, and decreased freezing behavior in contextual and cued fear conditioning. KRG treatment attenuated SPS-induced decreases in serotonin (5-HT) tissue concentrations in the hippocampus and medial prefrontal cortex. The increased 5-HT concentration during KRG treatment may be partially attributable to the 5-hydroxyindoleacetic acid/5-HT ratio in the hippocampus of rats with PTSD. These effects may be caused by the activation of hippocampal genes encoding tryptophan hydroxylase-1 and 2 mRNA levels.

Conclusion

Our findings suggest that KRG has an antidepressant effect in rats subjected to SPS and may represent an effective use of traditional medicine for the treatment of PTSD.

Antidepressant-Like Effects of Hesperidin in Animal Model of Post-Traumatic Stress Disorder

OBJECTIVE

Post-traumatic stress disorder (PTSD) is a psychiatric disorder characterized by depression and anxiety, that arises due to an imbalance of neurotransmitters in response to excessive stress. Hesperidin (HSD) is a naturally occurring flavonoid shown to exert a variety of biological activities, including antioxidant, anti-inflammatory, and neuroprotective effects.

METHODS

This study was used the open field test (OFT) and forced swimming test (FST) to examine the effects of HSD on the depression-like response of rats after exposure to a single prolonged stress (SPS) leading to the dysregulation of the serotonergic activation system. Male rats were given HSD (20, 50, and 100 mg/kg, intraperitoneal injection, n=6-7 per group) once daily for 14 days after exposure to SPS. The influence of administration of HSD on SPS-induced behavioral responses and concentrations of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), and monoamine oxidase-A (MAO-A) in the rat brain were also investigated using enzyme-linked immunoassays (ELISAs).

RESULTS

Daily HSD administration signifificantly improved depression-like behaviors in the FST (P0.05), increased the number of lines crossed in the central zone of the OFT (P0.01), and reduced freezing behavior both in contextual and cued fear conditioning. HSD treatment also attenuated the reduction in SPS-induced 5-HT concentrations in the hippocampus and amygdala. This increase in 5-HT concentrations during HSD treatment was partially attributed to a decrease in the 5-HIAA/5-HT ratio in the hippocampus of rats with PTSD. Furthermore, HSD treatment inhibited activity of MAO-A and decreases of tryptophan hydroxylase-1 expression in the hippocampus.

CONCLUSION

HSD was shown to exert antidepressant effects in rats exposed to SPS, suggesting that this natural flflavonoid may be an effective medicine for PTSD.

Heritable Differences in Catecholamine Signaling Modulate Susceptibility to Trauma and Response to Methylphenidate Treatment: Relevance for PTSD

Alterations in cortical catecholamine signaling pathways can modulate acute and enduring responses to trauma. Heritable variation in catecholamine signaling is produced by a common functional polymorphism in the catechol-O-methyltransferase (COMT), with Val carriers exhibiting greater degradation of catecholamines than Met carriers. Furthermore, it has recently been suggested that drugs enhancing cortical catecholamine signaling may be a new therapeutic approach for posttraumatic stress disorder (PTSD) patients. We hypothesized that heritable differences in catecholamine signaling regulate the behavioral response to trauma, and that methylphenidate (MPD), a drug that preferentially blocks catecholamine reuptake in the prefrontal cortex (PFC), exerts COMT-dependent effects on trauma-induced behaviors. We first examined the contribution of the functional mutation COMTval158met to modulate enduring behavioral responses to predator stress in a unique "humanized" COMTval158met mouse line. Animals were exposed to a predator (cat) for 10 min and enduring avoidance behaviors were examined in the open field, light-dark box, and "trauma-reminder" tests 1-2 weeks later. Second, we examined the efficacy of chronic methylphenidate to reverse predator stress effects and if these effects were modulated by COMTval158met genotype. Mice were exposed to predator stress and began treatment with either saline or methylphenidate (3 mg/kg/day) 1 week after stress until the end of the testing [avoidance behaviors, working memory, and social preference (SP)]. In males, predator stress and COMTval158met had an additive effect on enduring anxiety-like behavior, with Val stressed mice showing the strongest avoidance behavior after stress compared to Met carriers. No effect of COMT genotype was observed in females. Therefore methylphenidate effects were investigated only in males. Chronic methylphenidate treatment reversed the stress-induced avoidance behavior and increased social investigation independently of genotype. Methylphenidate effects on working memory, however, were genotype-dependent, decreasing working memory in non-stressed Met carriers, and improving stress-induced working memory deficit in Val carriers. These results suggest that heritable variance in catecholamine signaling modulates the avoidance response to an acute trauma. This work supports recent human findings that methylphenidate might be a therapeutic alternative for PTSD patients and suggests that methylphenidate effects on anxiety (generalized avoidance, social withdrawal) vs. cognitive (working memory) symptoms may be modulated through COMT-independent and dependent mechanisms, respectively.

