Treatment resistant depression and axis I co-morbidity

Use of transcranial magnetic stimulation (TMS) for studying cognitive control in depressed patients: A systematic review

Major depressive disorder (MDD) is a debilitating mental disorder and the leading cause of disease burden. Major depressive disorder is associated with emotional impairment and cognitive deficit. Cognitive control, which is the ability to use perceptions, knowledge, and information about goals and motivations to shape the selection of goal-directed actions or thoughts, is a primary function of the prefrontal cortex (PFC). Psychotropic medications are one of the main treatments for MDD, but they are not effective for all patients. An alternative treatment is transcranial magnetic stimulation (TMS). Previous studies have provided mixed results on the cognitive-enhancing effects of TMS treatment in patients with MDD. Some studies have found significant improvement, while others have not. There is a lack of understanding of the specific effects of different TMS protocols and stimulation parameters on cognitive control in MDD. Thus, this review aims to synthesize the effectiveness of the TMS methods and a qualitative assessment of their potential benefits in improving cognitive functioning in patients with MDD. We reviewed 21 studies in which participants underwent a treatment of any transcranial magnetic stimulation protocol, such as repetitive TMS or theta-burst stimulation. One of the primary outcome measures was any change in the cognitive control process. Overall, the findings indicate that transcranial magnetic stimulation (TMS) may enhance cognitive function in patients with MDD. Most of the reviewed studies supported the notion of cognitive improvement following TMS treatment. Notably, improvements were predominantly observed in inhibition, attention, set shifting/flexibility, and memory domains. However, fewer significant improvements were detected in evaluations of visuospatial function and recognition, executive function, phonemic fluency, and speed of information processing. This review found evidence supporting the use of TMS as a treatment for cognitive deficits in patients with MDD. The results are promising, but further research is needed to clarify the specific TMS protocol and stimulation locations that are most effective.

Signature-based approaches for informed drug repurposing: targeting CNS disorders

CNS disorders, and in particular psychiatric illnesses, lack definitive disease-altering therapeutics. The limited understanding of the mechanisms driving these illnesses with the slow pace and high cost of drug development exacerbates this issue. For these reasons, drug repurposing - both a less expensive and time-efficient practice compared to de novo drug development - has been a promising strategy to overcome the paucity of treatments available for these debilitating disorders. While empirical drug-repurposing has been a routine practice in clinical psychiatry, innovative, informed, and cost-effective repurposing efforts using big data ("omics") have been designed to characterize drugs by structural and transcriptomic signatures. These strategies, in conjunction with ontological integration, provide an important opportunity to address knowledge-based challenges associated with drug development for CNS disorders. In this review, we discuss various signature-based in silico approaches to drug repurposing, its integration with multiple omics platforms, and how this data can be used for clinically relevant, evidence-based drug repurposing. These tools provide an exciting translational avenue to merge omics-based drug discovery platforms with patient-specific disease signatures, ultimately facilitating the identification of new therapies for numerous psychiatric disorders.

Prediction on treatment improvement in depression with resting state connectivity: A coordinate-based meta-analysis

BACKGROUND

Previous neuroimaging studies revealed abnormal resting-state functional connectivity between distributed brain areas in patients with major depressive disorder. Those abnormalities were normalized after treatment. Moreover, the functional connectivity could predict clinical response to those treatments. However, there has currently been no meta-analysis to verify these findings.

METHODS

The current study aimed to investigate how the resting-state connectivity patterns predict antidepressant response to various treatments across depressive studies by using coordinate-based meta-analysis named activation likelihood estimation. The relevant articles were obtained by searching on PubMed and Web of Science.

RESULTS

Following exclusion criteria of inappropriate studies, seventeen papers with 392 individual depressive patients were included. Those articles contained repetitive transcranial magnetic stimulation (rTMS) treatment, pharmacotherapy, cognitive behavioral therapy (CBT), electroconvulsive therapy (ECT) and transcutaneous vagus nerve stimulation in patients with depression. Meta-analysis revealed that clinical response to all treatments could be predicted by baseline default mode network connectivity in patients with depression. The rTMS treatment had larger effect size compared to other treatment strategies. Furthermore, subgroup meta-analysis showed that the baseline connectivity of perigenual anterior cingulate cortex (pgACC) and ventral medial prefrontal cortex could predict symptoms improvement of rTMS treatment.

LIMITATIONS

More resting-state connectivity studies of CBT and ECT treatment are needed.

CONCLUSIONS

This study highlighted crucial role of DMN, especially the pgACC, in understanding the underlying treatment mechanism of depression.

miR‑155 mediates inflammatory injury of hippocampal neuronal cells via the activation of microglia

MicroRNA (miR)-155 has a crucial role in various cellular functions, including differentiation of hematopoietic cells, immunization, inflammation and cardiovascular diseases. The present study aimed to investigate the roles and mechanisms of miR-155 in treatment-resistant depression (TRD). A Cell Counting Kit-8 assay and flow cytometry were performed to assess the cell viability and apoptosis of microglial cells, respectively. Western blotting and reverse transcription-quantitative polymerase chain reaction assays were used to evaluate the associated protein and mRNA expression, respectively. The results revealed that miR-155 reduced the cell viability of BV-2 microglial cells, and miR-155 enhanced the expression levels of pro-inflammatory cytokines in BV-2 microglial cells. Furthermore, conditioned medium from miR-155-treated microglia decreased the cell viability of HT22 hippocampal cells. miR-155-treated microglia increased the apoptosis of neuronal hippocampal cells by modulating the expression levels of apoptosis regulator Bax, apoptosis regulator Bcl-2, pro-caspase-3 and cleaved-caspase-3. The cell cycle distribution was disrupted by miR-155-treated microglia through induction of S phase arrest. Furthermore, the overexpression of suppressor of cytokine signaling 1 reversed the pro-apoptotic effect of activated microglia on hippocampal neuronal cells. In conclusion, the present results suggested that miR-155 mediated the inflammatory injury in hippocampal neuronal cells by activating the microglial cells. The potential effects of miR-155 on the activation of microglial cells suggest that miR-155 may be an effective target for TRD therapies.

