Spectral signatures of psilocybin, lysergic acid diethylamide (LSD) and ketamine in healthy volunteers and persons with major depressive disorder and treatment-resistant depression: A systematic review

BACKGROUND

Electrophysiologic measures provide an opportunity to inform mechanistic models and possibly biomarker prediction of response. Serotonergic psychedelics (SPs) (i.e., psilocybin, lysergic acid diethylamide (LSD)) and ketamine represent new investigational and established treatments in mood disorders respectively. There is a need to better characterize the mechanism of action of these agents.

METHODS

We conducted a systematic review investigating the spectral signatures of psilocybin, LSD, and ketamine in persons with major depressive disorder (MDD), treatment-resistant depression (TRD), and healthy controls.

RESULTS

Ketamine and SPs are associated with increased theta power in persons with depression. Ketamine and SPs are also associated with decreased spectral power in the alpha, beta and delta bands in healthy controls and persons with depression. When administered with SPs, theta power was increased in persons with MDD when administered with SPs. Ketamine is associated with increased gamma band power in both healthy controls and persons with MDD.

LIMITATIONS

The studies included in our review were heterogeneous in their patient population, exposure, dosing of treatment and devices used to evaluate EEG and MEG signatures. Our results were extracted entirely from persons who were either healthy volunteers or persons with MDD or TRD.

CONCLUSIONS

Extant literature evaluating EEG and MEG spectral signatures indicate that ketamine and SPs have reproducible effects in keeping with disease models of network connectivity. Future research vistas should evaluate whether observed spectral signatures can guide further discovery of therapeutics within the psychedelic and dissociative classes of agents, and its prediction capability in persons treated for depression.

Assessing the Effects of Metabolic Disruption, Body Mass Index and Inflammation on Depressive Symptoms in Post-COVID-19 Condition: A Randomized Controlled Trial on Vortioxetine

INTRODUCTION

To date, there are no therapeutics that have gained regulatory approval by the United States Food and Drug Administration (FDA) for the treatment of post-COVID-19 condition (PCC), a debilitating condition characterized by cognitive impairment and mood symptoms. Additionally, persistent inflammation, metabolic dysfunction, and risks associated with an elevated body mass index (BMI) have been observed. Herein, we aimed to assess the efficacy of vortioxetine in improving depressive symptoms among individuals with PCC,  as modulated by inflammation, metabolic dysfunction, and BMI.

METHODS

In this post-hoc analysis, we present preliminary data obtained from an 8-week randomized, double-blind, placebo-controlled trial. Participants included  adults aged 18 years and older residing in Canada who were experiencing symptoms of World Health Organization (WHO)-defined PCC. Recruitment began November 2021 and ended January 2023. Of the 200 participants enrolled, 147 were randomized (1:1) to receive vortioxetine (5-20 mg, n = 73) or placebo (n = 74) for daily treatment under double-blind conditions. The primary outcome measure was the change from baseline to endpoint in the 16-Item Quick Inventory of Depressive Symptomatology Self-Report Questionnaire (QIDS-SR-16).

RESULTS

Our findings revealed significant effects for time (χ2 = 9.601, p = 0.002), treatment (χ2 = 9.135, p = 0.003), and the treatment × time × CRP × TG-HDL × BMI interaction (χ2 = 26.092, p < 0.001) on PCC-related depressive symptoms in the adjusted model. Moreover, the between-group analysis showed a significant improvement with vortioxetine at endpoint as compared to placebo (mean difference = - 5.41, SEM = 1.335, p < 0.001).

CONCLUSION

Overall, vortioxetine significantly improved depressive symptoms among participants with PCC in the adjusted model. Notably, individuals with baseline markers of increased inflammation, metabolic disruption, and elevated BMI exhibited a more pronounced antidepressant effect at endpoint.

TRIAL REGISTRATION NUMBER

NCT05047952 (ClinicalTrials.gov).

Impact of elevated body mass index (BMI) on cognitive functioning and inflammation in persons with post-COVID-19 condition: a secondary analysis

BACKGROUND

Individuals who have recovered from the acute stage of SARS-CoV-2 infection may be at risk of developing post-COVID-19 condition (PCC), characterised by a spectrum of persisting, non-specific, and functionally impairing symptoms across multiple organ systems. Obesity has been implicated as a risk factor for PCC, mediated by chronic systemic inflammation. The foregoing has also been separately reported to mediate cognitive dysfunction in PCC.

METHODS

This is a post-hoc analysis of a randomised, double-blinded, placebo-controlled clinical trial evaluating vortioxetine treatment for cognitive impairments in persons with PCC who received vortioxetine or placebo for eight weeks. This analysis comprises baseline data, examining the impact of BMI on cognitive functioning measured by the Digit Symbol Substitution Test (DSST) and Trails Making Tests (TMT)-A/B, as well as inflammation, via serum c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

RESULTS

Complete data from 70 participants were statistically analysed and adjusted for age and sex. BMI was negatively correlated with performance on the DSST (β = -0.003, p = 0.047), TMT-A (β = -0.006, p = 0.025), and TMT-B (β = -0.006, p = 0.002). BMI was positively correlated with serum CRP (unstandardized β = 0.193, standardized β = 0.612, p < 0.001) and ESR (β = 0.039, p < 0.001) levels.

CONCLUSION

We observed a significant negative correlation between BMI and cognitive functioning, and a significant positive correlation between BMI and inflammation in persons with PCC, suggesting a bidirectional interplay between BMI, PCC, and cognitive function; individuals with an elevated BMI may be at a greater risk of developing PCC and/or presenting with greater cognitive deficits mediated by chronic systemic inflammation.

A comparison between psilocybin and esketamine in treatment-resistant depression using number needed to treat (NNT): A systematic review

BACKGROUND

Inadequate outcomes with monoamine-based treatments in depressive disorders are common and provide the impetus for mechanistically-novel treatments. Esketamine is a proven treatment recently approved for adults with Treatment-Resistant Depression (TRD) while psilocybin is an investigational treatment. Translation of the clinical meaningfulness for these foregoing agents in adults with TRD is required. Herein we evaluate the Number Needed to Treat (NNT) and Harm (NNH) of esketamine and psilocybin in adults with TRD.

METHODS

We conducted a systematic review of randomized controlled trials, comparing the clinical efficacy of oral psilocybin to the co-commencement of intranasal esketamine with an oral antidepressant in adults with TRD.

RESULTS

25 mg psilocybin had a significant reduction in depressive symptoms at 21-days post-dose, the NNT was 5 [95 % CI = 3.1, 18.5]. Psilocybin-induced nausea had a significant NNH = 5. Fixed-dosed esketamine at 56 mg and 84 mg had a significant effect at 28-days post-dose, (NNT of 7 [95 % CI56mg = 3.5, 46.7], [95 % CI84mg = 3.6, 142.2]). Esketamine-induced headache, nausea, dizziness, and dissociation had NNHs <10.

LIMITATIONS

The preliminary results may only reflect a small portion of the patient population. These results require replication and longer term studies investigating maintenance therapy.

CONCLUSION

Relatively few pharmacologic agents are proven safe and effective in adults with TRD. NNT estimates for investigational psilocybin and esketamine in TRD indicate clinical meaningfulness. The NNH profile for both aforementioned agents is clinically acceptable. Our results underscore the clinical relevance of these treatment options in adults with TRD.

