Antisuicidal Response Following Ketamine Infusion Is Associated With Decreased Nighttime Wakefulness in Major Depressive Disorder and Bipolar Disorder

Functional changes in sleep-related arousal after ketamine administration in individuals with treatment-resistant depression

The glutamatergic modulator ketamine is associated with changes in sleep, depression, and suicidal ideation (SI). This study sought to evaluate differences in arousal-related sleep metrics between 36 individuals with treatment-resistant major depression (TRD) and 25 healthy volunteers (HVs). It also sought to determine whether ketamine normalizes arousal in individuals with TRD and whether ketamine's effects on arousal mediate its antidepressant and anti-SI effects. This was a secondary analysis of a biomarker-focused, randomized, double-blind, crossover trial of ketamine (0.5 mg/kg) compared to saline placebo. Polysomnography (PSG) studies were conducted one day before and one day after ketamine/placebo infusions. Sleep arousal was measured using spectral power functions over time including alpha (quiet wakefulness), beta (alert wakefulness), and delta (deep sleep) power, as well as macroarchitecture variables, including wakefulness after sleep onset (WASO), total sleep time (TST), rapid eye movement (REM) latency, and Post-Sleep Onset Sleep Efficiency (PSOSE). At baseline, diagnostic differences in sleep macroarchitecture included lower TST (p = 0.006) and shorter REM latency (p = 0.04) in the TRD versus HV group. Ketamine's temporal dynamic effects (relative to placebo) in TRD included increased delta power earlier in the night and increased alpha and delta power later in the night. However, there were no significant diagnostic differences in temporal patterns of alpha, beta, or delta power, no ketamine effects on sleep macroarchitecture arousal metrics, and no mediation effects of sleep variables on ketamine's antidepressant or anti-SI effects. These results highlight the role of sleep-related variables as part of the systemic neurobiological changes initiated after ketamine administration. Clinical Trials Identifier: NCT00088699.

The role of NMDA receptors in bipolar disorder: A systematic review

OBJECTIVES

Glutamatergic transmission and N-methyl-D-aspartate receptors (NMDARs) have been implicated in the pathophysiology schizophrenic spectrum and major depressive disorders. Less is known about the role of NMDARs in bipolar disorder (BD). The present systematic review aimed to investigate the role of NMDARs in BD, along with its possible neurobiological and clinical implications.

METHODS

We performed a computerized literature research on PubMed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, using the following string: (("Bipolar Disorder"[Mesh]) OR (manic-depressive disorder[Mesh]) OR ("BD") OR ("MDD")) AND ((NMDA [Mesh]) OR (N-methyl-D-aspartate) OR (NMDAR[Mesh]) OR (N-methyl-D-aspartate receptor)).

RESULTS

Genetic studies yield conflicting results, and the most studied candidate for an association with BD is the GRIN2B gene. Postmortem expression studies (in situ hybridization and autoradiographic and immunological studies) are also contradictory but suggest a reduced activity of NMDARs in the prefrontal, superior temporal cortex, anterior cingulate cortex, and hippocampus.

CONCLUSIONS

Glutamatergic transmission and NMDARs do not appear to be primarily involved in the pathophysiology of BD, but they might be linked to the severity and chronicity of the disorder. Disease progression could be associated with a long phase of enhanced glutamatergic transmission, with ensuing excitotoxicity and neuronal damage, resulting into a reduced density of functional NMDARs.

A comparative analysis of antidepressant and anti-suicidal effects of repeated ketamine infusions in elderly and younger adults with depression

OBJECTIVES

This study aims to investigate the differences in safety and antidepressant effects of multi-infusion ketamine treatment between elderly and young adults with depression.

METHODS

The safety, antidepressant, and anti-suicidal effects of multi-infusion ketamine were compared between 19 elderly (≥50 years) and 116 younger (<50 years) adults with depression; all were treated with six ketamine infusions (0.5 mg/kg). Montgomery-Åsberg Depression Rating Scale (MADRS) was used to measure the depressive symptoms, and suicidal ideation was measured with Beck Scale for Suicide Ideation (SSI)-part 1, Hamilton Rating Scale for Depression (HAMD) item 3, and (MADRS) item 10. Dissociative and psychotomimetic symptoms were evaluated based on the Clinician-Administered Dissociative States Scale (CADSS) and the Brief Psychiatric Rating Scale (BPRS)-four items.

RESULTS

Multi-Ketamine infusions resulted in a lower (trend) antidepressant response (37.1 % versus 57.8 %) and antidepressant remission (15.8 % versus 47.4 %) in elderly patients with depression compared with younger patients with depression (all ps > 0.05). Interestingly, elderly patients with depression had a higher MADRS score after six ketamine infusions compared with younger patients (p = 0.04). No significant differences in SSI-part 1 scores, HAMD item 3 scores, MADRS item 10 scores, CADSS scores, and BPRS-four items scores were found between the two groups at any assessment point (all ps > 0.05).

CONCLUSION

Our study shows that repeated-dose infusions of ketamine may be a feasible treatment strategy in elderly Chinese patients with depression; however, elderly patients with depression may be less responsive to ketamine compared with younger adults with depression.

Psychosocial predictors of persistent suicidal ideation among Chinese adolescents: A longitudinal study

BACKGROUND

Suicide is the fourth leading cause of death among adolescents. Studies have shown that persistent suicidal ideation has a more important effect on suicidal behavior. The objective of this study was to identify predictors of persistent suicidal ideation.

METHODS

Data were collected from 4225 Chinese middle and high school students. These adolescents were assessed for suicidal ideation at baseline and the second year. We used multinomial logistic regression (n = 4171) for the predictive effect of these factors on persistent suicidal ideation. We controlled for gender, residence, clinical diagnosis, clinical diagnosis family, suicide planning, and suicide attempts.

RESULTS

Depressive symptoms are essential in predicting persistent suicidal ideation (OR = 14.0; p < 0.001). Persistent suicidal ideation was predicted by sleep disorders, such as poor sleep quality (OR = 2.3; p = 0.008), difficulty falling asleep (OR = 2.4; p = 0.005), frequently midnight awakening (OR = 1.9; p = 0.044), and frequent nightmares (OR = 2.1; p = 0.040). There was a significant association between concern with persistent ideation and parental-peer alienation (OR for father, 1.9[p = 0.024]; OR for mother, 3.1[p < 0.001]; OR for peer, 2.3[p = 0.003]).

LIMITATIONS

All measures are based on self-report rather than objective assessment or clinical diagnostic assessment.

CONCLUSIONS

Persistent suicidal ideation had a more important role in influencing suicide planning and attempt. Interventions targeting sleep disorders and attention to attachments in the home and school are particularly important in preventing persistent suicidal ideation in adolescents.

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.

Antidepressant and anti-suicidal effects of ketamine in treatment-resistant depression associated with psychiatric and personality comorbidities: A double-blind randomized trial

OBJECTIVE

To evaluate the effects of ketamine treatment on depression and suicidal ideation in treatment resistant depression (TRD) and to determine whether they are influenced by other psychiatric and personality comorbidities.

METHODS

A randomized double-blind parallel-arm controlled study on 36 patients with TRD. Patients were divided into two treatment groups: ketamine (K group) and placebo (P group). Patients in the K and P groups received one infusion of medicine per week for two weeks. All participants were assessed using the Structured Interview for the Five-Factor Personality Model (SIFFM), Hamilton Depression Rating Scale (HDRS), Suicide Probability Scale (SPS), and Symptom Checklist 90 (SCL 90).

RESULTS

After treatment, there was a significant decrease in the total HDRS and SPS scores in the K group compared to the P group, but the magnitude of response was not influenced by the presence of other psychiatric symptoms. Regression model, only receive ketamine treatment was significant factor for improve suicide and depression scores.

LIMITATIONS

lack of data on other outcomes that are important to patients (e.g., quality of life, cognition) and need for a larger sample size.

