Ketamine for suicidal ideation in adults with psychiatric disorders: A systematic review and meta-analysis of treatment trials

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.

Ketamine for depressive symptoms: A retrospective chart review of a private ketamine clinic

Background

There is currently no published evidence demonstrating the effectiveness and safety of subanaesthetic doses of ketamine, when administered intravenously as an adjunct treatment for depressive symptoms, in a real world setting in South Africa.

Aim

This retrospective chart review reports the clinical response (change in Patient Health Questionnaire - 7 score) to an initial infusion series of ketamine added to usual treatment, and the pattern of its subsequent maintenance use, for depressive symptoms.

Setting

A private ketamine clinic in Hilton, KwaZulu-Natal.

Methods

The medical records of all patients who attended a private ketamine clinic between August 2019 and 31 May 2021 were retrospectively analysed. Depression symptoms were evaluated using the Patient Health Questionaire-9 (PHQ-9) administered immediately before and 24 h after each treatment. Response was defined as a score decrease of more than 50%.

Results

Among the 154 patients who received ketamine infusions for depression, 67 completed a six infusion initial series, with a response rate of 60.6% and remission rate of 32.4%. Of the 154, 50% no longer experienced any suicidal ideation after treatment and adverse events were uncommon, with 6.2% of infusions requiring intervention for adverse events, mostly nausea. In addition, 48.5% of those who completed the initial series continued to receive maintenance infusions, with no evidence of escalating use or abuse.

Conclusion

Incorporating intravenous ketamine into the existing treatment regimens at a private clinic was associated with reduced acuteness of depression severity and suicidal ideation. This approach appeared safe and tolerable, showing no signs of abuse or dependence.

Contribution

This is the first known naturalistic study reporting on ketamine use for depressive symptoms in South Africa.

Clinical predictive factors and trajectories of suicidal remission over 6 weeks following intravenous ketamine for suicidal ideation

BACKGROUND

Ketamine is efficient for short-term reduction of suicidal ideas. Predictive factors and outcome trajectories are poorly characterized.

METHODS

Secondary analyses were conducted on the KETIS study (Abbar et al. BMJ 2022): 156 suicidal patients were randomized to two intravenous infusions of racemic ketamine (0.5 mg/kg) or placebo. Response or remission was assessed over six weeks based on the Beck Scale for Suicidal Ideation (SSI). We calculated i) predictive values of 12 baseline variables on remission ii) outcome courses, and iii) positive (PPV) and negative predictive values.

RESULTS

In multivariate analyses, bipolar disorder, lower patient-rated suicidal ideas, and higher physical pain were predictive of suicidal remission at day 3. No clinical factor predicted remission at week 6. Twenty and 24 different clinical courses were identified in early (day 3) and later (week 6) follow-up, respectively, including around 40 % sustained remission, 50 % fluctuating course and 10 % no response. Suicidal remissions at day 1 and day 3 were highly predictive of remissions at day 3 and week 6 (PPV = 96.8 and 92.6 %).

LIMITATIONS

SSI may not be adapted for rapid variations and repeated measures.

CONCLUSIONS

Clinical factors were poorly predictive of remission. Fluctuations in suicidal ideas were frequent, even after ketamine (although less than placebo), necessitating vigilance and multimodal care. Remission at day 1 after one infusion was highly predictive of future remission. The benefits of a second infusion will have to be tested.

A systematic review and meta-analysis of the efficacy of ketamine and esketamine on suicidal ideation in treatment-resistant depression

PURPOSE

To systematically assess the evidence of efficacy and safety of the use of ketamine and esketamine for patients with treatment-resistant depression (TRD) with suicidal ideation (SI).

METHODS

We independently searched for clinical trials from inception to January 2023 using electronic databases, e.g., PubMed and EMBASE. A systematic review and meta-analysis were performed to assess SI scores of depression rating scales, which were regarded as the outcomes.

RESULTS

A total of five independent double-blind, placebo controlled randomized clinical trials (RCTs) are eligible for inclusion. Four of the studies used ketamine as an intervention and one used esketamine as an intervention. Three hundred ninety-one patients with TRD were included (the intervention group with ketamine or esketamine is 246, and the control group is 145). No statistically significant interaction between the subscales of suicide ideation (SMD = - 0.66, 95% CI (- 1.61, 0.29); Z = 1.36, P = 0.17) and antidepressant effects (SMD = - 0.99, 95% CI (- 2.33, 0.34); Z = 1.46, P = 0.15) based on the results of ketamine and esketamine, compared with placebo groups.

CONCLUSION

This meta-analysis suggested that esketamine and ketamine have failed to reduce suicidal ideation in patients with TRD. Further studies are desirable to confirm the effects of ketamine and esketamine in TRD patients.

Efficacy and safety of ketamine and esketamine for unipolar and bipolar depression: an overview of systematic reviews with meta-analysis

Background

Unipolar and bipolar depression present treatment challenges, with patients sometimes showing limited or no response to standard medications. Ketamine and its enantiomer, esketamine, offer promising alternative treatments that can quickly relieve suicidal thoughts. This Overview of Reviews (OoR) analyzed and synthesized systematic reviews (SRs) with meta-analysis on randomized clinical trials (RCTs) involving ketamine in various formulations (intravenous, intramuscular, intranasal, subcutaneous) for patients with unipolar or bipolar depression. We evaluated the efficacy and safety of ketamine and esketamine in treating major depressive episodes across various forms, including unipolar, bipolar, treatment-resistant, and non-resistant depression, in patient populations with and without suicidal ideation, aiming to comprehensively assess their therapeutic potential and safety profile.

Methods

Following PRIOR guidelines, this OoR's protocol was registered on Implasy (ID:202150049). Searches in PubMed, Scopus, Cochrane Library, and Epistemonikos focused on English-language meta-analyses of RCTs of ketamine or esketamine, as monotherapy or add-on, evaluating outcomes like suicide risk, depressive symptoms, relapse, response rates, and side effects. We included studies involving both suicidal and non-suicidal patients; all routes and formulations of administration (intravenous, intramuscular, intranasal) were considered, as well as all available comparisons with control interventions. We excluded meta-analysis in which the intervention was used as anesthesia for electroconvulsive therapy or with a randomized ascending dose design. The selection, data extraction, and quality assessment of studies were carried out by pairs of reviewers in a blinded manner. Data on efficacy, acceptability, and tolerability were extracted.

Results

Our analysis included 26 SRs and 44 RCTs, with 3,316 subjects. The intervention is effective and well-tolerated, although the quality of the included SRs and original studies is poor, resulting in low certainty of evidence.

Limitations

This study is limited by poor-quality SRs and original studies, resulting in low certainty of the evidence. Additionally, insufficient available data prevents differentiation between the effects of ketamine and esketamine in unipolar and bipolar depression.

Conclusion

While ketamine and esketamine show promising therapeutic potential, the current evidence suffers from low study quality. Enhanced methodological rigor in future research will allow for a more informed application of these interventions within the treatment guidelines for unipolar and bipolar depression.

Systematic review registration

[https://inplasy.com/inplasy-2021-5-0049/], identifier (INPLASY202150049).

Comparative efficacy, tolerability and acceptability of intravenous racemic ketamine with intranasal esketamine, aripiprazole and lithium as augmentative treatments for treatment-resistant unipolar depression: A systematic review and network meta-analysis

BACKGROUND

Intravenous racemic ketamine is a promising treatment for treatment-resistant depression. However, its clinical utility compared with intranasal esketamine and the other well-studied conventional pharmacological interventions (i.e., aripiprazole and lithium) as augmentative treatments for treatment-resistant unipolar depression in adults remains unclear. Therefore, we aimed to compare the efficacy, tolerability and acceptability of intravenous racemic ketamine with intranasal esketamine, aripiprazole and lithium under such conditions.

METHODS

The Cochrane Library, PubMed, CINHAL and ClinicalTrials.gov databases were systematically searched from their inception to 10 May 2023. Randomised controlled trials evaluating these drugs were included. A random-effects network meta-analysis was also performed.

RESULTS

In the primary analysis, all four drugs were significantly more effective than placebo. In addition, intravenous racemic ketamine was significantly more effective and acceptable than intranasal esketamine and aripiprazole. Intravenous racemic ketamine was not significantly different from placebo in tolerability, whereas intranasal esketamine and aripiprazole were significantly less tolerable than placebo. Lithium did not differ significantly from intravenous racemic ketamine in efficacy, tolerability and acceptability.

LIMITATIONS

The sample size of patients treated with intravenous racemic ketamine was small.

CONCLUSIONS

Intravenous racemic ketamine may be a better augmentative treatment for treatment-resistant unipolar depression than intranasal esketamine and aripiprazole. Whether intravenous racemic ketamine or lithium is superior is unclear currently. A larger head-to-head trial of intravenous racemic ketamine versus conventional augmentative treatments for treatment-resistant unipolar depression is needed.