Number of illness episodes as predictor of residual symptoms in major depressive disorder

Notwithstanding major depressive disorder (MDD) is a recurring and chronic condition, relatively few variables have consistently been shown to predict its course. Residual depressive symptoms may be associated with disability and functional impairment but few studies evaluated clinical correlates associated with these symptoms and their impact on functioning after adjustment for potential confounders. Therefore, our study aimed to investigate factors associated with residual depressive symptoms and their impact on the course of MDD. The sample consisted of 210 consecutive MDD euthymic outpatients (67.6% females; mean age = 52.1 ± 15.5), admitted to the Section of Psychiatry, University of Genoa (Italy). Residuals depressive symptoms were significantly associated with female gender; use of short half-life benzodiazepines; longer duration of the current depressive episode; higher number of illness episodes; and higher duration of illness. Conversely, prior treatment with first-generation antipsychotics, later age of illness onset and first hospitalization were less frequently observed among patients with residual symptoms. After multivariate analyses, only duration of current illness episodes (ß = 0.003; p = <0.005) and substance abuse (ß = 0.042; p = <0.05) remained significantly associated with residual symptoms. Our findings indicate that residual depressive symptoms conferred a pernicious illness course in this specific cohort of MDD patients. Future trials mainly targeting these burdensome symptoms are warranted.

Antidepressant combination versus antidepressants plus second-generation antipsychotic augmentation in treatment-resistant unipolar depression

Patients with treatment-resistant unipolar depression (TRD) are treated with antidepressant combinations (ADs) or with second-generation antipsychotics plus AD (SGA+AD) augmentation; however, the clinical characteristics, the factors associated independently with response to SGA+AD, and the outcome trajectories have not yet been characterized. We performed a naturalistic study on the latest stable trial (medication unchanged for about 3 months) in 86 TRD patients with resistance to at least two ADs trials, who received ADs (n=36) or SGA+AD (n=50) treatments. Montgomery-Asberg Depression Rating Scale (MADRS), Hamilton-Depression Rating Scale (HAM-D17), and other scales were administered before (T0) and after the latest 3-month stable trial (T3). Compared to ADs, the SGA+AD group showed increased percentage of depression with psychotic features, comorbidity for personality disorders and substance use disorders (SUD), higher number of failed ADs pharmacotherapies and depressive symptoms at T0 on all scales (P<0.001). Compared to T0, both treatments significantly decreased depressive symptoms on MADRS and HAM-D17 at T3 (P<0.001); however, the SGA+AD augmentation produced a greater decline in mean score. Logistic regression analysis indicated that psychotic features, personality disorders, and SUD were independently associated with SGA+AD treatment. Given the greater improvement in depression following SGA+AD augmentation, SGA augmentation should be indicated as a first-line treatment in severe TRD with psychotic features, SUD, and personality disorders.

Pathogenic beliefs among patients with depressive disorders

INTRODUCTION

Pathogenic belief is a central construct within control-mastery theory, which is an integrated dynamic-cognitive-relational approach in psychotherapy. Pathogenic beliefs result from traumatic life experiences and are considered the root of any psychological disorders presented clinically. Nevertheless, how and what type of pathogenic beliefs are attributed to clinical depressive disorder is unknown. The present study aimed to examine this issue.

PATIENTS AND METHODS

Thirty patients with depressive disorder, who came for psychotherapy at a psychotherapy clinic, were matched based on age and gender with healthy controls who were medical students. The 54-item pathogenic belief scale (PBS) was administered and compared between depressive and control groups using odds ratio (OR).

RESULTS

The depressed group's PBS mean score was significantly higher than the healthy controls (t=3.78, P<0.001). Thirteen of 54 items significantly differed between the two groups with ORs ranging from 3.76 to 16.79. The content of pathogenic beliefs centered on the issues of negative sense of self, lack of self-efficacy and control, and relational difficulties related to feelings of fear and humiliation. Influences of culture and gender differences on pathogenic beliefs were discussed.

CONCLUSION

Pathogenic beliefs relate to depression such that the higher the number of pathogenic beliefs one has, the more the likelihood of having depression. Since the PBS was developed based on clinical data (rather than theory based), cultural issues as well as age and gender may influence the development of pathogenic beliefs. Further study should be warranted and implications for clinical practice are discussed.