Brain-derived neurotrophic factor Val66Met and CYP2B6 polymorphisms as predictors for ketamine effectiveness in patients with treatment-resistant depression

BACKGROUND

Converging lines of evidence indicate that ketamine is a rapid antidepressant for individuals with treatment-resistant depression. Hitherto, no reliable a priori predictors of ketamine response have been reported. Pharmacogenetic biomarkers have yielded mixed results regarding potential candidate genes associated with ketamine's biochemistry as reliable predictors of response.

AIMS

No studies have examined the effects of Val66Met and CYP2B6 genotypes on patients receiving repeated infusions of intravenous ketamine.

METHODS

In all, 85 participants with major depressive disorder who had previously received four infusions of intravenous ketamine were recruited to the foregoing study. Buccal swabs were collected and genotype variants across the Val66Met and CYP2B6 genes were analyzed. A repeated measures mixed linear model was used to assess change in depressive symptoms, suicidality, and anxiety, correcting for sex and age. Multiple regression was run to determine whether these genetic markers were associated with treatment efficacy for depressive severity, suicidal ideation, anxiolytic response, and degree of dissociation to intravenous ketamine.

RESULTS

Participants experienced significant overall reductions in depression, suicide, and anxiety. Overall, 25% met the response criteria and 15% met the remission criteria. However, Val66Met and CYP2B6 did not significantly predict changes in symptoms of depression, suicide, anxiety, or average dissociation.

CONCLUSIONS

This study contributes to the growing literature that ketamine efficacy is unlikely to be predicted by single genes, and a pleiotropic approach may likely be necessary for developing reliable predictors of clinical benefits.

Subjective and Objective Measures of Cognitive Function are Correlated in Persons with Post-COVID-19 Condition: A Secondary Analysis of a Randomized Controlled Trial

Background

It remains unclear whether subjective and objective measures of cognitive function in Post COVID-19 Condition (PCC) are correlated. The extent of correlation has mechanistic and clinical implications.

Methods

This post-hoc analysis of a randomized, double-blind, placebo-controlled clinical trial contains baseline data of subjective and objective measures of cognition in a rigorously characterized cohort living with PCC. Herein, we evaluated the association between subjective and objective condition function, as measured by the Perceived Deficits Questionnaire, 20-item (PDQ-20) and the Digit Symbol Substitution Test (DSST) and Trails Making Test (TMT)-A/B, respectively.

Results

A total of 152 participants comprised the baseline sample. Due to missing data, our statistical analyses included 150 for self-reported PDQ-20, 147 individuals for combined DSST-measured cognitive function (composite z-score of the Pen/Paper plus Online CogState Version, N combinedDSST ), 71 for in-person DSST-measured cognitive function (Pen/Paper Version), 70 for TMT-A-measured cognitive function, and 70 for TMT-B-measured cognitive function. After adjusting for age, sex, and education, PDQ-20 was significantly correlated with pen-and-paper DSST (β = -0.003, p = 0.002) and TMT-B (β = 0.003, p = 0.008) scores, but not with TMT-A scores (β = -0.001, p = 0.751).

Conclusions

Overall, a statistically significant correlation was observed between subjective and objective cognitive functions. Clinicians providing care for individuals with PCC who have subjective cognitive function complaints may consider taking a measurement-based approach to cognition at the point of care that focuses exclusively on patient-reported measures.

Impacts of metabolic disruption, body mass index and inflammation on cognitive function in post-COVID-19 condition: a randomized controlled trial on vortioxetine

BACKGROUND

Post-COVID-19 Condition (PCC), as defined by the World Health Organization (WHO), currently lacks any regulatory-approved treatments and is characterized by persistent and debilitating cognitive impairment and mood symptoms. Additionally, metabolic dysfunction, chronic inflammation and the associated risks of elevated body mass index (BMI) have been reported. In this study, we aim to investigate the efficacy of vortioxetine in improving cognitive deficits in individuals with PCC, accounting for the interaction of metabolic dysfunction, elevated inflammation and BMI.

METHODS

This is a post-hoc analysis of an 8-week randomized, double-blind, placebo-controlled trial that was conducted among adults aged 18 years and older living in Canada who were experiencing WHO-defined PCC symptoms. The recruitment of participants began in November 2021 and concluded in January 2023. A total of 200 individuals were enrolled, where 147 were randomized in a 1:1 ratio to receive either vortioxetine (5-20 mg, n = 73) or placebo (n = 74) for daily treatment under double-blind conditions. The primary outcome measure was the change in the Digit Symbol Substitution Test (DSST) score from baseline to endpoint.

RESULTS

Our findings showed significant effects for time (χ2 = 7.771, p = 0.005), treatment (χ2 = 7.583, p = 0.006) and the treatment x time x CRP x TG-HDL x BMI interaction (χ2 = 11.967, p = 0.018) on cognitive function. Moreover, the between-group analysis showed a significant improvement with vortioxetine at endpoint (mean difference = 0.621, SEM = 0.313, p = 0.047).

CONCLUSION

Overall, vortioxetine demonstrated significant improvements in cognitive deficits among individuals with baseline markers of metabolic dysfunction, elevated inflammation and higher BMI at endpoint as compared to placebo.

TRIAL REGISTRATION

NCT05047952 (ClinicalTrials.gov; Registration Date: September 17, 2021).

The efficacy of zuranolone in postpartum depression and major depressive disorder: a review & number needed to treat (NNT) analysis

INTRODUCTION

Major depressive disorder (MDD) is a common and debilitating mental illness. Postpartum depression (PPD) impacts women globally and is one of the most common complications of childbirth that is underdiagnosed and undertreated, adversely impacting the mental health of women, children, and partners.Available antidepressant medications require weeks to months before showing effect. In this setting, zuranolone, an oral neuroactive steroid and a positive allosteric modulator of GABAA receptors, is an attractive alternative as a rapid-acting antidepressant treatment.

AREAS COVERED

This article reviews zuranolone (SAGE217), focusing on available clinical studies in individuals with PPD and MDD. This paper adds to the extant literature by presenting the efficacy data as Number Needed to Treat (NNT) to facilitate indirect comparisons with other antidepressants.

EXPERT OPINION

Zuranolone is a novel rapid-acting (i.e. two week course) oral antidepressant for the treatment of adults with PPD with ongoing clinical trials evaluating its efficacy in adults with MDD. Zuranolone is well tolerated with no significant safety concerns in any clinical trials completed to date. Zuranolone will be scheduled by the Drug Enforcement Agency (DEA).

Clinical efficacy and safety of Zuranolone (SAGE-217) in individuals with major depressive disorder

Major depressive disorder (MDD) is a common mental disorder with a high rate of morbidity and mortality. Dysfunctional signaling of gamma-aminobutyric acid (GABA) has been implicated in some studies in the etiology of MDD. Zuranolone (SAGE-217) is a novel, oral neuroactive steroid and an investigational positive allosteric modulator of synaptic and extrasynaptic GABAA receptors. Herein, we aimed to evaluate the efficacy and safety of Zuranolone in individuals with MDD. We reviewed seven studies including 1662 participants with MDD. Zuranolone was investigated as an oral, once-daily, 14-day treatment course. The results of our synthesis indicate that the antidepressant effects of Zuranolone are rapid, clinically meaningful, and replicated across multiple randomized clinical trials. In addition to replicated efficacy, Zuranolone is associated with an acceptable level of treatment-emergent adverse events and discontinuation without serious adverse events. It is believed that Zuranolone's antidepressant effects arise from its ability to enhance inhibitory GABAergic signaling by increasing synaptic and extrasynaptic GABAA activity and regulation of GABAA receptor expression. Taken together, preliminary evidence suggests the potential for antidepressant effects of Zuranolone. Zuranolone has been approved by FDA for postpartum depression, and is showing efficacy in major depressive disorder. Future research vistas should seek to determine the durability of this treatment approach as well as its effects on domain-specific outcomes (e.g., anhedonia, circadian rhythm, arousal systems) along with application in other diagnostic entities (e.g., bipolar depression).