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.

Predicting risk of suicidal behavior from insurance claims data vs. linked data from insurance claims and electronic health records

PURPOSE

Observational studies assessing effects of medical products on suicidal behavior often rely on health record data to account for pre-existing risk. We assess whether high-dimensional models predicting suicide risk using data derived from insurance claims and electronic health records (EHRs) are superior to models using data from insurance claims alone.

METHODS

Data were from seven large health systems identified outpatient mental health visits by patients aged 11 or older between 1/1/2009 and 9/30/2017. Data for the 5 years prior to each visit identified potential predictors of suicidal behavior typically available from insurance claims (e.g., mental health diagnoses, procedure codes, medication dispensings) and additional potential predictors available from EHRs (self-reported race and ethnicity, responses to Patient Health Questionnaire or PHQ-9 depression questionnaires). Nonfatal self-harm events following each visit were identified from insurance claims data and fatal self-harm events were identified by linkage to state mortality records. Random forest models predicting nonfatal or fatal self-harm over 90 days following each visit were developed in a 70% random sample of visits and validated in a held-out sample of 30%. Performance of models using linked claims and EHR data was compared to models using claims data only.

RESULTS

Among 15 845 047 encounters by 1 574 612 patients, 99 098 (0.6%) were followed by a self-harm event within 90 days. Overall classification performance did not differ between the best-fitting model using all data (area under the receiver operating curve or AUC = 0.846, 95% CI 0.839-0.854) and the best-fitting model limited to data available from insurance claims (AUC = 0.846, 95% CI 0.838-0.853). Competing models showed similar classification performance across a range of cut-points and similar calibration performance across a range of risk strata. Results were similar when the sample was limited to health systems and time periods where PHQ-9 depression questionnaires were recorded more frequently.

CONCLUSION

Investigators using health record data to account for pre-existing risk in observational studies of suicidal behavior need not limit that research to databases including linked EHR data.

Anti-suicidal effects of IV ketamine in a real-world setting

The current study evaluated the effectiveness of intravenous ketamine treatment for suicidality in a community-based clinical sample of 295 outpatients (mean age=  40.37; 58.6 % male). We conducted growth mixture modeling to estimate latent classes of changes in symptoms of suicidality measured by the Concise Health Risk Tracking - Self-Report (CHRT-SR) across five infusions in a two-week course of treatment. Best-fit indices indicated three trajectory groups demonstrating non-linear, quadratic changes in CHRT-SR scores during ketamine treatment. The largest group of patients (n=  170, 57.6 %) had moderate CHRT-SR scores at baseline and showed gradual improvement during treatment. The other two groups of patients had severe CHRT-SR scores at baseline and diverged into one group with no improvement throughout treatment (n = 63, 21  %) and one group with rapid improvement (n = 62, 21 %). Of the clinical and demographic variables available and tested, only higher scores pertaining to active thoughts of death and/or plan were found to predict which of the patients with severe CHRT-SR scores at baseline would not benefit from treatment. The present study provides an important contribution to the knowledge of ketamine's effects on symptoms related to suicide over time. providing support for the possible effectiveness of ketamine in a proportion of patients.

[Ketamine and suicidal behavior: Contribution of animal models of aggression-impulsivity to understanding its mechanism of action]

More than two-thirds of suicides occur during a major depressive episode. Acting out prevention measures and therapeutic options to manage the suicidal crisis are limited. The impulsive-aggressive dimensions are vulnerability factors associated with suicide in patients suffering from a characterized depressive episode: this can be a dimension involved in animals. Impulsive and aggressive rodent models can help analyze, at least in part, the neurobiology of suicide and the beneficial effects of treatments. Ketamine, a glutamatergic antagonist, by rapidly improving the symptoms of depressive episodes, would help reduce suicidal thoughts in the short term. Animal models share with humans impulsive and aggressive endophenotypes modulated by the serotonergic system (5-HTB receptor, MAO-A enzyme), neuroinflammation or the hypothalamic-pituitary-adrenal axis and stress. Significant effects of ketamine on these endophenotypes remain to be demonstrated.

Restorative effect of NitroSynapsin on synaptic plasticity in an animal model of depression

In the search for new options for the pharmacological treatment of major depressive disorder, compounds with a rapid onset of action and high efficacy but lacking a psychotomimetic effect are of particular interest. In the present study, we evaluated the antidepressant potential of NitroSynapsin (NS) at behavioural, structural, and functional levels. NS is a memantine derivative and a dual allosteric N-methyl-d-aspartate receptors (NMDAR) antagonist using targeted delivery by the aminoadamantane of a warhead nitro group to inhibitory redox sites on the NMDAR. In a chronic restraint stress (CRS) mouse model of depression, five doses of NS administered on three consecutive days evoked antidepressant-like activity in the chronically stressed male C57BL/6J mice, reversing CRS-induced behavioural disturbances in sucrose preference and tail suspension tests. CRS-induced changes in morphology and density of dendritic spines in cerebrocortical neurons in the medial prefrontal cortex (mPFC) were also reversed by NS. Moreover, CRS-induced reduction in long-term potentiation (LTP) in the mPFC was found to be prevented by NS based on the electrophysiological recordings. Our study showed that NS restores structural and functional synaptic plasticity and reduces depressive behaviour to the level found in naïve animals. These results preliminarily revealed an antidepressant-like potency of NS.

Short term ketamine treatment in patient with bipolar disorder with comorbidity with borderline personality disorder: Focus on impulsivity

OBJECTIVES

Borderline personality disorder (BPD) and bipolar disorder (BD) often co-occur and frequently do not respond adequately to traditional antidepressant treatments. Ketamine has shown rapid antidepressant and anti-suicidal effects. However, there is limited literature on the safety and tolerance of using ketamine to treat patients with comorbid BD and BPD.

METHODS

This case presents a female patient diagnosed with both Bipolar Disorder (BD) and Borderline Personality Disorder (BPD) who received intravenous ketamine treatment to alleviate acute depressive symptoms.

RESULTS

Initially, ketamine ameliorated depressed symptoms. However, as the ketamine treatment continued, the patient showed an increase in nonsuicidal self-injury (NSSIs) and impulsive conduct with a aggravation of dissociative symptoms. As a result, intravenous ketamine was discontinued, and the patient received the medication, which proved helpful.

CONCLUSIONS

Although ketamine presents antidepressant properties, reports on its impact on emotional dysregulation and impulsive conduct are unclear and not alike to its antidepressant effect. Therefore, there is a need for more studies investigating the effectiveness and safety of this rapid-acting medicine in this patient population.

Selective Serotonin Reuptake Inhibitors and Other Treatment Modalities for Deep Space Missions

INTRODUCTION: As humankind ventures further into the depths of space, planning is already underway for long-duration exploration missions that will test the bounds of human performance. Deep space travel will include added risk related to stressors from the isolated, confined, and extreme environment that lies outside the boundaries of low Earth orbit. Currently, selective serotonin reuptake inhibitors (SSRIs) are considered the standard of care for many mental health diagnoses, including anxiety and depression; however, SSRIs are also associated with several undesired side effects. The utility of nonpharmacological therapies for the management of behavioral health conditions has not yet been fully explored.METHODS: A comprehensive literature search was performed using PubMed. Relevant articles pertaining to the psychological impacts of isolated, confined, and extreme environments, use of SSRIs in spaceflight, side effects associated with SSRIs, and nonpharmacological treatments for anxiety and depression were reviewed. Over 70 studies were reviewed in total.RESULTS: Reduced bone mineral density, impaired hemostatic function, significant individual variability resulting from gene polymorphisms, and drug-drug interactions are well described adverse effects of SSRIs that may complicate their operational use in the deep space environment. Four alternative therapies for the treatment of anxiety and depression may show promise for long duration missions.DISCUSSION: Although SSRIs have long been considered standard of care treatment for many behavioral health conditions, we cannot trivialize the risk that prolonged pharmacological therapy may pose. The need to mitigate these risks by exploring alternative therapies has never been more relevant.El-Khoury BB, Ray KL, Altchuler SI, Reichard JF, Dukes CH. Selective serotonin reuptake inhibitors and other treatment modalities for deep space missions. Aerosp Med Hum Perform. 2023; 94(11):843-851.

Alterations of BDNF, mGluR5, Homer1a, p11 and excitatory/inhibitory balance in corticolimbic brain regions of suicide decedents

BACKGROUND

Developing biological based approaches for preventing suicide has become a priority. In recent years, there has been a surge in studies investigating the role of the glutamatergic system in suicide, although it remains unclear.