Socio-demographic and clinical predictors of non-response/non-remission in treatment resistant depressed patients: A systematic review

Up to one third of patients adequately treated for Major Depressive Disorder (MDD) do not respond to multiple interventions. Many studies investigated predictors in MDD outcome, but no study focused on predictors of non-response or non-remission to antidepressants in subjects with treatment resistant depression (TRD). The present study aimed to evaluate possible socio-demographic and clinical predictors of non-response and non-remission in MDD patients who failed to benefit from at least one antidepressant trial. A total of 51 papers were included. A number of severity indicators, such as longer duration of depressive episode, moderate-high suicidal risk, anxious comorbidity, higher number of hospitalizations and higher dosage of antidepressants, were associated with non-response as well as age. Interestingly, severity of illness, as well as comorbid personality disorders and anxiety symptoms, had also a predictive value in non-remission with the addition of marital status. Considering limitations, selected studies were observational or randomized non controlled/controlled trials and different TRD definitions and outcome measures were used. Overall, predictors of outcome were similar to MDD, but specific socio-demographic and clinical factors should be considered in clinical practice to formulate a more focused treatment in TRD patients.

The effects of repetitive transcranial magnetic stimulation on cognitive performance in treatment-resistant depression. A systematic review

BACKGROUND

Major depressive disorder (MDD) is a disabling illness associated with significant functional and psychosocial impairment. Although many psychopharmacological agents are currently available for its treatment, many MDD patients suffer from treatment-resistant depression (TRD).

METHODS

A systematic review of the current literature (Pubmed/Medline, Scopus and ScienceDirect search) has been conducted with the primary aim to investigate the role of repetitive transcranial magnetic stimulation (rTMS) in improving neurocognition in patients with TRD. Studies were included according to the following criteria: (a) being an original paper in a peer-reviewed journal and (b) having analyzed the effect of rTMS on neurocognitive functioning in TRD.

RESULTS

The combined search strategy yielded a total of 91 articles, of which, after a complete analysis, 22 fulfilled our inclusion criteria. Based on the main findings, most of the selected studies suggested the existence of a trend towards improvements in the neurocognitive profile using rTMS. Negative findings have also been reported. However, most studies were limited by their small sample size or included mixed samples, or the adopted single-blind designs potentially biased the blinding of the study design.

CONCLUSION

rTMS is a noninvasive brain stimulation that may be considered a valuable and promising technique for cognitive enhancement in TRD.

Socio-demographic and clinical predictors of treatment resistant depression: A prospective European multicenter study

BACKGROUND

Few studies investigated socio-demographic and clinical predictors of non response and remission in treatment resistant depression (TRD) in the case of failure of more than two adequate antidepressant (AD) trial. The primary aim of this study was to investigate socio-demographic and clinical predictors of TRD defined as the lack of response to at least three adequate AD treatments, two of which prospectively evaluated. As secondary aims, we also investigated predictors of non response and remission to: (1) at least two adequate AD treatment (one of which prospectively assessed); (2) at least one adequate and retrospectively assessed AD treatment.

METHODS

In the context of a European multicenter project, 407 major depressive disorder (MDD) patients who failed to respond to a previous AD treatment were recruited for a 2 stage trial, firstly receiving venlafaxine and then escitalopram. MINI, HRSD, MADRS, UKU, CGI-S and CGI-I were administered.

RESULTS

Ninety eight subjects (27.61%) were considered as resistant to three AD treatments. Clinical predictors were: longer duration and higher severity of the current episode (p=0.004; ES=0.24; p=0.01; RR=1.41, respectively), outpatient status (p=0.04; RR=1.58), higher suicidal risk level (p=0.02; RR=1.49), higher rate of the first/second degree psychiatric antecedents (MDD and others) (p=0.04; RR=1.31, p=0.03; RR=1.32 respectively) and side effects during treatments (p=0.002; RR=2.82). Multivariate analyses underlined the association between TRD and the severity of the current episode (p=0.04). As for secondary outcomes, predicting factors were partially overlapping.

LIMITATIONS

The limited sample size and specific drugs used limit present findings.

CONCLUSION

Subjects with a high degree of resistance to AD treatments show specific features which may guide the clinicians to the choice of more appropriate therapies at baseline.

Significantly decreased mRNA levels of BDNF and MEK1 genes in treatment-resistant depression

The aim of the current study was to investigate whether the levels of mRNA expression of brain-derived neurotrophin factor (BDNF) and a related gene MEK1 were more obviously decreased in treatment-resistant depression (TRD). In total, 50 patients with major depressive disorder (including 26 with TRD and 24 with treatment-responsive depression) and 48 healthy controls were enrolled. BDNF and MEK1 mRNA levels in blood samples from all patients and controls were measured using reverse transcriptase-PCR. BDNF and MEK1 mRNA levels were significantly reduced in patients with major depressive disorder when compared with healthy controls (BDNF: P<0.01; MEK1: P<0.001), as well as among treatment-resistant depressive patients as compared with treatment-responsive depressive patients (BDNF: P<0.001; MEK1: P<0.01). Our findings support the hypothesis that BDNF and MEK1 mRNA expression levels are more obviously decreased in patients with TRD.

Disrupted structural connectivity network in treatment-naive depression

BACKGROUND

Neuroimaging studies suggest that treatment-naive depression (TD) is characterized by abnormal functional connectivity between specific brain regions. However, the question surrounding the structural basis of functional aberrations in TD patients still remains.

METHODS

In the present study, diffusion tensor imaging tractography was employed to construct structural connectivity networks in 22 early adult-onset, first-episode TD patients and 19 healthy controls (HC). Graph theory and network-based statistic (NBS) were then employed to investigate systematically the alteration of whole brain structural topological organization and structural connectivity in TD patients.