CONCLUSIONS

Ketamine infusions in TRD reduce suicidal ideation and depression despite the presence other psychiatric and personality disorders.

Ketamine study: Protocol for naturalistic prospective multicenter study on subcutaneous ketamine infusion in depressed patients with active suicidal ideation

Background

Psychiatric disorders are associated with more than 90% of reported suicide attempts worldwide, but few treatments have demonstrated a direct effect in reducing suicide risk. Ketamine, originally an anesthetic, has been shown anti-suicide effects in clinical trials designed to treat depression. However, changes at the biochemical level were assessed only in protocols of ketamine with very limited sample sizes, particularly when the subcutaneous route was considered. In addition, the inflammatory changes associated with ketamine effects and their correlation with response to treatment, dose-effect, and suicide risk warrant further investigation. Therefore, we aimed to assess whether ketamine results in better control of suicidal ideation and/or behavior in patients with depressive episodes and whether ketamine affects psychopathology and inflammatory biomarkers.

Materials and methods

We report here the design of a naturalistic prospective multicenter study protocol of ketamine in depressive episodes carried out at Hospital de Clínicas de Porto Alegre (HCPA) and Hospital Moinhos de Vento (HMV). The study was planned to recruit adult patients with Major depressive disorder (MDD) or Bipolar disorder (BD) types 1 or 2, who are currently in a depressive episode and show symptoms of suicidal ideation and/or behavior according to the Columbia-Suicide Severity Rating Scale (C-SSRS) and have been prescribed ketamine by their assistant psychiatrist. Patients receive ketamine subcutaneously (SC) twice a week for 1 month, but the frequency can be changed or the dose decreased according to the assistant physician’s decision. After the last ketamine session, patients are followed-up via telephone once a month for up to 6 months. The data will be analyzed using repeated measures statistics to evaluate the reduction in suicide risk as a primary outcome, as per C-SSRS.

Discussion

We discuss the need for studies with longer follow-ups designed to measure a direct impact on suicide risk and that additional information about the safety and tolerability of ketamine in particular subset of patients such as those with depression and ideation suicide. In line, the mechanism behind the immunomodulatory effects of ketamine is still poorly understood.

Trial registration

https://clinicaltrials.gov/, identifier NCT05249309.

Insomnia and treatment-resistant depression

Depression and sleep disturbance are related closely with bidirectional relationship. The heterogenic diagnostic criteria of major depressive disorder composed by the myriad combination of symptoms including sleep disturbance. Insomnia is an identifiable risk factor for depression and the treatment of insomnia might be able to prevent subsequent major depressive episodes which draws psychiatrists' attention to the interface of psychiatry and sleep medicine field. It is important to identify occult sleep disturbance in patients with treatment-resistant depression to improve treatment outcome. New tools to objectively measure sleep at home environment represent a great march in clinical care and research modalities but need further validation before they can be applying widespread at sleep and depression intersection. Careful evaluation and measurement of the phenotype and nature of sleep disturbance will continue to advance understanding of the biological bases of psychiatric disorders and the connections with sleep.

Objective sleep markers of suicidal behaviors in patients with psychiatric disorders: A systematic review and meta-analysis

Close relationships have been reported between sleep alterations and suicidal behaviors, nevertheless few studies used objective measures of sleep. Such objective markers would be interesting in clinical practice to better screen and prevent suicide. We conducted a systematic review and meta-analysis of published studies examining the relationship between sleep markers and suicidal behaviors using PubMed, Cochrane Library, and Web of Science databases. Actigraphy, polysomnography, and nocturnal EEG were considered. The qualitative analysis retained 15 original studies, including 1179 participants (939 with a psychiatric disorder), and 11 studies were included for the meta-analysis. Current suicidal behaviors were associated with a decreased total sleep time (TST) (SMD = -0.35, [95% CI: -0.66 to -0.04], p = 0.026, I² = 39.8%). The evaluation of possible moderators shows that age, gender, and depression scores had no effects on the random effect model. No significant differences were observed regarding sleep efficiency, REM latency, or percentage of REM sleep. In conclusion, among candidate objective markers, decreased total sleep time seems associated with suicidal behaviors and could be easily used to assess suicide risk. Alterations of regular sleep duration should invite healthcare professionals to screen the cause and propose sleep interventions to prevent suicide.

Glial-Neuronal Interaction in Synapses: A Possible Mechanism of the Pathophysiology of Bipolar Disorder

Bipolar disorder (BD) is a severe and chronic psychiatric disorder that affects approximately 1-4% of the world population and is characterized by recurrent episodes of mania or hypomania and depression. BD is also associated with illnesses marked by immune activation, such as metabolic syndrome, obesity, type 2 diabetes mellitus, and cardiovascular diseases. Indeed, a connection has been suggested between neuroinflammation and peripheral inflammatory markers in the pathophysiology of BD, which can be associated with the modulation of many dysfunctional processes, including synaptic plasticity, neurotransmission, neurogenesis, neuronal survival, apoptosis, and even cognitive/behavioral functioning. Rising evidence suggests that synaptic dysregulations, especially glutamatergic system dysfunction, are directly involved in mood disorders. It is becoming clear that dysregulations in connection and structural changes of glial cells play a central role in the BD pathophysiology. This book chapter highlighted the latest findings that support the theory of synaptic dysfunction in BD, providing an overview of the alterations in neurotransmitters release, astrocytic uptake, and receptor signaling, as well as the role of inflammation on glial cells in mood disorders. Particular emphasis is given to the alterations in presynaptic and postsynaptic neurons and glial cells, all cellular elements of the "tripartite synapse," compromising the neurotransmitters system, excitatory-inhibitory balance, and neurotrophic states of local networks in mood disorders. Together, these studies provide a foundation of knowledge about the exact role of the glial-neuronal interaction in mood disorders.

Advances in the pathophysiology of bipolar disorder

PURPOSE OF REVIEW

Due to bipolar disorder clinical heterogeneity, a plethora of studies have provided new genetic, epigenetic, molecular, and cellular findings associated with its pathophysiology.

RECENT FINDINGS

Genome-wide association studies and epigenetic evidence points to genotype-phenotype interactions associated with inflammation, oxidative stress, abnormalities in signaling pathways, hypothalamic-pituitary-adrenal axis, and circadian rhythm linked to mitochondrial dysfunction in bipolar disorder. Although the literature is constantly increasing, most of the genetic variants proposed as biomarkers remain to be validated by independent groups and use bigger samples and longitudinal approaches to enhance their power and predictive ability.

SUMMARY

Regardless of which of the mechanisms described here plays a primary or secondary role in the pathophysiology of bipolar disorder, all of these interact to worsen clinical outcomes for patients. Identifying new biomarkers for early detection, prognosis, and response to treatment might provide novel targets to prevent progression and promote general well being.

Sex differences in ketamine's therapeutic effects for mood disorders: A systematic review

Replicated clinical trials have demonstrated rapid and robust antidepressant effects with ketamine in treatment resistant mood disorders. Sex (biological) and gender differences in therapeutic effects for any new intervention is an important consideration, however, the differential efficacy, safety and tolerability of ketamine in males versus females remains underexplored. The objective of the present systematic review is to identify and qualitatively synthesize all published clinical studies relevant to the sex differential effects of ketamine for mood disorders. A systematic search of PubMed, Medline, and PsycInfo from inception until January 20, 2021, yielded 27 reports including 1715 patients (742 males and 973 females) that met inclusion criteria. Results from the vast majority of studies (88.8%) do not support significant sex differences in antidepressant response, tolerability or safety of ketamine. Nine (33.3%) of the reports included a bioanalytical component in the analysis and only one reported on sex differences. Evidence from the present review does not support clinically or statistically significant sex differences in therapeutic effects with ketamine. Nevertheless, future studies should continue to consider sex and biological sex differences in study design and data analytic plans.