METHODS

We evaluated changes in the gene expression of the metabotropic glutamate receptor 5 (mGluR5) and its scaffolding proteins Homer1a and p11 in the dorsolateral prefrontal cortex (DLPFC), amygdala (AMY), and hippocampus (HIP) of 28 suicide decedents (S) (with no clinical psychiatric history or treatment with anxiolytics or antidepressants) and 26 controls (C) by real-time PCR (qPCR). Indeed, we measured BDNF gene expression and VGluT1 and VGAT immunoreactivities in the HIP by qPCR and immunohistochemistry, respectively. Cases and controls matched for age (C: 48.6 ± 11.6 years; S: 46.9 ± 14.5 years) and postmortem interval (PMI; C: 20.1 ± 13h; S: 16.9 ± 5h).

RESULTS

In DLPFC, S had lower p11 gene expression levels, but no differences were found in mGluR5 or Homer1a. In the AMY and HIP, mGluR5 and Homer1a were increased, p11 and BDNF were reduced. In the HIP, there were less VGAT-ir and more VGluT1-ir.

LIMITATIONS

Future studies are necessary to evaluate protein levels, and determine the cell types and potential compensatory mechanisms in a larger sample including S diagnosed with psychiatric disorders, females and different ethnicities.

CONCLUSIONS

This study identified significant alterations in mGluR5, Homer1a, p11, BDNF and excitatory/inhibitory balance in corticolimbic brain areas of S. These results further characterize the biological basis of suicide, contributing to the identification of potential biomarkers for suicide prevention.

Exploring the Potential Utility of Psychedelic Therapy for Patients With Amyotrophic Lateral Sclerosis

Background: Amyotrophic lateral sclerosis (ALS) is an aggressive, terminal neurodegenerative disease that causes death of motor neurons and has an average survival time of 3-4 years. ALS is the most common motor neuron degenerative disease and is increasing in prevalence. There is a pressing need for more effective ALS treatments as available pharmacotherapies do not reverse disease progression or provide substantial clinical benefit. Furthermore, despite psychological distress being highly prevalent in ALS patients, psychological treatments remain understudied. Psychedelics (i.e., serotonergic psychedelics and related compounds like ketamine) have seen a resurgence of research into therapeutic applications for treating a multitude of neuropsychiatric conditions, including psychiatric and existential distress in life-threatening illnesses. Methods: We conducted a narrative review to examine the potential of psychedelic assisted-psychotherapy (PAP) to alleviate psychiatric and psychospiritual distress in ALS. We also discussed the safety of using psychedelics in this population and proposed putative neurobiological mechanisms that may therapeutically intervene on ALS neuropathology. Results: PAP has the potential to treat psychological dimensions and may also intervene on neuropathological dimensions of ALS. Robust improvements in psychiatric and psychospiritual distress from PAP in other populations provide a strong rationale for utilizing this therapy to treat ALS-related psychiatric and existential distress. Furthermore, relevant neuroprotective properties of psychedelics warrant future preclinical trials to investigate this area in ALS models. Conclusion: PAP has the potential to serve as an effective treatment in ALS. Given the lack of effective treatment options, researchers should rigorously explore this therapy for ALS in future trials.

Systematic review: Electroconvulsive therapy for treatment-resistant mood disorders in children and adolescents

Electroconvulsive therapy (ECT) is a well-established treatment for adults with mood disorders. However, its use in child and adolescent populations is less common. At the same time, approximately 60% of child and adolescent patients do not respond satisfactorily to first-line treatments for mood disorders. Given the need for effective treatments for severe mood disorders in adolescents and the low use rate of ECT, this systematic review examines the existing literature on the effectiveness and adverse effect profile of ECT when used for treatment-resistant mood disorders in children and adolescents. Searches were conducted in Medline, Embase, and PsycInfo using search terms related to (1) children and adolescents, (2) mood disorders, and (3) ECT. Searches identified 1715 unique articles. The full text of 71 selected articles were reviewed, leading to 41 studies included in the study. A standardized data extraction tool was used to collect key information from each study (i.e. author and publication year, objectives, participants and setting, design, measures, clinical outcomes, and side effects). As most of the studies found were case series, the Joanna Briggs Institute Case Series Critical Appraisal tool was used to assess quality. Studies were summarized qualitatively by comparing findings across key study parameters. Our review identified 41 studies for inclusion. Twenty were case series, two were case-control studies, and nineteen were case reports. Overall treatment response rates ranged from 51 to 92%, with patients receiving an average of 12 treatments. Among studies with n > 30, response rates were largely 70-82% for depression and 87-90% for mania. Seven studies used the Mini-Mental State Exam and found no evidence of significant post-treatment cognitive impairment. The majority of side effects were minor and transient. Tardive seizure was reported in 4 (0.6%) patients. ECT was discontinued early due to side effects in 11 (1.5%) cases. No fatalities were reported. Our data suggest that ECT is safe and effective for the treatment of mood disorders in child and adolescent populations, and should be considered in severe and treatment-refractory cases. Controlled studies with objective measures and long-term follow-up are needed to advance the evidence base.

Suicidal ideation and suicide attempt following ketamine prescription in patients with treatment-resistant depression: a nation-wide cohort study

Ketamine, including esketamine, is an effective treatment for patients with treatment-resistant depression (TRD); however, its long-term efficacy in real-world populations remains poorly characterized. This is a retrospective cohort study using TriNetX US Collaborative Network, a platform aggregating electronic health records (EHRs) data from 93 million patients from 56 health care organizations in the US, and the study population includes 321,367 patients with a diagnosis of TRD who were prescribed relevant treatment in their EHRs. The prescription of ketamine (including esketamine) was associated with significant decreased risk of suicidal ideation compared to prescription of other common antidepressants: HR = 0.65 (95% CI: 0.53 - 0.81) at 1 day - 7 days, 0.78 (95% CI: 0.66 - 0.92) at 1 day - 30 days, 0.81 (95% CI: 0.70 - 0.92) at 1 day - 90 days, 0.82 (95% CI: 0.72 - 0.92) at 1 day - 180 days, and 0.83 (95% CI: 0.74 - 0.93) at 1 day - 270 days. This trend was especially robust among adults over 24 years of age, males, and White patients with TRD. No significant difference was observed for suicide attempts, except significantly increased risk for adolescents (aged 10-24) at 1 day - 30 days with HR = 2.22 (95% CI: 1.01-4.87). This study provides real-world evidence that ketamine has long-term benefits in mitigating suicidal ideation in patients with treatment-resistant depression. Future work should focus on optimizing dosage regimens for ketamine, understanding the mechanism, and the difference in various demographic subpopulations.

Baseline cognitive function predicts full remission of suicidal symptoms among patients with treatment-resistant depression and strong suicidal ideation after low-dose ketamine infusion

BACKGROUND

Whether pretreatment working memory and response inhibition function are associated with the rapid and sustained antisuicidal effect of low-dose ketamine among patients with treatment-resistant depression (TRD) and strong suicidal ideation is unclear.

METHODS

We enrolled 65 patients with TRD, comprising 33 who received a single infusion of 0.5 mg/kg ketamine and 32 who received a placebo infusion. The participants performed working memory and go/no-go tasks prior to infusion. We assessed suicidal symptoms at baseline and on postinfusion Days 2, 3, 5, and 7.

RESULTS

The full remission of suicidal symptoms persisted for 3 days after a single ketamine infusion and the ketamine-related antisuicidal effect persisted for 1 week. Lower cognitive impairment at baseline (indicated by a higher rate of correct responses on a working memory task) was associated with the rapid and sustained antisuicidal effect of low-dose ketamine in patients with TRD and strong suicidal ideation.

DISCUSSION

Patients with TRD and strong suicidal ideation but low cognitive impairment may benefit the most from the antisuicidal effect of low-dose ketamine.

Case series of intravenous ketamine infusion in patients with suicidal thought

Suicide is the fourth leading cause of death. The annual global prevalence of suicidal ideas in adult population is 2%. Antidepressants are considered to be the first line of treatment for depression but the maximum response is noted only after 4-6 weeks. However, adding ketamine has shown very rapid response (within hours) and high remission rates in patients with depression. Here, we present case series of five depressive patients on treatment with antidepressants having suicidal thoughts. All participants received ketamine infusion 0.5 mg/kg over 45 min at a weekly interval as add-on treatment to ongoing treatment. The responses were assessed by using Montgomery Åsberg Depression Rating Scale psychometric tool. The finding indicates that ketamine infusion had a rapid, antisuicidal effect and is safe when used for a short period.

