Study to determine the epidemiology of treatment-resistant depression among the Saudi Arabian population: A cross-sectional study

BACKGROUND

Depression is a common mental health disorder that affects millions of people worldwide. Globally, major depressive disorder (MDD) is a public health concern; nearly, it affects more than 300 million people. The coronavirus disease 2019 (COVID-19) pandemic lockdown, travel restrictions, social distancing, and COVID-19 vaccine acceptance have aggravated psychological disorders, such as depression and suicidal tendencies. Treatment-resistant depression (TRD) is typically defined as a lack of response to at least two different antidepressant medications or psychotherapies. TRD is common and has been associated with higher comorbidities and prolonged duration of illness, leading to a substantial medical and economic burden.

MATERIALS AND METHODS

A cross-sectional study was designed to determine the epidemiology and estimate the prevalence of TRD in Abha City, Assir Region, Kingdom of Saudi Arabia. The study includes adult patients who were attended to the psychiatry department and aged 18-65 years diagnosed with major depressive depression. A total of 651 study participants were recruited.

RESULTS

Of the total 651 depressive disorder cases, 134 (20.6%) were reported as TRD and the remaining 517 (79.4%) were nontreatment-resistant depressive cases. Of the 651 depression participants, 176 (27%) were males and 475 (73%) were females. More than one-quarter (180 (28%)) had been associated with chronic morbidity. One-tenth of the depressive patients were suffering from thyroid disorders, followed by hypertension (10%), autoimmune diseases (10%), and diabetes mellitus (8%).

CONCLUSIONS

TRD emerged as a threat to public health and challenging psychiatric care providers, and further innovative techniques and effective newer drugs to treat depression need to be researched. The treatment complaint mechanism is warranted, encouraging people to get treatment from the psychiatrist by removing the stigma of mental illness, which is needed to improve the quality of life of TRD patients.

Investigating genetic variants for treatment response to selective serotonin reuptake inhibitors in syndromal factors and side effects among patients with depression in Taiwanese Han population

Major depressive disorder (MDD) is associated with high heterogeneity in clinical presentation. In addition, response to treatment with selective serotonin reuptake inhibitors (SSRIs) varies considerably among patients. Therefore, identifying genetic variants that may contribute to SSRI treatment responses in MDD is essential. In this study, we analyzed the syndromal factor structures of the Hamilton Depression Rating Scale in 479 patients with MDD by using exploratory factor analysis. All patients were followed up biweekly for 8 weeks. Treatment response was defined for all syndromal factors and total scores. In addition, a genome-wide association study was performed to investigate the treatment outcomes at week 4 and repeatedly assess all visits during follow-up by using mixed models adjusted for age, gender, and population substructure. Moreover, the role of genetic variants in suicidal and sexual side effects was explored, and five syndromal factors for depression were derived: core, insomnia, somatic anxiety, psychomotor-insight, and anorexia. Subsequently, several known genes were mapped to suggestive signals for treatment outcomes, including single-nucleotide polymorphisms (SNPs) in PRF1, UTP20, MGAM, and ENSG00000286536 for psychomotor-insight and in C4orf51 for anorexia. In total, 33 independent SNPs for treatment responses were tested in a mixed model, 12 of which demonstrated a p value <0.05. The most significant SNP was rs2182717 in the ENSR00000803469 gene located on chromosome 6 for the core syndromal factor (β = -0.638, p = 1.8 × 10^-4) in terms of symptom improvement over time. Patients with a GG or GA genotype with the rs2182717 SNP also exhibited a treatment response (β = 0.089, p = 2.0 × 10^-6) at week 4. Moreover, rs1836075352 was associated with sexual side effects (p = 3.2 × 10^-8). Pathway and network analyses using the identified SNPs revealed potential biological functions involved in treatment response, such as neurodevelopment-related functions and immune processes. In conclusion, we identified loci that may affect the clinical response to treatment with antidepressants in the context of empirically defined depressive syndromal factors and side effects among the Taiwanese Han population, thus providing novel biological targets for further investigation.

Efficacy of dextromethorphan for the treatment of depression: a systematic review of preclinical and clinical trials

INTRODUCTION

The large percentage of adults with major depressive disorder (MDD) insufficiently responding and/or tolerating conventional monoamine-based antidepressants invites the need for mechanistically novel treatments. Convergent evidence implicates glutamatergic signaling as a potential therapeutic target in MDD.