The bidirectional association of nonalcoholic fatty liver disease with depression, bipolar disorder, and schizophrenia

Nonalcoholic fatty liver disease (NAFLD) is a complex metabolic-inflammatory disease associated with poor outcomes and decreased quality of life. NAFLD is overrepresented in patients with psychiatric disorders like depression, bipolar disorder, and schizophrenia; however, a comprehensive review on NAFLD and psychiatric disorders remains to be delineated. This review endeavors to investigate the association of NAFLD with psychiatric disorders, including shared pathogenesis and future clinical derivatives. Extant literature suggests that patients with psychiatric disorders (in particular, mood disorders) are more susceptible to the development of NAFLD due to multiple reasons, including but not limited to hypothalamic-pituitary-adrenal axis dysregulation, metabolic syndrome, and chronic perceived stress. Moreover, the clinical manifestations of mood disorders (e.g., anhedonia, psychomotor retardation, lifestyle modification, etc.), and potentially long-term treatment with weight-gaining agents, differentially affect these patients, making them more prone to NAFLD. Considering the increased morbidity associated with both mood disorders and NAFLD, our review recommends regular screenings for NAFLD in select patients with mood disorders exhibiting signs of increased risk (i.e., obesity, metabolic syndrome, diabetes, or family history of NAFLD) for better diagnosis and holistic care of both potentially interrelated conditions.

Oral ketamine for depression: An updated systematic review

Objectives: Ketamine is a glutamate N-methyl-D-aspartate receptor antagonist that can be used to treat major depressive disorder by single or repeated infusions. However, the accessibility and scalability of oral ketamine make it preferred over intravenous ketamine. In this systematic review, we aim to evaluate the efficacy, tolerability, and safety of oral ketamine, esketamine and r-ketamine for unipolar and bipolar depression. Materials and methods: Electronic databases were searched from inception to September 2022 to identify relevant articles. Results: Twenty-two studies, including four randomized clinical trials (RCTs), one case series, six case reports, five open-label trials and six retrospective chart review studies involving 2336 patients with depression were included. All included studies reported significant improvement following ketamine administration. Ketamine was well tolerated without serious adverse events. However, RCTs had a high risk of bias due to analysis methods and adverse events monitoring. Ketamine dosage varied from 0.5 to 1.25 mg/kg. The frequency of administration was daily to monthly. Several important limitations were identified, most notably the small number of RCTs. Conclusions: Taken together, preliminary evidence suggests the potential for antidepressant effect of oral ketamine. However, further research with large sample size and long follow-up period is needed to better determine the antisuicidal effect and efficacy in treatment-resistant depression.

Real-world effectiveness of repeated intravenous ketamine infusions for treatment-resistant depression in transitional age youth

BACKGROUND

Ketamine is an emerging treatment for treatment-resistant depression (TRD) associated with rapid and robust improvements in depressive symptoms and suicidality. However, the efficacy and safety of ketamine in transitional age youth (TAY; age 18-25) populations remains understudied.

METHODS

In this retrospective analysis, TAY patients (n = 52) receiving ketamine for TRD were matched for sex, primary diagnosis, baseline depression severity, and treatment resistance with a general adult (GA) sample (age 30-60). Patients received four ketamine infusions over 2 weeks (0.5-0.75 mg/kg over 40 min). The primary outcome was the change in Quick Inventory of Depressive Symptomatology Self-Report 16-item (QIDS-SR16) over time. Secondary outcomes were changes in QIDS-SR16 suicidal ideation (SI) item, anxiety (Generalized Anxiety Disorder 7-item (GAD-7)), and adverse effects (ClinicalTrials.gov: NCT04209296).

RESULTS

A significant main effect of infusions on reduction of total QIDS-SR16 (p < 0.001), QIDS-SR16 SI (p < 0.001), and GAD-7 (p < 0.001) scores was observed in the TAY group with moderate effect sizes, indicative of clinically significant improvements in depression, anxiety, and suicidality. There were no significant differences between TAY and GA groups on these measures over time, suggesting comparable improvements in both groups. Safety and tolerability outcomes were comparable between groups with only mild, transient adverse effects observed.

CONCLUSION

Ketamine was associated with comparable clinical benefits, safety, and tolerability in a TAY sample as compared to a matched GA TRD sample.

COVID-19 vaccination for the prevention and treatment of long COVID: A systematic review and meta-analysis

Empirical evidence addressing the association between SARS-CoV-2 vaccination and long COVID would guide public health priorities and inform personal health decisions. Herein, the co-primary objectives are to determine the differential risk of long COVID in vaccinated versus unvaccinated patients, and the trajectory of long COVID following vaccination. Of 2775 articles identified via systematic search, 17 were included, and 6 were meta-analyzed. Meta-analytic results determined that at least one vaccine dose was associated with a protective effect against long COVID (OR 0.539, 95% CI 0.295-0.987, p = 0.045, N = 257 817). Qualitative analysis revealed that trajectories of pre-existing long COVID following vaccination were mixed, with most patients reporting no changes. The evidence herein supports SARS-CoV-2 vaccination for the prevention of long COVID, and recommends long COVID patients adhere to standard SARS-CoV-2 vaccination schedules.

Glucagon-like peptide 1 (GLP-1) receptor agonists as a protective factor for incident depression in patients with diabetes mellitus: A systematic review

Glucagon-like peptide 1 (GLP-1) receptor agonists are widely used for glycemic control in patients with diabetes mellitus (DM) and are primarily indicated for type 2 diabetes mellitus (T2DM). GLP-1 receptor agonists have also been shown to have neuroprotective and antidepressant properties. Replicated evidence suggests that individuals with DM are significantly more likely to develop depression. Herein, we aim to investigate whether GLP-1 receptor agonists can be used prophylactically on patients with DM to lower the risk of incident depression. We conducted a systematic search for English-language articles published on the PubMed/MEDLINE, Scopus, Embase, APA, PsycInfo, Ovid and Google Scholar databases from inception to June 6, 2022. Four retrospective observational studies were identified that evaluated the neuroprotective effects of GLP-1 receptor agonists on incident depression in patients with DM. We found mixed results with regards to lowering the risk of incident depression, with two studies demonstrating a significant reduction in risk and two studies showing no such effect. A single study found that dulaglutide may lower susceptibility to depression. Our results were limited by high interstudy heterogeneity, paucity of literature, and lack of controlled trials. While we did not find evidence of GLP-1 receptor agonists significantly lowering risk of incident depression in patients with DM, promising neuroprotective data presented in two of the included papers, specifically on dulaglutide where information is scarce, provide the impetus for further investigation. Future research should focus on better elucidating the neuroprotective potential of different classes and doses of GLP-1 receptor agonists using controlled trials.

The Role of Ketamine in the Treatment of Bipolar Depression: A Scoping Review

Bipolar depression remains a clinical challenge with a quarter of patients failing to respond to initial conventional treatments. Although ketamine has been extensively studied in unipolar depression, its role in bipolar disorder remains inconclusive. The aim of our scoping review was to comprehensively synthesize the current clinical literature around ketamine use in bipolar depression. A total of 10 clinical studies (5 randomized controlled trials and 5 open label studies) were selected. The preliminary evidence, albeit weak, suggests that ketamine is a promising treatment and calls for further interest from the research community. Overall, ketamine treatment appeared to be tolerable with minimal risk for manic/hypomanic switching and showed some effectiveness across parameters of depression and suicidality. Moreover, ketamine is a potential treatment agent in patients with treatment-resistant bipolar depression with promising data extracted from extant controlled trials and real-world effectiveness studies. Future studies are needed to identify ketamine's role in acute and maintenance treatment phases of bipolar depression. Moreover, future researchers should study the recurrence prevention and anti-suicidal effects of ketamine in the treatment of bipolar depression.