Suicide prevention and ketamine: insights from computational modeling

Suicide is a pressing public health issue, with over 700,000 individuals dying each year. Ketamine has emerged as a promising treatment for suicidal thoughts and behaviors (STBs), yet the complex mechanisms underlying ketamine's anti-suicidal effect are not fully understood. Computational psychiatry provides a promising framework for exploring the dynamic interactions underlying suicidality and ketamine's therapeutic action, offering insight into potential biomarkers, treatment targets, and the underlying mechanisms of both. This paper provides an overview of current computational theories of suicidality and ketamine's mechanism of action, and discusses various computational modeling approaches that attempt to explain ketamine's anti-suicidal effect. More specifically, the therapeutic potential of ketamine is explored in the context of the mismatch negativity and the predictive coding framework, by considering neurocircuits involved in learning and decision-making, and investigating altered connectivity strengths and receptor densities targeted by ketamine. Theory-driven computational models offer a promising approach to integrate existing knowledge of suicidality and ketamine, and for the extraction of model-derived mechanistic parameters that can be used to identify patient subgroups and personalized treatment approaches. Future computational studies on ketamine's mechanism of action should optimize task design and modeling approaches to ensure parameter reliability, and external factors such as set and setting, as well as psychedelic-assisted therapy should be evaluated for their additional therapeutic value.

Pharmacotherapy: Ketamine and Esketamine

Ketamine and esketamine have rapid-onset antidepressant effects and may be considered for the management of treatment-resistant depression. Intranasal esketamine has regulatory approval in the United States and European Union. Intravenous ketamine is often administered off-label as an antidepressant, though no standard operating procedures exist. Repeated administrations and the use of a concurrent standard antidepressant may maintain antidepressant effects of ketamine/esketamine. Possible adverse effects of ketamine and esketamine include psychiatric, cardiovascular, neurologic and genitourinary effects, and the potential for abuse. The long-term safety and efficacy of ketamine/esketamine as antidepressants require further study.

Successful use of ketamine to treat severe depression with suicidality post-COVID-19 - A case report

Every second patient who suffers from COVID-19 experiences is at risk for depression. The treatment of severe depression with suicidal risk is challenging in patients with COVID-19 given the restrictions in access to and safety concerns with the use of electroconvulsive therapy during the COVID pandemic. Although ketamine is effective in treating depression, especially in presence of acute suicidality, to date, there are no reports on ketamine use to treat severe depression in the context of COVID-19. In this case report, we describe the success of ketamine to treat a person with severe depression and suicidality following COVID-19 infection.

The antidepressant actions of ketamine and its enantiomers

Ketamine, an N-methyl-d-aspartate receptor (NMDAR) antagonist first developed as an anesthetic, has shown significant promise as a medication with rapid antidepressant properties in treatment-resistant depression. However, concerns such as adverse side effects and potential misuse liability have limited its widespread use. Racemic ketamine has two enantiomers-(S)- and (R)-ketamine-that appear to have disparate underlying mechanisms. This brief review summarizes some of the most recent preclinical and clinical research regarding the convergent and divergent prophylactic, immediate, and sustained antidepressant effects of (S)- and (R)-ketamine while addressing potential differences in their side effect and misuse liability profiles. Preclinical research suggests divergent mechanisms underlying (S)- and (R)-ketamine, with (S)-ketamine more directly affecting mechanistic target of rapamycin complex 1 (mTORC1) signaling and (R)-ketamine more directly affecting extracellular signal-related kinase (ERK) signaling. Clinical research suggests that (R)-ketamine has a milder side effect profile than (S)-ketamine and decreases depression rating scale scores, but recent randomized, controlled trials found that it had no significant antidepressant efficacy compared to placebo, suggesting that caution is warranted in interpreting its therapeutic potential. Future preclinical and clinical research is needed to maximize the efficacy of each enantiomer, either by optimizing dose, route of administration, or administration paradigm.

Repeated oral esketamine in patients with treatment resistant depression and comorbid posttraumatic stress disorder

Introduction

Ketamine and its S-enantiomer esketamine are novel pharmacotherapeutic options for treatment resistant depression (TRD). There is growing evidence on the efficacy for other psychiatric disorders, including posttraumatic stress disorder (PTSD). It is hypothesized that psychotherapy may further potentiate the effects of (es)ketamine in psychiatric disorders.

Methods

Repeated oral esketamine was prescribed once or twice weekly in five patients suffering from TRD and comorbid PTSD. We describe the clinical effects of esketamine and report data from psychometric instruments and patients' perspectives.

Results

Esketamine treatment duration ranged from six weeks to a year. In four patients, we observed improvement in depressive symptoms, increased resilience and more receptiveness to psychotherapy. One patient experienced symptom worsening in response to a threatening situation during esketamine treatment, highlighting the need for a safe setting.

Discussion

(Es)ketamine treatment within a psychotherapeutic framework appears promising in patients with treatment resistant symptoms of depression and PTSD. Controlled trials are warranted to validate these results and to elucidate the optimal treatment methods.

Effect of Ketamine on Sleep in Treatment-Resistant Depression: A Systematic Review

BACKGROUND

Depression is a debilitating disease with a high socioeconomic burden. Regular antidepressants usually require several weeks to ameliorate symptoms; however, numerous patients do not achieve remission. What is more, sleep disturbances are one of the most common residual symptoms. Ketamine is a novel antidepressant with rapid onset of action with a proven antisuicidal effect. Little is known about its impact on sleep-wake and circadian rhythm alterations. The aim of this systematic review is to research the impact ketamine has on sleep disturbances in depression.

METHODS

PubMed, Web of Science, and APA PsycINFO were searched for relevant studies on ketamine's impact on sleep disturbances in depression. Preferred Reporting Items for Systematic Reviews and Meta-Analyses PRISMA2020 methodology was applied. The systematic review protocol was registered in the PROSPERO Registry (CRD42023387897).

RESULTS

Five studies were included in this review. Two studies reported significant improvement in sleep measured by MADRS (Montgomery-Åsberg Depression Rating Scale) and QIDS-SR16 (Quick Inventory of Depressive Symptomatology Self-Report (16-item)) scales after intravenous ketamine and intranasal esketamine administration. One case report showed mitigation of symptoms in PSQI (Pittsburgh Sleep Quality Index) and ISI (Insomnia Severity Index) during 3-month treatment with esketamine. In two studies, sleep was objectively measured by nocturnal EEG (electroencephalography) and showed a decrease in nocturnal wakefulness accompanied by an increase in slow wave (SWS) and rapid eye movement (REM) sleep.

CONCLUSION

Ketamine reduces the severity of sleep insomnia in depression. Robust data are lacking. More research is needed.

Intravenous ketamine for severe alcohol use disorder at Moi Teaching & Referral Hospital, Kenya: a case report

BACKGROUND

Alcohol use disorder is prevalent globally and in Kenya, and is associated with significant health and socio-economic consequences. Despite this, available pharmacological treatment options are limited. Recent evidence indicates that intravenous (IV) ketamine can be beneficial for the treatment of alcohol use disorder, but is yet to be approved for this indication. Further, little has been done to describe the use of IV ketamine for alcohol use disorder in Africa. The goal of this paper, is to: 1) describe the steps we took to obtain approval and prepare for off-label use of IV ketamine for patients with alcohol use disorder at the second largest hospital in Kenya, and 2) describe the presentation and outcomes of the first patient who received IV ketamine for severe alcohol use disorder at the hospital.

CASE PRESENTATION

In preparing for the off-label use of ketamine for alcohol use disorder, we brought together a multi-disciplinary team of clinicians including psychiatrists, pharmacists, ethicists, anesthetists, and members of the drug and therapeutics committee, to spearhead the process. The team developed a protocol for administering IV ketamine for alcohol use disorder that took into account ethical and safety issues. The national drug regulatory authority, the Pharmacy and Poison's Board, reviewed and approved the protocol. Our first patient was a 39-year-old African male with severe alcohol use disorder and comorbid tobacco use disorder and bipolar disorder. The patient had attended in-patient treatment for alcohol use disorder six times and each time had relapsed between one to four months after discharge. On two occasions, the patient had relapsed while on optimal doses of oral and implant naltrexone. The patient received IV ketamine infusion at a dose of 0.71 mg/kg. The patient relapsed within one week of receiving IV ketamine while on naltrexone, mood stabilizers, and nicotine replacement therapy.

DISCUSSION & CONCLUSIONS

This case report describes for the first time the use of IV ketamine for alcohol use disorder in Africa. Findings will be useful in informing future research and in guiding other clinicians interested in administering IV ketamine for patients with alcohol use disorder.

Ketamine and esketamine in suicidal thoughts and behaviors: a systematic review

BACKGROUND

More than 2% of the general population experience suicidal ideas each year and a large number of them will attempt suicide. Evidence-based therapeutic options to manage suicidal crisis are currently limited.

OBJECTIVES

The aim of this study was to overview the findings on the use of ketamine and esketamine for the treatment of suicidal ideas and acts.