Proceedings of the Fourth Annual Deep Brain Stimulation Think Tank: A Review of Emerging Issues and Technologies

This paper provides an overview of current progress in the technological advances and the use of deep brain stimulation (DBS) to treat neurological and neuropsychiatric disorders, as presented by participants of the Fourth Annual DBS Think Tank, which was convened in March 2016 in conjunction with the Center for Movement Disorders and Neurorestoration at the University of Florida, Gainesveille FL, USA. The Think Tank discussions first focused on policy and advocacy in DBS research and clinical practice, formation of registries, and issues involving the use of DBS in the treatment of Tourette Syndrome. Next, advances in the use of neuroimaging and electrochemical markers to enhance DBS specificity were addressed. Updates on ongoing use and developments of DBS for the treatment of Parkinson's disease, essential tremor, Alzheimer's disease, depression, post-traumatic stress disorder, obesity, addiction were presented, and progress toward innovation(s) in closed-loop applications were discussed. Each section of these proceedings provides updates and highlights of new information as presented at this year's international Think Tank, with a view toward current and near future advancement of the field.

Escitalopram reversed the traumatic stress-induced depressed and anxiety-like symptoms but not the deficits of fear memory

RATIONALE

Posttraumatic stress disorder (PTSD) is a trauma-induced mental disorder characterised by fear extinction dysfunction in which fear circuit monoamines are possibly associated. PTSD often coexists with depressive/anxiety symptoms, and selective serotonin reuptake inhibitors (SSRIs) are recommended to treat PTSD. However, therapeutic mechanisms of SSRIs underlying the PTSD fear symptoms remain unclear.

OBJECTIVES

Using a rodent PTSD model, we examined the effects of early SSRI intervention in mood and fear dysfunctions with associated changes of monoamines within the fear circuit areas.

METHODS

A 14-day escitalopram (ESC) regimen (5 mg/kg/day) was undertaken in two separate experiments in rats which previously received a protocol of single prolonged stress (SPS). In experiment 1, sucrose preference and elevated T-maze were used to index anhedonia depression and avoidance/escape anxiety profiles. In experiment 2, the percentage of freezing time was measured in a 3-day fear conditioning paradigm. At the end of our study, tissue levels of serotonin (5-HT) in the medial prefrontal cortex, amygdala, hippocampus, and striatum were measured in experiment 1, and the efflux levels of infralimbic (IL) monoamines were measured in experiment 2.

RESULTS

In experiment 1, ESC corrected both behavioural (depression/anxiety) and neurochemical (reduced 5-HT tissue levels in amygdala/hippocampus) abnormalities. In experiment 2, ESC was unable to correct the SPS-impaired retrieval of fear extinction. In IL, ESC increased the efflux level of 5-HT but failed to reverse SPS-reduced dopamine (DA) and noradrenaline (NA).

