Structuro-functional surrogates of response to subcallosal cingulate deep brain stimulation for depression.

Subcallosal cingulate deep brain stimulation produces long-term clinical improvement in approximately half of patients with severe treatment-resistant depression. We hypothesized that both structural and functional brain attributes may be important in determining responsiveness to this therapy. In a treatment-resistant depression subcallosal cingulate deep brain stimulation cohort, we retrospectively examined baseline and longitudinal differences in MRI-derived brain volume (n = 65) and 18F-fluorodeoxyglucose-PET glucose metabolism (n = 21) between responders and non-responders. Support vector machines were subsequently trained to classify patients' response status based on extracted baseline imaging features. A machine learning model incorporating preoperative frontopolar, precentral/frontal opercular and orbitofrontal local volume values classified binary response status (12 months) with 83% accuracy [leave-one-out cross-validation (LOOCV): 80% accuracy] and explained 32% of the variance in continuous clinical improvement. It was also predictive in an out-of-sample subcallosal cingulate deep brain stimulation cohort (n = 21) with differing primary indications (bipolar disorder/anorexia nervosa; 76% accuracy). Adding preoperative glucose metabolism information from rostral anterior cingulate cortex and temporal pole improved model performance, enabling it to predict response status in the treatment-resistant depression cohort with 86% accuracy (LOOCV: 81% accuracy) and explain 67% of clinical variance. Response-related patterns of metabolic and structural post-deep brain stimulation change were also observed, especially in anterior cingulate cortex and neighbouring white matter. Areas where responders differed from non-responders-both at baseline and longitudinally-largely overlapped with depression-implicated white matter tracts, namely uncinate fasciculus, cingulum bundle and forceps minor/rostrum of corpus callosum. The extent of patient-specific engagement of these same tracts (according to electrode location and stimulation parameters) also served as an independent predictor of treatment-resistant depression response status (72% accuracy; LOOCV: 70% accuracy) and augmented performance of the volume-based (88% accuracy; LOOCV: 82% accuracy) and combined volume/metabolism-based support vector machines (100% accuracy; LOOCV: 94% accuracy). Taken together, these results indicate that responders and non-responders to subcallosal cingulate deep brain stimulation exhibit differences in brain volume and metabolism, both pre- and post-surgery. Moreover, baseline imaging features predict response to treatment (particularly when combined with information about local tract engagement) and could inform future patient selection and other clinical decisions.

The Differential Relation of Emotional, Physical, and Sexual Abuse Histories to Antidepressant Treatment Remission and Persistence of Anhedonia in Major Depression: A CAN-BIND-1 Report.

OBJECTIVE: Childhood maltreatment is a potent enviromarker of risk for poor response to antidepressant medication (ADM). However, childhood maltreatment is a heterogeneous construct that includes distinct exposures that have distinct neurobiological and psychological correlates. The purpose of the current study is to examine the differential associations of emotional, physical, and sexual maltreatment to ADM outcome and to examine the unique role of anhedonia in driving poor response in patients with specific maltreatment histories. METHODS: In a multicentre clinical trial of major depression, 164 individuals were assessed for childhood emotional, physical, and sexual maltreatment with a contextual interview with independent, standardized ratings. All individuals received 8 weeks of escitalopram, with nonresponders subsequently also receiving augmentation with aripiprazole, with outcomes measured with depression rating scales and an anhedonia scale. RESULTS: Greater severity of emotional maltreatment perpetrated by the mother was a significant and direct predictor of lower odds of week 16 remission (odds ratio [OR] = 1.68, P = 0.02). In contrast, the relations of paternal-perpetrated emotional maltreatment and physical maltreatment to week 16 remission were indirect, mediated through greater severity of anhedonia at week 8. CONCLUSIONS: We identify emotional maltreatment as a specific early exposure that places patients at the greatest risk for nonremission following pharmacological treatment. Further, we suggest that anhedonia is a key symptom domain driving nonremission in patients with particular maltreatment histories.

Comparative study of the pencil-and-paper and digital formats of the Spanish DARS scale.