DESIGN

Systematic review.

DATA SOURCES AND METHODS

PubMed, article references, and Clinicaltrials.gov up to June 30, 2022. Meta-analyses published within the last 2 years were also reviewed.

RESULTS

We identified 12 randomized controlled trials with reduction of suicidal ideation as the primary objective and 14 trials as secondary objectives. Intravenous racemic ketamine was superior to control drugs (placebo or midazolam) within the first 72 h, in spite of large placebo effects. Adverse events were minor and transient. In contrast, intranasal esketamine did not differ from placebo in large-scale studies. Limitations, clinical considerations, and opportunities for future research include the following points: large placebo effects when studying suicidal ideation reduction; small concerns about blinding quality due to dissociative effects; no studies on the risk/prevention of suicidal acts and mortality; lack of studies beyond affective disorders; no studies in adolescents and older people; lack of knowledge of long-term side effects, notably liability for abuse; no robust predictive markers; limited understanding of the mechanisms of ketamine on suicidal ideas; need for improved assessment of suicidal ideation in clinical trials; need for studies in outpatient settings, emergency room, and liaison consultation; need for research on ketamine administration; limited knowledge on the positive and negative effects of concomitant treatments.

CONCLUSION

Overall, there is compelling evidence for a favorable short-term benefit-risk balance with intravenous racemic ketamine but not intranasal esketamine. The place of ketamine will have to be defined within a multimodal care strategy for suicidal patients. Caution remains necessary for clinical use, and pharmacovigilance will be essential.

Ketamine and its metabolites: Potential as novel treatments for depression

Depression is a well-known serious mental illness, and the onset of treatment using traditional antidepressants is frequently delayed by several weeks. Moreover, numerous patients with depression fail to respond to therapy. One major breakthrough in antidepressant therapy is that subanesthetic ketamine doses can rapidly alleviate depressive symptoms within hours of administering a single dose, even in treatment-resistant patients. However, specific mechanisms through which ketamine exerts its antidepressant effects remain elusive, leading to concerns regarding its rapid and long-lasting antidepressant effects. N-methyl-d-aspartate receptor (NMDAR) antagonists like ketamine are reportedly associated with serious side effects, such as dissociative symptoms, cognitive impairment, and abuse potential, limiting the large-scale clinical use of ketamine as an antidepressant. Herein, we reviewed the pharmacological properties of ketamine and the mechanisms of action underlying the rapid antidepressant efficacy, including the disinhibition hypothesis and synaptogenesis, along with common downstream effector pathways such as enhanced brain-derived neurotrophic factor and tropomyosin-related kinase B signaling, activation of the mechanistic target of rapamycin complex 1 and transforming growth factor β1. We focused on evidence supporting the relevance of these potential mechanisms of ketamine and its metabolites in mediating the clinical efficacy of the drug. Given its reported antidepressant efficacy in preclinical studies and limited undesirable adverse effects, (R)-ketamine may be a safer, more controllable, rapid antidepressant. Overall, understanding the potential mechanisms of action of ketamine and its metabolites in combination with pharmacology may help develop a new generation of rapid antidepressants that maximize antidepressant effects while avoiding unfavorable adverse effects. This article is part of the Special Issue on 'Ketamine and its Metabolites'.

Acute Effects of Intravenous Sub-Anesthetic Doses of Ketamine and Intranasal Inhaled Esketamine on Suicidal Ideation: A Systematic Review and Meta-Analysis

Purpose

Suicide is a major public health concern with currently no validated and efficacious treatments approved. Preliminary evidence suggests that intravenous ketamine has rapid and sustained antidepressant effects, making it a candidate with therapeutic potential for depressed patients at risk for suicide. We conducted a meta-analysis to evaluate the efficacy of ketamine and esketamine in reducing suicidal ideation (SI), as well as their respective onset and duration of action.

Data Sources

We searched PubMed, Embase, Ovid, Cochrane, and Web of Science databases for studies published from inception to September 29, 2022.

Study Eligibility Criteria

We conducted a systematic review of all parallel randomized controlled trials (RCTs) examining the effect and duration of ketamine or esketamine on SI. Our primary outcome measure was the Suicide Scale score, which was measured using the Scale for Suicidal Ideation (SSI), Beck Scale for Suicide Ideation (BSS), Beck Depression Inventory (BDI), or Modified Scale for Suicidal Ideation (MSSI). To obtain effect sizes (Cohen's d), we calculated the difference in Suicide Scale scores before and after administration in each group.

Results

Our study showed that intravenous sub-anesthetic doses of ketamine and intranasal inhaled esketamine had a significant anti-SI effect. Specifically, ketamine produced a large degree of anti-SI effect within the 4-6 hours (Cohen's d = 1.16, 95% CI: 0.50, 1.81) and a medium-large degree in the 24 hours (Cohen's d = 0.95, 95% CI: 0.48, 1.41). Esketamine, on the other hand, produced a small-medium degree of anti-SI effect within the 4-6 hours timeframe (Cohen's d = 0.26, 95% CI: 0.09, 0.44) and the 24 hours (Cohen's d = 0.30, 95% CI: 0.17, 0.47).

Conclusion

Intravenous sub-anesthetic doses of ketamine and intranasal inhaled esketamine could reduce SI within 4 hours and last for 24 hours.

Gap between the Scientificization and Utilization of Korean Medicine for Depressive Disorder in South Korea with the Highest Suicide Rate among OECD Countries

In South Korea, with the highest suicide rate among Organization for Economic Co-operation and Development countries, doctors of both Korean medicine (KM) and Western medicine (WM) are licensed in the national healthcare system. The beneficial effects of complementary and integrative medicine, including KM, for depressive disorders, a major cause of suicide, have been reported in some clinical studies. Longitudinal change (2012-2021) of KM and WM use for depressive disorders and the attempts to scientificize KM in the context of depressive disorders were investigated. Specifically, clinical practice guidelines (CPGs) and national R&D projects of KM in the treatment of depressive disorders were investigated. The use of KM treatment for patients with a depressive disorder appears to be gradually decreasing in South Korea (annual number of patients in 2012 and 2021: 3607 and 2151 (-40.37%)), while the use of WM treatment is increasing (662,947 and 989,909 (+49.32%)). With the support of the government, KM CPG for depressive disorders and some R&D projects on KM for depressive disorders are being implemented. Our findings highlight the gap between the accumulation of clinical evidence, or the government's efforts to promote the evidence-based use of KM for depressive disorders, and its practical use in South Korea.

The effect of ketamine on cognition, anxiety, and social functioning in adults with psychiatric disorders: A systematic review and meta-analysis

Background

It has been shown that ketamine can improve suicidality and depression. Evidence for other dimensions of psychopathology is lacking. We undertook a systematic review to investigate the effect of ketamine on cognition, anxiety, quality of life, and social functioning in adults with psychiatric disorders.

Methods

PubMed (Medline), Scopus, PsycINFO, and EMBASE were searched up to April 2022. Randomized controlled trials (RCTs) on ketamine [or its S (+) enantiomer] reporting data on cognition, anxiety, quality of life, social functioning in adults with psychiatric disorders were included. Standardized mean difference (SMD) was used for summarizing continuous outcomes.

Results

Twenty-two reports were included in the final selection, of which 20, corresponding to 1,298 participants, were included in the quantitative synthesis. Affective disorders were the predominant diagnostic category. Median follow-up time was 21 days. The evidence was rated moderate to very low. In most trials, ketamine was administered intravenously or as adjuvant to electro-convulsant therapy (ECT). Only 2 trials of intranasal esketamine were identified. The effect of ketamine on depression was confirmed (SMD: -0.61 [95% CI: -1.06; -0.16]). Furthermore, by pooling results of 6 RCTs, ketamine may be effective in reducing anxiety symptoms (SMD: -0.42 [95% CI: -0.84; 0.003]), particularly when administered not within ECT (5 trials; SMD: -0.58 [95% CI: -1.07; -0.09]). However, there was moderate heterogeneity of results. Patients treated with ketamine also had an improvement in social functioning (SMD: -0.31 [95% CI: -0.52; -0.10]), although the estimate was based only on 2 studies. No difference to comparators was found with respect to cognition and quality of life.

Conclusion

Alongside the antidepressant effect, ketamine may also improve anxiety and social functioning in adults with affective disorders.

