Is Ketamine the Future Clozapine for Depression? A Case Series and Literature Review on Maintenance Ketamine in Treatment-resistant Depression With Suicidal Behavior

Efficacy of Ketamine with and without Lamotrigine in Treatment-Resistant Depression: A Preliminary Report

Intravenous (IV) ketamine and FDA-approved intranasal (IN) esketamine are increasingly used for treatment-resistant depression (TRD). Preliminary studies have suggested a synergistic effect of ketamine and lamotrigine, although the data are inconclusive. Herein, we report the response to serial ketamine/esketamine treatment among patients with TRD with or without lamotrigine therapy. In this historical cohort study, we included adult patients with TRD who received serial IV racemic ketamine (0.5 mg/kg over 40-100 min) or IN esketamine (56/84 mg) treatments. A change in depressive symptoms was assessed using the 16-item Quick Inventory of Depressive Symptomatology self-report (QIDS-SR) scale. There were no significant differences in response or remission rates among the patients on or not on lamotrigine during the ketamine/esketamine treatments. For a percent change in the QIDS-SR from baseline, no interaction was found between the lamotrigine groups and treatment number (p = 0.70), nor the overall effect of the group (p = 0.38). There was a trend towards lower dissociation (based on the CADSS score) among current lamotrigine users, especially in patients who received IV ketamine. A major limitation is the limited number of patients taking lamotrigine (n = 13). This preliminary study provides insufficient evidence that continuing lamotrigine therapy attenuates the antidepressant effect of repeated ketamine/esketamine; however, there seems to be a signal toward attenuating dissociation with lamotrigine in patients receiving serial ketamine treatments. Further observational studies or randomized controlled trials are needed to replicate these findings.

Maintenance ketamine treatment for depression: a systematic review of efficacy, safety, and tolerability

Ketamine has rapid yet often transient antidepressant effects in patients with treatment-resistant depression. Different strategies have been proposed to prolong these effects. Maintenance ketamine treatment appears promising, but little is known about its efficacy, safety, and tolerability in depression. We searched Pubmed, Embase, and the Cochrane Library and identified three randomised controlled trials, eight open-label trials, and 30 case series and reports on maintenance ketamine treatment. We found intravenous, intranasal, oral, and possibly intramuscular and subcutaneous maintenance ketamine treatment to be effective in sustaining antidepressant effect in treatment-resistant depression. Tachyphylaxis, cognitive impairment, addiction, and serious renal and urinary problems seem uncommon. Despite the methodological limitations, we conclude that from a clinical view, maintenance ketamine treatment seems to be of therapeutic potential. We recommend both controlled and naturalistic studies with long-term follow-up and sufficient power to determine the position of maintenance ketamine treatment within routine clinical practice.

Case report: Effectiveness of brexpiprazole and esketamine/ketamine combination: A novel therapeutic strategy in five cases of treatment-resistant depression

A significant proportion of patients with treatment-resistant depression do not attain functional recovery despite administration of multiple steps of pharmacotherapeutic strategies. This highlights the elusiveness of meeting unmet needs in existing pharmacotherapies for treatment-resistant depression. There is accumulating evidence that antidepressant agents involving the glutamatergic system such as brexpiprazole and esketamine/ketamine have more rapid onset of action and potentially improved effectiveness as an augmentation therapy in treatment-resistant depression. This case series aimed to report five complex cases of unipolar and bipolar treatment-resistant depression where conventional treatment strategies were inadequate in managing high risk suicidal behavior and achieving functional recovery. We discussed further the possible synergistic mechanisms of the novel combination strategy of brexpiprazole and esketamine/ketamine, clinical and patient factors that influenced treatment response, challenges with this combination strategy and implications for future practice and research.

A Southeast Asian expert consensus on the management of major depressive disorder with suicidal behavior in adults under 65 years of age

BACKGROUND

The high prevalence of suicidal behavior among individuals with major depressive disorder (MDD) in Southeast Asia (SEA) underscores the need for optimized management to address depressive symptoms, reduce suicide risk and prevent suicide in these individuals. Given the lack of clear guideline recommendations for assessing and managing these patients, regional consensus-based recommendations which take into account diverse local contexts across SEA may provide useful guidance for clinical practice.