Efficacy, safety, and tolerability of ulotaront (SEP-363856, a trace amine-associated receptor 1 agonist) for the treatment of schizophrenia and other mental disorders with similar pathophysiology: a systematic review of preclinical and clinical trials

INTRODUCTION

Schizophrenia is a mental illness that can disrupt emotions, perceptions, cognition, and reduce quality of life. The classical approach to treat schizophrenia uses typical and atypical antipsychotics; however, limitations include low efficacy in mitigating negative symptoms and cognitive dysfunctions, and a range of adverse effects. Evidence has accumulated on trace amine-associated receptor 1 (TAAR1) as a novel therapeutic target for treating schizophrenia. This systematic review investigates the available evidence on a TAAR1 agonist, ulotaront, as a treatment for schizophrenia.

METHODS

A systematic search was conducted on PubMed/MEDLINE, and Ovid databases for English-published articles from inception to December 18, 2022. Literature focusing on the association between ulotaront and schizophrenia were evaluated based on an inclusion/exclusion criterion. Selected studies were assessed for risk of bias, using Cochrane Collaboration tool, and summarized in a table to generate discussion topics.

RESULTS

Three clinical, two comparative, and five preclinical studies examining ulotaront's pharmacology, tolerability and safety, and/or efficacy were identified. Results indicate that ulotaront has a differing adverse effects profile from other antipsychotics, may mitigate metabolic-related adverse effects commonly associated with antipsychotics, and may be effective for treating positive and negative symptoms.

CONCLUSIONS

Findings from available literature present ulotaront as a potential and promising alternative treatment method for schizophrenia. Despite this, our results were limited due to lack of clinical trials on ulotaront's long-term efficacy and mechanisms of action. Future research should focus on these limitations to elucidate ulotaront's efficacy and safety for the treatment of schizophrenia and other mental disorders with similar pathophysiology.

Real world effectiveness of repeated ketamine infusions for treatment-resistant depression with comorbid borderline personality disorder

Borderline personality disorder (BPD) has high rates of comorbidity with mood disorders, including treatment-resistant depression (TRD). Comorbidity of BPD with depression is associated with poorer response to antidepressants. Intravenous ketamine is a novel treatment for TRD that has not been specifically evaluated in patients with comorbid BPD. In this retrospective analysis of data collected from participants who received care at the Canadian Rapid Treatment Centre of Excellence (CRTCE; Braxia Health; ClinicalTrials.gov: NCT04209296), we evaluated the effectiveness of intravenous ketamine in a TRD population with comorbid BPD (N=100; n=50 BPD-positive compared with n=50 BPD-negative). Participants were administered four doses of intravenous ketamine (0.5-0.75mg/kg over 40 minutes) over two weeks. The primary outcome measures were changes in depressive symptom severity (as measured by Quick Inventory of Depressive Symptomatology-Self Report 16-item (QIDS-SR₁₆)) and borderline symptom severity (as measured by Borderline Symptom List 23-item (BSL-23)). Both BPD-positive and BPD-negative groups improved significantly on the QIDS-SR₁₆, QIDS-SR₁₆ suicide ideation item, anxiety, and functionality scales with large effect sizes. There was no significant difference between groups. The BPD-positive group exhibited significant reduction of 0.64 on BSL-23 scores and a significant reduction of 5.95 on QIDS-SR₁₆ scores. Patients with TRD and comorbid BPD receiving ketamine exhibited a significant reduction in symptoms of depression, borderline personality, suicidality, and anxiety.

Real-world effectiveness of repeated ketamine infusions for treatment-resistant bipolar depression

BACKGROUND

Clinical trials have demonstrated rapid antidepressant effects with intravenous (IV) ketamine for major depressive disorder, with relatively less research specifically for bipolar depression. Herein, we describe the real-world effectiveness of repeated ketamine infusions for treatment-resistant bipolar depression.

METHODS

This study was conducted in a community clinic in Mississauga, Ontario (Canadian Rapid Treatment Centre of Excellence; Braxia Health). In this observational study (NCT04209296), patients with treatment-resistant bipolar I/II depression (n = 66) received four sub-anesthetic doses of IV ketamine (0.5-0.75 mg/kg) over a two-week period. Symptoms of depression, suicidality, anxiety, and functioning were assessed with validated self-report measures.

RESULTS

Statistically and clinically significant antidepressant effects were observed in the overall sample, as measured by the Quick Inventory for Depression Symptomatology-Self Report-16 (QIDS-SR16 ) with further reductions in depressive symptoms observed after each subsequent infusion (n = 66; mean QIDS-SR16 reduction of 6.08+/-1.39; p < 0.0001). Significant reductions of suicidal thoughts (QIDS-SR16 -Suicide Item) and anxiety (Generalized Anxiety Disorder-7) were also observed with functional improvements on the Sheehan Disability Scale (p < 0.0001 on all measures). Moreover, the response rate (QIDS-SR16 total score decrease ≥50% from baseline) was 35% and remission rate (QIDS-SR16 total score ≤5) was 20% after four infusions. Infusions were generally well tolerated with treatment-emergent hypomania observed in only three patients (4.5%) with zero cases of mania or psychosis.

CONCLUSIONS

Real-world effectiveness of IV ketamine for bipolar depression was observed. Repeated doses were associated with greater symptom reduction and adequate tolerability.

Biomarkers of ketamine's antidepressant effect: An umbrella review

Ketamine is a NMDA receptor antagonist that has a rapid acting antidepressant effect with high efficacy in treatment-resistant patients. Ketamine is a beneficial antidepressant for many individuals with depression, but not all of the patients respond, and some even exhibit symptom deterioration. The discovery of repeatable and mechanistically relevant biomarkers would address a major gap in treatment response prediction. Numerous potential peripheral biomarkers have been reported, but their current utility is unclear. We conducted an umbrella review to evaluate the biomarkers of ketamine's antidepressant effect in individuals with depression. PubMed and copus were searched using terms appropriate to each area of research, from their inception until July 2022. Five systematic reviews and meta analyses including 108 studies with 4912 participants were included. Blood-based and neuroimaging biomarkers were investigated. The results of this review indicate that ketamine can produce an anti-inflammatory effect and decrease at least one inflammatory marker following administration. Data from neuroimaging studies demonstrated that the cingulate cortex is the key locus of ketamine's action. The majority of the blood-based, neuroimaging, and neurophysiological investigations reviewed herein indicate ketamine induced normalization of major depressive disorder pathogenesis via synaptic plasticity and functional connectivity. Currently, no biomarker/biosignature is sufficiently validated for clinical utility, but several are promising. Now that ketamine is more widely available, biomarker discovery and replication should be attempted in larger, real-world populations.

The association between stage of treatment-resistant depression and clinical utility of ketamine/esketamine: A systematic review

OBJECTIVE

Ketamine has demonstrated rapid and significant antidepressant effects in patients with treatment resistant depression (TRD). Herein, we conducted a systematic review to determine ketamine's efficacy as a function of the stage of treatment resistance (e.g., number of failed treatments) among individuals with TRD.