A century of research on psychedelics: A scientometric analysis on trends and knowledge maps of hallucinogens, entactogens, entheogens and dissociative drugs

A scientometric analysis was realized to outline clinical research on psychedelics over the last century. Web of Science Core Collection was searched up to March 18, 2022, for publications on psychedelics. Network analyses and bibliometrics were combined, to identify research themes and trends with Bibliometrix and CiteSpace. The primary aim was to measure research trends evolution over time, and the secondary aims were to identify bibliometric performance and influence networks of publications, authors, institutions, and countries. Sensitivity analyses were conducted for 2016-2022, and 2021 time periods. We included 31,687 documents (591,329 references), which aggregated into a well-structured network with credible clustering. Research productivity was split into an early less productive period mainly focusing on safety issues, and a "psychedelic renaissance" after the 1990s. Major trends were identified for hallucinogens/entheogens, entactogens, novel psychoactive substances (NPS), and on dissociative substances. There was a translational evolution from the bench to the bedside, with phase 2 and 3 trials and/or evidence synthesis in particular. The most recent trends concerned NPS, ketamine-associated brain changes, and ayahuasca-assisted psychotherapy. The USA and Canada were the most productive settings for the research overall, and more recently this geographical distribution became more prominent, reflecting legislative context/policy making. A translational evolution of psychedelics has been occurring, that has brought approval of esketamine for depression and will likely lead to approval of additional psychedelics across mental and physical conditions. Toxicology screening tools for NPS are urgently needed, which in turn might follow the same translational evolution of psychedelics in the future.

(Es)Ketamine for Suicidal Ideation and Behavior: Clinical Efficacy

Suicidal ideation and behavior are among the most severe psychiatric presentations, warranting emergency room visits and psychiatric admission for higher levels of care. In the United States, suicide rates continue to climb, especially in younger patients, and the continued psychosocial stressors of the COVID-19 pandemic may further exacerbate this crisis. Suicidal ideation and behavior are core features of a major depressive episode, but there are limited treatment options to rapidly redress these life-threatening symptoms. Racemic ketamine and its S-enantiomer, esketamine, are N-methyl-D-aspartate receptor antagonists and glutamate modulators that have robust antidepressant efficacy in treatment-resistant major depressive disorder and bipolar depression. Additionally, both ketamine and esketamine have demonstrated rapid-acting antisuicidal efficacy in major mood disorders. In August 2020, this culminated in a first-in-class approval of Spravato® (intranasal esketamine) for the treatment of major depressive disorder with acute suicidal ideation and behavior. In this article, we review the literature in support of the antisuicidal efficacy of ketamine and esketamine.

Real-world depression, anxiety and safety outcomes of intramuscular ketamine treatment: a retrospective descriptive cohort study

BACKGROUND

Ketamine has emerged as a promising pharmacotherapy for depression and other mental illnesses, and the intramuscular (IM) administration of ketamine is now offered at many North American outpatient psychiatric clinics. However, a characterization of the outpatient population receiving IM ketamine treatment and an evaluation of the real-world depression, anxiety, and safety outcomes of long-term psychiatric IM ketamine treatment has not been reported. This study aimed to evaluate the clinical characteristics, treatment patterns, clinical outcomes, and adverse events of patients receiving IM ketamine treatment.

METHODS

Patient data from the electronic health records of a private outpatient psychiatric clinic network in the United States were collected and analyzed retrospectively. Adults with any psychiatric diagnosis who received ketamine treatment only by IM administration from January 2018 to June 2021 were included. A total of 452 patients were included in the cohort.

RESULTS

Patients receiving IM ketamine treatment had a mean of 2.8 (SD 1.4) psychiatric diagnoses. 420 (93%) patients had a diagnosis of major depressive disorder, 243 (54%) patients had a diagnosis of generalized anxiety disorder, and 126 (28%) patients had a diagnosis of post-traumatic stress disorder. Patients received a median of 4 (range 1-48) IM ketamine treatments. Median depression scores (PHQ-9) improved 38% from 16.0 (IQR 11.3-21.8) at baseline to 10.0 (IQR 6.0-15.0) at last treatment (p < .001). Median anxiety scores (GAD-7) improved 50% from 14.0 (IQR 8.0-17.0) at baseline to 7.0 (IQR 4.3-11.8) at last treatment (p < .001). With maintenance ketamine treatments, average improvements in depression (PHQ-9) and anxiety (GAD-7) scores of at least 4.7 and 4.9 points were maintained for over 7 months. An adverse event occurred during 59 of 2532 treatments (2.3%).

CONCLUSIONS

IM ketamine is being utilized to treat psychiatric outpatients with multiple mental illnesses not limited to depression. Average depression and anxiety levels significantly improve throughout IM ketamine treatment and do not regress to baseline during patients' maintenance treatment phase. Prospective studies are recommended to confirm the long-term effectiveness and safety of IM ketamine.

Genetics and epigenetics of self-injurious thoughts and behaviors: Systematic review of the suicide literature and methodological considerations

Suicide is a multifaceted and poorly understood clinical outcome, and there is an urgent need to advance research on its phenomenology and etiology. Epidemiological studies have demonstrated that suicidal behavior is heritable, suggesting that genetic and epigenetic information may serve as biomarkers for suicide risk. Here we systematically review the literature on genetic and epigenetic alterations observed in phenotypes across the full range of self-injurious thoughts and behaviors (SITB). We included 577 studies focused on genome-wide and epigenome-wide associations, candidate genes (SNP and methylation), noncoding RNAs, and histones. Convergence of specific genes is limited across units of analysis, although pathway-based analyses do indicate nervous system development and function and immunity/inflammation as potential underlying mechanisms of SITB. We provide suggestions for future work on the genetic and epigenetic correlates of SITB with a specific focus on measurement issues.

Suicidal behavior-advances in clinical and neurobiological research and improvement of prevention strategies

Suicide is the 14^th leading cause of death worldwide. It is responsible for 1%-5% of all mortality. This article highlights the latest developments in universal, selective, and indicated prevention strategies. Concerning universal suicide prevention, current research has shown that strategies such as restricting access to lethal means (e.g., control of analgesics and hot-spots for suicide by jumping) and school-based awareness programs are most efficacious. Regarding selective prevention, substantial progress can be expected in psychological screening methods for suicidal behavior. The measurement of implicit cognition proved to be more valid in predicting future suicide attempts than classic clinical assessment. Latest developments are smartphone-based interventions and real-time monitoring of suicidal behavior. Great effort has been made to establish valid neurobiological screening methods (e.g., genetic and epigenetic risk factors for suicide, hypothalamic-pituitary-adrenal axis) without yielding a major bre-akthrough. Potentially, multiple biomarkers rather than a single one are necessary to identify individuals at risk. With regard to indicated prevention in form of psychopharmacological treatment, recent pharmacoepidemiological studies and meta-analyses have supported a protective role of antidepressants, lithium, and clozapine. However, the data concerning a specific anti-suicidal effect of these drugs are currently not consistent. Promising results exist for ketamine in reducing suicidal ideation, independently of its antidepressant effect. Concerning psychotherapy, recent findings suggest that psychotherapeutic interventions specifically designed to prevent suicide re-attempts are most efficacious. Specifically, cognitive behavioral therapy and psychodynamic therapy approaches proved to decrease the number of suicide re-attempts significantly.

Association of intranasal esketamine, a novel 'standard of care' treatment and outcomes in the management of patients with treatment-resistant depression: protocol of a prospective cohort observational study of naturalistic clinical practice

INTRODUCTION

Esketamine is the S-enantiomer of racemic ketamine and has been approved by the Food and Drug Administration for the management of treatment resistant depression, demonstrating effective and long-lasting benefits. The objective of this observational study is to elucidate the association of intranasal (IN) esketamine with beneficial and negative outcomes in the management of treatment resistant major depressive disorder.

METHODS AND ANALYSIS

This is a multicentre prospective cohort observational study of naturalistic clinical practice. We expect to recruit 10 patients per research centre (6 centres, total 60 subjects). After approval to receive IN esketamine as part of their standard of care management of moderate to severe treatment resistant depression, patients will be invited to participate in this study. Association of esketamine treatment with outcomes in the management of depression will be assessed by measuring the severity of depression symptoms using the Montgomery-Åsberg Depression Rating Scale (MADRS), and tolerability by systematically tracking common side effects of ketamine treatment, dissociation using the simplified 6-Item Clinician Administered Dissociative Symptom Scale and potential for abuse using the Likeability and Craving Questionnaire (LCQ). Change in depressive symptoms (MADRS total scores) over time will be evaluated by within-subject repeated measures analysis of variance. We will calculate the relative risk associated with the beneficial (reduction in total scores for depression) outcomes, and the side effect and dropout rates (tolerability) of adding IN esketamine to patients' current pharmacological treatments. Covariate analysis will assess the impact of site and demographic variables on treatment outcomes.

ETHICS AND DISSEMINATION

Approval to perform this study was obtained through the Health Sciences Research Ethics Board at Queen's University. Findings will be shared among collaborators, through departmental meetings, presented on different academic venues and publishing our manuscript.