CONCLUSIONS

PTSD-induced mood dysfunction is psychopathologically different from PTSD-induced fear disruption in terms of disequilibrium of monoamines within the fear circuit areas.

An examination of the association between 5-HTTLPR, combat exposure, and PTSD diagnosis among U.S. veterans

Objective

To examine the association between the 5-HTTLPR polymorphism of the serotonin transporter (SLC6A4) gene, combat exposure, and posttraumatic stress disorder (PTSD) diagnosis and among two samples of combat-exposed veterans.

Method

The first sample included 550 non-Hispanic Black (NHB) combat-exposed veterans. The second sample included 555 non-Hispanic White (NHW) combat-exposed veterans. Participants were genotyped for the 5-HTTLPR/rs25531 variants of the SLC6A4 gene. A structured clinical interview was used to diagnose PTSD. Combat and civilian trauma exposure were assessed with validated self-report instruments. Logistic regression was used to test for main effects of 5-HTTLPR on PTSD diagnosis as well as gene x environment (GxE) interactions after adjusting for sex, ancestry proportion scores, civilian trauma exposure, and combat exposure.

Results

Within the NHB sample, a significant additive effect was observed for 5-HTTLPR (OR = 1.502, p = .0025), such that the odds of having a current diagnosis of PTSD increased by 1.502 for each additional S’ allele. No evidence for an association between 5-HTTLPR and PTSD was observed in the NHW sample. In addition, no evidence for combat x 5-HTTLPR effects were observed in either sample.

Conclusion

The present study suggests that there may be an association between 5-HTTLPR genotype and PTSD diagnosis among NHB veterans; however, no evidence for the hypothesized 5-HTTLPR x combat interaction was found.

The effectiveness of cognitive behavioral therapy with respect to psychological symptoms and recovering autobiographical memory in patients suffering from post-traumatic stress disorder

OBJECTIVES

Given the persistence of post-traumatic stress disorder (PTSD) and its major impact on everyday life, it is important to identify effective treatments. In additional to pharmacological treatments, psychotherapeutic treatments are also highly effective. The aim of the present study was to investigate, among a sample of patients suffering from PTSD, the influence of an additional cognitive behavioral therapy (CBT) intervention on their symptoms of PTSD, depression, and anxiety, and on autobiographical memory.

METHODS

A total of 40 patients suffering from PTSD (mean age: 31.64 years; 78.6% female patients) and under psychopharmacological treatment were randomly assigned to an intervention or control condition. The intervention consisted of ten group sessions (one 60-90 minute session per week) of CBT. At baseline and 10 weeks later, a series of self-rating and experts'-rating questionnaires were completed.

RESULTS

Over time, symptoms of PTSD, depression, and anxiety decreased; however, greater improvement was observed in the experimental than the control condition. Likewise, as a general pattern of results, memory performance improved over time, though again this improvement was greater in the experimental condition.

CONCLUSION

Compared to a control condition, additional CBT improves the treatment of PTSD, with respect to both symptoms and autobiographical memory.

Potential pharmacological strategies for the improved treatment of organophosphate-induced neurotoxicity

Organophosphates (OP) are highly toxic compounds that cause cholinergic neuronal excitotoxicity and dysfunction by irreversible inhibition of acetylcholinesterase, resulting in delayed brain damage. This delayed secondary neuronal destruction, which arises primarily in the cholinergic areas of the brain that contain dense accumulations of cholinergic neurons and the majority of cholinergic projection, could be largely responsible for persistent profound neuropsychiatric and neurological impairments such as memory, cognitive, mental, emotional, motor, and sensory deficits in the victims of OP poisoning. The therapeutic strategies for reducing neuronal brain damage must adopt a multifunctional approach to the various steps of brain deterioration: (i) standard treatment with atropine and related anticholinergic compounds; (ii) anti-excitotoxic therapies to prevent cerebral edema, blockage of calcium influx, inhibition of apoptosis, and allow for the control of seizure; (iii) neuroprotection by aid of antioxidants and N-methyl-d-aspartate (NMDA) antagonists (multifunctional drug therapy), to inhibit/limit the secondary neuronal damage; and (iv) therapies targeting chronic neuropsychiatric and neurological symptoms. These neuroprotective strategies may prevent secondary neuronal damage in both early and late stages of OP poisoning, and thus may be a beneficial approach to treating the neuropsychological and neuronal impairments resulting from OP toxicity.