METHODS

A systematic search of PubMed and Scopus from inception to August 2021 was conducted. Where applicable, the studies were categorized into low and high stages of resistance, where low category included studies where the mean number of failed antidepressants was <3 or had a higher proportion of subjects with ≤2 antidepressant trials. Reported indicators of treatment resistance and efficacy were extracted from randomized-controlled trials (RCTs) assessing ketamine or esketamine for TRD.

RESULTS

In total, 18 RCTs were included in the current review. There was variability across reported indicators of disease severity, definition of treatment resistance, as well as treatment protocols, preventing clear direct and indirect comparison of relative efficacy of ketamine at different stages of treatment resistance. Ketamine was effective in reducing depressive symptoms in RCTs at both lower and higher stages of treatment resistance; however, the effect size and duration of effects was greater in RCTs of lower stage of treatment resistance.

CONCLUSIONS

Our findings suggested that ketamine has antidepressant efficacy across all identified stages of treatment resistance, however with increasing failed treatment trials, treatment might be less efficacious. At this time, the comparative efficacy as a function of resistance stage remains to be well-established. Evaluation of participant level data is required to more clearly determine the association between level of treatment resistance and likelihood of response.

Changes in insulin resistance following antidepressant treatment mediate response in major depressive disorder

BACKGROUND

Insulin resistance (IR) is a potential predictor of antidepressant treatment response.

AIMS

We assess changes in IR after antidepressant treatment and whether these changes have any effect on treatment response. Also, to see whether changes in IR mediates relationship between C-reactive protein (CRP) and antidepressant efficacy.

METHODS

This is a secondary analysis of an 8-week, open-label clinical trial with 95 adults experiencing a major depressive episode. Response to vortioxetine was measured using the Montgomery-Åsberg Depression Rating Scale (MADRS). Generalized estimating equation models were utilized for this intent-to-treat analysis.

RESULTS

When adjusted for age, sex, and body mass index, there was a significant increase in IR following treatment in the overall sample (p = 0.035). This finding was detected in treatment non-responders (p = 0.019), whereas it was not observed in responders (p = 0.329). Mediation analysis revealed that change in IR during treatment was responsible for change in MADRS as well as the relationship between baseline CRP and treatment response.

CONCLUSIONS

Exacerbation of IR during antidepressant treatment mediated non-response. Conversely in treatment responders IR reduced. Like previous studies, baseline CRP moderated treatment response. This relationship was also mediated by changes in IR. These findings further elucidate the role of IR in terms of antidepressant response as well as potentially explain inflammation's relationship with the latter.

Brain-Derived Neurotrophic Factor (BDNF) as a biomarker of treatment response in patients with Treatment Resistant Depression (TRD): A systematic review & meta-analysis

Multiple lines of evidence have implicated brain-derived neurotrophic factor (BDNF) in treatment-resistant depression (TRD). The aim of this synthesis was to determine the impact of TRD treatments on peripheral BDNF levels, and ascertain whether these changes are associated with antidepressant effects. Thirty-six articles involving 1198 patients with TRD were included herein. Electroconvulsive therapy (ECT), ketamine, and repetitive transcranial magnetic stimulation (rTMS) were the most common TRD treatments investigated. Serum BDNF levels significantly increased in six, two, four and one studies following ECT, ketamine, rTMS and atypical antipsychotics, respectively. The estimated mean baseline serum BDNF concentration in TRD patients ± 95% CI was 15.5 ± 4.34 ng/mL. Peripheral BDNF levels significantly increased overall (Hedges' g ± 95% CI = 0.336 ± 0.302; p < 0.05), but no association with depressive symptoms was found (p ≥ 0.05). These results demonstrate that peripheral measurements of total BDNF (i.e., mature and percursor forms of BDNF) are inadequate predictors of treatment response in TRD patients, and other considerations suggest that this would still apply to separable measurements of mature BDNF and its precursor.

Ketamine use in pediatric depression: A systematic review

Pediatric depression is a common psychiatric disorder that is associated with significant morbidity and mortality. Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist with demonstrated antidepressant effects in the adult population, however, the efficacy and safety of ketamine for the treatment of pediatric depression remains poorly understood. Electronic databases were searched from inception to June 2022 to identify relevant articles. Six articles involving 46 participants with a mean age of 15.7 years were included in this systematic review. Out of six articles, three were case reports, one was a randomized clinical trial (RCT) and two were open-label trials. All studies used 0.5 mg/kg intravenous ketamine except for one, which used 2-7 micrograms/kg. Ketamine was significantly associated with reduced depressive symptoms without severe adverse events. Taken together, the results of these studies demonstrated the potential role of ketamine for treating pediatric depression. Several important limitations were identified, most notably the small sample sizes of the component studies, and that all studies administered intravenous ketamine. Further studies with larger sample sizes and different administration modalities are needed to better determine the efficacy and safety of ketamine in pediatric depression.

Active mechanisms of ketamine-assisted psychotherapy: A systematic review

BACKGROUND

Few studies have evaluated the efficacy of ketamine-assisted psychotherapy (KAP) in the treatment of treatment-resistant depression (TRD) and substance use disorders (SUD).

METHODS

A systematic review of clinical trials reporting on the efficacy of KAP and discussing mechanisms of action, identified on PubMed and PsycInfo.

RESULTS

Five randomized-controlled trials reported on the efficacy of KAP treatment and discussed active mechanisms. Four of the studies treated adults with SUD and a single study treated adults with TRD. Overall, KAP had a significant positive effect on primary outcome measures compared to controls, however, the data is mixed. The study examining KAP for TRD found no benefit.

LIMITATIONS

Lack of large, replicated clinical trials. No studies actively examining mechanisms of action.

CONCLUSION

Evidence suggests that temporary neural changes caused by ketamine such as n-methyl-d-aspartate receptor (NMDAR) inhibition and increase of synaptic neuroplasticity affect treatment outcomes of KAP. Based on reports of preliminary findings, we speculate that adjunct psychotherapy, changes in perspective, and spirituality may also play a role.

Lumateperone for the Treatment of Adults With Schizophrenia: a Systematic Review

PURPOSE OF REVIEW

Lumateperone (LUM) is the U.S. Food and Drug Administration approved atypical antipsychotic agent for adults with schizophrenia (SCZ) and bipolar depression (for both bipolar I and bipolar II disorder as as monotherapy or as adjunctive treatment to lithium or valproate). LUM simultaneously modulates serotonin, dopamine, and glutamate neurotransmission. The foregoing pleiotropic mechanism of action is predictive of therapeutic benefits across multiple domains of psychopathology in SCZ (i.e., positive, negative, cognitive, and prosocial symptoms). Herein, the overarching aim is to synthesize the extant literature reporting on the efficacy, safety, and tolerability of LUM in adults with SCZ.

RECENT FINDINGS

Four clinical studies (i.e., three RCTs and one open-label trial) were included in this synthesis. Overall, LUM significantly reduced the severity of SCZ compared with placebo. The open label study provided the real-world effectiveness of shifting stable patients with SCZ to LUM from other atypical antipsychotics. With respect to safety and tolerability profile, LUM demonstrated placebo-level rates of weight gain, metabolic shift, prolactin elevation, extrapyramidal side effects (EPS), and akathisia across short term trials (i.e., 4-6 weeks). Taken together, our results indicate that LUM significantly improves symptoms severity in adults with SCZ. LUM also exhibits a favorable tolerability and safety profile with placebo level rates of weight gain, metabolic disruption, akathisia, extrapyramidal side effects (excluding akathisia), and prolactin elevation. Lumateperone should be conceptualized as a first-line treatment strategy for adults with SCZ.