New investigational agents for the treatment of major depressive disorder

INTRODUCTION

Pharmacotherapy of depression is characterized by the delayed onset of action, chronic treatment requirements, and insufficient effectiveness. Ketamine, with its rapid action and long-lasting effects, represents a breakthrough in the modern pharmacotherapy of depression.

AREAS COVERED

: The current review summarizes the latest findings on the mechanism of the antidepressant action of ketamine and its enantiomers and metabolites. Furthermore, the antidepressant potential of psychedelics, non-hallucinogenic serotonergic modulators and metabotropic glutamate receptor ligands was discussed.

EXPERT OPINION

Recent data indicated that to achieve fast and long-acting antidepressant-like effects, compounds must induce durable effects on the architecture and density of dendritic spines in brain regions engaged in mood regulation. Such mechanisms underlie the actions of ketamine and psychedelics. These compounds trigger hallucinations; however, it is thought that these effects might be essential for their antidepressant action. Behavioral studies with serotonergic modulators affecting 5-HT1A (biased agonists), 5-HT4 (agonists), and 5-HT-7 (antagonists) receptors exert rapid antidepressant-like activity, but they seem to be devoid of this effects. Another way to avoid psychomimetic effects and achieve the desired rapid antidepressant-like effects is combined therapy. In this respect, ligands of metabotropic receptors show some potential.

Pharmacological Strategies for Suicide Prevention Based on the Social Pain Model: A Scoping Review

Suicidal behaviour is a public health problem whose magnitude is both substantial and increasing. Since many individuals seek medical treatment following a suicide attempt, strategies aimed at reducing further attempts in this population are a valid and feasible secondary prevention approach. An evaluation of the available evidence suggests that existing treatment approaches have a limited efficacy in this setting, highlighting the need for innovative approaches to suicide prevention. Existing research on the neurobiology of social pain has highlighted the importance of this phenomenon as a risk factor for suicide, and has also yielded several attractive targets for pharmacological strategies that could reduce suicidality in patients with suicidal ideation or a recent attempt. In this paper, the evidence related to these targets is synthesized and critically evaluated. The way in which social pain is related to the “anti-suicidal” properties of recently approved treatments, such as ketamine and psilocybin, is examined. Such strategies may be effective for the short-term reduction in suicidal ideation and behaviour, particularly in cases where social pain is identified as a contributory factor. These pharmacological approaches may be effective regardless of the presence or absence of a specific psychiatric diagnosis, but they require careful evaluation.

Nitrous oxide for the treatment of psychiatric disorders: A systematic review of the clinical trial landscape

OBJECTIVE

To systematically review published research studies and ongoing clinical trials investigating nitrous oxide (N₂ O) in psychiatric disorders, providing an up-to-date snapshot of the clinical research landscape.

METHODS

A comprehensive literature search was conducted for studies published until June 2021 using the OVID databases (MEDLINE, Embase, APA PsycInfo) and the clinical trial registries (ClinicalTrials.gov, ICTRP).

RESULTS

In total, five relevant published articles were identified, among which four investigated N₂ O for depression. One single-dose randomized controlled trial (RCT) for treatment-resistant depression (TRD), one triple crossover RCT comparing 50% vs. 25% N₂ O for TRD, and one repeated-dose RCT for major depressive disorder (MDD) suggest that N₂ O has preliminary feasibility with rapid-acting effects on symptoms of depression. From the public registries, 10 relevant ongoing clinical trials were identified. They aim to explore the use of N₂ O for MDD, post-traumatic stress disorder, bipolar disorder, obsessive-compulsive disorder, and suicidal ideation. To date, the typical treatment protocol parameters were a single session of 50% N₂ O delivered for 60 min, although the concentration of 25% is also being explored. Projected enrolment numbers for ongoing trials (M = 55.0) were much higher than sample sizes for published studies (M = 13.0), suggesting that there potentially will be more large-scale RCTs published in the next few years.

CONCLUSION

Preliminary studies support the feasibility of administering N₂ O for depression; however, appropriate blinding is a critical challenge. Larger-scale RCTs with repeated doses of N₂ O and follow-up times beyond 1 month are needed to confirm the feasibility, therapeutic efficacy, and sustainability of response.

Single, Fixed-Dose Intranasal Ketamine for Alleviation of Acute Suicidal Ideation. An Emergency Department, Trans-Diagnostic Approach: A Randomized, Double-Blind, Placebo-Controlled, Proof-of-Concept Trial

BACKGROUND

Suicidal patients often present to the emergency department, where specific anti-suicidal treatment is lacking. Ketamine, a Glutamate modulator and a rapidly acting antidepressant with anti-suicidal properties, might offer relief.

AIMS

Evaluation of single, fixed-dosed intranasal ketamine for acute suicidal ideation in the emergency department.

METHODS

Between August 2016 and April 2018, 30 eligible suicidal subjects, scheduled for psychiatric hospitalization, independently of their psychiatric diagnosis, were randomized to intranasal ketamine 40 mg or saline placebo. Safety and efficacy evaluations were scheduled for 30, 60, 120 and 240 min post administration and on days 1, 2, 3, 4, 5, 7, 21 and 28. Primary outcome was suicidal ideation.

RESULTS

Fifteen subjects were randomized for each study group. All were analyzed for primary and secondary outcomes. Four hours post administration, the mean difference in suicidal symptoms between the groups, measured by the Montgomery-Åsberg Depression Rating Scale (MADRS) item of suicidal thoughts (MADRS-SI), was 1.267 (95% confident interval 0.1-2.43, p < 0.05) favoring treatment. Remission from suicidal ideation was evident in 80% for the ketamine group compared with 33% for the controls (p < 0.05). The mean difference in depressive symptoms, measured by MADRS, at the same time was 9.75 (95% confident interval 0.72-18.79, p < 0.05) favoring ketamine. Treatment was safe and well-tolerated.

CONCLUSIONS

Single, fixed-dose, intranasal ketamine alleviated suicidal ideation and improved depressive symptoms four hours post administration. We present here an innovative paradigm for emergency department management of suicidal individuals. Future larger-scale studies are warranted. ClinicalTrials.gov Identifier: NCT02183272.

Risk of self-harm or suicide associated with specific drug use disorders, 2004-2016: a population-based cohort study

BACKGROUND AND AIMS

Drug use disorders are associated with increased risk of self-harm. Risk differences associated with specific types of drug use disorders are yet to be comprehensively reported. This study aimed to examine the risk of self-harm or suicide associated with different drug use disorders in Hong Kong.

DESIGN

Population-based cohort study.

SETTING

The Clinical Data Analysis and Reporting System (CDARS) managed by the Hong Kong Hospital Authority.

PARTICIPANTS

Cases were people ages 10 years or older who visited a hospital Accident and Emergency department between 1 January, 2004 and 31 December, 2016 with any of 10 specific drug use disorders (comprising opioid; ketamine; methamphetamine; sedative, hypnotic, or anxiolytic; amphetamine or related stimulant; cocaine; cannabis; hallucinogen; unspecified or other drug; and polydrug). Each case was matched with two controls, selected from a subset of people in CDARS sharing the same gender, age and psychiatric profile. A total of 8270 cases and 16 540 matched controls were included.

MEASUREMENTS

Incidence and adjusted hazard ratio (aHR) of subsequent self-harm or suicide for each specific drug use disorder were estimated.

FINDINGS

The most prevalent drug use disorder was opioid use disorder (2523; 30.51%) and the least prevalent was hallucinogen use disorder (77; 0.93%). The crude incidence of self-harm or suicide ranged from 26.57 (95% CI, 14.23-44.55) per 1000 person-years for cannabis use disorder to 91.97 (77.32-108.37) for polydrug use disorder. The highest risk of self-harm or suicide was observed in ketamine (aHR, 16.36; 95% CI, 11.03-24.29) and opioid (15.97; 10.73-23.23) use disorders.

CONCLUSIONS

In Hong Kong, all types of drug use disorders appear to be significantly associated with increased risk of self-harm or suicide, but risk levels vary by type of drug use disorder.

Efficacy and safety of racemic ketamine and esketamine for depression: a systematic review and meta-analysis

BACKGROUND

Racemic ketamine and esketamine have demonstrated rapid antidepressant effects. We aimed to review the efficacy and safety of racemic and esketamine for depression.

RESEARCH DESIGN AND METHODS

We conducted a PRISMA-guided review for relevant randomized controlled trials of racemic or esketamine for unipolar or bipolar major depression from database inception through 2021. We conducted random-effects meta-analyses using pooled rate ratios (RRs) and Cohen's standardized mean differences (d) with their 95% confidence intervals (CI).