The Dimensional Anhedonia Rating Scale (DARS) is a novel questionnaire to assess anhedonia of recent validation. In this work, we aim to study the equivalence between the traditional paper-and-pencil and the digital format of DARS. Sixty-nine patients filled the DARS in a paper-based and digital versions. We assessed differences between formats (Wilcoxon test), validity of the scales [Kappa and intraclass correlation coefficients (ICCs)], and reliability (Cronbach's alpha and Guttman's coefficient). We calculated the comparative fit index and the root mean squared error (RMSE) associated with the proposed one-factor structure. Total scores were higher for paper-based format. Significant differences between both formats were found for three items. The weighted Kappa coefficient was approximately 0.40 for most of the items. Internal consistency was greater than 0.94, and the ICC for the digital version was 0.95 and 0.94 for the paper-and-pencil version (F = 16.7, p < 0.001). Comparative Adjustment Index was 0.97 for the digital DARS and 0.97 for the paper-and-pencil DARS, and RMSE was 0.11 for the digital DARS and 0.10 for the paper-and-pencil DARS. We concluded that the digital DARS is consistent in many respects with the paper-and-pencil questionnaire, but equivalence with this format cannot be assumed without caution.

Neuroanatomical predictors of response to subcallosal cingulate deep brain stimulation for treatment-resistant depression

Background: Deep brain stimulation targeting the subcallosal cingulate gyrus (SCG DBS) improves the symptoms of treatment-resistant depression in some patients, but not in others. We hypothesized that there are pre-existing structural brain differences between responders and nonresponders to SCG DBS, detectable using structural MRI. Methods: We studied preoperative, T1-weighted MRI scans of 27 patients treated with SCG DBS from 2003 to 2011. Responders (n = 15) were patients with a >50% improvement in Hamilton Rating Scale for Depression score following 12 months of SCG DBS. Preoperative subcallosal cingulate gyrus grey matter volume was obtained using manual segmentation by a trained observer blinded to patient identity. Volumes of hippocampus, thalamus, amygdala, whole-brain cortical grey matter and white matter volume were obtained using automated techniques. Results: Preoperative subcallosal cingulate gyrus, thalamic and amygdalar volumes were significantly larger in patients who went on to respond to SCG-DBS. Hippocampal volume did not differ between groups. Cortical grey matter volume was significantly smaller in responders, and cortical grey matter:white matter ratio distinguished between responders and nonresponders with high sensitivity and specificity. Limitations: Normalization by intracranial volume nullified some between-group differences in volumetric measures. Conclusion: There are structural brain differences between patients with treatment-resistant depression who respond to SCG DBS and those who do not. Specifically, the structural integrity of the subcallosal cingulate gyrus target region and its connected subcortical areas, and variations in cortical volume across the entire brain, appear to be important determinants of response. Structural MRI shows promise as a biomarker in deep brain stimulation for depression, and may play a role in refining patient selection for future trials.

Early change in reward and punishment sensitivity as a predictor of response to antidepressant treatment for major depressive disorder: a CAN-BIND-1 report.

BACKGROUND: In an effort to optimize patient outcomes, considerable attention is being devoted to identifying patient characteristics associated with major depressive disorder (MDD) and its responsiveness to treatment. In the current study, we extend this work by evaluating whether early change in these sensitivities is associated with response to antidepressant treatment for MDD. METHODS: Participants included 210 patients with MDD who were treated with 8 weeks of escitalopram and 112 healthy comparison participants. Of the original 210 patients, 90 non-responders received adjunctive aripiprazole for an additional 8 weeks. Symptoms of depression and anhedonia were assessed at the beginning of treatment and 8 weeks later in both samples. Reward and punishment sensitivity were assessed using the BIS/BAS scales measured at the initiation of treatment and 2 weeks later. RESULTS: Individuals with MDD exhibited higher punishment sensitivity and lower reward sensitivity compared with healthy comparison participants. Change in reward sensitivity during the first 2 weeks of treatment was associated with improved depressive symptoms and anhedonia following 8 weeks of treatment with escitalopram. Similarly, improvement in reward responsiveness during the first 2 weeks of adjunctive therapy with aripiprazole was associated with fewer symptoms of depression at post-treatment. CONCLUSIONS: Findings highlight the predictive utility of early change in reward sensitivity during antidepressant treatment for major depression. In a clinical setting, a lack of change in early reward processing may signal a need to modify a patient's treatment plan with alternative or augmented treatment approaches.

Presentation and Neurobiology of Anhedonia in Mood Disorders: Commonalities and Distinctions.

