Low Dose Ketamine Infusion for Comorbid Posttraumatic Stress Disorder and Chronic Pain: A Randomized Double-Blind Clinical Trial

Combined Effects of Nasal Ketamine and Trauma-Focused Psychotherapy in Treatment-Resistant Post-Traumatic Stress Disorder: A Pilot Case Series

OBJECTIVE

This pilot case series investigated the feasibility and efficacy of an eight-week therapy program, combining nasally administered ketamine (0.5 mg/kg) with trauma-focused psychotherapy, for individuals with chronic, treatment-resistant post-traumatic stress disorder (PTSD).

METHOD

Three patients with chronic, treatment-resistant PTSD underwent the eight-week therapy program. Clinical assessments included the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) and the Hamilton Depression Rating Scale (HAMD) at baseline, post-assessment, and follow-up assessment, along with additional measures assessing other relevant symptoms and side effects.

RESULTS

The results demonstrated clinically relevant reductions in PTSD symptoms, indicated by a change in the CAPS-5 score at post-assessment (M = -18.00; SE = 6.48) and follow-up assessment (M = -25.33, SE = 5.58). Additionally, depressive symptoms showed notable improvement, with changes in HAMD scores at post-assessment (M = -8.33, SE = 3.07) and follow-up assessment (M = -9.00, SE = 3.77). Positive effects were also observed in anxiety reduction, decreased dissociations, and improvements in emotion regulation and disturbances of self-organization.

CONCLUSIONS

Despite potential variations in clinical profiles among the patients, the therapy program demonstrated positive outcomes for all participants. Nasally administered ketamine was well tolerated and resulted in immediate symptom reduction in tension, anxiety, and common PTSD symptoms. However, to validate these findings and compare treatment efficacy, future randomized controlled trials are warranted, especially in comparison with trauma-focused therapy alone.

The Impact of Ketamine for Treatment of Post-Traumatic Stress Disorder: A Systematic Review With Meta-Analyses

BACKGROUND

Ketamine has been used in anesthesia, pain management, and major depressive disorder. It has recently been studied in patients with post-traumatic stress disorder (PTSD).

OBJECTIVE

To determine the impact of ketamine on PTSD symptomatology and depression scores.

METHODS

We conducted a literature search of Medline 1960 to May 20, 2023, and found 6 randomized controlled trials that met our inclusion criteria. We extracted data on the Clinician-Administered PTSD (CAPS), PTSD Checklist (PCL), or Montgomery-Asberg Depression Rating (MADRS) scales.

RESULTS

The use of ketamine significantly reduced CAPS scores (n = 5, MD: -10.63 [95% CI -14.95 to -6.32]), PCL scores (n = 3, MD: -6.13 [95% CI -8.61 to -3.64]), and MADRS scores (n = 3, MD: -6.33 [95% CI -8.97 to -3.69]) at the maximal follow-up times versus control. Significant benefits were found at day 1 and weeks 1, 2, and 4 for CAPS and PCL scores as well as MADRS scores at day 1, week 1, and week 4 for ketamine versus control. The time to PTSD relapse was prolonged in the patients receiving ketamine versus control (n = 2, 15.74 days [95% CI 3.57 to 29.91 days]). More dry mouth (n = 2, OR 5.85 [95% CI 1.32 to 25.95]), dizziness (n = 2, OR 3.83 [95% CI 1.28 to 11.41]), and blurred vision (n = 2, OR 7.57 [1.00 to 57.10]) occurred with ketamine than control therapy.

CONCLUSIONS AND RELEVANCE

Ketamine modestly reduced PTSD and depression scores as early as 1 day of therapy, but the longevity of effect needs to be determined. Given similar magnitude of benefit with SSRIs and venlafaxine, ketamine would not supplant these traditional options for chronic use.

[Pharmacological treatment of posttraumatic stress disorder]

In addition to trauma-focussed psychotherapy, pharmacological treatment is often unavoidable, especially in patients with severe posttraumatic stress disorder (PTSD). As long as comorbid disorders do not dictate the pharmacotherapy approach, sertraline and paroxetine, along with other off-label prescribable substances approved in Germany, can be used for the treatment of PTSD. Venlafaxine, in particular, has shown good effectiveness in studies, whereas risperidone has shown lower effectiveness in augmentation. Overall, only a small to medium effect size is to be expected for all substances. Psychopharmacotherapy plays an important role in addressing sleep disorders, which are highly prevalent in PTSD. Treatment of trauma-related nightmares can be attempted with doxazosin or clonidine. In contrast, there are limited empirical data available for sleep disorders associated with PTSD, but the pharmacological treatment of insomnia can provide some guidance.