AREAS COVERED

The synthesis herein of preclinical and clinical studies indicates that dextromethorphan (DXM) is well tolerated and exhibits clinically significant antidepressant effects; DXM combined with bupropion has demonstrated replicated and relatively rapid onset efficacy in adults with MDD. DXM efficacy has been preliminarily reported in adults with bipolar depression. The combination of DXM and bupropion represents a pharmacokinetic and pharmacodynamic synergy which may account for the rapidity of action in MDD.

EXPERT OPINION

The combination of DXM and bupropion is a safe, well tolerated and efficacious treatment option in adults with MDD. Priority questions are whether DXM/bupropion is uniquely effective across discrete domains of psychopathology (e.g. anhedonia, reward processing, general cognitive systems) and/or whether it is able to significantly improve patient-reported outcomes (e.g. quality of life, psychosocial functioning). The availability of ketamine/esketamine and DXM/bupropion instantiates the relevance of glutamate as a treatment target in MDD. Studies in bipolar depression with DXM/bupropion are warranted as well as in MDD with suicidality.

Prevalence, median time, and associated factors with the likelihood of initial antidepressant change: a cross-sectional study in Qatar

BACKGROUND

Major Depressive Disorder (MDD) requires therapeutic interventions during the initial month after being diagnosed for better disease outcomes. International guidelines recommend a duration of 4-12 weeks for an initial antidepressant (IAD) trial at an optimized dose to get a response. If depressive symptoms persist after this duration, guidelines recommend switching, augmenting, or combining strategies as the next step. Premature discontinuation of IAD due to ineffectiveness can cause unfavorable consequences. We aimed to determine the prevalence and the patterns of strategies applied after an IAD was changed because of a suboptimal response as a primary outcome. Secondary outcomes included the median survival time on IAD before any change; and the predictors that were associated with IAD change.

METHODS

This was a retrospective study conducted in Mental Health Services in Qatar. A dataset between January 1, 2018, and December 31, 2019, was extracted from the electronic health records. Inclusion and exclusion criteria were defined and applied. The sample size was calculated to be at least 379 patients. Descriptive statistics were reported as frequencies and percentages, in addition, to mean and standard deviation. The median time of IAD to any change strategy was calculated using survival analysis. Associated predictors were examined using several cox regression models.

RESULTS

A total of 487 patients met the inclusion criteria of the study, 431 (88%) of them had an occurrence of IAD change to any strategy before end of the study. Almost half of the sample (212 (49%); 95% CI [44-53%]) had their IAD changed less than or equal to 30 days. The median time to IAD change was 43 days with 95% CI [33.2-52.7]. The factors statistically associated with higher hazard of IAD change were: younger age, un-optimization of the IAD dose before any change, and comorbid anxiety.

CONCLUSIONS

Because almost half of the patients in this study changed their IAD as early as within the first month, efforts to avoid treatment failure are needed to ensure patient-treatment targets are met. Our findings offered some clues to help clinicians identify the high-risk predictors of short survival and subsequent failure of IAD.

Investigation of early and lifetime clinical features and comorbidities for the risk of developing treatment-resistant depression in a 13-year nationwide cohort study

BACKGROUND

To investigate the risk of treatment-resistant depression (TRD) in patients with depression by examining their clinical features, early prescription patterns, and early and lifetime comorbidities.

METHODS

In total, 31,422 depressive inpatients were followed-up from diagnostic onset for more than 10-years. Patients were diagnosed with TRD if their antidepressant treatment regimen was altered ≥two times or if they were admitted after at least two different antidepressant treatments. Multiple Cox regression model were used to determine whether physical and psychiatric comorbidities, psychosis, and prescription patterns increased the risk of TRD by controlling for relevant demographic covariates. Survival analyses were performed for important TRD-associated clinical variables.

RESULTS

Females with depression (21.24%) were more likely to suffer from TRD than males (14.02%). Early anxiety disorders were more commonly observed in the TRD group than in the non-TRD group (81.48 vs. 58.96%, p < 0.0001). Lifetime anxiety disorders had the highest population attributable fraction (42.87%). Seventy percent of patients with multiple psychiatric comorbidities developed TRD during follow-up. Cox regression analysis further identified that functional gastrointestinal disorders significantly increased TRD risk (aHR = 1.19). Higher doses of antidepressants and benzodiazepines and Z drugs in the early course of major depressive disorder increased TRD risk (p < 0.0001).