RESULTS

Graph theoretical analysis revealed that, compared with HC, TD patients exhibited altered structural topological measures, including decreased shortest path length, normalized clustering coefficient, normalized shortest path length, and small-worldness, as well as increased global and local efficiency. NBS results further revealed that TD patients showed two altered structural sub-networks. One sub-network mainly involved connections between the right orbitofrontal cortex (OFC) and the right insula, putamen, caudate, hippocampus, fusiform gyrus, inferior temporal gyrus and lingual gyrus. The other sub-network mainly included connections between the left OFC and the left gyrus rectus, insula, putamen, caudate, thalamus, pallidum and middle occipital gyrus.

CONCLUSIONS

The findings suggest that TD patients exhibit a disruption in the topological organization of structural brain networks. The altered orbitofrontal connectivity may particularly contribute to the manifestation of symptoms in TD patients. The abnormalities may facilitate understanding of the functional disturbances of mood and cognition in the disease.

The role of ketamine in treatment-resistant depression: a systematic review

Background:

At least 10-20% of the patients suffering from depression meet criteria for treatment-resistant depression (TRD). In the last decades, an important role of glutamate in mood modulation has been hypothesized and ketamine, a non noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptors, has been demonstrated to be effective in both MDD and TRD. However, concerns emerged about the optimal dosage, and frequency of administration of this treatment.

Methods:

aiming to systematically review the current literature focusing on the main pharmacological properties and impact of ketamine in TRD, a detailed literature search in PubMed/Medline and ScienceDirect databases was conducted. Twenty-four manuscripts including a total of 416 patients fulfilled inclusion criteria.

Results:

Most studies demonstrated that the NMDA antagonist ketamine has rapid antidepressant effects in TRD patients, confirming the active role of glutamate in the pathophysiology of this complex condition. Ketamine has been demonstrated to be rapidly effective and was associated with a significant clinical improvement in depressive symptoms within hours after administration. Also, ketamine was also found to be effective in reducing suicidality in TRD samples.

Limitations:

The long-term efficacy of ketamine has not been investigated by most studies. The psychotomimetic properties may complicate the application of this pharmacological agent.

Conclusions:

Ketamine may be considered a valid and intriguing antidepressant option for the treatment of TRD. Further studies are needed to evaluate its long-term antidepressant efficacy in patients with TRD.

Decreased interhemispheric coordination in treatment-resistant depression: a resting-state fMRI study

Background

Previous studies have demonstrated that patients with treatment-resistant depression (TRD) and treatment-sensitive depression (TSD) differed at neural level. However, it remains unclear if these two subtypes of depression differ in the interhemispheric coordination. This study was undertaken for two purposes: (1) to explore the differences in interhemispheric coordination between these two subtypes by using the voxel-mirrored homotopic connectivity (VMHC) method; and (2) to determine if the difference of interhemispheric coordination can be used as a biomarker(s) to differentiate TRD from both TSD and healthy subjects (HS).

Methods

Twenty-three patients with TRD, 22 with TSD, and 19 HS participated in the study. Data of these participants were analyzed with the VMHC and seed-based functional connectivity (FC) approaches.

Results

Compared to the TSD group, the TRD group showed significantly lower VMHC values in the calcarine cortex, fusiform gyrus, hippocampus, superior temporal gyrus, middle cingulum, and precentral gyrus. Lower VMHC values were also observed in the TRD group in the calcarine cortex relative to the HS group. However, the TSD group had no significant change in VMHC value in any brain region compared to the HS group. Receiver operating characteristic curves (ROC) analysis revealed that the VMHC values in the calcarine cortex had discriminatory function distinguishing patients with TRD from patients with TSD as well as those participants in the HS group.

Conclusions

Lower VMHC values of patients with TRD relative to those with TSD and those in the HS group in the calcarine cortex appeared to be a unique feature for patients with TRD and it may be used as an imaging biomarker to separate patients with TRD from those with TSD or HS.

Abnormal resting-state cerebellar-cerebral functional connectivity in treatment-resistant depression and treatment sensitive depression

BACKGROUND

Previous studies have commonly shown that patients with treatment-resistant depression (TRD) and treatment-sensitive depression (TSD) demonstrate a different cerebellar activity. No study has yet explored resting-state cerebellar-cerebral functional connectivity (FC) in these two groups. Here, seed-based FC approach was employed to test the hypothesis that patients with TRD and TSD had a different cerebellar-cerebral FC. The identified FC might be used to differentiate TRD from TSD.

METHODS

Twenty-three patients with TRD, 22 patients with TSD, and 19 healthy subjects (HS) matched with age, gender, and education level participated in the scans. Seed-based connectivity analyses were performed by using cerebellar seeds.

RESULTS

Relative to HS, both patient groups showed significantly decreased cerebellar-cerebral FC with the prefrontal cortex (PFC) (superior, middle, and inferior frontal gyrus) and default mode network (DMN) [superior, middle, and inferior temporal gyrus, precuneus (PCu), and inferior parietal lobule (IPL)], and increased FC with visual recognition network (lingual gyrus, middle occipital gyrus, and fusiform) and parahippocampal gyrus. However, the TRD group exhibited a more decreased FC than the TSD group, mainly in connected regions within DMN [PCu, angular gyrus (AG) and IPL]. Further receiver operating characteristic curves (ROC) analyses showed that cerebellar-DMN couplings could be applied as markers to differentiate the two subtypes with relatively high sensitivity and specificity.

CONCLUSIONS

Both patient groups demonstrate similar pattern of abnormal cerebellar-cerebral FC. Decreased FC between the cerebellum and regions within DMN might be used to separate the two patient groups.