Effects of stress on endophenotypes of suicide across species: A role for ketamine in risk mitigation

Suicide is a leading cause of death and morbidity worldwide, yet few interventions are available to mitigate its risk. Barriers to effective treatments involve a limited understanding of factors that predict the onset of suicidal thoughts and behaviors. In the context of suicide risk, stress is a precipitating factor that is largely overlooked in the literature. Indeed, the pathophysiology of stress and suicide are heavily interconnected, underscoring the need to target the stress system in suicide prevention. In this review, we integrate findings from the preclinical and clinical literature that links stress and suicide. We focus specifically on the effects of stress on underlying biological functions and processes associated with suicide, allowing for the review of research using animal models. Owing to the rapid anti-suicidal effects of (R,S)-ketamine, we discuss its ability to modulate various stress-related endophenotypes of suicide, as well as its potential role in preventing suicide in those with a history of chronic life stress (e.g., early life adversity). We highlight future research directions that could advance our understanding of stress-related effects on suicide risk, advocating a dimensional, endophenotype approach to suicide research.

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Suicide and chronic stress pathophysiology are interconnected.

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Chronic stress has profound impacts on several endophenotypes of suicide.

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Animal and human research points to stress as a precipitating factor in suicide.

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Ketamine modulates specific biological processes associated with stress and suicide.

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Suicide research into endophenotypes can help inform risk-mitigation strategies.

Optimized Clinical Strategies for Treatment-Resistant Depression: Integrating Ketamine Protocols with Trauma- and Attachment-Informed Psychotherapy

Strategically timed trauma- and attachment-informed psychotherapy to address underlying emotional wounds, paired with ketamine administered in precision-calibrated doses to ensure high-entropy brain states, may be key to improving the quality and duration of ketamine’s therapeutic efficacy for treatment-resistant depression. This approach optimizes the opportunities for change created by ketamine’s known effects as a rapid antidepressant that stimulates synaptogenesis, normalizes neural connectivity and coherence, enhances neuroplasticity, reduces inflammation, and induces high-entropy brain states with associated subjective psychedelic experiences. Ketamine, a non-selective N-methyl-D-aspartate (NMDA) receptor antagonist is a safe, effective, fast-acting dissociative anesthetic that, as a standalone treatment, also exhibits rapid sustained antidepressant effects, even in many patients with treatment-resistant depression. A prior history of developmental trauma and attachment injuries are known primary factors in the etiology of treatment resistance in depression and other mental disorders. Thus, the adjunct of targeted psychotherapy attuned to trauma and attachment injuries may enhance and prolong ketamine efficacy and provide an opportunity for lasting therapeutic change. Psychotherapy engagement during repeated ketamine sessions for patient safety and integration of altered states, paired with separate individualized psychotherapy-only sessions timed 24–48 h post ketamine induction, takes advantage of peak ketamine-induced dendritic spine growth in the prefrontal cortex and limbic system, and normalized network connectivity across brain structures. This strategically timed paired-session approach also exploits the therapeutic potential created by precision-calibrated ketamine-linked high-entropy brain states and associated psychedelic experiences that are posited to disrupt overly rigid maladaptive thoughts, behaviors, and disturbing memories associated with treatment-resistant depression; paired sessions also support integration of the felt sense of happiness and connectivity associated with psychedelic experiences.

The Dynamic Relationship Between Alpha and Beta Power and Next-Day Suicidal Ideation in Individuals With Treatment-Resistant Depression

Background

Nocturnal wakefulness has emerged as a potential predictor of short-term suicide risk. This analysis used dynamic temporal patterns in alpha and beta power and global sleep metrics to explore the possible link between next-day suicidal ideation (NDSI) and wakefulness measures in unmedicated participants with treatment-resistant depression.

Methods

Thirty-three medication-free participants with treatment-resistant depression completed overnight polysomnography. Alpha and beta spectral power as functions over time were used to represent arousal-related components of the dynamic sleep process. A functional data analytic approach (multilevel functional principal component analysis [MFPCA]) was used to preserve the oscillatory nature of the data; MFPCA PC scores were then associated with NDSI. Associations between NDSI and polysomnography-defined wakefulness after sleep onset, sleep efficiency, and total sleep time were also evaluated.

Results

NDSI had the strongest relationship with the second beta PC score (slope = 0.09 [90% credible interval, 0.03 to 0.14]), which represented an oscillating pattern that reflected disturbed sleep. The first PCs from both alpha and beta MFPCAs represented the overall magnitude of power and were most closely associated with traditional polysomnography metrics but were not related to NDSI. Results were equivocal for wakefulness after sleep onset with NDSI and did not support a relationship between NDSI and either sleep efficiency or total sleep time, highlighting the value of information contained in oscillating electroencephalogram patterns for identifying physiological links between nocturnal wakefulness and NDSI.

Conclusions

This study leveraged the dynamic nature of wakefulness-related electroencephalogram frequencies and provides a potential electrophysiological link between suicidal ideation and wakefulness during sleep in individuals with treatment-resistant depression.

Plasma VEGF Concentrations and Ketamine's Effects on Suicidal Ideation in Depression With Suicidal Ideation

OBJECTIVES

Accumulating evidence supports a role for vascular endothelial growth factor (VEGF) in the pathogenesis of depression, but its relationship with the antisuicidal effects of ketamine is not clear. Our objective was to determine whether there was an association between the plasma VEGF (pVEGF) concentrations and the antisuicidal response to serial ketamine infusions.

METHODS

Six ketamine infusions (0.5 mg/kg) over a 12-day period were administered to sixty depressed individuals suffering from suicidal ideation. The Hamilton Depression Rating Scale (HAMD) suicide item, the Montgomery-Åsberg Depression Rating Scale (MADRS) suicide item, and the Beck Scale for Suicide Ideation (SSI-part I) were used to assess suicidal ideation at baseline, 1 day after the first infusion (day 1), 1 day following the last infusion (day 13), and again 2 weeks post-infusion (day 26). For this purpose, plasma was obtained at baseline, day 13 and 26.

RESULTS

The rates of antisuicidal response to ketamine were 61.7% (37/60), 81.7% (49/60), and 73.3% (44/60) at days 1, 13, and 26, respectively. The linear mixed model revealed significant time effects on suicidal ideation and pVEGF concentrations over time (all Ps < 0.05). Antisuicidal responders did not have significantly altered pVEGF concentrations compared with non-responders on day 13 and day 26 (all Ps > 0.05). No significant correlation was found between the baseline pVEGF concentration and suicidal ideation as measured by the SSI part 1, HAMD suicide item and MADRS suicide item on days 1, 13, and 26 (all ps > 0.05).

CONCLUSION

This preliminary finding does not support a role for VEGF in the antisuicidal effects of serial ketamine treatments in individuals with depression and suicidal ideation. Further research is needed to confirm and expand these findings.

Targeting inflammation in depression: Ketamine as an anti-inflammatory antidepressant in psychiatric emergency

Major depressive disorder (MDD) is a common psychiatric disorder with multifactorial aetiology and complex pathophysiology. Despite availability of various pharmacological and non-pharmacological therapeutic strategies, treatment resistant depression (TRD) remains a significant challenge with specific concern for those patients with severe depressive symptoms in particular suicidal ideations who require immediate and effective intervention. Inflammation has been widely studied for its association with MDD and treatment response. Ketamine known as a dissociative anaesthetic has a novel rapid-acting antidepressant effect at lower doses. Anti-inflammatory actions of ketamine appear to play a role in mechanisms underlying its antidepressant effects. Considering the rapid antidepressant action of ketamine, this review provides a brief overview of antidepressant properties of ketamine as well as its effects on peripheral and central inflammation to better understand the mechanisms underlying the therapeutic action of ketamine as an anti-inflammatory antidepressant target in psychiatric emergency. Development of effective medications, which act rapidly with dual effect on both inflammation and MDD would be of a significant clinical importance for a successful and personalised treatment of inflammatory-induced TRD and suicidal thoughts and behaviour.

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Anti-inflammatory actions of ketamine play a role in mechanisms underlying its antidepressant effects.

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Ketamine’s dual effect on inflammation and depression is particularly important in treatment of inflammatory-induced TRD and suicidal patients.