CONCLUSION

Our findings indicate the need to monitor early comorbidities and polypharmacy patterns in patients with depression associated with elevated TRD risk.

Antidepressants: bleeding or thrombosis?

The contribution of depression to the pathogenesis of cardiovascular disease includes autonomic disturbances, endothelial dysfunction, inflammation, smoking, sedentary lifestyle, carbohydrate craving, and impaired fibrinolysis. There is evidence that serotonergic antidepressants (selective serotonin reuptake inhibitors and serotonin and noradrenaline reuptake inhibitors) restore the fibrinolytic profile. Contrary to common belief, such antidepressants do not affect platelet aggregation induced by adenosine diphosphate or adrenaline but reduce platelet adhesion to collagen. Since platelet collagen receptor glycoprotein VI binds to fibrin, it is possible that fibrinolytic properties of serotonergic antidepressants could impair platelet adhesion to collagen. The profibrinolytic and antiplatelet properties of serotonergic antidepressants help explain the increased risk of gastrointestinal, intracranial, and surgical bleeding in patients using these medications. Studies evaluating the impact of antidepressants on thrombotic and cardiovascular risk have yielded contradictory results. Corroborating the hypothesis that serotonergic antidepressants have profibrinolytic and antiplatelet properties, some authors showed that these medications prevent both cardiovascular and thromboembolic events. Others showed an increased risk of ischemic stroke, cardiac events and thromboembolic disease. Silent brain infarction may present in some elders with depressive symptoms, so it is presumed that antidepressants are prescribed for subclinical stroke patients. Another explanation for the increased risk of cardiovascular and thromboembolic events reported by some authors in individuals taking antidepressants includes antidepressant side effects such as sedation and weight gain and depression comorbidities such as anxiety, obesity and hyperhomocysteinemia. In conclusion, we suggest that serotonergic antidepressants be considered weak anticoagulants. We also suggest that depressed patients with comorbidities increasing the risk of cardiovascular and thromboembolic disease be recommended to follow a balanced diet and engage in physical activity, such as daily walking.

The Association Between the Sedative Loads and Clinical Severity Indicators in the First-Onset Major Depressive Disorder

Background: High sedative use in a major depressive episode may imply specific clinical features. This study aims to examine the correlation between sedative use and clinical severity indicators in the initial treatment phase of first-onset major depressive disorder. Methods: A study cohort in the first episode of major depressive disorder was used to conduct pharmacological dissection. All participants had at least a 2-year follow-up period with a complete treatment record. The defined daily dose of antidepressants and augmentation agents were calculated as the antidepressant load and augmentation load, respectively. Sedative use, which was calculated as the equivalent dosage of lorazepam, were defined as the sedative load. These psychotropic loads were measured monthly and the averaged psychotropic loads for each day were obtained. Results: A total of 106 individuals (75.5% female) were included. The mean duration of disease course in participants was 5.5 ± 3.5 years. In the multiple regression analysis, after controlling for other classes of psychotropics and comorbid anxiety disorders, the sedative load independently correlated with higher number of antidepressants used, higher number of antidepressant used with an adequate dose and duration, more psychiatric emergency and outpatient visits within 2 years of disease onset. Conclusion: High loading of sedatives correlated with several indicators of clinical severity in major depressive disorder. The sedative load may be used as a specifier to identify subgroups in patients with major depressive disorder.

Vagus Nerve Stimulation For Treatment Resistant Depression: Case Series Of Six Patients - Retrospective Efficacy And Safety Observation After One Year Follow Up

OBJECTIVE

One year observation and evaluation of the VNS (vagus nerve stimulation) efficacy and safety for patients with treatment resistant depression in Polish conditions.

METHODS

An open label, uncontrolled and one center retrospective study of VNS therapy was implemented with stable pharmacotherapy in 6 patients with treatment resistant depression (TRD). For the first 3 months, only VNS parameters were altered but the pharmacological treatment was unchanged and in the following 9 months, medication and VNS dosing parameters were altered according to the clinical state of the patients.