RESULTS

We found 36 studies (2903 participants, 57% female, 45.1 +/- 7.0 years). Nine trials used esketamine, while the rest used racemic ketamine. The overall study quality was high. Treatment with any form of ketamine was associated with improved response (RR=2.14; 95% CI, 1.72-2.66; I2=65%), remission (RR=1.64; 95% CI, 1.33-2.02; I2=39%), and depression severity (d=-0.63; 95% CI, -0.80 to -0.45; I2=78%) against placebo. Overall, there was no association between treatment with any form of ketamine and retention in treatment (RR=1.00; 95% CI, 0.99-1.01; I2<1%), dropouts due to adverse events (RR=1.56; 95% CI, 1.00-2.45; I2<1%), or the overall number of adverse events reported per participant (OR=2.14; 95% CI, 0.82-5.60; I2=62%) against placebo.

CONCLUSIONS

Ketamine and esketamine are effective, safe, and acceptable treatments for individuals living with depression.

Suicide and self-harm

Suicide and self-harm are major health and societal issues worldwide, but the greatest burden of both behaviours occurs in low-income and middle-income countries. Although rates of suicide are higher in male than in female individuals, self-harm is more common in female individuals. Rather than having a single cause, suicide and self-harm are the result of a complex interplay of several factors that occur throughout the life course, and vary by gender, age, ethnicity, and geography. Several clinical and public health interventions show promise, although our understanding of their effectiveness has largely originated from high-income countries. Attempting to predict suicide is unlikely to be helpful. Intervention and prevention must include both a clinical and community focus, and every health professional has a crucial part to play.

Key considerations for the use of ketamine and esketamine for the treatment of depression: focusing on administration, safety, and tolerability

INTRODUCTION

Racemic ketamine, a derivative of phencyclidine, has been used as a dissociative anesthetic since 1970. In 2000, the first randomized controlled trial showed a rapid relief of depressive symptoms. Since then, intravenous ketamine and intranasal S-ketamine have been validated for the treatment of depression and suicidal ideation following dose-response and double-blind placebo-controlled clinical trials. In clinical practice, after dose titration and with repeated treatments, patients may experience approximately 2-3 weeks of symptomatic relief from depression.

AREAS COVERED

Areas covered in this narrative review include mechanism of action, dosing, safety, and tolerability. Some attention is paid to the possibility of R-ketamine as a future antidepressant.

EXPERT OPINION

We recommend further investigation into treatment dosing and frequency strategies as well as approaches that prolong the therapeutic effects. The current fixed dosing of esketamine for obese individuals may be insufficient. Additional investigation into co-administration with somatic and neuromodulation treatments needs investigation. Finally, continuing to monitor research subjects and patients long-term for the emergence of adverse effects on cognition or other organ systems is critical.

Suicide versus Accidental Death by Autoerotic Asphyxiation in a Patient Receiving Intravenous Ketamine for Depression

Background. Clinical trials have demonstrated that subanesthetic intravenous ketamine exerts antidepressant effects lasting a week or longer postinfusion, as well as antisuicidal effects starting approximately 4 hours postinfusion and lasting 72 hours or longer. These findings have generated considerable enthusiasm within psychiatry. However, reports of treatment-emergent suicide attempts and completed suicides in some patients receiving ketamine or the ketamine enantiomer esketamine have begun to emerge. Here, we contribute to the small literature on suicide-related adverse events and ketamine with an unusual case of a patient who died either by suicide or accidental death via autoerotic asphyxiation approximately four days after a ketamine infusion. Case Presentation. The patient was a 28-year-old man with major depressive disorder, generalized anxiety disorder, panic disorder, obsessive compulsive disorder, autism spectrum disorder without intellectual disability, attention deficit hyperactivity disorder, hypothyroidism, low testosterone, and sleep apnea referred for management of treatment resistant depression. His depression briefly remitted with ketamine, and suicidality briefly disappeared. However, these improvements were short-lived. Four days after his seventh and final scheduled ketamine infusion, the patient was found dead, presumably due to autoerotic asphyxiation. Interestingly, ketamine use has been reported in association with autoerotic asphyxiation. However, given our patient’s recent severe suicidality, methods of his past suicide attempts, and family history of suicide, death from suicide seems more likely. Discussion. Here we consider the possibility of whether ketamine may have contributed to the patient’s possible suicide, either via a direct worsening of his suicidality or psychological withdrawal following cessation of treatment, given recent concerns about psychological withdrawal's potential role insuicides following esketamine treatment. Conclusions. Though we are uncertain about the patient’s cause of death, this case provides an opportunity to highlight important gaps in our understanding of the suicide-related risks of subanesthetic intravenous ketamine treatment for mood disorders and suicidality.

Ketamine for suicidality: an umbrella review

The urgent need for appropriate treatment for suicide, the tenth leading cause of death, has led to numerous studies. This study aims to systematically identify and appraise systematic reviews with or without meta-analyses investigating ketamine in suicidal ideation and behaviors. The study protocol was published in PROSPERO (CRD42021285320). Scopus, ISI, Embase, PubMed, CINAHL, PsycINFO, Cochrane Library, Google Scholar, and two registries were searched on October 29 without any restrictions for systematic reviews investigating the efficacy of ketamine on suicidal ideation and behaviors. The primary outcome was the final inference of ketamine effectiveness. A formal narrative synthesis was conducted, and the AMSTAR-2 tool was used to evaluate the quality of the studies. No funding was received. Of 27 studies that addressed ketamine for suicidal ideation, only four reported mixed or negative results, and out of nine reviews, esketamine was significantly beneficial only in five. A transient rise in pulse rate and blood pressure, dissociation, confusion, blurred vision, nausea, and vertigo were of the most common adverse effects; however, most were mild. More than two-thirds of the included studies qualified as low or critically low quality. Preliminary evidence for the short-term efficacy of ketamine in suicidality was noted by the majority of reviews; however, long-term effects remained unknown. Due to the non-high quality of many studies and the limitations of core studies, further studies are required.

mTORC1 inhibitor effects on rapid ketamine-induced reductions in suicidal ideation in patients with treatment-resistant depression

Suicide is a public health crisis with limited treatment options. Ketamine has demonstrated rapid and robust improvements in suicidal ideation (SI). The parent study for the secondary pilot analyses presented here was a double-blind, cross-over trial that found pretreatment with the mechanistic target of rapamycin complex 1 (mTORC1) prolonged the antidepressant effects of ketamine. Here we examined the effect of mTORC1 inhibition on ketamine's antisuicidal effects. Twenty patients in a major depressive episode were randomized to pretreatment with oral rapamycin (6 mg) or placebo prior to IV ketamine (0.5 mg/kg). We found ketamine administration resulted in significant improvements across all measures with the largest effect at 24 h with only the Beck Scale for Suicide remaining significant at the two-week follow-up. There were no significant main effects of pretreatment. While these analyses are pilot in nature and overall severity of SI was relatively low, the antisuicidal findings (no effect of rapamycin) being in contrast to the antidepressant effects (prolonged effect with rapamycin), suggest the rapid-acting antisuicidal and antidepressant effects of ketamine may be mechanistically distinct and the trajectories of response, recovery, and relapse may be independent. These findings provide additional evidence of ketamine's antisuicidal effects and highlight the importance of future studies that continue to examine potential differences in mechanisms and trajectory of outcomes.

Ketamine treatment for depression: a review

This manuscript reviews the clinical evidence regarding single-dose intravenous (IV) administration of the novel glutamatergic modulator racemic (R,S)-ketamine (hereafter referred to as ketamine) as well as its S-enantiomer, intranasal esketamine, for the treatment of major depressive disorder (MDD). Initial studies found that a single subanesthetic-dose IV ketamine infusion rapidly (within one day) improved depressive symptoms in individuals with MDD and bipolar depression, with antidepressant effects lasting three to seven days. In 2019, esketamine received FDA approval as an adjunctive treatment for treatment-resistant depression (TRD) in adults. Esketamine was approved under a risk evaluation and mitigation strategy (REMS) that requires administration under medical supervision. Both ketamine and esketamine are currently viable treatment options for TRD that offer the possibility of rapid symptom improvement. The manuscript also reviews ketamine's use in other psychiatric diagnoses-including suicidality, obsessive-compulsive disorder, post-traumatic stress disorder, substance abuse, and social anxiety disorder-and its potential adverse effects. Despite limited data, side effects for antidepressant-dose ketamine-including dissociative symptoms, hypertension, and confusion/agitation-appear to be tolerable and limited to around the time of treatment. Relatively little is known about ketamine's longer-term effects, including increased risks of abuse and/or dependence. Attempts to prolong ketamine's effects with combined therapy or a repeat-dose strategy are also reviewed, as are current guidelines for its clinical use. In addition to presenting a novel and valuable treatment option, studying ketamine also has the potential to transform our understanding of the mechanisms underlying mood disorders and the development of novel therapeutics.