METHODS

A narrative literature review and pre-meeting survey were conducted prior to the consensus meeting of an SEA expert panel comprising 13 psychiatrists with clinical experience in managing patients with MDD with suicidal behavior. Utilizing the RAND/UCLA Appropriateness Method, the expert panel developed consensus-based recommendations on the assessment and treatment of adult patients with MDD with suicidal behavior under 65 years.

RESULTS

Screening of adult patients under 65 years with MDD for suicide risk using both a validated assessment tool and clinical interview is recommended. An improved suicide risk stratification - incorporating both severity and temporality, or using a prevention-focused risk formulation - should be considered. For a patient with an MDD episode with low risk of suicide, use of antidepressant monotherapy, and psychotherapy in combination with pharmacological treatment are both recommended approaches. For a patient with an MDD episode with high risk of suicide, or imminent risk of suicide requiring rapid clinical response, or for a patient who had received adequate AD but still reported suicidal behavior, recommended treatment strategies include antidepressant augmentation, combination use of psychotherapy or electroconvulsive therapy with pharmacological treatment, and inpatient care. Suicide-specific psychosocial interventions are important for suicide prevention and should also be part of the management of patients with MDD with suicidal behavior.

CONCLUSIONS

There are still unmet needs in the assessment of suicide risk and availability of treatment options that can deliver rapid response in patients with MDD with suicidal behavior. These consensus recommendations on the management of adult patients with MDD with suicidal behavior under 65 years may serve as a useful guidance in diverse clinical practices across the SEA region. Clinical judgment based on careful consideration of individual circumstances of each patient remains key to determining the most appropriate treatment option.

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

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

Ketamine and Lamotrigine Combination in Psychopharmacology: Systematic Review

Background and Objectives: Ketamine is a rapid-acting antidepressant with proven efficacy as an add-on agent in unipolar and bipolar treatment-resistant depression. Although many studies have been published, there is still not enough data on the effect of ketamine in combination with other medications. Particularly interesting is the combination of ketamine and lamotrigine, and its potential role in bipolar depression. The aim of this review was to identify animal and human studies in which ketamine and lamotrigine were used together in order to find out if there is scientific ground for combining ketamine and lamotrigine in the treatment of mood disorders. Directions for future studies are presented. Materials and Methods: PubMed and Web of Science were searched. Preferred Reporting Items for Systematic Reviews and Meta-Analyses PRISMA 2020 methodology was applied. Results: Seventeen studies were included for review. Animal studies using models of depression suggested a synergistic effect of ketamine and lamotrigine in combination. Studies on healthy humans showed a reduction in ketamine-induced dissociative symptoms with lamotrigine pretreatment. In a study on patients with depression, ketamine and lamotrigine did not have a stronger antidepressant effect than ketamine alone, but in this study only one ketamine infusion was administered. One case series described the antidepressant and anti-suicidal effect of the combination in two bipolar patients. Available clinical studies on patients with mood disorders did not support the hypothesis that lamotrigine reduces ketamine-induced dissociative symptoms. Conclusions: The results of the analyzed studies were not sufficient to answer any of the stated questions; however, they allowed us to delineate future research directions. The identified animal studies suggested a possible synergistic antidepressant effect of ketamine and lamotrigine. The available clinical studies were not conclusive. No controlled studies on large groups of bipolar patients with multiple ketamine infusions combined with lamotrigine treatment have been published so far. There is some evidence for the reduction of ketamine’s side effects by lamotrigine, and there are reports suggesting that lamotrigine can reduce ketamine craving. More studies with follow-up are needed in order to investigate the ketamine–lamotrigine combination in bipolar patients.

Synthesizing the Evidence for Ketamine and Esketamine in Treatment-Resistant Depression: An International Expert Opinion on the Available Evidence and Implementation

Replicated international studies have underscored the human and societal costs associated with major depressive disorder. Despite the proven efficacy of monoamine-based antidepressants in major depression, the majority of treated individuals fail to achieve full syndromal and functional recovery with the index and subsequent pharmacological treatments. Ketamine and esketamine represent pharmacologically novel treatment avenues for adults with treatment-resistant depression. In addition to providing hope to affected persons, these agents represent the first non-monoaminergic agents with proven rapid-onset efficacy in major depressive disorder. Nevertheless, concerns remain about the safety and tolerability of ketamine and esketamine in mood disorders. Moreover, there is uncertainty about the appropriate position of these agents in treatment algorithms, their comparative effectiveness, and the appropriate setting, infrastructure, and personnel required for their competent and safe implementation. In this article, an international group of mood disorder experts provides a synthesis of the literature with respect to the efficacy, safety, and tolerability of ketamine and esketamine in adults with treatment-resistant depression. The authors also provide guidance for the implementation of these agents in clinical practice, with particular attention to practice parameters at point of care. Areas of consensus and future research vistas are discussed.