RESULTS

The baseline 24-item Hamilton Depression Rating Scale (HAMD-24) score averaged 24. Both response (>50% reduction in baseline scores) and remission rates after 3 months of treatment were only 40%. After 1 year of VNS therapy, the response rates increased to 86%. Most frequent side-effects were voice alteration (86% at 3 months of stimulation) and headaches (40%).

CONCLUSION

VNS treatment was safe and effective in TRD patients and its efficacy increased with time. Efficacy ratings are similar to the previously reported studies using a congenial protocol.

Vagus Nerve Stimulation (VNS) and Other Augmentation Strategies for Therapy-Resistant Depression (TRD): Review of the Evidence and Clinical Advice for Use

In addition to electroconvulsive therapy (ECT) and repetitive transcranial magnetic stimulation (rTMS), vagus nerve stimulation (VNS) is one of the approved neurostimulation tools for treatment of major depression. VNS is particularly used in therapy-resistant depression (TRD) and exhibits antidepressive and augmentative effects. In long-term treatment, up to two-thirds of patients respond. This mini-review provides a comprehensive overview of augmentation pharmacotherapy and neurostimulation-based treatment strategies, with a special focus on VNS in TRD, and provides practical clinical advice for how to select TRD patients for add-on neurostimulation treatment strategies.

Efficacy of adding nutritional supplements in unipolar depression: A systematic review and meta-analysis

In this article, we aimed to assess the efficacy of adjunctive administration of nutritional supplements to antidepressants by means of a systematic review and meta-analysis. The supplements included were inositol, vitamin D, folic acid, vitamin B12, S-adenosyl-L-methionine (SAMe), omega-3 polyunsaturated fatty acids (n-3 PUFA) and zinc. A structured database search (MEDLINE, EBSCO, CENTRAL, Web of Science) was performed using terms for the respective substances in conjunction with terms for depression and the mode of treatment ("add-on" OR "adjunctive" OR "augmentation"). Meta-analyses, randomized controlled trials (RCTs) and non-randomized comparative studies that investigated the supplements as an add-on in the treatment of clinically diagnosed MDD were included. Agents had to be added to an existing antidepressant regime (augmentation) or started simultaneously with the antidepressant (acceleration). For n-3 PUFAs, folic acid and zinc, new meta-analyses were performed as part of this work. Our meta-analyses of 10 articles on n-3 PUFAs and four on zinc support their efficacy. For folic acid, our meta-analysis does not support efficacy. For n-3 PUFAs, sensitivity analysis showed no difference between acceleration and augmentation designs, but significant differences between individuals with or without comorbidities. For the remaining substances, only a few RCTs were available. The preliminary data on inositol was negative, while one RCT for vitamin D demonstrated positive results. For vitamin B12 one and for SAMe two RCTs and a few open trials are available reporting positive and mixed results. To summarize, for most of the substances, the available data is not yet sufficient or inconclusive.

Electroconvulsive Therapy Hasn't Negative Effects on Short-Term Memory Function, as Assessed Using a Bedside Hand-Held Device

Electroconvulsive therapy (ECT) is effective in the treatment of treatment-resistant major depression. The fear of cognitive impairment after ECT often deters patients from choosing this treatment option. There is little reliable information regarding the effects of ECT on overall cognitive performance, while short-term memory deficits are well known but not easy to measure within clinical routines. In this pilot study, we examined ECT recipients' pre- and post-treatment performances on a digital ascending number tapping test. We found that cognitive performance measures exhibited good reproducibility in individual patients and that ECT did not significantly alter cognitive performance up to 2 hours after this therapy was applied. Our results can help patients and physicians make decisions regarding the administration of ECT. Digital measurements are recommended, especially when screening for the most common side effects on cognitive performance and short-term memory.

Efficacy of off-label augmentation in unipolar depression: A systematic review of the evidence