Decreased interhemispheric resting-state functional connectivity in first-episode, drug-naive major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is shown to have structural and functional abnormalities in specific brain areas and connections by recent neuroimaging studies. However, little is known about the alterations of the interhemispheric resting-state functional connectivity (FC) in patients with MDD. In the present study, we used a newly developed voxel-mirrored homotopic connectivity (VMHC) method to investigate the interhemispheric FC of the whole brain in patients with MDD at rest.

METHODS

Twenty-four first-episode, drug-naive patients with MDD and 24 age-, gender-, and education-matched healthy subjects underwent a resting-state functional magnetic resonance imaging (fMRI). An automated VMHC approach was used to analyze the data.

RESULTS

Patients with MDD showed lower VMHC than healthy subjects in the medial prefrontal cortex (MPFC) and the posterior cingulate cortex/precuneus (PCC/PCu), two core regions within default mode network (DMN). Both left and right MPFC showed reduced FC with the other frontal areas and with right anterior cingulate gyrus (ACC), while PCC/PCu exhibited abnormal FC with the frontal areas and thalamus in patient group. Significant positive correlation was observed between VMHC in MPFC and persistent error response of Wisconsin Card Sorting Test (WCST-Pre) in patients. Further ROC analysis revealed that VMHC in the MPFC and PCC/PCu could be used to differentiate the patients from healthy subjects with relatively high sensitivity and specificity.

CONCLUSIONS

Our results suggest that decreased VMHC in brain regions within DMN may underlie the pathogenesis of MDD.

Abnormal neural activity of brain regions in treatment-resistant and treatment-sensitive major depressive disorder: a resting-state fMRI study

BACKGROUND

Patients with treatment-resistant depression (TRD) and those with treatment-sensitive depression (TSD) responded to antidepressants differently. Previous studies have commonly shown that patients with TRD or TSD had abnormal neural activity in different brain regions. In the present study, we used a coherence-based ReHo (Cohe-ReHo) approach to test the hypothesis that patients with TRD or TSD had abnormal neural activity in different brain regions.

METHODS

Twenty-three patients with TRD, 22 with TSD, and 19 healthy subjects (HS) matched with gender, age, and education level participated in the study.

RESULTS

ANOVA analysis revealed widespread differences in Cohe-ReHo values among the three groups in different brain regions which included bilateral superior frontal gyrus, bilateral cerebellum, left inferior temporal gyrus, left occipital cortex, and both sides of fusiform gyrus. Compared to HS, lower Cohe-ReHo values were observed in TRD group in bilateral superior frontal gyrus and left cerebellum; in contrast, in TSD group, lower Cohe-ReHo values were mainly found in bilateral superior frontal gyrus. Compared to TSD group, TRD group had lower Cohe-ReHo in bilateral cerebellum and higher Cohe-ReHo in left fusiform gyrus. There was a negative correlation between Cohe-ReHo values of the left fusiform gyrus and illness duration in the pooled patients (r = 0.480, p = 0.001). The sensitivity and specificity of cerebellar Cohe-ReHo values differentiating TRD from TSD were 83% and 86%, respectively.

CONCLUSIONS

Compared to healthy controls, both TRD and TSD patients shared the majority of brain regions with abnormal neural activity. However, the lower Cohe-ReHo values in the cerebellum might be as a marker to differentiate TRD from TSD with high sensitivity and specificity.

Altered white matter integrity of forebrain in treatment-resistant depression: a diffusion tensor imaging study with tract-based spatial statistics

BACKGROUND

The association between alterations of the white matter (WM) integrity in brain regions and mood dysregulation has been reported in major depressive disorder (MDD). However, there has never been a neuroimaging study in patients who have treatment-resistant depression (TRD) and are in a current treatment-resistant state. In the present study, we used diffusion tensor imaging (DTI) with tract-based spatial statistics (TBSS) method to investigate the WM integrity of different brain regions in patients who had TRD and were in a current treatment-resistant state.

METHODS

Twenty-three patients with TRD and Hamilton Rating Scale total score of ≥18 and 19 healthy controls matched with age, gender, and education level to patients were scanned with DTI. Thirty 4 mm thick, no gap, contiguous axial slices were acquired and fractional anisotropy (FA) images were generated for each participant. An automated TBSS approach was used to analyze the data.

RESULTS

Voxel-wise statistics revealed that patients with TRD had lower FA values in the right anterior limb of internal capsule, the body of corpus callosum, and bilateral external capsule compared to healthy subjects. Patients with TRD did not have increased FA values in any brain regions compared to healthy subjects. There was no correlation between the FA values in any brain region and patients' demographics and the severity of illness.

CONCLUSIONS

Our findings suggest the abnormalities of the WM integrity of neuronal tracts connecting cortical and subcortical nuclei and two brain hemispheres may play a key role in the pathogenesis of TRD.

Alterations of the amplitude of low-frequency fluctuations in treatment-resistant and treatment-response depression: a resting-state fMRI study

BACKGROUND

Patients with treatment-resistant depression (TRD) and those with treatment-response depression (TSD) respond to antidepressants differently and previous studies have commonly reported different brain networks in resistant and nonresistant patients. Using the amplitude of low-frequency fluctuations (ALFF) approach, we explored ALFF values of the brain regions in TRD and TSD patients at resting state to test the hypothesis of the different brain networks in TRD and TSD patients.

METHODS

Eighteen TRD patients, 17 TSD patients and 17 gender-, age-, and education-matched healthy subjects participated in the resting-state fMRI scans.

