Definition and Identification of Patients with Treatment-Resistant Depression in Real-World Clinical Practice Settings Across Asia

Effects of deep brain stimulation on dopamine D2 receptor binding in patients with treatment-refractory depression

BACKGROUND

Depression is a chronic psychiatric disorder related to diminished dopaminergic neurotransmission. Deep brain stimulation (DBS) has shown effectiveness in treating patients with treatment-refractory depression (TRD). This study aimed to evaluate the effect of DBS on dopamine D2 receptor binding in patients with TRD.

METHODS

Six patients with TRD were treated with bed nucleus of the stria terminalis (BNST)-nucleus accumbens (NAc) DBS were recruited. Ultra-high sensitivity [11C]raclopride dynamic total-body positron emission tomography (PET) imaging was used to assess the brain D2 receptor binding. Each patient underwent a [11C]raclopride PET scan for 60-min under DBS OFF and DBS ON, respectively. A simplified reference tissue model was used to generate parametric images of binding potential (BPND) with the cerebellum as reference tissue.

RESULTS

Depression and anxiety symptoms improved after 3-6 months of DBS treatment. Compared with two-day-nonstimulated conditions, one-day BNST-NAc DBS decreased [11C]raclopride BPND in the amygdala (15.9 %, p < 0.01), caudate nucleus (15.4 %, p < 0.0001) and substantia nigra (10.8 %, p < 0.01).

LIMITATIONS

This study was limited to the small sample size and lack of a healthy control group.

CONCLUSIONS

Chronic BNST-NAc DBS improved depression and anxiety symptoms, and short-term stimulation decreased D2 receptor binding in the amygdala, caudate nucleus, and substantia nigra. The findings suggest that DBS relieves depression and anxiety symptoms possibly by regulating the dopaminergic system.

Why the irremediability requirement is not sufficient to deny psychiatric euthanasia for patients with treatment-resistant depression

Treatment-resistant depression (TRD) holds centrality in many debates regarding psychiatric euthanasia. Among the strongest reasons cited by opponents of psychiatric euthanasia is the uncertainty behind the irremediability of psychiatric illnesses. According to this argument, conditions that cannot be considered irremediable imply that there are possible remedies that remain for the condition. If there are possible remedies that remain for the condition, then patients with that condition cannot be considered for access to euthanasia. I call this the irremediability requirement (IR). I argue that patients with TRD can, indeed, meet the operationalisation of irremediability in the IR. This is because the irremediability it asks for is not some global or absolute irremediability, but rather a present irremediability based on the current state of medical science. I show this by considering irremediability relating to (1) possible future treatments and (2) not trying presently available alternative treatments. I extend Schuklenk nd van de Vathorst's argument from parity to terminal malignancies, to show that (1) is an unreasonable expectation for all cases of euthanasia. Taking (2) as a more serious opponent to psychiatric euthanasia, I show how the IR, based on how it is presently operationalised, can be realistically applied to cases of TRD. I do this by further developing Tully's argument on broad-sense treatment resistance with the robust empirical data from the STAR*D trials. If my argument from Tully's is valid, then we have reasons to, again, seek parity between the operationalisations of irremediability in terminal malignancies and TRD.

Longitudinal Outcomes of Resilience, Quality of Life, and Community Integration in Treatment-Resistant Depression: A Two-Group Matched Controlled Trial

BACKGROUND

Current evidence of nonpharmacological intervention for patients with treatment-resistant depression (TRD) is lacking. AIMS: To examine whether an 8-week nurse-led cognitive-behavioral based group intervention would enhance resilient coping and life quality among community-based patients with TRD.

METHOD

The participants were randomly sampled from a cohort of TRD recruited from two general teaching hospitals. The two groups were assessed with multiple outcome measures at baseline (T0); 8-week post-baseline (T1); and at 3, 6, and 9 months after T1 (T2-4). Psychoeducation was nested in the cognitive behavioral group intervention to facilitate discussion.