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Ketamine affects CNS receptors and pathways, neurotransmitter systems, synaptogenesis, and inflammatory responses.

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Ketamine remains a promising target for treatment of TRD and suicidal thoughts.

The Evolving Nexus of Sleep and Depression

Sleep disturbances and depression are closely linked and share a bidirectional relationship. These interconnections can inform the pathophysiology underlying each condition. Insomnia is an established and modifiable risk factor for depression, the treatment of which offers the critical opportunity to prevent major depressive episodes, a paradigm-shifting model for psychiatry. Identification of occult sleep disorders may also improve outcomes in treatment-resistant depression. Sleep alterations and manipulations may additionally clarify the mechanisms that underlie rapid-acting antidepressant therapies. Both sleep disturbance and depression are heterogeneous processes, and evolving standards in psychiatric research that consider the transdiagnostic components of each are more likely to lead to translational progress at their nexus. Emerging tools to objectively quantify sleep and its disturbances in the home environment offer great potential to advance clinical care and research, but nascent technologies require further advances and validation prior to widespread application at the interface of sleep and depression.

A wake-up call: Sleep physiology and related translational discrepancies in studies of rapid-acting antidepressants

Depression is frequently associated with sleep problems, and clinical improvement often coincides with the normalization of sleep architecture and realignment of circadian rhythm. The effectiveness of treatments targeting sleep in depressed patients, such as sleep deprivation, further demonstrates the confluence of sleep and mood. Moreover, recent studies showing that the rapid-acting antidepressant ketamine influences processes related to sleep-wake neurobiology have led to novel hypotheses explaining rapid and sustained antidepressant effects. Despite the available evidence, studies addressing ketamine’s antidepressant effects have focused on pharmacology and often overlooked the role of physiology. To explore this discrepancy in research on rapid-acting antidepressants, we examined articles published between 2009–2019. A keyword search algorithm indicated that vast majority of the articles completely ignored sleep. Out of the 100 most frequently cited preclinical and clinical research papers, 89 % and 71 %, respectively, did not mention sleep at all. Furthermore, only a handful of these articles disclosed key experimental variables, such as the times of treatment administration or behavioral testing, let alone considered the potential association between these variables and experimental observations. Notably, in preclinical studies, treatments were preferentially administered during the inactive period, which is the polar opposite of clinical practice and research. We discuss the potential impact of this practice on the results in the field. Our hope is that this perspective will serve as a wake-up call to (re)-examine rapid-acting antidepressant effects with more appreciation for the role of sleep and chronobiology.

When reason sleeps: attempted suicide during the circadian night

None

Disrupted sleep and nocturnal wakefulness are evidence-based risk factors for suicidal thoughts and behaviors. We present a suicide attempt following a rapid increase in nocturnal wakefulness. This case illustrates how nocturnal wakefulness may drive suicide risk through circadian misalignment.

Repurposing Ketamine in Depression and Related Disorders: Can This Enigmatic Drug Achieve Success?

Repurposing ketamine in the therapy of depression could well represent a breakthrough in understanding the etiology of depression. Ketamine was originally used as an anesthetic drug and later its use was extended to other therapeutic applications such as analgesia and the treatment of addiction. At the same time, the abuse of ketamine as a recreational drug has generated a concern for its psychotropic and potential long-term effects; nevertheless, its use as a fast acting antidepressant in treatment-resistant patients has boosted the interest in the mechanism of action both in psychiatry and in the wider area of neuroscience. This article provides a comprehensive overview of the actions of ketamine and intends to cover: (i) the evaluation of its clinical use in the treatment of depression and suicidal behavior; (ii) the potential use of ketamine in pediatrics; (iii) a description of its mechanism of action; (iv) the involvement of specific brain areas in producing antidepressant effects; (v) the potential interaction of ketamine with the hypothalamic-pituitary-adrenal axis; (vi) the effect of ketamine on neuronal transmission in the bed nucleus of stria terminalis and on its output; (vii) the evaluation of any gender-dependent effects of ketamine; (viii) the interaction of ketamine with the inflammatory processes involved in depression; (ix) the evaluation of the effects observed with single or repeated administration; (x) a description of any adverse or cognitive effects and its abuse potential. Finally, this review attempts to assess whether ketamine's use in depression can improve our knowledge of the etiopathology of depression and whether its therapeutic effect can be considered an actual cure for depression rather than a therapy merely aimed to control the symptoms of depression.

Advances in the psychopharmacotherapy of bipolar disorder type I

INTRODUCTION

Research into the pharmacologic management of bipolar type I illness continues to progress.

AREAS COVERED

Randomized clinical trials performed with type I bipolar disorder in the years 2015 to August 2020 are reviewed. There are new indications for the use of cariprazine, for bipolar mania and depression, and a long-acting injectable formulation of aripiprazole has also been approved for relapse prevention in bipolar illness. Most of the randomized clinical trials are effectiveness studies.

EXPERT OPINION

Over the 20 years from 1997 through 2016, the use of lithium and other mood stabilizers has declined by 50%, while the use of both second-generation antipsychotics (SGAs) and antidepressants has increased considerably. Over the same time period (1990-2017), disability-adjusted life years (DALYs) increased by 54.4%, from 6.02 million in 1990 to 9.29 million in 2017 which is greater than the 47.74% increase in incidence of the disease, suggesting that the changes in prescribing patterns have not been helpful for our patients. Furthermore, recent effectiveness studies continue to confirm the superiority of lithium and other mood stabilizers in the management of bipolar illness for both psychiatric and medical outcomes, reaffirming their role as foundational treatments in the management of type I bipolar disorder. Clinicians need to reassess their prescribing habits.

Clinical trials for rapid changes in suicidal ideation: Lessons from ketamine

Rapid-acting treatments for suicidal thoughts are critically needed. Consequently, there is a burgeoning literature exploring psychotherapeutic, pharmacologic, or device-based brief interventions for suicidal thoughts characterized by a rapid onset of action. Not only do these innovative treatments have potentially important clinical benefits to patient populations, they also highlight a number of methodological considerations for suicide research. First, while most clinical trials related to suicide risk focus on suicide attempts, new clinical trials that use suicidal thoughts as the primary outcome require a number of slight modifications to their clinical trial design. Second, the rapid onset of these new interventions permits an experimental therapeutics approach to suicide research, in which psychological and neurobiological markers are embedded into clinical trials to better understand the underlying pathophysiology of suicidal thoughts. The following review discusses these methodological innovations in light of recent research using the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine, which has been associated with rapid effects on suicidal thoughts. We hope that "lessons learned" from the ketamine literature will provide a blueprint for all researchers evaluating rapid-acting treatments for suicidal thoughts, whether pharmacologic or psychotherapeutic.

Chronic lithium exposure attenuates ketamine-induced mania-like behavior and c-Fos expression in the forebrain of mice

Ketamine, a dissociative anaesthetic, has been used in the treatment of major depressive disorder (MDD) as a rapid acting antidepressant drug. Recent studies have shown that ketamine may increase the potential risk of treatment-induced mania in MDD patients. Lithium is a well-known mood stabilizer and has been widely used for the treatment of mania. It is not fully understood which forebrain regions are involved in ketamine- and lithium-induced expression of c-Fos. Therefore, our aim was to investigate the effect of chronic lithium treatment on mania-like behavior and c-Fos expression in the mouse forebrain activated by a single administration of ketamine. In the open field test, our results showed that ketamine significantly increased the total distance and total cumulative duration of movement in mice, while chronic lithium could attenuate these effects of ketamine. In addition, acute ketamine induced higher c-Fos expression in the lateral septal nucleus, hypothalamus, amygdala, and hippocampus of mice in the treatment group compared to those in the control group. However, chronic lithium inhibited the significant increase in c-Fos-immunoreactive neurons following acute ketamine administration in the dentate gyrus of the hippocampus, field CA1 of the hippocampus, dorsal subiculum, ventral subiculum, ventral subiculum, central amygdaloid nucleus and basolateral amygdaloid nucleus. In summary, our research shows that pretreatment with lithium moderates the effects of acute ketamine administration on mania-like behavior and c-Fos expression in the forebrain. These findings could be helpful in better understanding the episodes of mania related to ketamine treatment for MDD and bipolar disorder.