Ketamine in the effective management of chronic pain, depression, and posttraumatic stress disorder for Veterans: A meta-analysis and systematic review

Introduction

Ketamine has emerged as a promising treatment alternative for the management of chronic pain. Despite encouraging findings in civilian populations, and favourable results from trials examining its efficacy in military populations, there is still a dearth of information pointing to optimal specifications related to ketamine administration for pain, depression, and posttraumatic stress disorder (PTSD) in military populations. This meta-analysis and systematic review synthesised available evidence on the effectiveness, tolerability, and feasibility of ketamine in the management of chronic pain and mental health conditions in military populations.

Methods

This review followed the Cochrane's Guide for systematic reviews of interventions and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) as frameworks for data collection and synthesis.

Results

A total of 11 studies and 22 independent samples were retained for data analyses. Across samples, improvements in pain, depression, and PTSD outcomes were evident, with the use of ketamine leading to significant reductions, g = 1.76, SE = 0.19, 95% CI (1.39, 2.13), Z = 9.26, p <.001. These effect sizes were robust with moderate-to-large effects. In addition, the reductions in symptoms were observed in both active-duty and Veteran groups, and for different routes of ketamine administration, frequencies of ketamine administration, duration of ketamine treatments, dosage, study design, and allowance for concurrent treatments.

Discussion

This review provides a preliminary synthesis of available evidence which suggests that ketamine may be a potential option for the treatment of depression, PTSD, and chronic pain in military populations. The viability of ketamine as an alternative treatment may be particularly impactful for those who are treatment resistant, experience chronic symptoms, and/or have exhausted conventional treatments. More research is warranted in order verify the findings presented in this review.

Post-traumatic stress disorder: the role of the amygdala and potential therapeutic interventions - a review

Introduction

Post-traumatic stress disorder (PTSD) is a psychiatric disorder triggered by exposure to a life-threatening or sexually violent traumatic event, and is characterized by symptoms involving intrusive re-experiencing, persistent avoidance of associated stimuli, emotional and cognitive disturbances, and hyperarousal for long periods after the trauma has occurred. These debilitating symptoms induce occupational and social impairments that contribute to a significant clinical burden for PTSD patients, and substantial socioeconomic costs, reaching approximately $20,000 dollars per individual with PTSD each year in the US. Despite increased translational research focus in the field of PTSD, the development of novel, effective pharmacotherapies for its treatment remains an important unmet clinical need.

Observations

In this review, we summarize the evidence implicating dysfunctional activity of the amygdala in the pathophysiology of PTSD. We identify the transient receptor potential canonical (TRPC) ion channels as promising drug targets given their distribution in the amygdala, and evidence from animal studies demonstrating their role in fear response modulation. We discuss the evidence-based pharmacotherapy and psychotherapy treatment approaches for PTSD.

Discussion

In view of the prevalence and economic burden associated with PTSD, further investigation is warranted into novel treatment approaches based on our knowledge of the involvement of brain circuitry and the role of the amygdala in PTSD, as well as the potential added value of combined pharmacotherapy and psychotherapy to better manage PTSD symptoms.

The Effectiveness of Interventions for Improving Chronic Pain Symptoms Among People With Mental Illness: A Systematic Review

Chronic pain (CP) and mental illness (MI) are leading causes of years lived with disability and commonly co-occur. However, it remains unclear if available interventions are effective in improving pain outcomes in patients with co-existing CP and MI. This systematic review synthesised evidence for the effectiveness of interventions to improve pain outcomes for people with comorbid CP and clinically diagnosed MI. Ten electronic databases were searched from inception until May 2023. Randomised controlled trials (RCTs) were included if they evaluated interventions for CP-related outcomes among people with comorbid CP and clinically diagnosed MI. Pain-related and mental health outcomes were reported as primary and secondary outcomes, respectively. 26 RCTs (2,311 participants) were included. Four trials evaluated the effectiveness of cognitive-behavioural therapy, 6 mindfulness-based interventions, 1 interpersonal psychotherapy, 5 body-based interventions, 5 multi-component interventions, and 5 examined pharmacological-based interventions. Overall, there was considerable heterogeneity in sample characteristics and interventions, and included studies were generally of poor quality with insufficient trial details being reported. Despite the inconsistency in results, preliminary evidence suggests interventions demonstrating a positive effect on CP may include cognitive-behavioural therapy for patients with depression (with a small to medium effect size) and multi-component intervention for people with substance use disorders (with a small effect size). Despite the high occurrence/burden of CP and MI, there is a relative paucity of RCTs investigating interventions and none in people with severe MI. More rigorously designed RCTs are needed to further support our findings. PERSPECTIVE: This systematic review presents current evidence evaluating interventions for CP-related and MH outcomes for people with comorbid CP and clinically diagnosed MI. Our findings could potentially help clinicians identify the most effective treatments to manage these symptoms for this vulnerable patient group.