Ketamine treatment for individuals with treatment-resistant depression: longitudinal qualitative interview study of patient experiences

BACKGROUND

Ketamine has recently received considerable attention regarding its antidepressant and anti-suicidal effects. Trials have generally focused on short-term effects of single intravenous infusions. Research on patient experiences is lacking.

AIMS

To investigate the experiences over time of individuals receiving ketamine treatment in a routine clinic, including impacts on mood and suicidality.

METHOD

Twelve fee-paying patients with treatment-resistant depression (6 females, 6 males, age 21-70 years; 11 reporting suicidality and 6 reporting self-harm) who were assessed as eligible for ketamine treatment participated in up to three semi-structured interviews: before treatment started, a few weeks into treatment and ≥2 months later. Data were analysed thematically.

RESULTS

Most participants hoped that ketamine would provide respite from their depression. Nearly all experienced improvement in mood following initial treatments, ranging from negligible to dramatic, and eight reported a reduction in suicidality. Improvements were transitory for most participants, although two experienced sustained consistent benefit and two had sustained but limited improvement. Some participants described hopelessness when treatment stopped working, paralleled by increased suicidal ideation for three participants. The transient nature and cost of treatment were problematic. Eleven participants experienced side-effects, which were significant for two participants. Suggestions for improving treatment included closer monitoring and adjunctive psychological therapy.

CONCLUSIONS

Ketamine treatment was generally experienced as effective in improving mood and reducing suicidal ideation in the short term, but the lack of longer-term benefit was challenging for participants, as was treatment cost. Informed consent procedures should refer to the possibilities of relapse and associated increased hopelessness and suicidality.

Next-Step Treatment Considerations for Patients With Treatment-Resistant Depression That Responds to Low-Dose Intravenous Ketamine

Numerous short-term randomized trials support the acute-phase efficacy of low-dose intravenous (IV) ketamine for patients with treatment-resistant unipolar or bipolar depression. Ketamine's antidepressive effects generally have limited duration, highlighting the need for maintenance treatment after an acute-phase response. It is increasingly likely that psychiatrists will be called upon to manage the care of patients with treatment-resistant unipolar or bipolar depression who have responded acutely to ketamine and to recommend or initiate next-step treatments. However, there is a paucity of controlled evidence to guide best practices for managing treatment of patients with treatment-resistant unipolar or bipolar depression who have had a positive initial response to ketamine. This article reviews the available evidence supporting specific strategies for extending and maintaining acute antidepressive responses to low-dose IV ketamine in patients with treatment-resistant unipolar or bipolar depression and provides some preliminary considerations for clinical practice.

Rodent ketamine depression-related research: Finding patterns in a literature of variability

Discovering that the anesthetic drug ketamine has rapidly acting antidepressant effects in many individuals with major depression is one of the most important findings in clinical psychopharmacology in recent decades. The initial report of these effects in human subjects was based on a foundation of rodent preclinical studies carried out in the 1990s, and subsequent investigation has included both further studies in individuals with depression, as well as reverse translational experiments in animal models, especially rodents. While there is general agreement in the rodent literature that ketamine has rapidly-acting, and generally sustained, antidepressant-like properties, there are also points of contention across studies, including the precise mechanism of action of this drug. In this review, we briefly summarize prominent yet variable findings regarding the mechanism of action. We also discuss a combination of similarities and variances in the rodent literature in the antidepressant-like effects of ketamine as a function of dose, species and strain, test, stressor, and presumably sex of the experimenter. We then present previously unpublished mouse strain comparison data suggesting that subanesthetic ketamine does not have robust antidepressant-like properties in unstressed animals, and may actually promote depression-like behavior, in contrast to widely reported findings. We conclude that the data best support the notion of ketamine action principally via NMDA receptor antagonism, transiently boosting glutamatergic (and possibly other) signaling in diverse brain circuits. We also suggest that future studies should address in greater detail the extent to which antidepressant-like properties of this drug are stress-sensitive, in an effort to better model major depression present in humans.