The abuse liability of ketamine: A scoping review of preclinical and clinical studies

While ketamine has been used clinically over the past decades, it has only been recently shown to be a promising therapy for treatment-resistant depression (TRD). However, ketamine and related dissociative agents may also be misused recreationally, creating significant concerns for abuse liability when prescribed for depression. Although the abuse potential of ketamine is widely recognized, there is limited evidence on the differential abuse liability of ketamine enantiomers, (S)-ketamine and (R)-ketamine. The current scoping review aims to summarize the extant literature on the abuse liability of (R,S)-ketamine and the enantiomers. A systematic search was conducted on the Embase, Medline, and APA PsycInfo databases from 1947 to July 29, 2021. Clinical and preclinical studies that assessed the abuse potential of (R,S)-ketamine, (S)-ketamine, and (R)-ketamine were screened and assessed for eligibility by two independent reviewers. A total of 65 eligible studies were identified; 55 were preclinical studies and 10 were clinical studies. Only 4 preclinical studies evaluated the abuse liability of ketamine enantiomers. Available preclinical evidence suggests that (R,S)-ketamine and (S)-ketamine have greater risk for abuse compared to (R)-ketamine. (R)-ketamine, at the antidepressant-relevant doses in rodents, appears to be safe with minimal liability for abuse. Although the abuse potential of (R,S)-ketamine is well-established in animals, limited clinical studies indicate that single or repeated ketamine administrations in professionally controlled settings did not result in misuse, dependence, diversion and/or gateway activity in patients with TRD. However, most clinical studies were retrospective and did not systematically evaluate the abuse liability of ketamine via validated psychological scales/questionnaires. Future randomized controlled trials are warranted to ascertain the abuse liability of racemic, (S)- and (R)-ketamine in TRD population, especially among patients with comorbid substance use disorders.

Real-world effectiveness of ketamine in treatment-resistant depression: A systematic review & meta-analysis

Ketamine is a promising therapeutic option in treatment-resistant depression (TRD). The acute efficacy of ketamine in TRD has been demonstrated in replicated randomised-controlled trials (RCTs), but the generalizability of RCT data to real-world practice is limited. To this end, we conducted a systematic review (Search date: 25/12/2021; 1482 records identified) and meta-analysis of studies evaluating the real-world clinical effectiveness of ketamine in TRD patients. Four overlapping syntheses (Total n = 2665 patients; k = 79 studies) and 32 meta-regressions (Total n = 2050; k = 37) were conducted. All results suggest that the mean antidepressant effect is substantial (mean ± 95% CI, % responded = 45 ± 10%; p< 0.0001, % remitted = 30 ± 5.9%; p< 0.0001, Hedges g of symptomatological improvement = 1.44 ± 0.609; p < 0.0001), but the effect varies considerably among patients. The more treatment-resistant cases were found to remit less often (p < 0.01), but no such effect on response was evident (p > 0.05). Meta-regressions also confirmed that the therapeutic effect does not significantly decline with repeated treatments (p > 0.05). These results demonstrate that even the most treatment-resistant patients may benefit from ketamine, and that mid-to-long term treatment is effective in many patients.

The effects of psychostimulants on cognitive functions in individuals with attention-deficit hyperactivity disorder: A systematic review

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is associated with a broad range of deficits in cognitive functions which has significant implications for quality of life. Psychostimulants are demonstrated to improve symptoms of inattention and hyperactivity/impulsivity, however, their impact on cognition remains incompletely characterized. Herein, the aim of this systematic review is to synthesize the extant literature reporting on the effects of psychostimulants on cognitive function in individuals with ADHD.

METHOD

A systematic search of PubMed, Scopus, and Web of Science from inception to July 2021 was conducted. Additional studies were identified through Google Scholar and a manual search of the reference lists of relevant articles. Inclusion criteria were original studies that evaluated the cognitive function of individuals with ADHD taking psychostimulants drugs. We assessed the quality of the included papers using the Newcastle-Ottawa scale (NOS).

RESULTS

A total of 10 studies involving 753 subjects with ADHD and 194 healthy controls were identified and eligible for inclusion. Nine studies evaluated the impact of methylphenidate on cognitive function and one study investigated the use of lisdexamfetamine. Results indicated that attentional deficits such as memory, vigilance, divided attention, phasic and tonic alertness, and focused attention were improved in ADHD patients treated with psychostimulants. The efficacy of psychostimulants in improving other domains of cognition remains inconclusive due to conflicting evidence or insignificant findings (ie. academic performance and executive function). Overall, results indicate that psychostimulants may improve only select domains of cognition (ie. memory and attention).

CONCLUSION

Psychostimulants are reported to improve several disparate aspects of cognition among individuals with ADHD. Further research is needed to better understand the complex relationships between cognition and behavior in ADHD, as well as the impact of medication on these distinct aspects of functioning. Further research is also needed to determine whether the pro-cognitive effect of stimulants would be transferable to other mental disorders.

The efficacy and safety of adjunctive intranasal esketamine treatment in major depressive disorder: a systematic review and meta-analysis

INTRODUCTION

Intranasal (IN) esketamine represents an innovative treatment for individuals with treatment resistant depression and depression with suicidal ideation and behavior. Herein, we synthesize extant long-term studies (≥ 4 weeks) regarding this treatment.

RESEARCH DESIGN AND METHODS

The interventional studies of IN esketamine in patients with depression having a study period of at least four weeks were included for our synthesis. A meta-analysis was undertaken for the efficacy and safety parameters of adjunctive IN esketamine vs IN placebo with an oral antidepressant. The data excluded from meta-analysis were synthesized narratively.

RESULTS

After pooling data from seven randomized controlled trials, treatment with adjunctive IN esketamine vs IN placebo was safe overall, and more effective at decreasing depressive symptoms (d = -0.239; 95%CI = -0.335,-0.142;p < 0.0001), with higher response (RR = 1.221; 95% CI = 1.055,1.428; p = 0.017) and remission (RR = 1.366; 95% CI = 1.182,1.578; p < 0.0001) rates. The year-long trials showed that treatment with adjunctive IN esketamine led to lower relapse rates with no considerable long-term side effects.

CONCLUSION

Intranasal esketamine was demonstrated to be safe, well tolerated, and rapidly effective in individuals with treatment resistant depression, suicidal ideation, and suicidal behavior.

Olanzapine and samidorphan combination treatment: A systematic review

INTRODUCTION

The overarching aim of this review is to synthesize the efficacy, tolerability, and weight-mitigation effects of the olanzapine/samidorphan (OLZ/SAM) combination treatment in adults with schizophrenia and bipolar disorder-I.

METHODS

A systematic search of PubMed, Web of Science, Embase, and The Cochrane Library was conducted on August 15th, 2021. Studies were included if they investigated the use of OLZ/SAM treatment in patients with schizophrenia or bipolar disorder-I, and reported the clinical outcomes: efficacy, change in weight or waist circumference, tolerability, pharmacokinetics, or change in metabolic parameters. A narrative synthesis was undertaken of the data.

RESULTS

Eight studies met the inclusion criteria. All identified studies were conducted in adults with schizophrenia. Compared to OLZ-monotherapy, OLZ/SAM was associated with decreased odds of developing clinically significant (>10%) weight gain (OR=0.50, 95% CI:0.31,0.80; p= 0.003) and increase in waist circumference (risk difference = -17.1% 95% CI:-26.3,-7.8) from baseline measurements respectively. In another study, OLZ was 2.7 times more associated with clinically significant weight gain as compared to OLZ/SAM (OR=2.73, 95% CI:1.11, 6.67; p = 0.023). The clinical efficacy of OLZ/SAM remained similar to OLZ with improved tolerability in both short- and long-term studies with no significantly altered pharmacokinetic properties of the constituent agents.