An Integrative Approach to Ketamine Therapy May Enhance Multiple Dimensions of Efficacy: Improving Therapeutic Outcomes With Treatment Resistant Depression

Research over the last two decades has established ketamine as a safe, effective, fast-acting, and sustained antidepressant that significantly reduces adverse symptoms associated with depression, even in patients who are treatment resistant. Much of this research has evolved within the framework of several independent branches of scientific inquiry: in addition to the study of ketamine is a non-selective NMDAR antagonist with rapid antidepressant effects, it has also been found effective as a psychoplastogen that stimulates synaptogenesis and increases neuroplasticity, as a powerful anti-inflammatory that may improve inflammation-related depressive symptoms, as a substance that induces beneficial high entropy brain states, and as a subjectively impactful psychedelic agent. Each branch of inquiry has generated independent evidence of ketamine's efficacy but has advanced without substantive coordination or communication with other lines of inquiry. Integrative research that considers these branches of research together may lead toward a better understanding of ketamine's effects and improved treatment protocols and clinical outcomes. Such an overview can inform more comprehensive patient care through: (a) informed patient psychoeducation that encompasses all of ketamine's mechanisms of action; (b) calibration of optimal dosage to ensure induction and maintenance of high entropy brain states during each ketamine session utilizing EEG measurement; (c) Improved management of emergence side effects through proper care for set and setting; (d) inclusion of pre-selected appropriate music to enhance the emotional experience; (e) increased monitoring of ketamine effects on cortical activity, inter-hemispheric imbalance, and inflammation-related levels of cytokines to further improvements in ketamine protocols; and (f) appropriate timing of any adjunctive psychotherapy sessions to coincide with peak neurogenesis at 24-48 h post ketamine treatment.

Sleep and suicide: A systematic review and meta-analysis of longitudinal studies

The current review provides a quantitative synthesis of the empirical literature on sleep disturbance as a risk factor for suicidal thoughts and behaviors (STBs). A systematic search of PsycINFO, MEDLINE, and the references of prior reviews resulted in 41 eligible studies included in this meta-analysis. Sleep disturbance, including insomnia, prospectively predicted STBs, yielding small-to-medium to medium effect sizes for these associations. Complicating interpretation of these findings however, is that few studies of suicidal ideation and suicide attempts, as well as none of suicide deaths, assessed short-term risk (i.e., employed follow-up assessments of under a month). Such studies are needed to evaluate current conceptualizations of sleep dysregulation as being involved in acute risk for suicidal behavior. This want of short-term risk studies also suggests that current clinical recommendations to monitor sleep as a potential warning sign of suicide risk has a relatively modest empirical basis, being largely driven by cross-sectional or retrospective research. The current review ends with recommendations for generating future research on short-term risk and greater differentiation between acute and chronic aspects of sleep disturbance, and by providing a model of how sleep disturbance may confer risk for STBs through neuroinflammatory and stress processes and associated impairments in executive control.

Neurobiological biomarkers of response to ketamine

As a field, psychiatry is undergoing an exciting paradigm shift toward early identification and intervention that will likely minimize both the burden associated with severe mental illnesses as well as their duration. In this context, the rapid-acting antidepressant ketamine has revolutionized our understanding of antidepressant response and greatly expanded the pharmacologic armamentarium for treatment-resistant depression. Efforts to characterize biomarkers of ketamine response support a growing emphasis on early identification, which would allow clinicians to identify biologically enriched subgroups with treatment-resistant depression who are more likely to benefit from ketamine therapy. This chapter presents a broad overview of a range of translational biomarkers, including those drawn from imaging and electrophysiological studies, sleep and circadian rhythms, and HPA axis/endocrine function as well as metabolic, immune, (epi)genetic, and neurotrophic biomarkers related to ketamine response. Ketamine's unique, rapid-acting properties may serve as a model to explore a whole new class of novel rapid-acting treatments with the potential to revolutionize drug development and discovery. However, it should be noted that although several of the biomarkers reviewed here provide promising insights into ketamine's mechanism of action, most studies have focused on acute rather than longer-term antidepressant effects and, at present, none of the biomarkers are ready for clinical use.

Baseline insomnia as a predictor of antidepressant efficacy to repeated intravenous ketamine for unipolar and bipolar depression: A preliminary study

OBJECTIVE

Ketamine has been demonstrated to have robust and rapid antidepressant effects, and few studies have focused on the relationship between insomnia and the efficacy of ketamine. The objective of this study was to examine whether baseline insomnia predicted the antidepressant efficacy of repeated intravenous ketamine infusions for unipolar and bipolar depression.

METHOD

Patients with high insomnia (n = 64) or low insomnia (n = 68) received six intravenous infusions of ketamine (0.5 mg/kg over 40 min) over 12 days (Monday-Wednesday-Friday). The Montgomery-Asberg Depression Rating Scale (MADRS) without sleep item was used to assess depressive symptoms. Response was defined as a MADRS total score ≥ 50%, and remission was defined as a MADRS total score ≤ 10.

RESULT

There were no differences in response or remission rates between patients with high and low insomnia. However, the logistic regression model showed that high insomnia predicted an increased likelihood of response and remission. Cox proportional hazards models showed a reduced latency to respond and remit in patients with high insomnia. A linear mixed model showed that the high insomnia subgroup had greater improvement than the low insomnia subgroup (all p < 0.05).

LIMITATION

The major limitation of this study is the open-label design.

CONCLUSION

When given six ketamine infusions, patients with high insomnia were more likely to respond and remit than those with low insomnia. Patients with high insomnia showed not only a shorter latency to respond and remit, but also greater improvement than those with low insomnia.

Ecological Studies of Sleep Disturbances During Suicidal Crises

PURPOSE OF REVIEW

Several reviews and metanalyses have shown that sleep disturbances, such as insomnia and nightmares, can predict suicidal ideations and behaviors. Common physio-pathological pathways may explain this relationship. However, only in recent years, some research groups have tried to apply this knowledge in the quest for a reliable tool of suicide risk prediction. We aim to describe in this paper the results of studies using ecological or quasi-ecological assessment methods that connect sleep disturbances and suicide risk.

RECENT FINDINGS

Our review confirms the paucity of studies on this topic. The few studies that we could analyze suggest the interest of ecological methods of sleep assessment since sleep disturbances predicted the onset or worsening of suicidal ideations and behaviors. Ecological assessment of sleep can help to understand how sleep disturbances contribute to the emergence of suicidal ideations and behaviors. Sleep disturbances appear as a promising "real-life" marker of risk, but further studies are needed to determine if sleep monitoring could guide preventive interventions.

Ketamine as an antidepressant: overview of its mechanisms of action and potential predictive biomarkers

Ketamine, a drug introduced in the 1960s as an anesthetic agent and still used for that purpose, has garnered marked interest over the past two decades as an emerging treatment for major depressive disorder. With increasing evidence of its efficacy in treatment-resistant depression and its potential anti-suicidal action, a great deal of investigation has been conducted on elucidating ketamine's effects on the brain. Of particular interest and therapeutic potential is the ability of ketamine to exert rapid antidepressant properties as early as several hours after administration. This is in stark contrast to the delayed effects observed with traditional antidepressants, often requiring several weeks of therapy for a clinical response. Furthermore, ketamine appears to have a unique mechanism of action involving glutamate modulation via actions at the N-methyl-D-aspartate (NMDA) and α -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, as well as downstream activation of brain-derived neurotrophic factor (BDNF) and mechanistic target of rapamycin (mTOR) signaling pathways to potentiate synaptic plasticity. This paper provides a brief overview of ketamine with regard to pharmacology/pharmacokinetics, toxicology, the current state of clinical trials on depression, postulated antidepressant mechanisms and potential biomarkers (biochemical, inflammatory, metabolic, neuroimaging sleep-related and cognitive) for predicting response to and/or monitoring of therapeutic outcome with ketamine.

