Treatment-resistant bipolar depression: concepts and challenges for novel interventions

Symptom modulation and tolerability of intravenous ketamine in treatment-resistant bipolar depression: A retrospective study

Ketamine's use in treating bipolar depression must account for risks, such as switching to manic episodes or worsening symptoms. This study examines ketamine's impact on depressive symptoms, focusing on 'inner tension,' 'sleep reduction,' and 'suicidal ideation' over four weeks in treatment-resistant bipolar disorder (TR-BD) patients. Fifty-nine patients with TR-BD were treated consecutively with ketamine (avg dose 0.8 mg/kg). Results showed significant reductions in MADRS scores without manic switches. Ketamine was well-tolerated despite polypharmacy. Antidepressant treatment of bipolar depression requires great caution because of the risk of switching to manic-mixed episodes and worsening of symptoms such as internal tension, psychomotor agitation, and suicide risk. The aim of this study was to evaluate the efficiency and tolerability of intravenous ketamine in patients with bipolar I or bipolar II disorder and a current treatment-resistant depressive episode (TR-BD), with the aim of examining: 1) the risk of manic switches; 2) the effect on global depressive symptoms as measured by the Montgomery-Åsberg Depression Rating Scale (MADRS); and 3) the specific effects on the MADRS items of internal tension, sleep disturbance, and suicidal ideation over a four-week period. Fiftynine patients with TR-BD (51.4 ± 12.3 years; 30 % female) treated consecutively with intravenous ketamine (mean dose 0.8 mg/kg) were included in this study. No ketamine-treated patient experienced a manic switch during the observation period. A statistically significant decrease (i.e., improvement) in MADRS global score and scores on the Internal Tension, Reduced Sleep, and Suicidal Ideation items was observed from the second week, with no evidence of worsening of the above symptoms. Patient-reported adverse events were generally mild to moderate.

Accelerated intermittent theta burst stimulation for pharmacological treatment-resistant bipolar depression: Protocol for double-blind, randomized, sham-controlled trial

Background

With 30%-50% of people with bipolar depression (BDep) not responding to multiple pharmacological treatments, alternative therapies are needed. Accelerated intermittent theta burst stimulation (aiTBS) over the left dorsolateral prefrontal cortex (L-DLPFC) has been employed for individuals with pharmacological treatment-resistant major depressive disorder (TR-MDD). Imaging studies have revealed reduced regional activity of the L-DLPFC for both TR-MDD and pharmacological treatment-resistant BDep (TR-BDep), suggesting that aiTBS over the L-DLPFC may be beneficial for people with TR-BDep.

Methods

A 6-week, double-blind, sham-controlled, randomized trial will be conducted to compare the efficacy and safety of aiTBS to the L-DLPFC in people with TR-BDep (jRCTs042240019). Fifty iTBS sessions (1800 pulses/session) will be delivered in 10 daily sessions over 5 consecutive days at 90% resting motor threshold. This aiTBS protocol is termed as Fujita Neuromodulation Therapy for Bipolar Depression (FNT-BD). Twenty-two participants (both sexes, aged 18-64 years) with TR-BDep (DSM-5-TR, Type I) will be recruited. The response rate at any given week of follow-up will be the primary efficacy outcome, defined as a reduction of ≥50% in the Montgomery Åsberg Depression Rating Scale (MADRS) score. Other outcomes will include MADRS score changes, remission rate (10 ≥ MADRS score), Clinical Global Impression-Improvement score, Clinical Global Impression-Severity score, discontinuation rate, and incidence of individual adverse events.

Results

We anticipate that individuals who receive the aiTBS treatment show significant improvement in depressing symptoms compared to those receiving sham treatment.

Conclusions

This study will provide valuable evidence for both patients with TR-BDep and clinicians.