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

Objective

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

Method

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

Results

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

Conclusions

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

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

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

Ketamine in neuropsychiatric disorders: an update

The discovery of ketamine as a rapid-acting antidepressant led to a new era in the development of neuropsychiatric therapeutics, one characterized by an antidepressant response that occurred within hours or days rather than weeks or months. Considerable clinical research supports the use of-or further research with-subanesthetic-dose ketamine and its (S)-enantiomer esketamine in multiple neuropsychiatric disorders including depression, bipolar disorder, anxiety spectrum disorders, substance use disorders, and eating disorders, as well as for the management of chronic pain. In addition, ketamine often effectively targets symptom domains associated with multiple disorders, such as anxiety, anhedonia, and suicidal ideation. This manuscript: 1) reviews the literature on the pharmacology and hypothesized mechanisms of subanesthetic-dose ketamine in clinical research; 2) describes similarities and differences in the mechanism of action and antidepressant efficacy between racemic ketamine, its (S) and (R) enantiomers, and its hydroxynorketamine (HNK) metabolite; 3) discusses the day-to-day use of ketamine in the clinical setting; 4) provides an overview of ketamine use in other psychiatric disorders and depression-related comorbidities (e.g., suicidal ideation); and 5) provides insights into the mechanisms of ketamine and therapeutic response gleaned from the study of other novel therapeutics and neuroimaging modalities.

The Psychedelic Future of Post-Traumatic Stress Disorder Treatment

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

A transdiagnostic systematic review and meta-analysis of ketamine's anxiolytic effects

BACKGROUND

Ketamine may be effective in treating symptoms of anxiety, but the time profile of ketamine's anxiolytic effect is ill-defined. This systematic review and meta-analysis investigated the anxiolytic effect of ketamine at different time points across a range of clinical settings.

METHODS

Electronic databases were searched to capture randomised control trials measuring the anxiolytic effects of ketamine in contexts including mood disorders, anxiety disorders and chronic pain. Meta-analyses were conducted using a random-effects model. The correlations between (1) improvements in mean anxiety and depression scores, and (2) peak dissociation and improvements in mean anxiety scores were also assessed.

RESULTS

In all, 14 studies met inclusion criteria. Risk of bias was high in 11 studies. Ketamine significantly reduced anxiety scores compared to placebo at acute (<12 h; standard mean difference (SMD): -1.17, 95% confidence interval (CI) [-1.89, -0.44], p < 0.01), subacute (24 h; SMD: -0.44, 95% CI [-0.65, -0.22], p < 0.01) and sustained (7-14 days; SMD: -0.40, 95% CI [-0.63, -0.17], p < 0.01) time points. Exploratory analyses revealed improvements in anxiety and depression symptoms correlated at both subacute (R2 = 0.621, p = 0.035) and sustained time points (R2 = 0.773, p = 0.021). The relationship between peak dissociation and improvement in anxiety was not significant.

CONCLUSIONS

Ketamine appears to offer rapid and sustained anxiety symptom relief across a range of clinical settings, with anxiolytic effects occurring within the first 12 h of administration and remaining effective for 1-2 weeks. Future studies could explore the effects of ketamine maintenance therapy on anxiety symptoms.

Ketamine for Treatment of Posttraumatic Stress Disorder: State of the Field

Posttraumatic stress disorder (PTSD) is a chronic and debilitating condition. Although several psychotherapeutic and pharmacological treatments are recommended for PTSD, many individuals do not respond to treatment or respond only partially, highlighting a critical need for additional treatments. Ketamine has the potential to address this therapeutic need. This review discusses how ketamine emerged as a rapid-acting antidepressant and has become a potential treatment for PTSD. A single dose of intravenous (IV) ketamine has been shown to facilitate rapid reduction of PTSD symptoms. Repeated IV ketamine administration significantly improved PTSD symptoms, compared with midazolam, in a predominantly civilian sample of individuals with PTSD. However, in a veteran and military population, repeated IV ketamine did not significantly reduce PTSD symptoms. Further study of ketamine as a treatment for PTSD is necessary, including which populations benefit most from this therapy and the potential benefits of combining psychotherapy and ketamine.