Single and repeated ketamine infusions for reduction of suicidal ideation in treatment-resistant depression

Repeated administration of subanesthetic intravenous ketamine may prolong the rapid decrease in suicidal ideation (SI) elicited by single infusions. The purpose of this secondary analysis was to evaluate reduction in SI with a single ketamine infusion compared with an active control, and prolonged suppression of SI with repeated and maintenance infusions. Thirty-seven participants with treatment-resistant depression (TRD) and baseline SI first received a single ketamine infusion during a randomized, double-blind crossover with midazolam. Following relapse of depressive symptoms, participants received six open-label ketamine infusions administered thrice-weekly over 2 weeks. Antidepressant responders (≥50% decrease in Montgomery-Åsberg Depression Rating Scale [MADRS] scores) received four further open-label infusions administered once-weekly. Changes in SI were assessed with the suicide items on the MADRS (item 10, MADRS-SI) and the Quick Inventory of Depressive Symptomatology-Self Report (item 12, QIDS-SI). Linear mixed models revealed that compared with midazolam, a single ketamine infusion elicited larger reduction in SI (P = 0.01), with maximal effects measured at 7 days postinfusion (P < 0.001, Cohen's d = 0.83). Participants had cumulative reductions in MADRS-SI scores with repeated infusions (P < 0.001), and no further change with maintenance infusions (P = 0.94). QIDS-SI results were consistent with MADRS-SI. Overall, 69% of participants had a complete alleviation of SI following repeated infusions. In TRD, single and repeated ketamine infusions resulted in decreases in SI which were maintained with once-weekly maintenance infusions. This study adds to the growing body of research suggesting ketamine as a possible novel treatment strategy for SI in mood disorders.

Ketamine Alleviates Postoperative Depression-Like Symptoms in Susceptible Mice: The Role of BDNF-TrkB Signaling

Patients are more likely to suffer from central nervous system (CNS) complications after anesthesia and surgery. However, postoperative depression (POD) has not yet received sufficient attentions, and its pathogenesis and therapeutic strategies remain poorly understood. We here aimed to investigate whether brain derived neurotrophic factor (BDNF)-tropomyosin-related kinase B (TrkB) signaling plays an important role in POD. BDNF-TrkB signaling was altered in brain and peripheral tissues, including medial prefrontal cortex (mPFC), hippocampus, liver, and muscle, among control, POD susceptible, and resilient groups. Additionally, we demonstrated that 7,8-dihydroxyflavone (7,8-DHF), a TrkB agonist, could exert its pharmacologic property to alleviate POD-like symptoms. More importantly, ketamine, a non-competitive N-methyl-D-aspartic acid (NMDA) receptor antagonist, also has significant antidepressant effects in POD model, associating with the improving effects on levels of BDNF-TrkB signaling in brain and peripheral tissues. Interestingly, the beneficial effects of ketamine on POD-like symptoms are fully attenuated by a TrkB antagonist. These findings suggest that abnormal expressions of BDNF-TrkB signaling in brain and peripheral tissues are implicated in the pathogenesis of POD, and that therapeutic agents targeting BDNF-TrkB, particularly ketamine, could favor the beneficial effects for POD.

Association between plasma levels of BDNF and the antisuicidal effects of repeated ketamine infusions in depression with suicidal ideation

BACKGROUND

This study is the first to examine the association between plasma levels of brain-derived neurotrophic factor (BDNF) and the antisuicidal effects of repeated ketamine infusions in depressed patients with suicidal ideation.

METHODS

Fifty-seven depressed patients with suicidal ideation received six ketamine infusions (0.5 mg/kg) during a 12 days period. Suicidality was measured with the Scale for Suicidal Ideations (SSI-part 1), item 10 of the Montgomery-Åsberg Depression Rating Scale (MADRS), and item 3 of the Hamilton Depression Rating Scale (HAMD) at baseline, 1 day after the first infusion (1 day), 1 day after the sixth infusion (13 days), and at 2 weeks after the last infusion (26 days). Plasma levels of BDNF were measured by enzyme-linked immunosorbent assay at baseline, 13 days, and 26 days.

RESULTS

Overall, 46 (80.7%) depressed patients with suicidal ideation had an antisuicidal response at 13 days. Despite a significant reduction in suicidal symptoms over time, no changes in plasma levels of BDNF were found after ketamine treatment when compared with baseline. Correlation analysis showed that no significant association was observed between the plasma levels of BDNF and the changes in the severity of suicidal symptoms as measured by SSI-part 1, item 10 of the MADRS, or item 3 of the HAMD at 1 day, 13 days, and 26 days (all p < 0.05).

CONCLUSION

Our results indicated that plasma levels of BDNF may not serve as a biomarker for determining the antisuicidal effects of six ketamine infusions in depressed patients with suicidal ideation.

Suicide Has Many Faces, So Does Ketamine: a Narrative Review on Ketamine's Antisuicidal Actions

PURPOSE OF REVIEW

Suicidal behaviours are a challenge for a medical system and public health, partly due to the current lack of evidence-based, effective, rapid tools for suicidal crisis management. Ketamine and its enantiomer esketamine have raised hopes regarding this issue in the recent years. However, their efficacy in suicidal behaviours and mechanisms for it remain a topic of debate.

RECENT FINDINGS

Subanesthetic ketamine doses rapidly, albeit transiently decrease suicidal ideation, with effects emerging within an hour and persisting up to a week. Current evidence points to various and not necessarily exclusive mechanisms for ketamine's antisuicidal action, including effects on neuroplasticity, inflammation, reward system and pain processing. Ketamine rapidly decreases suicidal ideation, but whether it leads to meaningful clinical outcomes past 1 week is unclear. Multiple putative mechanisms drive ketamine's antisuicidal action. Future studies will have to show long-term ketamine treatment outcomes and further elucidate its mechanisms of action.

Infusing hope into the treatment of suicidality: A review of ketamine's effects on suicidality

PURPOSE OF REVIEW

Given recent increases in rates of suicide and lack of rapid treatments for suicidality, ketamine has been identified as a potential fast-acting anti-suicidal treatment. Our review seeks to describe the effects of ketamine on suicidality, given the growing literature on the use of ketamine in reducing suicidality. We examine open-label studies and randomized controlled trials evaluating treatment of suicidality with ketamine. Furthermore, our manuscript identifies potential mechanisms of ketamine's effects on suicidality.

RECENT FINDINGS

Based on existing RCTs, ketamine appears to have rapid anti-suicidal effects, with most literature studying such effects in timeframes less than one week. Although still in the early stages of research, mechanisms of ketamine include modulation of molecular, inflammatory, neural, cognitive, and behavioral processes.

SUMMARY

Thus, ketamine appears to be a promising treatment for suicidality, but requires larger scale and more robust RCTs to confirm the potential use of this agent in clinical settings.

Suicide and suicide risk

Although recent years have seen large decreases in the overall global rate of suicide fatalities, this trend is not reflected everywhere. Suicide and suicidal behaviour continue to present key challenges for public policy and health services, with increasing suicide deaths in some countries such as the USA. The development of suicide risk is complex, involving contributions from biological (including genetics), psychological (such as certain personality traits), clinical (such as comorbid psychiatric illness), social and environmental factors. The involvement of multiple risk factors in conveying risk of suicide means that determining an individual's risk of suicide is challenging. Improving risk assessment, for example, by using computer testing and genetic screening, is an area of ongoing research. Prevention is key to reduce the number of suicide deaths and prevention efforts include universal, selective and indicated interventions, although these interventions are often delivered in combination. These interventions, combined with psychological (such as cognitive behavioural therapy, caring contacts and safety planning) and pharmacological treatments (for example, clozapine and ketamine) along with coordinated social and public health initiatives, should continue to improve the management of individuals who are suicidal and decrease suicide-associated morbidity.