Exploring accelerated aging as a target of bipolar disorder treatment: A systematic review

Bipolar disorder (BD) has been linked to accelerated aging processes, with many studies suggesting that drugs used to treat BD may modulate pathways related to aging. This systematic review aimed to determine whether FDA-approved pharmacotherapies for BD have reported effects on aging biomarkers across clinical and preclinical studies. We conducted searches in PubMed and PsychINFO and followed PRISMA guidelines. Out of 6400 records identified, 19 studies met the inclusion criteria. Most preclinical studies tested the effects of BD drugs, especially lithium, on lifespan and telomere biology in cell and animal models. Clinical studies predominantly focused on lithium, evaluating aging markers like telomere length, telomerase, mitochondrial DNA copy number, and epigenetic age acceleration in individuals with BD. Findings indicate that chronic lithium treatment is associated with modulatory effects on aging biomarkers, particularly increased telomere length and telomerase activity. Conversely, some negative results were also reported. Limited evidence suggests potential aging-modulating properties of other mood stabilizers like valproic acid and lamotrigine, evidencing that further investigation is required. Despite variability across studies, the overall findings support the notion that pharmacotherapies used in BD present many effects of aging biomarkers. However, the field is still developing, with a clear emphasis on lithium and a lack of standardized methods to evaluate aging biomarkers in clinical samples. Further research exploring the anti-accelerated aging effects of BD drugs beyond lithium, their mechanisms of action, and potential synergistic effects is warranted.

Real-world case series of maintenance theta burst stimulation therapy following response to acute theta burst stimulation therapy for difficult-to-treat depression

OBJECTIVE

Treatment and management for difficult-to-treat depression are challenging, especially in a subset of patients who are at high risk for relapse and recurrence. The conditions that represent this subset are recurrent depressive disorder (RDD) and bipolar disorder (BD). In this context, we aimed to examine the effectiveness of maintenance transcranial magnetic stimulation (TMS) on a real-world clinical basis by retrospectively extracting data from the TMS registry data in Tokyo, Japan.

METHODS

Data on patients diagnosed with treatment-resistant RDD and BD who received maintenance intermittent theta burst stimulation (iTBS) weekly after successful treatment with acute iTBS between March 2020 and October 2023 were extracted from the registry.

RESULTS

All patients (21 cases: 10 cases with RDD and 11 cases with BD) could sustain response, and 19 of them further maintained remission. In this study, maintenance iTBS did not exacerbate depressive symptoms in any of the cases, but may rather have the effect of stabilizing the mental condition and preventing recurrence.

CONCLUSIONS

This case series is of great clinical significance because it is the first study to report on the effectiveness of maintenance iTBS for RDD and BD, with a follow-up of more than 2 years. Further validation with a randomized controlled trial design with a larger sample size is warranted.

The New Horizon of Antipsychotics beyond the Classic Dopaminergic Hypothesis-The Case of the Xanomeline-Trospium Combination: A Systematic Review

Although the dopamine hypothesis of schizophrenia explains the effects of all the available antipsychotics in clinical use, there is an increasing need for developing new drugs for the treatment of the positive, negative, and cognitive symptoms of chronic psychoses. Xanomeline-trospium (KarXT) is a drug combination that is based on the essential role played by acetylcholine in the regulation of cognitive processes and the interactions between this neurotransmitter and other signaling pathways in the central nervous system, with a potential role in the onset of schizophrenia, Alzheimer's disease, and substance use disorders. A systematic literature review that included four electronic databases (PubMed, Cochrane, Clarivate/Web of Science, and Google Scholar) and the US National Library of Medicine database for clinical trials detected twenty-one sources referring to fourteen studies focused on KarXT, out of which only four have available results. Based on the results of these trials, the short-term efficacy and tolerability of xanomeline-trospium are good, but more data are needed before this drug combination may be recommended for clinical use. However, on a theoretical level, the exploration of KarXT is useful for increasing the interest of researchers in finding new, non-dopaminergic, antipsychotics that could be used either as monotherapy or as add-on drugs.