Treatment of unipolar depression with currently available antidepressants is still unsatisfactory. Augmentation with lithium or second generation antipsychotics is an established practice in non-responders to antidepressant monotherapy, but is also associated with a substantial non-response rate and with non-tolerance. Based on a systematic review of the literature, including meta-analyses, randomized controlled trials (RCTs), non-randomized comparative studies and case studies, off-label augmentation agents (administered in addition to an antidepressant, without FDA approval for treatment of MDD) were identified and evaluated regarding their efficacy using levels of evidence. The agents had to be added to an existing antidepressant regime with the aim of achieving an improved clinical response to an ongoing antidepressant treatment (augmentation) or an earlier onset of effect when starting antidepressant and augmentation agent simultaneously (acceleration). Five substances, modafinil, ketamine, pindolol, testosterone and estrogen (the latter two in hormone-deficient patients) were shown to be clinically effective in high evidence studies. For the six drugs dexamethasone, mecamylamine, riluzole, amantadine, pramipexole and yohimbine clear proof of efficacy was not possible due to low levels of evidence, small sample sizes or discordant results. For the two agents methylphenidate and memantine only studies with negative outcomes could be found. Overall, the quality of study designs was low and results were often contradictory. However, the use of pindolol, ketamine, modafinil, estrogen and testosterone might be an option for depressed patients who are not responding to antidepressant monotherapy or established augmentation strategies. Further high quality studies are necessary and warranted.

Combining Antidepressants in Acute Treatment of Depression: A Meta-Analysis of 38 Studies Including 4511 Patients

OBJECTIVE

Combining antidepressants (ADs) for therapy of acute depression is frequently employed, but randomized studies have yielded conflicting results. We conducted a systematic review and meta-analysis aimed at determining efficacy and tolerability of combination therapy.

METHODS

MEDLINE, Embase, PsycINFO, and CENTRAL databases were systematically searched through March 2014 for controlled studies comparing combinations of ADs with AD monotherapy in adult patients suffering from acute depression. The prespecified primary outcome was standardized mean difference (SMD), secondary outcomes were response, remission, and dropouts.

RESULTS

Among 8688 articles screened, 38 studies were eligible, including 4511 patients. Combination treatment was statistically, significantly superior to monotherapy (SMD 0.29; 95% CI 0.16 to 0.42). During monotherapy, slightly fewer patients dropped out due to adverse events (OR 0.90; 95% CI 0.53 to 1.53). Studies were heterogeneous (I(2) = 63%), and there was indication of moderate publication bias (fail-safe N for an effect of 0.1:44), but results remained robust across prespecified secondary outcomes and subgroups, including analyses restricted to randomized controlled trials and low risk of bias studies. Meta-regression revealed an association of SMD with difference in imipramine-equivalent dose. Combining a reuptake inhibitor with an antagonist of presynaptic α2-autoreceptors was superior to other combinations.

CONCLUSION

Combining ADs seems to be superior to monotherapy with only slightly more patients dropping out. Combining a reuptake inhibitor with an antagonist of presynaptic α2-autoreceptors seems to be significantly more effective than other combinations. Overall, our search revealed a dearth of well-designed studies.

Bilateral repetitive transcranial magnetic stimulation for treatment-resistant depression: a systematic review and meta-analysis of randomized controlled trials

There has been concern regarding the use of controversial paradigms for repetitive transcranial magnetic stimulation (rTMS) to manage treatment-resistant depression (TRD). This meta-analysis assessed the efficacy of bilateral rTMS compared with unilateral and sham rTMS in patients with TRD. PubMed, Embase, CENTRAL, PsycINFO, Web of Science, EAGLE and NTIS databases were searched to identify relevant studies, and randomized controlled trials (RCTs) on bilateral rTMS for TRD patients were included. The response was defined as the primary outcome, and remission was the secondary outcome. Ten RCTs that included 634 patients met the eligibility criteria. The risk ratio (RRs) of both the primary and secondary outcomes of bilateral rTMS showed non-significant increases compared to unilateral rTMS (RR=1.01, P=0.93; odds ratio [OR]=0.77, P=0.22). Notably, the RR of the primary bilateral rTMS outcome was significantly increased compared to that for sham rTMS (RR=3.43, P=0.0004). The results of our analysis demonstrated that bilateral rTMS was significantly more effective than sham rTMS but not unilateral rTMS in patients with TRD. Thus, bilateral rTMS may not be a useful paradigm for patients with TRD.

High dosage of hypnotics predicts subsequent sleep-related breathing disorders and is associated with worse outcomes for depression

OBJECTIVES

The rates of sleep related breathing disorders (SRBD) and treatment outcomes of depression were compared among insomnia patients who had stratified levels of hypnotic use during a 10-year follow-up (2001-2010).

DESIGN

A nationwide population-based cohort study.

SETTING

A nationally representative cohort of 1,000,000 enrollees.

