Exploring the potential of Esketamine in the treatment of bipolar depression

Is there a risk of esketamine misuse in clinical practice?

In 2019, intranasal esketamine gained approval as a promising therapy for those individuals grappling with treatment-resistant depression. Both clinical trials and real-world studies have underscored its efficacy in alleviating and remitting depressive symptoms, with sustained benefits observed for nearly 4.5 years. As the S-enantiomer of ketamine, esketamine's dosing guidelines and strict medical supervision stem from prior research on ketamine's use in depression and history as a recreational drug. Despite initial concerns, long-term clinical studies have not documented instances of abuse, misuse, addiction or withdrawal, and the same was found in case reports or subsamples of high-risk populations with comorbidities such as substance use disorder or alcohol use disorder. Esketamine has proven to be safe and well tolerated without fostering new-onset substance use in vulnerable groups. Real-world studies reinforced these observations, reporting no adverse events (AEs) related to pharmacological interactions of esketamine with any other substance, and no new-onset drug or alcohol misuse, craving, misuse or diversion of use. Reports of esketamine craving remain rare, with only one case report documented in 2022. Most drug-related AEs reported in pharmacovigilance databases are those identified in the product's technical data sheet and with known reported frequency. More importantly, no register of illicit acquisition of esketamine or its tampering for obtaining ketamine or other altered products was found in our search. Overall, our review confirms esketamine's safety across diverse patient populations, reassuring its responsible use and the scarcity of reports of abuse or misuse since its introduction to the market.

Bipolar disorders: an update on critical aspects

Bipolar disorders are chronic psychiatric conditions characterized by recurrent episodes of mania and depression. Affecting over 1% of the global population, these disorders contribute significantly to disability and mortality, often due to suicide and cardiovascular disease. Diagnostic challenges arise from symptom overlap with unipolar depression, frequently leading to delays. Bipolar disorders are driven by complex genetic, neurobiological, and environmental factors and are commonly accompanied by psychiatric and medical comorbidities, further complicating diagnosis and treatment. Standard management strategies include mood stabilizers, antipsychotics, and selective use of antidepressants, complemented by psychosocial interventions like cognitive-behavioral therapy and psychoeducation, which are vital for relapse prevention. Despite recent advancements, the management of bipolar disorders remains challenging, constrained by clinical variability, an absence of specific biomarkers, and differences in approved treatments and treatment guidelines across regions. Emerging research underscores the potential of precision psychiatry and digital health tools to enhance diagnosis and treatment. Nonetheless, critical gaps persist, particularly in implementing equitable care worldwide. This review offers a comprehensive update on bipolar disorders, examining clinical presentation, early diagnosis, pathogenesis, therapeutic strategies, and future perspectives to guide clinicians and researchers in addressing these ongoing challenges in research and clinical practice.

Funding

None.

Ketamine treatment for anhedonia in unipolar and bipolar depression: a systematic review

Ketamine, an N-methyl-D-aspartate receptor antagonist, is a racemic mixture of esketamine and arketamine used to treat unipolar and bipolar depression. Preliminary reports indicate that it may be beneficial for depressed patients reporting symptoms of anhedonia. In this systematic review we aim to assess and analyze the existing body of evidence regarding the therapeutic effects of ketamine on the domain of anhedonia. Electronic databases (PubMed, APA Psycinfo and Web of Science) were searched from inception to November 2023. Protocol was registered in PROSPERO under the identifier CRD42023476603. A total of twenty-two studies, including four randomized-controlled trials and eighteen open-label trials were included. All studies reported alleviation of anhedonia symptoms following ketamine or esketamine administration, regardless of the number of infusions. Several important limitations were included, first and foremost low number of placebo-controlled randomized-controlled trials. This review indicates a potential anti-anhedonic effect of ketamine in patients with depression. Several trials used neuroimaging techniques which confirm ketamine's effect on functional connectivity correlating with the improvement in anhedonia. Despite considerable variations in methodology and the specific brain regions investigated, these studies collectively point towards ketamine's neuroplastic effects in mitigating anhedonia.

Patient-reported outcomes on sleep quality and circadian rhythm during treatment with intravenous ketamine for treatment-resistant depression

Background

Intravenous (IV) ketamine is a rapid acting antidepressant used primarily for treatment-resistant depression (TRD). It has been suggested that IV ketamine's rapid antidepressant effects may be partially mediated via improved sleep and changes to the circadian rhythm.

Objectives

This study explores IV ketamine's association with changes in patient-reported sleep quality and circadian rhythm in an adult population with TRD.

Methods

Adult patients (18-64 years) with TRD scheduled for IV ketamine treatment were recruited to complete patient rated outcomes measures on sleep quality using the Pittsburgh Sleep Quality Index (PSQI) and circadian rhythm using the Morningness-Eveningness Questionnaire (MEQ). Over a 4-week course of eight ketamine infusions, reports were obtained at baseline (T0), prior to second treatment (T1), prior to fifth treatment (T2), and 1 week after eighth treatment (T3).

Results

Forty participants with TRD (mean age = 42.8, 45% male) were enrolled. Twenty-nine (72.5%) had complete follow-up data. Paired t tests revealed statistically significant improvements at the end of treatment in sleep quality (PSQI) (p = 0.003) and depressive symptoms (Clinically Useful Depression Outcome Scale-Depression, p < 0.001) while circadian rhythm (MEQ) shifted earlier (p = 0.007). The PSQI subscale components of sleep duration (p = 0.008) and daytime dysfunction (p = 0.001) also improved. In an exploratory post hoc analysis, ketamine's impact on sleep quality was more prominent in patients with mixed features, while its chronobiotic effect was prominent in those without mixed features.

Conclusion

IV ketamine may improve sleep quality and advance circadian rhythm in individuals with TRD. Effects may differ in individuals with mixed features of depression as compared to those without. Since this was a small uncontrolled study, future research is warranted.

Short-term ketamine use in bipolar depression: a review of the evidence for short-term treatment management

Bipolar depression constitutes a major problem in psychiatry. It correlates with high suicidality, treatment resistance, chronicity, and poor quality of life. Registered treatment for bipolar depression is limited and insufficient. There is an urgent need for implementing new therapeutic strategies. Intranasal ketamine's enantiomer-esketamine is a novel rapid-acting antidepressant with proven efficacy in treatment-resistant depression. Research on bipolar depression, although not as comprehensive, indicates that it may be a viable and safe substitute with minimal risk for mood polarity changes. Reports suggest that ketamine treatment in bipolar depression may reduce suicidal tendencies, decrease anhedonia, and alleviate anxiety. Ketamine's mood-stabilizing properties are also hypothesized. In this narrative review, we focus on ketamine use as an add-on to standard medication for the acute treatment of bipolar depression.