Serum autoantibodies against α7-nicotinic receptors in subgroups of patients with bipolar disorder or schizophrenia: clinical features and link with peripheral inflammation

There is growing evidence that autoantibodies (AAbs) against proteins expressed in the brain are playing an important role in neurological and psychiatric disorders. Here, we explore the presence and the role of peripheral AAbs to the α7-nicotinic acetylcholine receptor (nAChR) in inflammatory subgroups of psychiatric patients with bipolar disorder (BD) or schizophrenia (SCZ) and healthy controls. We have identified a continuum of AAb levels in serum when employing a novel ELISA technique, with a significant elevation in patients compared to controls. Using unsupervised two-step clustering to stratify all the subjects according to their immuno-inflammatory background, we delineate one subgroup consisting solely of psychiatric patients with severe symptoms, high inflammatory profile, and significantly increased levels of anti-nAChR AAbs. In this context, we have used monoclonal mouse anti-human α7-nAChR antibodies (α7-nAChR-mAbs) and shown that TNF-α release was enhanced upon LPS stimulation in macrophages pre-incubated with α7-nAChR-mAbs compared to the use of an isotype control. These findings provide a basis for further study of circulating nicotinic AAbs, and the inflammatory profile observed in patients with major mood and psychotic disorders.

New Light on Prions: Putative Role of PrPc in Pathophysiology of Mood Disorders

Mood disorders are highly prevalent and heterogenous mental illnesses with devastating rates of mortality and treatment resistance. The molecular basis of those conditions involves complex interplay between genetic and environmental factors. Currently, there are no objective procedures for diagnosis, prognosis and personalization of patients' treatment. There is an urgent need to search for novel molecular targets for biomarkers in mood disorders. Cellular prion protein (PrPc) is infamous for its potential to convert its insoluble form, leading to neurodegeneration in Creutzfeldt-Jacob disease. Meanwhile, in its physiological state, PrPc presents neuroprotective features and regulates neurotransmission and synaptic plasticity. The aim of this study is to integrate the available knowledge about molecular mechanisms underlying the impact of PrPc on the pathophysiology of mood disorders. Our review indicates an important role of this protein in regulation of cognitive functions, emotions, sleep and biological rhythms, and its deficiency results in depressive-like behavior and cognitive impairment. PrPc plays a neuroprotective role against excitotoxicity, oxidative stress and inflammation, the main pathophysiological events in the course of mood disorders. Research indicates that PrPc may be a promising biomarker of cognitive decline. There is an urgent need of human studies to elucidate its potential utility in clinical practice.

Cariprazine Augmentation in Treatment-Resistant Bipolar Depression: Data from a Retrospective Observational Study

BACKGROUND

Treatment-resistant bipolar depression is one of the leading problems in psychiatry with serious consequences on patients functioning, quality of life and resource utilization. Despite this, there is a lack of consensus on diagnostic criteria and treatment algorithms.

OBJECTIVE

The objective of the present study is to assess the acute effectiveness and tolerability of cariprazine in the management of treatment resistant bipolar depression.

METHODS

This is a four weeks retrospective multicentric observational study on patients with treatment resistant bipolar depression receiving cariprazine in augmentation to the current treatment. Cariprazine dosage changed during the follow-up period according to clinical judgment. Since data followed a non-normal distribution, non-parametric tests were used to pursue the analysis. The effectiveness of cariprazine was assessed through the mean change in Hamilton Depression rating scale (HAM-D) scores from baseline to endpoint. For missing values, a "Last Observation Carried Forward" approach was applied.

RESULTS

Fifty-one patients were enrolled. Four patients (7.8%) discontinued cariprazine mainly due to adverse events. Mean cariprazine dose was 1.7 mg/day. The mean HAM-D score decreased significantly from baseline (T0) to week 4 (T4) at each evaluation point. Fourty-five one percent of the patients benefited of cariprazine add-on strategy: 23.5% achieved a clinical response and 21.6% were remitters. Among the completers, 70.6% experienced at least one adverse event. All side effects were mild to moderate.