Evaluation of anxiolytic activity of the essential oil of the aerial part of Foeniculum vulgare Miller in mice

BACKGROUND

Foeniculum vulgare locally known as ensilal, is an aromatic plant widely cultivated in temperate and tropical regions. The anti-anxiety activity of the crude extract of F. vulgare has been reported. However, the fraction responsible for anxiolytic activity is not known and there is no any report on the anti-anxiety activity of the essential oil of F. vulgare. The objective of study was to evaluate the anxiolytic activity of the essential oil of Foeniculum vulgare Miller.

METHODS

Adult Swiss albino male mice were randomly divided into six groups (n = 6). Groups I and II received Tween 80 (5%, v/v) and diazepam (0.5 mg/kg, ip), respectively, while groups III to V received orally 50, 100, and 200 and 400 mg/kg doses of the essential oil of F. vulgare, respectively. The mice were then individually placed in animal anxiety models: elevated plus maze (EPM), staircase test (SCT) and open field test (OFT) and evaluated for various parameters.

RESULTS

In EPM test, 100 and 200 mg/kg doses of the essential oil significantly increased percent number of entries and time spent in open arms compared to control. In SCT these doses also reduced rearing significantly compared to controls, while only the 200 mg/kg dose significantly increased number of squares crossed at the center in the OFT test.

CONCLUSION

The essential oil of F. vulgare was found to exhibit a promising anxiolytic activity.

Pilot study of the effect of lipophilic vs. hydrophilic beta-adrenergic blockers being taken at time of intracardiac defibrillator discharge on subsequent PTSD symptoms

A pathophysiological model of posttraumatic stress disorder (PTSD) posits that an overly strong stress response at the time of the traumatic event leads to overconsolidation of the event's memory in part through a central β-adrenergic mechanism. We hypothesized that the presence of a β-blocker in the patient's brain at the time of the traumatic event would reduce the PTSD outcome by blocking this effect. The unpredictable, uncontrollable discharge of an implantable intracardiac defibrillator (ICD) is experienced by most patients as highly stressful, and it has previously been shown to be capable of causing PTSD symptoms. The present pilot study evaluated a convenience sample of 18 male cardiac patients who had been taking either a lipophilic β-blocker (which penetrates the blood-brain barrier) or a hydrophilic β-blocker (which does not) at the time of a discharge of their ICD. The self- report PTSD Checklist-Specific Version quantified 17 PTSD symptoms pertaining to the ICD discharge during the month preceding the evaluation. There was a statistical trend for patients who had been taking a lipophilic β-blocker at the time of the ICD discharge to have (35%) less severe PTSD symptoms than patients who had been taking a hydrophilic β-blocker (one-tailed p=0.07, g=0.64). Further, prospective, randomized, controlled studies are suggested.