Glutamatergic Modulators in Depression

LEARNING OBJECTIVE

After participating in this activity, learners should be better able to evaluate the evidence supporting the antidepressant effects of glutamatergic modulators.Both preclinical and clinical studies have implicated glutamatergic system dysfunction in the pathophysiology of mood disorders such as bipolar depression and major depressive disorder. In particular, rapid reductions in depressive symptoms have been noted in response to subanesthetic doses of the glutamatergic modulator ketamine in subjects with major depressive disorder or bipolar depression. These results have prompted the repurposing or development of other glutamatergic modulators, both as monotherapy or adjunctive to other therapies. Here, we highlight the evidence supporting the antidepressant effects of various glutamatergic modulators, including (1) broad glutamatergic modulators (ketamine, esketamine, dextromethorphan, dextromethorphan-quinidine [Nuedexta], AVP-786, nitrous oxide [N2O], AZD6765), (2) subunit (NR2B)-specific N-methyl-D-aspartate (NMDA) receptor antagonists (CP-101,606/traxoprodil, MK-0657 [CERC-301]), (3) glycine-site partial agonists (D-cycloserine, GLYX-13, sarcosine, AV-101), and (4) metabotropic glutamate receptor modulators (AZD2066, RO4917523/basimglurant, JNJ40411813/ADX71149, R04995819 [RG1578]).

A preliminary study of anti-suicidal efficacy of repeated ketamine infusions in depression with suicidal ideation

BACKGROUND

Suicide is a tremendous public health crisis and is demanded urgent intervention. Previous studies found that ketamine intervention could rapidly reduce suicidal ideation in depression. However, the comparatively study in Chinese population remains absence. The current study aims to assess the anti-suicidal efficacy of repeated ketamine infusions for Chinese depressed suicidal patients, especially distinguish between low suicidal ideation (SI) group and high SI group.

METHODS

Eighty-six unipolar and bipolar depressive patients with current suicidal ideation received six ketamine infusions during a 12-day period. Hamilton Depression Rating Scale (HAMD) and Beck Scale for Suicide Ideation (SSI) was measured at baseline, 4 h and 24 h after each infusion, and two-week naturalistically follow-up.

RESULTS

Forty-nine (57.0%) patients relief of suicidal ideation after first infusion and 56 (65.1%) after six infusions. Anti-suicidal response rate in low SI group were higher than high SI group, and anti-suicidal response at 4 h after first infusion was significant predictor of response at 24 h after sixth infusion. Furthermore, at 24 h after the sixth infusion, correlation between changes in suicidal ideation and depression was 0.23, accounting for 7.4% in the variance of suicidal ideation change.

LIMITATION

The major limitation of this study was that lack of a placebo or other control group limits the interpretation of efficacy.

CONCLUSIONS

We confirmed that six repeated ketamine infusions for Chinese suicidal depressed patients were effective in generating a rapid response of suicidal ideation, especially low SI achieved more benefits from ketamine infusions.

Neurocognitive performance and repeated-dose intravenous ketamine in major depressive disorder

OBJECTIVE

Ketamine has demonstrated a rapid antidepressant and antisuicidal effect in patients with major depressive disorder (MDD), but the neurocognitive effects of ketamine are relatively unknown. This study aims to examine the neurocognitive effects of six ketamine infusions and the association of baseline neurocognitive function and the change in severity of depressive symptoms after the last infusions.

METHODS

Sixty-four patients with MDD completed six intravenous infusions of ketamine (0.5 mg/kg over 40 min) administered over a 12-day period (Monday-Wednesday-Friday), and were followed by a 2-week observational period. Four domains of neurocognitive function (including speed of processing, working memory, visual learning and verbal learning) were assessed using the MATRICS Consensus Cognitive Battery (MCCB) at 0, 13 and 26 days.

RESULTS

In linear mixed model, significant improvements were found in terms of speed of processing (F = 20.7, p < 0.001) and verbal learning (F = 11.1, p < 0.001). The Sobel test showed the improvement of speed of processing (Sobel test = 2.8, p < 0.001) and verbal learning (Sobel test = 3.6, p < 0.001) were significantly mediated by change in depressive symptoms. Other two neurocognitive domains showed no significant changes over time. Correlation analysis showed no significant association of change in depressive symptoms with neurocognitive function at baseline.

CONCLUSION

Our findings suggest that six ketamine infusions were associated with the improvement of speed of processing and verbal learning, which were partly accounted for by improvement in the severity of depression symptoms over time.

Directionality of change in obsessive compulsive disorder (OCD) and suicidal ideation over six years in a naturalistic clinical sample✰

BACKGROUND

Obsessive compulsive disorder (OCD) is associated with elevated suicide risk, but the directionality of the association between OCD severity and suicidal ideation has not been established, which was the goal of this study.

METHODS

Participants (n = 325) were adults with either a current or past diagnosis of Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) OCD who were assessed annually for suicidal ideation and OCD symptom severity for six years. Cross-lagged panel analyses statistically compared unidirectional and bidirectional models over time. Serious suicide-related adverse events were reported.

RESULTS

The best-fitting and most parsimonious model included paths predicting suicidal ideation from OCD symptom severity, but not vice versa. These results were confirmed by comparing a model with cross-lagged paths constrained equal to a freely estimated model. Higher OCD symptom severity in a given year was associated with a higher suicidal ideation severity in the subsequent year. Five suicide-related adverse events were reported throughout the duration of the study, including two suicide deaths and three suicide attempts.

LIMITATIONS

The study relied on a single-item, annual measure of suicidal ideation in adults, with substantial variability in severity of suicide risk, and missing data increased with later observations in the study.

DISCUSSION

OCD symptom severity predicted next year suicidal ideation severity. In contrast, suicidal ideation severity in a given year did not predict next-year OCD symptom severity in this OCD sample. Thus, rather than waiting for suicidal ideation to resolve, clinicians should consider providing empirically supported treatments for OCD.

Characterizing the course of suicidal ideation response to ketamine

BACKGROUND

No pharmacological treatments exist for active suicidal ideation (SI), but the glutamatergic modulator ketamine elicits rapid changes in SI. We developed data-driven subgroups of SI trajectories after ketamine administration, then evaluated clinical, demographic, and neurobiological factors that might predict SI response to ketamine.

METHODS

Data were pooled from five clinical ketamine trials. Treatment-resistant inpatients (n = 128) with DSM-IV-TR-diagnosed major depressive disorder (MDD) or bipolar depression received one subanesthetic (0.5 mg/kg) ketamine infusion over 40 min. Composite SI variable scores were analyzed using growth mixture modeling to generate SI response classes, and class membership predictors were evaluated using multinomial logistic regressions. Putative predictors included demographic variables and various peripheral plasma markers.

RESULTS

The best-fitting growth mixture model comprised three classes: Non-Responders (29%), Responders (44%), and Remitters (27%). For Responders and Remitters, maximal improvements were achieved by Day 1. Improvements in SI occurred independently of improvements in a composite Depressed Mood variable for Responders, and partially independently for Remitters. Indicators of chronic SI and self-injury were associated with belonging to the Non-Responder group. Higher levels of baseline plasma interleukin-5 (IL-5) were linked to Remitters rather than Responders.

LIMITATIONS

Subjects were not selected for active suicidal thoughts; findings only extend to Day 3; and plasma, rather than CSF, markers were used.

CONCLUSION

The results underscore the heterogeneity of SI response to ketamine and its potential independence from changes in Depressed Mood. Individuals reporting symptoms suggesting a longstanding history of chronic SI were less likely to respond or remit post-ketamine.

Rapid and longer-term antidepressant effects of repeated-dose intravenous ketamine for patients with unipolar and bipolar depression

OBJECTIVE

Single-dose intravenous (IV) injection of ketamine has shown rapid but transient antidepressant effects. The strategy of repeated-dose ketamine infusions to maintain antidepressant effects has received little systematic study. This study was conducted to examine the efficacy and tolerability of six ketamine infusions in Chinese patients with unipolar and bipolar depression.