CONCLUSION

OLZ/SAM-treatment is associated with mitigated weight-gain liability when compared to OLZ-monotherapy in adults with schizophrenia. Additional studies are needed to ascertain patient acceptability, appropriate selection and sequencing of OLZ/SAM in the treatment algorithms for adults with schizophrenia (and BD-I), as well as to determine cost-effectiveness and long-term metabolic effects.

Registered clinical trials investigating treatment of long COVID: a scoping review and recommendations for research

Background

A considerable proportion of individuals report persistent, debilitating and disparate symptoms despite resolution of acute COVID-19 infection (i.e. long COVID). Numerous registered clinical trials investigating treatment of long COVID are expected to be completed in 2021–2022. The aim of this review is to provide a scope of the candidate treatments for long COVID. A synthesis of ongoing long COVID clinical trials can inform methodologic approaches for future studies and identify key research vistas.

Methods

Scoping searches were conducted on multiple national and international clinical trial registries. Interventional trials testing treatments for long COVID were selected. The search timeline was from database inception to 28 July 2021.

Results

This scoping review included 59 clinical trial registration records from 22 countries with a total projected enrolment of 6718. Considerable heterogeneity was exhibited amongst component records with respect to the characterization of long COVID (i.e. name, symptoms- including frequency, intensity, trajectory and duration- mode of ascertainment, and definition of acute phase). In addition, the majority of proposed interventions were non-pharmacological and either targeted multiple long COVID symptoms simultaneously, or focussed on treatment of respiratory/pulmonary sequelae. Multiple interventions targeted inflammation, as well as tissue oxygenation and cellular recovery, and several interventions were repurposed from analogous conditions.

Conclusions

The results of this scoping review investigating ongoing clinical trials testing candidate treatments for long COVID suggest that a greater degree of definitional stringency and homogeneity is needed insofar as the characterization of long COVID and inclusion/exclusion criteria.

Fatigue and cognitive impairment in Post-COVID-19 Syndrome: A systematic review and meta-analysis

IMPORTANCE

COVID-19 is associated with clinically significant symptoms despite resolution of the acute infection (i.e., post-COVID-19 syndrome). Fatigue and cognitive impairment are amongst the most common and debilitating symptoms of post-COVID-19 syndrome.

OBJECTIVE

To quantify the proportion of individuals experiencing fatigue and cognitive impairment 12 or more weeks following COVID-19 diagnosis, and to characterize the inflammatory correlates and functional consequences of post-COVID-19 syndrome.

DATA SOURCES

Systematic searches were conducted without language restrictions from database inception to June 8, 2021 on PubMed/MEDLINE, The Cochrane Library, PsycInfo, Embase, Web of Science, Google/Google Scholar, and select reference lists.

STUDY SELECTION

Primary research articles which evaluated individuals at least 12 weeks after confirmed COVID-19 diagnosis and specifically reported on fatigue, cognitive impairment, inflammatory parameters, and/or functional outcomes were selected.

DATA EXTRACTION & SYNTHESIS

Two reviewers independently extracted published summary data and assessed methodological quality and risk of bias. A meta-analysis of proportions was conducted to pool Freeman-Tukey double arcsine transformed proportions using the random-effects restricted maximum-likelihood model.

MAIN OUTCOMES & MEASURES

The co-primary outcomes were the proportions of individuals reporting fatigue and cognitive impairment, respectively, 12 or more weeks following COVID-19 infection. The secondary outcomes were inflammatory correlates and functional consequences associated with post-COVID-19 syndrome.

RESULTS

The literature search yielded 10,979 studies, and 81 studies were selected for inclusion. The fatigue meta-analysis comprised 68 studies, the cognitive impairment meta-analysis comprised 43 studies, and 48 studies were included in the narrative synthesis. Meta-analysis revealed that the proportion of individuals experiencing fatigue 12 or more weeks following COVID-19 diagnosis was 0.32 (95% CI, 0.27, 0.37; p < 0.001; n = 25,268; I² = 99.1%). The proportion of individuals exhibiting cognitive impairment was 0.22 (95% CI, 0.17, 0.28; p < 0.001; n = 13,232; I² = 98.0). Moreover, narrative synthesis revealed elevations in proinflammatory markers and considerable functional impairment in a subset of individuals.

CONCLUSIONS & RELEVANCE

A significant proportion of individuals experience persistent fatigue and/or cognitive impairment following resolution of acute COVID-19. The frequency and debilitating nature of the foregoing symptoms provides the impetus to characterize the underlying neurobiological substrates and how to best treat these phenomena.

STUDY REGISTRATION

PROSPERO (CRD42021256965).

Frequency analysis of symptomatic worsening following ketamine infusions for treatment resistant depression in a real-world sample: Results from the canadian rapid treatment center of excellence

Antidepressants are associated with symptomatic worsening in a subgroup of patients. Replicated evidence has demonstrated rapid and robust antidepressant effects with intravenous (IV) ketamine in treatment resistant depression (TRD); however, the risk of ketamine worsening depressive symptoms in a subgroup of patients remains unknown. Herein we report a retrospective analysis on the rates of symptomatic worsening during an acute course of IV ketamine in individuals with unipolar (n = 142) and bipolar (n = 22) TRD. Adults (N = 164; mean age = 45.97) with TRD underwent four sub-anesthetic infusions (0.5-0.75 mg/kg over 40 min) of IV ketamine over two weeks, and were assessed with the Quick Inventory for Depression Symptomatology-Self Report-16 (QIDS-SR₁₆) at baseline and after each infusion. The primary outcome was the proportion of patients experiencing clinically significant worsening of depressive symptoms (≥20% increase on the QIDS-SR₁₆) at each time point relative to baseline. Secondary analyses explored trends in the results. The frequency of clinically significant worsening fluctuated between 1.83% to 5.49%, with no identifiable trend across time. Zero individuals with bipolar TRD reported symptomatic worsening. Limitations include the single-centered, uncontrolled, retrospective nature of this study. Rates of symptomatic worsening associated with IV ketamine therapy for TRD appear to be very low and similar to conventional antidepressants.

Pharmacogenomics of ketamine: A systematic review

Ketamine is a dissociative anesthetic used worldwide for anesthesia, pain management, treatment resistant depression (TRD) and suicidality. Predictors of antidepressant response and adverse effects to ketamine remain poorly understood due to contradictory results. The objective of the systematic review herein is to identify and evaluate the extant literature assessing pharmacogenomic predictors of ketamine clinical benefits and adverse effects. Electronic databases were searched from inception to July 2021 to identify relevant articles. Twelve articles involving 1,219 participants with TRD, 75 who underwent elective surgeries and received ketamine as an anesthetic, 49 with pain, and 68 healthy participants met the inclusion criteria and enrolled to this review. While identified articles reported mixed results, three predictors emerged: 1) Val66Met (rs6265) brain derived neurotrophic factor (BDNF; Met allele) was associated with reduced antidepressant and anti-suicidal effects, 2) CYP2B6*6 (e.g., CYB2B6 metabolizer) was associated with more severe dissociative effects and 3) NET allelic (rs28386840) variant were associated with greater cardiovascular complications (e.g., moderate to severe treatment emergent hypertension). Several important limitations were identified, most notably the small sample sizes and heterogeneity of study design and results. Taken together, preliminary evidence suggests the potential for pharmacogenomic testing to inform clinical practices; however, further research is needed to better determine genetic variants of greatest importance and the clinical validity of pharmacogenomics to help guide ketamine treatment planning.