RESULTS

There are widespread differences in ALFF values among TRD patients, TSD patients and healthy subjects throughout the cerebellum, the visual recognition circuit (middle temporal gyrus, middle/inferior occipital gyrus and fusiform), the hate circuit (putamen), the default circuit (ACC and medial frontal gyrus) and the risk/action circuit (inferior frontal gyrus). The differences in brain circuits between the TRD and TSD patients are mainly in the cerebellum, the visual recognition circuit and the default circuit.

CONCLUSIONS

The affected brain circuits of TRD patients might be partly different from those of TSD patients.

Staging methods for treatment resistant depression. A systematic review

BACKGROUND

Treatment resistant depressant (TRD) is classified in different staging models, but these are not used routinely. We aimed to identify staging models for TRD and compare them regarding predictive utility and reliability.

METHODS

Systematic review of Pubmed, Embase and PsycINFO (1985-January 2010) without language limits, plus articles identified from reference lists of previous reviews. We excluded articles focusing on TRD treatment. We qualitatively summarized characteristics of the identified staging models, describing strengths and limitations for each model. If available, we reported results of validation studies.

RESULTS

From 950 retrieved articles five staging models were found; the Antidepressant Treatment History Form, Thase and Rush Model, European Staging Model, Massachusetts General Hospital Staging model and the Maudsley Staging Model (MSM). Six studies investigated the predictive utility (of four models). We observed an evolution from single antidepressant adequacy ratings, towards a multidimensional and more continuous scored staging model which also introduced TRD characteristics (severity and duration). The operationalization criteria improved; the scoring of different treatment strategies (between/within class switching and augmentation/combination) changed according to the existing evidence. Over time, efforts to validate models improved. The predictive utility was assessed best for the MSM.

LIMITATIONS

Few staging models existed; their reliability was hardly assessed.

CONCLUSIONS

Despite validation of the MSM, further investigation of the reliability and predictive utility of TRD staging models and additional disease characteristics is required. Correct staging of TRD might improve generalizability of results from clinical studies and improve delivery of care to TRD patients. We propose methods to validate staging models in TRD.

Disrupted regional homogeneity in treatment-resistant depression: a resting-state fMRI study

BACKGROUND

Using a newly developed regional homogeneity (ReHo) approach, we were to explore the features of brain activity in patients with treatment-resistant depression (TRD) in resting state, and further to examine the relationship between abnormal brain activity in TRD patients and specific symptom factors derived from ratings on the Hamilton Rating Scale for Depression (HRSD).

METHODS

24 patients with TRD and 19 gender-, age-, and education-matched healthy subjects participated in the fMRI scans.

RESULTS

1. Compared with healthy controls, decreased ReHo were found in TRD patients in the left insula, superior temporal gyrus, inferior frontal gyrus, lingual gyrus and cerebellumanterior lobe (culmen) (p<0.05, corrected). 2. Compared with healthy controls, increased ReHo were found in the left superior temporal gyrus, cerebellum posterior lobe (tuber), cerebellum anterior lobe (culmen), the right cerebellar tonsil and bilateral fusiform gyrus (p<0.05, corrected). 3. There was no correlation between the ReHo values in any brain region detected in our study and the patients' age, years of education, illness duration, HRSD total score and its symptom factors.

LIMITATION

The influence of antidepressants to the brain activity in TRD patients was not fully eliminated.

CONCLUSIONS

The pathogenesis of TRD may be attributed to abnormal neural activity in multiple brain regions.

Acetylsalicylic acid as an augmentation agent in fluoxetine treatment resistant depressive rats

Clinical studies have reported that adjunctive acetylsalicylic acid (aspirin) therapy is beneficial for patients with treatment resistant depression (TRD). However, there still exist negative epidemiological data on the link between aspirin and depression. Therefore, this study aimed to further investigate whether aspirin can be used as an augmentation agent in fluoxetine treatment resistant depressive rats induced by chronic unpredictable mild stress (CUMS). In this study, the effects of CUMS regimen and antidepressant treatment were assessed by behavioral testing, hippocampal expression of cyclooxygenase-2 (COX-2) and prostaglandin E(2) (PGE(2)). 4-week fluoxetine treatment reversed the behavioral changes in approximately 70-80% depressive rats. That is, 20-30% depressive rats were resistant to fluoxetine. In the hippocampus of fluoxetine treatment resistant depressive rats, a significant upregulation of COX-2 level and PGE(2) concentration was observed. However, in these rats adjunctive aspirin treatment significantly improved the depressive behaviors and downregulated the COX-2 level and PGE(2) concentration in the hippocampus. Thus, our results suggest that aspirin can be served as an effective adjunctive agent in the treatment resistant depression mediated by inhibition of the COX-2 level and PGE(2) concentration.

Generalized anxiety disorder: clinical presentation, diagnostic features, and guidelines for clinical practice

Generalized anxiety disorder (GAD) is a prevalent and disabling disorder characterised by persistent worrying, anxiety symptoms, and tension. General practitioners and mental healthcare professionals frequently misdiagnose the presenting symptoms. This article addresses the clinical presentation of GAD and provides guidelines for discriminating GAD from other disorders, based on theoretical considerations and clinical experience. Debate relating to the validity of the definition of GAD is discussed, and suggestions are made for improving the criteria for GAD, which may guide future versions of classification systems such as the Diagnostic and Statistical Manual.