Alleviating anxiety and taming trauma: Novel pharmacotherapeutics for anxiety disorders and posttraumatic stress disorder

Psychiatric disorders associated with psychological trauma, stress and anxiety are a highly prevalent and increasing cause of morbidity worldwide. Current therapeutic approaches, including medication, are effective in alleviating symptoms of anxiety disorders and posttraumatic stress disorder (PTSD), at least in some individuals, but have unwanted side-effects and do not resolve underlying pathophysiology. After a period of stagnation, there is renewed enthusiasm from public, academic and commercial parties in designing and developing drug treatments for these disorders. Here, we aim to provide a snapshot of the current state of this field that is written for neuropharmacologists, but also practicing clinicians and the interested lay-reader. After introducing currently available drug treatments, we summarize recent/ongoing clinical assessment of novel medicines for anxiety and PTSD, grouped according to primary neurochemical targets and their potential to produce acute and/or enduring therapeutic effects. The evaluation of putative treatments targeting monoamine (including psychedelics), GABA, glutamate, cannabinoid, cholinergic and neuropeptide systems, amongst others, are discussed. We emphasize the importance of designing and clinically assessing new medications based on a firm understanding of the underlying neurobiology stemming from the rapid advances being made in neuroscience. This includes harnessing neuroplasticity to bring about lasting beneficial changes in the brain rather than - as many current medications do - produce a transient attenuation of symptoms, as exemplified by combining psychotropic/cognitive enhancing drugs with psychotherapeutic approaches. We conclude by noting some of the other emerging trends in this promising new phase of drug development.

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

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

Enhancing Fear Extinction: Pharmacological Approaches

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

Evidence for the beneficial effect of ketamine in the treatment of patients with post-traumatic stress disorder: A systematic review and meta-analysis

Post-traumatic stress disorder (PTSD) is an anxiety disorder with manifestations somatic resulting from reliving the trauma. The therapy for the treatment of PTSD has limitations, between reduced efficacy and "PTSD pharmacotherapeutic crisis". Scientific evidence has shown that the use of ketamine has benefits for the treatment of depressive disorders and other symptoms present in PTSD compared to other conventional therapies. Therefore, this study aims to analyze the available evidence on the effect of ketamine in the treatment of post-traumatic stress. The systematic review and the meta-analysis were conducted following PRISMA guidelines and RevManager software, using randomized controlled trials and eligible studies of quality criteria for data extraction and analysis. The sample design evaluated included the last ten years, whose search resulted in 594 articles. After applying the exclusion criteria, 35 articles were selected, of which 14 articles were part of the sample, however, only six articles were selected the meta-analysis. The results showed that the ketamine is a promising drug in the management of PTSD with effect more evident performed after 24 h evaluated by MADRS scale. However, the main limitations of the present review demonstrate that more high-quality studies are needed to investigate the influence of therapy, safety, and efficacy.

Dose-related effects of ketamine for antidepressant-resistant symptoms of posttraumatic stress disorder in veterans and active duty military: a double-blind, randomized, placebo-controlled multi-center clinical trial

This study tested the efficacy of repeated intravenous ketamine doses to reduce symptoms of posttraumatic stress disorder (PTSD). Veterans and service members with PTSD (n = 158) who failed previous antidepressant treatment were randomized to 8 infusions administered twice weekly of intravenous placebo (n = 54), low dose (0.2 mg/kg; n = 53) or standard dose (0.5 mg/kg; n = 51) ketamine. Participants were assessed at baseline, during treatment, and for 4 weeks after their last infusion. Primary analyses used mixed effects models. The primary outcome measure was the self-report PTSD Checklist for DSM-5 (PCL-5), and secondary outcome measures were the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) and the Montgomery Åsberg Depression Rating Scale (MADRS). There were no significant group-by-time interactions for PTSD symptoms measured by the PCL-5 or CAPS-5. The standard ketamine dose ameliorated depression measured by the MADRS significantly more than placebo. Ketamine produced dose-related dissociative and psychotomimetic effects, which returned to baseline within 2 h and were less pronounced with repeated administration. There was no evidence of differential treatment discontinuation by ketamine dose, consistent with good tolerability. This clinical trial failed to find a significant dose-related effect of ketamine on PTSD symptoms. Secondary analyses suggested that the standard dose exerted rapid antidepressant effects. Further studies are needed to determine the role of ketamine in PTSD treatment. ClinicalTrials.gov identifier: NCT02655692.