RESULTS

Of the 23 participants (mean age 56 years, 69.6% female) in the experimental group, higher resilient coping and lower mental distress levels at T1 as well as later improved quality of life and community integration at T2-4 were observed compared to the controls across COVID-19 (T3). Overall, the scores of resilience and community integration were higher throughout the four follow-up points of observations for the experimental group.

CONCLUSION

The findings indicated that an 8-week nurse-led cognitive-behavioral based group intervention may enhance the TRD patients' resilient coping and mental distress levels while providing the potentials for community reintegration after mental health psychoeducation engagement. It is imperative for the nurses caring for patients with TRD to extend from clinical-based intervention to community-based self-care approach, with the importance of short-term stress management and healthy lifestyle development highlighted during the community reintegration trajectory.

Modulation of resting-state functional connectivity in default mode network is associated with the long-term treatment outcome in major depressive disorder

BACKGROUND

Treatment non-response and recurrence are the main sources of disease burden in major depressive disorder (MDD). However, little is known about its neurobiological mechanism concerning the brain network changes accompanying pharmacotherapy. The present study investigated the changes in the intrinsic brain networks during 6-month antidepressant treatment phase associated with the treatment response and recurrence in MDD.

METHODS

Resting-state functional magnetic resonance imaging was acquired from untreated patients with MDD and healthy controls at baseline. The patients' depressive symptoms were monitored by using the Hamilton Rating Scale for Depression (HAMD). After 6 months of antidepressant treatment, patients were re-scanned and followed up every 6 months over 2 years. Traditional statistical analysis as well as machine learning approaches were conducted to investigate the longitudinal changes in macro-scale resting-state functional network connectivity (rsFNC) strength and micro-scale resting-state functional connectivity (rsFC) associated with long-term treatment outcome in MDD.

RESULTS

Repeated measures of the general linear model demonstrated a significant difference in the default mode network (DMN) rsFNC change before and after the 6-month antidepressant treatment between remitters and non-remitters. The difference in the rsFNC change over the 6-month antidepressant treatment between recurring and stable MDD was also specific to DMN. Machine learning analysis results revealed that only the DMN rsFC change successfully distinguished non-remitters from the remitters at 6 months and recurring from stable MDD during the 2-year follow-up.

CONCLUSION

Our findings demonstrated that the intrinsic DMN connectivity could be a unique and important target for treatment and recurrence prevention in MDD.

Overview of treatment-resistant depression

Patients with major depressive disorder (MDD) often exhibit an inadequate treatment response or failure to achieve remission following treatment with antidepressant drugs. Treatment-resistant depression (TRD) is proposed to identify this clinical scenario. Compared to those without TRD, patients with TRD have significantly lower health-related quality of life in mental and physical dimensions, more functional impairment and productivity loss, and higher healthcare costs. TRD imposes a massive burden on the individual, family, and society. However, a lack of consensus on the TRD definition limits the comparison and interpretation of TRD treatment efficacy across trials. Furthermore, because of the various TRD definitions, there is scarce treatment guideline specifically for TRD, in contrast to the rich treatment guidelines for MDD. In this chapter, common issues related to TRD, such as proper definitions of an adequate antidepressant trial and TRD, were carefully reviewed. Prevalence of and clinical outcomes related to TRD were summarized. We also summarized the staging models ever proposed for the diagnosis of TRD. Furthermore, we highlighted variations in the definition regarding the lack of or an inadequate response in treatment guidelines for depression. Up-to-date treatment options for TRD, including pharmacological strategies, psychotherapeutic interventions, neurostimulation techniques, glutamatergic compounds, and even experimental agents were reviewed.