CONCLUSION

Cariprazine seems to be an effective and well tolerated option in the management of patients with treatment resistant bipolar depression.

Magnetic seizure therapy and electroconvulsive therapy increase aperiodic activity

Major depressive disorder (MDD) is a leading cause of disability worldwide. One of the most efficacious treatments for treatment-resistant MDD is electroconvulsive therapy (ECT). Recently, magnetic seizure therapy (MST) was developed as an alternative to ECT due to its more favorable side effect profile. While these approaches have been very successful clinically, the neural mechanisms underlying their therapeutic effects are unknown. For example, clinical "slowing" of the electroencephalogram beginning in the postictal state and extending days to weeks post-treatment has been observed in both treatment modalities. However, a recent longitudinal study of a small cohort of ECT patients revealed that, rather than delta oscillations, clinical slowing was better explained by increases in aperiodic activity, an emerging EEG signal linked to neural inhibition. Here we investigate the role of aperiodic activity in a cohort of patients who received ECT and a cohort of patients who received MST treatment. We find that aperiodic neural activity increases significantly in patients receiving either ECT or MST. Although not directly related to clinical efficacy in this dataset, increased aperiodic activity is linked to greater amounts of neural inhibition, which is suggestive of a potential shared neural mechanism of action across ECT and MST.

Changes in Adipokine, Resitin, and BDNF Concentrations in Treatment-Resistant Depression after Electroconvulsive Therapy

OBJECTIVES

One of the current challenges in psychiatry is the search for answers on how to effectively manage drug-resistant depression. The occurrence of drug resistance in patients is an indication for the use of electroconvulsive therapy (ECT). This method is highly effective and usually results in relatively quick health improvement. Despite the knowledge of how ECT works, not all of the biological pathways activated during its use have been identified. Hence, based on the neuroinflammatory hypothesis of depression, we investigated the concentration of two opposite-acting adipokines (anti-inflammatory adiponectin and proinflammatory resistin) and BDNF in antidepressant-resistant patients undergoing ECT.

METHODS

The study group comprised 52 patients hospitalized due to episodes of depression in the course of unipolar and bipolar affective disorder. The serum concentration of adipokines and BDNF was determined before and after the therapeutic intervention using an ELISA method. In the analyses, we also included comparisons considering the type of depression, sex, and achieving remission.

RESULTS

Adiponectin, resistin, and BDNF concentrations change after ECT treatment. These changes are correlated with an improvement in the severity of depressive symptoms and are more or less pronounced depending on the type of depression.

CONCLUSIONS

Although not all observed changes reach statistical significance, adipokines in particular remain exciting candidates for biomarkers in assessing the course of the disease and response to ECT treatment.

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

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

Pramipexole Augmentation for Treatment-Resistant Unipolar and Bipolar Depression in the Real World: A Systematic Review and Meta-Analysis

BACKGROUND

Pramipexole is a dopamine full agonist approved for the treatment of Parkinson's disease and restless legs syndrome. Its high affinity for the D3 receptor and neuroprotective, antioxidant, and anti-inflammatory activity provides a rationale for the treatment of depression. In this paper, we review studies on the effectiveness and safety of antidepressant pramipexole augmentation in treatment-resistant depression.

METHODS

This comprehensive systematic review and meta-analysis of observational studies on pramipexole-antidepressant augmentation included patients with resistant unipolar and bipolar depression. The primary outcome measure was the treatment response, measured at the study endpoint.

RESULTS

We identified 8 studies including 281 patients overall, 57% women and 39.5% with bipolar disorder and 60.5% with major depressive disorder. The mean follow-up duration was 27.3 weeks (range 8-69). The pooled estimate of treatment response was 62.5%, without significant differences between unipolar and bipolar depression. Safety was good, with nausea and somnolence the most frequent side effects.

CONCLUSIONS

The findings of this systematic review, needing further confirmation, show that off-label use of pramipexole as augmentation of antidepressant treatment could be a useful and safe strategy for unipolar and bipolar treatment-resistant depression.