The Multivariate Effect of Ketamine on PTSD: Systematic Review and Meta-Analysis

BACKGROUND

Post-traumatic stress disorder (PTSD) is a serious stress-related disorder caused by traumatic experiences. However, identifying a key therapy that can be used for PTSD treatment remains difficult. Ketamine, a well-known dissociative anesthetic, is considered safe to be used in anesthesia, pain management, and antidepressant actions since 1970. At present, it is still controversial whether PTSD can be treated with ketamine. The authors performed a meta-analysis to determine whether the use of perioperative ketamine lowers the incidence of PTSD.

METHODS

Cochrane Central Register of Controlled Trials, Embase, PubMed, and Web of Science were searched to examine the use of ketamine for the treatment of PTSD among soldiers with combating experience. Studies were included if they were randomized placebo-controlled, case-control, and cohort studies. The primary outcome was the incidence of PTSD in the later stage of the wounded or burn soldiers. The secondary outcome was the influence of ketamine on PTSD-scale scores for early and chronic PTSD, respectively.

RESULTS

Our search yielded a total of three studies (n = 503 patients) comparing the use of ketamine (n = 349) to control (n = 154). The available evidence showed no significant difference in the incidence of PTSD between combatant soldiers on the battlefield with or without ketamine treatment (risk ratio = 0.81, 95% CI, 0.63-1.04; P = 0.10). In 65 patients from three trials, ketamine was not only ineffective in treating early PTSD but also lead to exacerbation of the disease (risk ratio = 2.45, 95% CI, 1.33-3.58; P < 0.001). However, in 91 patients from the other three trials, ketamine is effective in treating chronic PTSD (risk ratio = -3.66, 95% CI, -7.05 to -0.27; P = 0.03).

CONCLUSION

Ketamine was not effective on lower the PTSD incidence for soldiers on the battlefield, nor on the PTSD-scale scores in early PTSD patients. However, it may improve the PTSD-scale scores for chronic conditions.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021255516, PROSPERO, identifier: CRD42021255516.

Systematic review and meta-analysis of randomized controlled trials of ketamine in the treatment of refractory anxiety spectrum disorders

BACKGROUND

Anxiety disorders are common, associated with significant burden of disease, and have high levels of treatment resistance. Low-dose ketamine has been extensively studied in treatment-resistant depression, with fewer reports in treatment-resistant anxiety disorders.

AIMS

This systematic review and meta-analysis collected efficacy, safety, and tolerability data for ketamine as a treatment for anxiety spectrum disorders.

METHODS

We conducted a systematic search for randomized controlled trials (RCTs) of acute ketamine treatment for patients with anxiety disorders. Open-label trials of ketamine maintenance therapy were also considered. Qualitative and, where possible, quantitative syntheses of findings were performed using Review Manager software (RevMan). Acute dose-response and maintenance treatment data were also collected.

RESULTS

There were six eligible acute RCTs - two in social anxiety disorder (SAD), three in post-traumatic stress disorder (PTSD), and one in obsessive-compulsive disorder (OCD). Four of the six showed significant improvement in anxiety rating scores in ketamine compared with control groups. Pooled analysis showed ketamine was associated with an increased likelihood of treatment response for SAD (odds ratio (OR): 28.94; 95% confidence interval [CI]: 3.45-242.57; p = 0.002) but not for PTSD (OR: 2.03; 95% CI: 0.67-6.15; p = 0.21). A dose-response profile was observed for ketamine and changes in SAD symptoms, with doses ⩾0.5 mg/kg associated with greater reduction in anxiety rating scores than lower doses. Ketamine maintenance therapy was associated with sustained anxiolytic effects and improved social and/or work functioning.

CONCLUSION

These preliminary analyses suggest that acute ketamine may be broadly effective across treatment-resistant anxiety spectrum disorders. These effects can be prolonged with maintenance treatment. Future studies will be needed to provide critical knowledge gaps around off-label use, side effects, and potential risks for abuse in clinical settings.