Prognostic Significance of Blood-Based Baseline Biomarkers in Treatment-Resistant Depression: A Literature Review of Available Studies on Treatment Response

Major depressive disorder is a leading cause of disability worldwide and a major contributor to the overall global burden of disease. While there are several options for antidepressant treatment, only about 40–60% of patients respond to initial monotherapy, while 30–40% of patients may even show resistance to treatment. This article offers a narrative review of those studies evaluating the predictive properties of various blood-based baseline biomarkers regarding treatment responses to the pharmacological, stimulation, or behavioral treatment of patients with treatment-resistant depression (TRD). Our results show that overall, there is only a very limited number of studies assessing baseline peripheral biomarkers regarding treatment response in TRD. Although there is some evidence for the predictive significance of particular biomarkers (e.g., IL-6, CRP, BDNF), the majority of the results are either single-study reports or studies with conflicting results. This may contribute to the wide variety of treatment protocols and different TRD definition criteria, the small number of patients included, and the existence of different biological phenotypes of the disorder used within the various studies. Taken together, there does not yet appear to be any specific baseline peripheral biomarker with sufficient discriminative predictive validity that can be used in the routine clinical practice of TRD. The discovery of new biomarkers and the better clinical characterization of known biomarkers could support the better classification and staging of TRD, the development of personalized treatment algorithms with higher rates of remission and fewer side effects, and the development of new precision drugs for specific subgroups of patients.

Associations of Suicide Risk and Community Integration Among Patients With Treatment-Resistant Depression

INTRODUCTION

Treatment-resistant depression (TRD) is one of the primary causes of disability and a major risk for suicide among patients living in the community. However, the suicide risks and care needs for safety among patients with TRD during the community reintegration process appear to be underestimated. This study aimed to investigate the association between community integration and suicide risks among patients with treatment-resistant depression (TRD) with sub-analysis by gender.

METHODS

Patients diagnosed with major depressive disorder were recruited upon psychiatrists' referral in two general hospitals in northern Taiwan during 2018-2019. The participants who experienced more than two failed treatments of antidepressants with partial remission were defined as TRD. A structured questionnaire was used to collect socio-demographic, suicidality, and psychosocial information.

RESULTS

In a total of 125 participants, gender difference was identified in certain community integration aspects such as home integration, productivity, and electronic social networking. The male participants appeared to have better involvement in social contact with internet but slightly less video link than women, while women had higher level of home integration in the past month. The participants who performed worse in the social integration and better home-based activity or productivity levels had higher suicide risks including suicide ideation and overall suicide risks.

CONCLUSIONS

Community integration levels of home, social, and productivity were associated with suicidality in terms of overall suicide risk and recent suicide ideation. Facilitation of community integration at home and life arrangements might reduce suicide risks in TRD patients.

Blood transcriptional response to treatment-resistant depression during electroconvulsive therapy

Selective serotonin reuptake inhibitors (SSRIs) are currently the first-line antidepressant drug treatment for major depressive disorder (MDD). Treatment-resistant depression (TRD), defined as failure to achieve remission despite adequate treatment, affects ~30% of persons with MDD. The current recommended treatment for TRD is electroconvulsive therapy (ECT), while ketamine is an experimentally suggested treatment. This study aimed to elucidate the transcriptional differences in peripheral blood mononuclear cells (PBMC) between individuals with TRD and a control group without a psychiatric illness; and between patients with TRD, treated with either standard antidepressant drugs alone, or in combination with ECT or ketamine. Additionally, PBMC transcriptomics were compared between treatment responders, following completion of their treatment protocols. Total RNA was extracted from PBMC of the TRD group at two time points, and RNA and miRNA expression were profiled. Multiple mRNAs and miRNAs were found to be modified, with two protein coding genes, FKBP5 and ITGA2B, which are up- and downregulated, respectively; and several miRNAs have shown changes following successful ECT treatment. Further analysis demonstrated the direct functional regulation of ITGA2B by miR-24-3p. Our findings suggest that PBMC expression levels of FKBP5, ITGA2B, and miR-24-3p should be further explored as tentative ECT response biomarkers.