Brain microstructural abnormalities revealed by diffusion tensor images in patients with treatment-resistant depression compared with major depressive disorder before treatment

Treatment-resistant depression (TRD) is a therapeutic challenge for clinicians. Despite a growing interest in this area, an understanding of the pathophysiology of depression, particularly TRD, remains lacking. This study aims to detect the white matter abnormalities of whole brain fractional anisotropy (FA) in patients with TRD compared with major depressive disorder (MDD) before treatment by voxel-based analysis using diffusion tensor imaging. A total of 100 patients first diagnosed with untreated MDD underwent diffusion tensor imaging scans. 8 weeks after the first treatment, 54 patients showed response to the medication, whereas 46 did not. Finally, 20 patients were diagnosed with TRD after undergoing another treatment. A total of 20 patients with TRD and another 20 with MDD before treatment matched in gender, age, and education was enrolled in the research. For every subject, an FA map was generated and analyzed using SPM5. Subsequently, t-test was conducted to compare the FA values voxel to voxel between the two groups (p<0.001 [FDR corrected], t>7.57, voxel size>30). Voxel-based morphometric (VBM) analysis was performed using T1W images. Significant reductions in FA were found in the white matter located in the bilateral of the hippocampus (left hippocampus: t=7.63, voxel size=50; right hippocampus: t=7.82, voxel size=48). VBM analysis revealed no morphological abnormalities between the two groups. Investigation of brain anisotropy revealed significantly decreased FA in both sides of the hippocampus. Although preliminary, our findings suggest that microstructural abnormalities in the hippocampus indicate vulnerability to treatment resistance.

Morphology of the corpus callosum in treatment-resistant schizophrenia and major depression

OBJECTIVE

To identify possible differences in the mean midsagittal corpus callosum (CC) total and subdivision areas in treatment-resistant schizophrenia and depression (TRS and TRD) patients.

METHOD

Areas of the total CC and its five equidistant subregions (from CC1 to CC5) obtained by parallel grid partitioning schemes were manually segmented from brain MRI of 42 TRS, 45 TRD patients and 30 healthy controls. The intracranial volume (ICV) normalized areas were calculated and compared between groups.

RESULTS

When compared with controls, patients with TRS had reduced ICV and a larger CC5, and TRD patients had a smaller CC4 while no significant difference in CC total area in patients with TRS or TRD was found. Multiple individual segments and total CC areas were significantly larger in TRS than TRD patients after normalization.

CONCLUSION

Patients with TRS and TRD have different CC morphological characteristics, and therefore there may be aberrant interhemispheric connectivity in schizophrenia and major depressive disorder patients.

Magnetization transfer imaging reveals the brain deficit in patients with treatment-refractory depression

BACKGROUND

Studies on treatment resistant depression (TRD) using advanced magnetic resonance imaging techniques are very limited.

METHODS

A group of 15 patients with clinically defined TRD and 15 matched healthy controls underwent magnetization transfer imaging (MTI) and T1-weighted (T1W) imaging. MTI data were processed and analyzed voxel-wised in SPM2. A voxel based morphometric (VBM) analysis was performed using T1W images.

RESULTS

Reduced magnetization transfer ratio was observed in the TRD group relative to normal controls in the anterior cingulate, insula, caudate tail and amygdala-parahippocampal areas. All these regions were identified within the right hemisphere. VBM revealed no morphological abnormalities in the TRD group compared to the control group. Negative correlations were found between MRI and clinical measures in the inferior temporal gyrus.

LIMITATIONS

The cross-sectional design and small sample size.

CONCLUSIONS

The findings suggest that MTI is capable of identifying subtle brain abnormalities which underlie TRD and in general more sensitive than morphological measures.

Generalized anxiety disorder within the course of major depressive disorder: examining the utility of the DSM-IV hierarchy rule

BACKGROUND

The current Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) specifies that generalized anxiety disorder (GAD) should not be diagnosed if it occurs exclusively during an episode of a major depressive disorder (MDD) or another mood disorder. This hierarchy rule was intended to promote diagnostic parsimony, but may result in the loss of important clinical information. The goal of this study was to compare individuals with MDD, comorbid MDD and GAD, and GAD within the course of MDD at intake and 12-month follow-up on self-report measures, clinician ratings, and rates of comorbidity.

METHODS

Participants were divided into three diagnostic groups: MDD without GAD (n=124), comorbid MDD and GAD (n=59), and GAD within the course of MDD (n=166). All the participants completed a semi-structured clinical interview and self-report measures assessing psychopathology, temperament, and functional impairment. A subset of the total sample completed a follow-up assessment of 12 months postintake.

RESULTS

Individuals with comorbid MDD and GAD and GAD within the course of MDD reported more psychopathology, negative affect, and functional impairment at intake than individuals with MDD only. The presence of GAD at intake, however, did not differentially predict symptom severity, functional impairment, or the presence of comorbidity at 12-month follow-up.

CONCLUSIONS

Cross-sectional findings indicate that individuals with GAD within the course of MDD experience levels of psychopathology, functional impairment, and comorbidity similar to those found in individuals with comorbid GAD and MDD. Preliminary longitudinal findings, however, suggest that the presence of GAD in patients with MDD does not have prognostic significance.