PARTICIPANTS

Data were collected from patients with major depressive disorder (MDD) and comorbid insomnia during January 2001 to December 2003 (study cohort N = 3,235). The mean dosage of hypnotics at baseline in the study cohort was calculated, and this information was used to categorize the cohort into three equal-sized groups based on levels of hypnotic dosage.

MAIN OUTCOME MEASURES

Patient response to antidepressants during a period that extended from 1 year before to 1 year after the study (short-term outcome) and patient psychiatric and non-psychiatric visits and hospitalizations during follow-up (long-term outcome) were analyzed.

RESULTS

High-dosage patients presented the highest rates of subsequent SRBD diagnosis (3.9%), compared to medium-dosage patients (2.2%) and low-dosage patients (2.0%) (P = 0.011). Significantly more patients in the high-dosage group were difficult to treat with antidepressants compared to the other 2 groups (8.7% vs. 4.1% vs. 3.0%, P < 0.001), and their long-term depression outcome was worse for most parameters. Logistic regression showed that high-dosage hypnotics predicted the development of SRBD later (OR 1.678 [CI, 1.051 to 2.680], P = 0.030).

CONCLUSIONS

There is a reliable association between a history of high dosages of hypnotics, subsequent diagnosis of sleep related breathing disorder, and worse depression outcomes.

Interactions between diabetes and anxiety and depression: implications for treatment

Anxiety or depression may be a risk factor for the development of diabetes. This relationship may occur through a combination of genetic predispositions; epigenetic contingencies; exacerbating conditions such as metabolic syndrome (a precursor to diabetes); and other serious medical conditions. Medications used to treat anxiety and depression have significant side effects, such as weight gain, further increasing the possibility of developing diabetes. These components combine, interact, and reassemble to create a precarious system for persons with, or predisposed to, diabetes. Clinicians must be aware of these interrelationships to adequately treat the disease.

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 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.

Association between antidepressant resistance in unipolar depression and subsequent bipolar disorder: cohort study

BACKGROUND

People with major depressive disorder who fail to respond to adequate trials of antidepressant treatment may harbour hidden bipolar disorder.

AIMS

We aimed to compare the rates of a change in diagnosis to bipolar disorder among people with major depressive disorder with stratified responses to antidepressants during an 8-year follow-up period.

METHOD

Information on individuals with major depressive disorder identified during 2000 (cohort 2000, n = 1485) and 2003 (cohort 2003, n = 2459) were collected from a nationally representative cohort of 1,000,000 health service users in Taiwan. Participants responding well to antidepressants were compared with those showing poor responses to adequate trials of antidepressants.

RESULTS

In 7.6-12.1% of those with a diagnosis of unipolar major depressive disorder this diagnosis was subsequently changed to bipolar disorder, with a mean time to change of 1.89-2.98 years. Difficult-to-treat participants presented higher rates of change to a bipolar diagnosis (25.6% in cohort 2000; 26.6% in cohort 2003) than easy-to-treat participants (8.8-8.9% in cohort 2000; 6.8-8.6% in cohort 2003; P<0.0001). Regression analysis showed that the variable most strongly associated with the change in diagnosis was antidepressant use history. The difficult-to-treat participants were associated most with diagnostic changing (cohort 2000: odds ratio (OR) = 1.88 (95% CI 1.12-3.16); cohort 2003: OR = 4.94 (95% CI 2.81-8.68)).

CONCLUSIONS

This is the first large-scale study to report an association between antidepressant response history and subsequent change in diagnosis from major depressive disorder to bipolar disorder. Our findings support the view that a history of poor response to antidepressants in unipolar depression could be a useful predictor for bipolar diathesis.

Impact of citalopram on the HPA system. A study of the combined DEX/CRH test in 30 unipolar depressed patients

BACKGROUND

Dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) system is one of the best replicated pathophysiological findings in depression. However, studies on the influence of treatment on the HPA system have partly yielded inconsistent results.

OBJECTIVE

To assess the effects of citalopram monotherapy on the HPA system of mainly drug naïve patients with major depression by means of the combined DEX/CRH test.

METHODS

The DEX/CRH test was conducted twice in 30 patients (25 drug naïve for the index episode) with major depression (single episode or unipolar recurrent; SCID I- and II-confirmed): directly before the start of a citalopram monotherapy (day 0) and four weeks thereafter (day 28).