Ketamine monotherapy versus adjunctive ketamine in adults with treatment-resistant depression: Results from the Canadian Rapid Treatment Centre of Excellence

A proportion of individuals with major depressive disorder (MDD) do not receive adequate therapeutic benefit from conventional monoaminergic antidepressant drugs, leading to treatment-resistant depression (TRD). Ketamine has been shown to provide rapid and significant efficacy in treating patients with TRD. The majority of published studies have investigated the adjunctive efficacy of ketamine with one or more monoaminergic antidepressants. There remains a clinical need to ascertain the relative effectiveness of ketamine monotherapy versus adjunctive ketamine treatment in adults with TRD. In this retrospective study, we investigate multidimensional, self-reported outcomes (i.e., antidepressant, anti-suicidality, antianxiety, and anti-functional impairment) of 220 patients to compare monotherapy (n = 39) and adjunctive (n = 181) ketamine treatment for TRD at a community-based clinic. Both groups had clinically and statistically significant antidepressant effects (p < 0.05). Individuals receiving ketamine monotherapy exhibited a significantly greater reduction on the suicidal ideation (SI) item of the Quick Inventory for Depressive Symptomatology-Self Report 16-Item (QIDS-SR₁₆) than the adjunctive group, with a small effect size [F (1, 265) = 4.73; p = 0.03*; partial η² = 0.02], and a significantly higher proportion of partial responders at post-infusion 4 (p = 0.034*). No other between-group differences were significant. Limitations include the small sample, single-centred, open-label, non-randomized, uncontrolled, retrospective nature of this study and indication bias. Our real-world evidence suggests that ketamine may be effective as monotherapy or adjunct to monoamine-based treatments. A priority research and clinical vista is to identify subsets of individuals with TRD who are most likely to have a desired therapeutic outcome with monotherapy versus adjunctive ketamine treatment.

Safety, Tolerability, and Real-World Effectiveness of Intravenous Ketamine in Older Adults With Treatment-Resistant Depression: A Case Series

OBJECTIVE

To evaluate the safety, tolerability, and effectiveness of repeated doses of intravenous (IV) ketamine in older adults (i.e., ≥60 years of age) with treatment-resistant depression.

METHOD

In this case series, fifty-three older adults (M_age = 67, SD = 6; 57% female [n = 30]) received 4 IV ketamine infusions, administered over 1-2 weeks. Effectiveness of IV ketamine was measured using the Quick Inventory for Depressive Symptomatology-Self Report 16 (QIDS-SR16) approximately 2 days after infusions 1-3, and 1-2 weeks after infusion 4. Safety was measured as hemodynamic changes before, during, immediately after, and 20 minutes after each infusion. Tolerability was assessed via systematic reporting of treatment-emergent adverse events during and after each infusion, in addition to symptoms of dissociation measured using the Clinician Administered Dissociative States Scale. Partial response (25%-50% symptomatic improvement from baseline), response (≥50% symptomatic improvement from baseline), clinically significant improvements (≥25% symptomatic improvement from baseline), and remission rates (QIDS-SR16 ≤5) were also calculated.

RESULTS

Participants reported significant decreases in depressive symptoms (i.e., as measured by the QIDS-SR16) with repeated ketamine infusions (F(4, 92) = 7.412, p <0.001). The mean QIDS-SR16 score was 17.12 (SD = 5.33) at baseline and decreased to 12.52 (SD = 5.79) following 4 infusions. After 4 infusions, 31% (n = 8) of participants partially responded to IV ketamine, 27% (n = 7) responded, 58% (n = 15) experienced clinically significant improvements, and 10% (n = 3) met remission criteria. Thirty-six participants (69%) experienced treatment-emergent hypertension during at least 1 infusion, and 10 (19%) required intervention with an antihypertensive. Drowsiness was the most commonly reported adverse event (50% of infusions; n = 73).

CONCLUSION

Ketamine was associated with transient treatment-emergent hypertension. Response and remission rates were comparable to those reported in general adult samples. Findings are limited by the open-label, chart review nature of this study.

Real-world effectiveness of repeated ketamine infusions for treatment resistant depression during the COVID-19 pandemic

Herein we evaluate the impact of COVID-19 restrictions on antidepressant effectiveness of intravenous (IV) ketamine in adults with treatment-resistant depression (TRD). We conducted a case series analysis of adults with TRD (n = 267) who received four ketamine infusions at an outpatient clinic in Ontario, Canada, during COVID-19 restrictions (from March 2020 - February 2021; n = 107), compared to patients who received treatment in the previous year (March 2019 - February 2020; n = 160). Both groups experienced significant and comparable improvements in depressive symptoms, suicidal ideation, and anxiety with repeated ketamine infusions. Effectiveness of IV ketamine was not attenuated during the COVID-19 period.

Antisuicidal and antidepressant effects of ketamine and esketamine in patients with baseline suicidality: A systematic review

Suicide accounts for approximately 800,000 deaths per year globally. Previous research has shown that intranasal esketamine and intravenous ketamine can rapidly decrease the severity of depressive symptoms and suicidal ideation. However, the majority of clinical trials excluded individuals with moderate to high baseline suicidality scores (e.g., suicidal ideation with plan/intent at the time of recruitment). The current review aims to evaluate the effect of esketamine and ketamine in patients with suicidal ideation at baseline. A systematic search was conducted on EMBASE, PsychInfo and PubMed from inception to July 2020 following the PRISMA guidelines. 15 studies met inclusion criteria. Results from esketamine trials did not demonstrate antisuicidal effects, as between-group differences were not found. Intravenous ketamine appeared to rapidly decrease the severity of suicidal ideation and depressive symptoms in individuals with baseline suicidal ideation, though retrospective studies suggest that these effects may be short-lasting. During the double-blind treatment phases, 2.4% of patients from the treatment groups and 1.5% of patients from control groups attempted suicide, with zero deaths by suicide in both the treatment and control groups during this phase. Based on the overall pooled samples, studies were assessed to be relatively safe, and the continual inclusion of this study population in future clinical trials is encouraged. Future research should aim to assess the longitudinal efficacy of ketamine in patients with baseline suicidality.

The effectiveness, safety and tolerability of ketamine for depression in adolescents and older adults: A systematic review

The majority of antidepressant medication trials have focused on adult populations (ages 18-65), with much less research in older and younger populations. Moreover, key differences in the efficacy and safety of antidepressants have been identified between these age groups. Ketamine has emerged as a promising new treatment for treatment resistant depression (TRD). The objective of this review is to summarize and synthesize the extant literature on the effectiveness, safety and tolerability of ketamine for depression in special age populations (age ≤18 and ≥ 60). Following PRISMA guidelines, a systematic review was performed, searching EMBASE, PsycInfo, and PubMed from inception through July 2020. Studies reporting the use of any ketamine formulation with variable routes of administration to treat clinically diagnosed depression in adolescents or older adults were included. Thirteen studies were included in the analysis and ten observed rapid (≤2 week latency) antidepressant effects following ketamine treatments, with better outcomes following larger, repeated doses, and in open-label rather than blinded settings. Two case reports in adolescents assessed measures of suicidal ideation and both found ketamine to effectuate rapid anti-suicidal effects. Ketamine appears to be safe and well-tolerated in adolescents and older adults. The small quantity, high heterogeneity, and generally low quality of available studies precludes statistical syntheses and significantly limits the strength of our conclusions. Preliminary proof-of-concept studies are promising, however, rigorously designed randomized controlled trials (RCTs) are still required to ascertain effectiveness, safety and tolerability in these groups.