METHODS

Ninety seven patients with unipolar (n = 77) and bipolar (n = 20) depression received repeated ketamine infusions (0.5 mg/kg over 40 min) with continuous vital sign monitoring. Depressive symptoms were measured by the Montgomery-Asberg Depression Rating Scale (MADRS). Suicidal ideation was assessed using the Scale for Suicidal Ideations (SSI)-part 1. Anxiety symptoms were evaluated with the 14-item Hamilton Anxiety Scale (HAMA). Adverse psychopathological and dissociative effects were assessed using the Brief Psychiatric Rating Scale (BPRS)-positive symptoms and Clinician Administered Dissociative States Scale (CADSS), respectively. Patients were assessed at baseline, 4 and 24 h, and 3, 4, 5, 6, 8, 9, 10, 11, 12, 13 and 26 days.

RESULTS

After six ketamine infusions, the response and remission rates were 68.0% and 50.5%, respectively. There were significant decreases in MADRS, SSI-part 1, and HAMA scores within four hours following the first ketamine infusion, and the decreases were sustained over the subsequent infusion period. The nonresponder subgroup manifested rapid significant improvement in suicidal ideations throughout the course of treatment. After the six ketamine infusions, the response was positively associated with the response at 24 h after the first infusion (OR = 8.94), personal income ≥4000 yuan/month (OR = 3.04), and no history of psychiatric hospitalization (OR = 3.41). Only CADSS scores had a mild but marginally significant increase after the first infusion but with a significant BPRS score decrease.

CONCLUSION

Six ketamine infusions were safe and effective in patients with unipolar and bipolar depression. The rapid and robust antidepressant and antisuicidal effects of ketamine infusion within four hours were sustained following the subsequent infusions.

Antidepressant Efficacy and Tolerability of Ketamine and Esketamine: A Critical Review

Ketamine and its enantiomer S-ketamine (esketamine) are promising candidates to produce a rapid-onset antidepressant effect in treatment-resistant depression. Ketamine causes continued blockade of the glutamate N-methyl-D-aspartate (NMDA) receptor, though this might not primarily mediate the antidepressant effect. Alternative hypotheses include selectivity for the NMDA receptor subtype containing the NMDA receptor subunit 2B (NR2B), inhibition of the phosphorylation of the eukaryotic elongation factor 2 (eEF2) kinase, increased expression of brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (TrKB), and activation of the mammalian target of rapamycin (mTOR) signaling pathway, alongside other independent actions attributed to the ketamine metabolism to R-hydroxynorketamine (R-HNK). The enantiomer S-ketamine (esketamine) displays approximately fourfold greater affinity for the glutamate NMDA receptor in vitro than R-ketamine. Proof-of-concept single-dose and repeat-dose studies with intravenous ketamine show a significant antidepressant and probably antisuicidal effect in the short term, with response rates over 60% as early as 4.5 h after a single dose, with a sustained effect after 24 h, and over 40% after 7 days. This response can be further sustained over several weeks with repeated doses (two to three doses per week). Tolerability seems acceptable in the short term, with transient elevation of blood pressure and mild and transient dissociative and psychotomimetic effects. Intranasal esketamine has shown a comparable antidepressant effect, which has resulted in the US FDA granting the drug a "breakthrough therapy" designation, and theoretically it may offer an improved tolerability profile. However, major concerns remain regarding an effective protocol to maintain the clinical antidepressant effect of ketamine seen with acute administration and the safety of ketamine and esketamine in the long term, specifically related to potential neurocognitive and urologic toxicity, together with the potential induction of substance use disorders. Ketamine and esketamine are not currently approved treatments for depression, but the clinical use of ketamine is increasing in a variety of practice settings internationally.

Dose-Related Effects of Adjunctive Ketamine in Taiwanese Patients with Treatment-Resistant Depression

The antidepressant effects of ketamine are thought to depend on brain-derived neurotrophic factor (BDNF) genotype and dose. The purpose of this study was to characterize the dose-related antidepressant effects of ketamine in patients with treatment-resistant depression drawn from a Chinese population predominately possessing lower activity BDNF genotypes (Val/Met, Met/Met). We conducted a double-blind, randomized, parallel-group, placebo-controlled trial of a single ketamine infusion (saline, 0.2 mg/kg, 0.5 mg/kg). Patients (N=71; BDNF genotype: Val/Val (N=12, 17%), Val/Met (N=40, 56.3%), and Met/Met (N=19, 26.8%)) received mood ratings before infusion, after infusion, and for the subsequent 14 days. Plasma ketamine levels and BDNF genotypes were assessed. This study found a significant dose-related ketamine effect on scores on the Hamilton Depression Rating Scale (HAMD). The responder analysis (>50% reduction from baseline HAMD on at least 2 days between days 2 and 5) also revealed a significant dose-related effect (saline: 12.5%, 0.2 mg/kg: 39.1%; 0.5 mg/kg: 45.8%). This is the first report to our knowledge to demonstrate the dose-related efficacy of R/S-ketamine for treatment-resistant depression and the first to characterize ketamine effects in a genotyped Chinese population in which most (83%) patients possessed at least one copy of the lower functioning Met allele of the BDNF gene.

Active suicidal ideation during clinical antidepressant trials

Suicidal patients are often excluded from clinical trials of psychiatric medications and from investigations using neurobiological techniques. To evaluate the presence, impact, and stability of active suicidal ideation (SI) across a range of antidepressant trials, we reviewed 14 clinical trials conducted in patients with either major depressive disorder (MDD) or bipolar disorder (BD) (N = 269). Active SI at any time point in the clinical trial was identified and linked to participation in other research procedures. Stability of active SI across subsequent days was evaluated using intraclass correlation coefficients (ICCs) and compared to other depressive symptoms. Across 14 clinical trials, 63 participants (23%) reported active SI at some point during study participation. Of these participants, 33 completed a neuroimaging procedure and 16 completed polysomnography within a week of active SI. When active SI was subsequently assessed, only 39% of patients continued to report active SI after three days of assessment, despite receiving no additional treatment. ICCs were not significant for either SI or pessimism; other depressive symptoms showed stability over time. The results suggest that research can be conducted in depressed patients with active SI if such research coincides with careful observation. Active SI and pessimism may be particularly vulnerable to fluctuation.

Ketamine-Induced Glutamatergic Mechanisms of Sleep and Wakefulness: Insights for Developing Novel Treatments for Disturbed Sleep and Mood

Ketamine, a drug with rapid antidepressant effects and well-described effects on slow wave sleep (SWS), is a useful intervention for investigating sleep-wake mechanisms involved in novel therapeutics. The drug rapidly (within minutes to hours) reduces depressive symptoms in individuals with major depressive disorder (MDD) or bipolar disorder (BD), including those with treatment-resistant depression. Ketamine treatment elevates extracellular glutamate in the prefrontal cortex. Glutamate, in turn, plays a critical role as a proximal element in a ketamine-initiated molecular cascade that increases synaptic strength and plasticity, which ultimately results in rapidly improved mood. In MDD, rapid antidepressant response to ketamine is related to decreased waking as well as increased total sleep, SWS, slow wave activity (SWA), and rapid eye movement (REM) sleep. Ketamine also increases brain-derived neurotrophic factor (BDNF) levels. In individuals with MDD, clinical response to ketamine is predicted by low baseline delta sleep ratio, a measure of deficient early night production of SWS. Notably, there are important differences between MDD and BD that may be related to the effects of diagnosis or of mood stabilizers. Consistent with its effects on clock-associated molecules, ketamine alters the timing and amplitude of circadian activity patterns in rapid responders versus non-responders with MDD, suggesting that it affects mood-dependent central neural circuits. Molecular interactions between sleep homeostasis and clock genes may mediate the rapid and durable elements of clinical response to ketamine and its active metabolite.