RESULTS

Twenty-three patients responded (≥50% reduction in the HDRS(21)-score), and 17 of them also reached criteria of remission (HDRS ≤ 7). Baseline (dexamethasone-suppressed) and CRH-stimulated ACTH concentrations significantly decreased from day 0 to day 28. CRH-stimulated cortisol concentrations also fell, although not significantly, but baseline cortisol concentrations exhibited a significant increase from day 0 to day 28.

CONCLUSIONS

The blunting of the ACTH response in the DEX/CRH test under citalopram is in line with what has been observed in most studies with antidepressants. However, the partial rise in cortisol concentrations indicates an increase in the sensitivity of the adrenal cortex to ACTH. State-dependent alterations in the volume and the ACTH responsiveness of the adrenal gland have repeatedly been reported in depressed subjects, which indicates the possibility that SSRIs such as citalopram might exhibit a direct or indirect effect on the adrenal cortex.

Lithium monotherapy increases ACTH and cortisol response in the DEX/CRH test in unipolar depressed subjects. A study with 30 treatment-naive patients

BACKGROUND

Distorted activity of the hypothalamic-pituitary-adrenocortical (HPA) system is one of the most robustly documented biological abnormalities in major depression. Lithium is central to the treatment of affective disorders, but little is known about its effects on the HPA system of depressed subjects.

OBJECTIVE

To assess the effects of lithium monotherapy on the HPA system of patients with major depression by means of the combined DEX/CRH test.

METHOD

Thirty drug-naive outpatients with major depression (single episode or unipolar recurrent; SCID I- and II-confirmed) were treated with lithium monotherapy for four weeks. The DEX/CRH test was conducted directly before intake of the first lithium tablet and four weeks thereafter. Weekly ratings with the HDRS(21) were used to determine response (≥50% symptom reduction) and remission (HDRS ≤7).

RESULTS

Lithium levels within the therapeutic range were achieved rapidly. Tolerability was good; no patient terminated the treatment prematurely. Response and remission rates were 50% and 33% respectively. Compared to the DEX/CRH test before the start of the treatment, a considerable and significant increase in all CRH-stimulated ACTH and cortisol parameters could be detected in the second DEX/CRH test. When analysed with particular regard to responders and non-responders, that significant increase was only present in the responders.

CONCLUSIONS

We were able to demonstrate that lithium leads to a significant activation of the HPA system. This is possibly connected to stimulation of hypothalamic arginine vasoporessin (AVP), to direct intracellular effects of lithium on pituitary cells and to an induction of gene expression.

TRIAL REGISTRATION

drks-nue.uniklinik-freiburg.de DRKS00003185.

Differential modulation of emotion processing brain regions by noradrenergic and serotonergic antidepressants

RATIONALE

Most widely used antidepressant drugs affect the serotonergic and noradrenergic pathways. However, there are currently no neurobiological criteria for selecting between these targets and predicting the treatment response in individual depressed patients.

OBJECTIVES

The current study is aimed at differentiating brain regions known to be pathophysiologically and functionally involved in depression-related emotion processing with respect to their susceptibility to serotonergic and noradrenergic modulation.

METHODS

In a single-blind pseudo-randomized crossover study, 16 healthy subjects (out of 21 enrolled) were included in analysis after ingesting a single dose of citalopram (a selective serotonin-reuptake inhibitor, 40 mg), reboxetine (a selective noradrenaline-reuptake inhibitor, 8 mg), or placebo at three time points prior to functional magnetic resonance imaging (fMRI). During fMRI, subjects anticipated and subsequently viewed emotional pictures. Effects of serotonergic and noradrenergic modulation versus placebo on brain activity during the perception of negative pictures were analyzed with a repeated measures ANOVA in the whole brain and in specific regions of interest relevant to depression.

RESULTS

Noradrenergic modulation by reboxetine increased brain activity in the thalamus, right dorsolateral prefrontal cortex and occipital regions during the perception of negative emotional stimuli. Citalopram primarily affected the ventrolateral prefrontal cortical regions.

CONCLUSION

The brain regions involved in the processing of negative emotional stimuli were differentially modulated by selective noradrenergic and serotonergic drugs: thalamic activity was increased by reboxetine, whereas citalopram primarily affected ventrolateral prefrontal regions. Thus, dysfunction in these regions, which could be identified in depressed patients, may predict treatment responses to either noradrenergic or serotonergic antidepressants.

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.

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.