EMSAM (deprenyl patch): how a promising antidepressant was underutilized

The EMSAM patch is a unique monoamine oxidase inhibitor (MAOI) being the only antidepressant utilizing a transdermal delivery system. This was welcomed by clinicians who hoped that EMSAM would be better tolerated than oral MAOIs and non-MAOI antidepressants, as well as being effective for treatment in a wide spectrum of depressed patients including atypical depression, bipolar depression, and refractory depression. Unfortunately, the clinical use of EMSAM has been underutilized and its potential usefulness overlooked. This article suggests that fear of possible side effects, particularly the "cheese reaction" and serotonin syndrome, are some of the main contributors to underutilization by clinicians. These risks have been significantly exaggerated with the 6 mg/day dose not even requiring a special diet. Other contributing factors leading to underutilization are reviewed such as: the lack of studies addressing many important clinical questions; inadequate data analyses; not evaluating the effect of EMSAM on comorbid psychiatric conditions, particularly anxiety disorders; lack of antidepressant comparators versus EMSAM; no dose-response relationship examined; various depressive subtypes and conditions are unexplored, eg, bipolar depression and refractory depression; poor insurance coverage for an expensive medication; as well as minimal marketing efforts and postmarketing studies. On the other hand, many potential advantages of EMSAM are not highlighted enough in the literature and by pharmaceutical companies which might have increased clinical interest and utilization of the antidepressant. For example, the advantages of EMSAM include: avoidance of swallowing issues, as can be seen with oral antidepressants; minimal side effects, probably due to a favorable pharmacokinetic profile; minimal evidence of suicidal behavior, probably relating to the transdermal route of administration; low rates of inducing hypomanic/manic episodes; as well as significant efficacy in "anxious depression" and atypical depression. Recent efforts in conducting some post hoc analyses and presentations on EMSAM may yet stimulate further clinical interest and use of this antidepressant.

Anxiolytic effects of flavonoids in animal models of posttraumatic stress disorder

The dysregulation of the serotonergic system has long been recognized as an important factor underlying the pathophysiology of PTSD. To date, SSRIs have already been established as the firstline pharmacotherapeutic agents for treating acute and chronic PTSD. However, SSRIs largely have several disadvantages which limit their utility. Our previous study has also shown that administration of the total flavonoids, isolated from the extract of Xiaobuxin-Tang (XBXT, mild mind-easing decoction), comprising four Chinese medicines including Haematitum, Flos Inulae, Folium Phyllostachydis Henonis, and Semen Sojae Preparatum, exerted significant antidepressant-like effect in chronically mildly stressed rats, possibly mediated by serotonergic activation. Since the central serotonergic dysfunction is an important and well-known cause mediating the pathophysiology of trauma-related symptoms in PTSD, it is reasonable to predict that flavonoids may exert therapeutic effects on PTSD in animal models. Therefore, the present study aims to examine the effect of flavonoids in alleviating the enhanced anxiety and fear response induced in two PTSD animal models. Ser, an SSRI, was administered as a positive control. Furthermore, the changes of brain monoaminergic neurotransmitters after chronic flavonoids administration have also been assessed in SPS-treated rats.

Recognizing anxiety disorders

The majority of patients with anxiety disorders present in primary care settings, and many are undiagnosed or undertreated-each disorder has defining characteristics. Anxiety disorders are debilitating, and proper treatment can improve quality of life. Preferred treatments are cognitive-behavior therapy and pharmacotherapy with selective serotonin reuptake inhibitors.

Targeting memory processes with drugs to prevent or cure PTSD

INTRODUCTION

Post-traumatic stress disorder (PTSD) is a chronic debilitating psychiatric disorder resulting from exposure to a severe traumatic stressor and an area of great unmet medical need. Advances in pharmacological treatments beyond the currently approved SSRIs are needed.

AREAS COVERED

Background on PTSD, as well as the neurobiology of stress responding and fear conditioning, is provided. Clinical and preclinical data for investigational agents with diverse pharmacological mechanisms are summarized.

EXPERT OPINION

Advances in the understanding of stress biology and mechanisms of fear conditioning plasticity provide a rationale for treatment approaches that may reduce hyperarousal and dysfunctional aversive memories in PTSD. One challenge is to determine if these components are independent or reflect a common underlying neurobiological alteration. Numerous agents reviewed have potential for reducing PTSD core symptoms or targeted symptoms in chronic PTSD. Promising early data support drug approaches that seek to disrupt dysfunctional aversive memories by interfering with consolidation soon after trauma exposure, or in chronic PTSD, by blocking reconsolidation and/or enhancing extinction. Challenges remain for achieving selectivity when attempting to alter aversive memories. Targeting the underlying traumatic memory with a combination of pharmacological therapies applied with appropriate chronicity, and in combination with psychotherapy, is expected to substantially improve PTSD treatment.