A magnetic resonance imaging study of the entorhinal cortex in treatment-resistant depression

Despite a growing interest in this area, we continue to lack an understanding of the pathophysiology of depression and of treatment-resistant depression (TRD) in particular. The role of the medial temporal lobe, particularly the hippocampus, has been widely implicated in the aetiology of depression. However, related structures such as the entorhinal cortex have not been systematically examined. This research study aimed to examine possible abnormalities in the volume of the entorhinal cortex (ERC) in TRD patients. A group of 45 TRD patients and 30 healthy age- and sex-matched controls underwent magnetic resonance imaging (MRI). ERC volumes were manually traced from MRI data using ANALYZE software. An analysis of variance was conducted between subject groups and in the sexes separately while controlling for the effects of brain size via intracranial volume (ICV). Results revealed significant reductions in the volume of the left ERC of female patients. Although preliminary, our findings suggest that anatomical abnormalities in the ERC may confer vulnerability to treatment resistance. Confirmatory longitudinal studies are required to determine whether these abnormalities predate the onset of depression or are the result of a more chronic, treatment-resistant course of illness.

Quetiapine augmentation of treatment-resistant depression: a comparison with lithium

OBJECTIVE

The prevalence of and morbidity associated with treatment-resistant depression has motivated the exploration of treatment alternatives. In this study, quetiapine was compared with lithium in the augmentation of treatment-resistant depression.

RESEARCH DESIGN AND METHODS

Open-label, comparative study in 20 patients with major depression who had failed to respond after 4 weeks of treatment with an antidepressant at the maximal recommended dose. Patients were randomised to either lithium or quetiapine in addition to the maximally dosed antidepressant and any other concurrent medications. Lithium was initiated at 600 mg/day; quetiapine was titrated to 400 mg by day 7.

RESULTS

Depression, measured by the Hamilton Depression Rating Scale (HAM-D), significantly improved from baseline in both quetiapine (F(1,90) = 25.11, p < 0.0001) and lithium (F(1,90) = 34.54, p < 0.0001). The difference in improvement between the two groups began at day 14 and was seen at all timepoints thereafter (p < 0.05), with the quetiapine group showing greater improvement than the lithium group. In the Montgomery-Asberg Depression Rating Scale (MADRS) analysis, the difference between the quetiapine and lithium group was significant from day 28 onwards (p < 0.05), with subjects improving more in the quetiapine group than the lithium group. The treatment by week interaction showed a significant difference overall between the two groups (p < 0.0001). The severity of psychomotor retardation showed a significant decrease in the Widlocher Psychomotor Retardation Scale scores in the quetiapine (p < 0.0001) and lithium (p < 0.0001) groups.

CONCLUSIONS

In this pilot study, quetiapine was an effective augmenting agent in treatment-resistant depression.

Defining anxious depression: going beyond comorbidity

OBJECTIVE

Since publication of the DSM-IV, there remains a group of patients with depression and anxiety symptoms who are not well classified. We therefore wanted to determine more accurately the type of patients best described by the term "anxious depression." We also wanted to review the literature to assess the most appropriate treatment(s) for these patients.

METHOD

We surveyed the medical literature published after 1994 for all articles containing the relevant terms and assessed all possible articles in detail to determine those relevant to the diagnosis and those that involved relevant clinical studies.

RESULTS

The term anxious depression can encompass 3 groups of patients: those with comorbid major depressive disorder (MDD) and an anxiety disorder, those with MDD but with subthreshold anxiety symptoms, and those with subthreshold depressive and subthreshold anxiety symptoms (also called mixed anxiety and depressive disorder).

CONCLUSIONS

Based upon our literature review, we believe that the term anxious depression should only be used for the second group; that is, those patients with an MDD and subthreshold anxiety symptoms. From our literature review to determine the most appropriate treatment for this group of patients, it appears likely that drugs inhibiting the reuptake of both noradrenaline and serotonin may have greater clinical utility than single-action drugs such as the selective serotonin reuptake inhibitors (SSRIs). However, it is also clear that much more research needs to be undertaken in this important patient group so that we can better understand its prevalence, clinical features, and treatment.

Diagnosis and definition of treatment-resistant depression

Treatment-resistant depression (TRD) typically refers to inadequate response to at least one antidepressant trial of adequate doses and duration. TRD is a relatively common occurrence in clinical practice, with up to 50% to 60% of the patients not achieving adequate response following antidepressant treatment. A diagnostic re-evaluation is essential to the proper management of these patients. In particular, the potential role of several contributing factors, such as medical and psychiatric comorbidity, needs to be taken into account. An accurate and systematic assessment of TRD is a challenge to both clinicians and researchers, with the use of clinician-rated or self-rated instruments being perhaps quite helpful. It is apparent that there may be varying degrees of treatment resistance. Some staging methods to assess levels of treatment resistance in depression are being developed, but need to be tested empirically.

Is treatment-resistant depression a unique subtype of depression?

Treatment-resistant depression (TRD) continues to represent a major challenge for treating clinicians. This report reviews the relevant literature to evaluate whether TRD can be considered a specific subtype of depression based on 1) clinical characteristics and course (behavioral phenotype), 2) neurobiological profile, and 3) context and environment in which TRD develops. Although patients with TRD share a number of clinical, neurobiological, and context and environment characteristics, the lack of available data and the clinical heterogeneity of this condition do not currently permit the classification of TRD as a unique subtype of depression; however, this topic is worthy of further evaluation and research. Performing genetics and neuroimaging studies on patients enrolled in large, prospective and controlled studies may provide enough data for classifying TRD (or at least a part of what is currently described as TRD) as a specific subtype of depression. This in turn may facilitate the identification of more effective treatment strategies.