Organophosphate-induced brain damage: mechanisms, neuropsychiatric and neurological consequences, and potential therapeutic strategies

Organophosphate (OP)-induced brain damage is defined as progressive damage to the brain, resulting from the cholinergic neuronal excitotoxicity and dysfunction induced by OP-induced irreversible AChE inhibition. This delayed secondary neuronal damage that occurs mainly in the cholinergic regions of the brain that contain dense accumulations of cholinergic neurons and the majority of cholinergic projection, might be largely responsible for persistent profound neuropsychiatric and neurological impairments (memory, cognitive, mental, emotional, motor and sensory deficits) in the victims of OP poisoning. Neuroprotective strategies for attenuating OP-induced brain damage should target different development stages of OP-induced brain damage, and may include but not limited to: (1) Antidote therapies with atropine and related efficient anticholinergic drugs; (2) Anti-excitotoxic therapies targeting attenuation of cerebral edema and inflammatory reaction, blockage of calcium influx, inhibition of apoptosis program, and the control of seizures; (3) Neuroprotective strategies using cytokines, antioxidants and NMDAR antagonists (a single drug or a combination of drugs) to slow down the process of secondary neuronal damage; and (4) Therapies targeting individual symptoms or clusters of chronic neuropsychiatric and neurological symptoms. These neuroprotective strategies may help limit or prevent secondary neuronal damage at the early stage of OP poisoning and attenuate the subsequent neuropsychiatric and neurological impairments, thus reducing the long-term disability caused by exposure to OPs.

Pharmacological treatment of PTSD - established and new approaches

A large proportion of humans will experience a traumatic event at least once in their lifetime, with up to 10% then going on to developing posttraumatic stress disorder (PTSD). In this review we will discuss established pharmacological interventions for PTSD as well as highlight novel therapeutic strategies undergoing extensive pre-clinical research as well as ongoing clinical research. Such strategies include prophylactic treatments and use of pharmacotherapy as adjunctive treatment with established trauma-focused psychological therapies. These potential treatment approaches include modulation of stress effects on memory consolidation after trauma (e.g., glucocorticoid, corticotropin-releasing factor and norepinephrine signalling modulators), as well as putative cognitive enhancers that target mechanisms of conditioned fear extinction and reconsolidation (e.g., glucocorticoid receptor modulators and modulators of glutamate signalling such as positive allosteric modulators of glutamate receptors, glycine transporter inhibitors, or glycine agonists). We will discuss evidence for and against these potential novel treatment strategies and their limitations. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

Treating nightmares and insomnia in posttraumatic stress disorder: a review of current evidence

Emerging evidence supports the notion of disrupted sleep as a core component of Posttraumatic Stress Disorder (PTSD). Effective treatments for nighttime PTSD symptoms are critical because sleep disruption may be mechanistically linked to development and maintenance of PTSD and is associated with significant distress, functional impairment, and poor health. This review aimed to describe the state of science with respect to the impact of the latest behavioral and pharmacological interventions on posttraumatic nightmares and insomnia. Published studies that examined evidence for therapeutic effects upon sleep were included. Some behavioral and pharmacological interventions show promise, especially for nightmares, but there is a need for controlled trials that include valid sleep measures and are designed to identify treatment mechanisms. Our ability to treat PTSD-related sleep disturbances may be improved by moving away from considering sleep symptoms in isolation and instead conducting integrative studies that examine sequential or combined behavioral and/or pharmacological treatments targeting both the daytime and nighttime aspects of PTSD. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.