PURPOSE OF REVIEW: To focus on the clinical and behavioral presentation of anhedonia in mood disorders, as well as the differences and commonalities in the underlying neurocircuitry. RECENT FINDINGS: Evidence suggests that depression is characterized by hypofunction of the reward system, while bipolar disorder manifests dysregulation of the behavioral activation system that increases goal-directed reward behavior. Importantly, strong evidence does not exist to suggest significant differences in anhedonia severity between depressed unipolar and bipolar patients, suggesting that there are more nuanced fluctuations in reward processing deficits in bipolar patients depending on their state. Both euthymic unipolar and bipolar patients frequently report residual reward dysfunction, which highlights the potential of reward processing deficits that give rise to the clinical symptom of anhedonia to be trait factors of mood disorders; however, the possibility that therapies are not adequately treating anhedonia could also explain the presence of residual symptoms. Reward processing represents a potential diagnostic and treatment marker for mood disorders. Further research should systematically explore the facets of reward processing in at-risk, affected, and remitted patients.

Functional neuroimaging biomarkers of anhedonia response to escitalopram plus adjunct aripiprazole treatment for major depressive disorder.

BACKGROUND: Identifying neuroimaging biomarkers of antidepressant response may help guide treatment decisions and advance precision medicine. AIMS: To examine the relationship between anhedonia and functional neurocircuitry in key reward processing brain regions in people with major depressive disorder receiving aripiprazole adjunct therapy with escitalopram. METHOD: Data were collected as part of the CAN-BIND-1 study. Participants experiencing a current major depressive episode received escitalopram for 8 weeks; escitalopram non-responders received adjunct aripiprazole for an additional 8 weeks. Functional magnetic resonance imaging (on weeks 0 and 8) and clinical assessment of anhedonia (on weeks 0, 8 and 16) were completed. Seed-based correlational analysis was employed to examine the relationship between baseline resting-state functional connectivity (rsFC), using the nucleus accumbens (NAc) and anterior cingulate cortex (ACC) as key regions of interest, and change in anhedonia severity after adjunct aripiprazole. RESULTS: Anhedonia severity significantly improved after treatment with adjunct aripiprazole.There was a positive correlation between anhedonia improvement and rsFC between the ACC and posterior cingulate cortex, ACC and posterior praecuneus, and NAc and posterior praecuneus. There was a negative correlation between anhedonia improvement and rsFC between the ACC and anterior praecuneus and NAc and anterior praecuneus. CONCLUSIONS: Eight weeks of aripiprazole, adjunct to escitalopram, was associated with improved anhedonia symptoms. Changes in functional connectivity between key reward regions were associated with anhedonia improvement, suggesting aripiprazole may be an effective treatment for individuals experiencing reward-related deficits. Future studies are required to replicate our findings and explore their generalisability, using other agents with partial dopamine (D2) agonism and/or serotonin (5-HT2A) antagonism.

An empirical analysis of structural neuroimaging profiles in a staging model of depression.

We examine structural brain characteristics across three diagnostic categories: at risk for serious mental illness; first-presenting episode and recurrent major depressive disorder (MDD). We investigate whether the three diagnostic groups display a stepwise pattern of brain changes in the cortico-limbic regions. Integrated clinical and neuroimaging data from three large Canadian studies were pooled (total n = 622 participants, aged 12-66 years). Four clinical profiles were used in the classification of a clinical staging model: healthy comparison individuals with no history of depression (HC, n = 240), individuals at high risk for serious mental illness due to the presence of subclinical symptoms (SC, n = 80), first-episode depression (FD, n = 82), and participants with recurrent MDD in a current major depressive episode (RD, n = 220). Whole-brain volumetric measurements were extracted with FreeSurfer 7.1 and examined using three different types of analyses. Hippocampal volume decrease and cortico-limbic thinning were the most informative features for the RD vs HC comparisons. FD vs HC revealed that FD participants were characterized by a focal decrease in cortical thickness and global enlargement in amygdala volumes. Greater total amygdala volumes were significantly associated with earlier onset of illness in the FD but not the RD group. We did not confirm the construct validity of a tested clinical staging model, as a differential pattern of brain alterations was identified across the three diagnostic groups that did not parallel a stepwise clinical staging approach. The pathological processes during early stages of the illness may fundamentally differ from those that occur at later stages with clinical progression.

Polish adaptation of the Dimensional Anhedonia Rating Scale (DARS) - validation in the clinical sample.

Background: Anhedonia is the core symptom of depression. Its presence has been linked to worsened prognosis. The Dimensional Anhedonia Rating Scale (DARS) is a scale measuring desire, motivation, effort and consummatory pleasure across different domains. The aim of this paper was to confirm factor structure, assess reliability and validity of the Polish adaptation of the DARS in a clinical sample of patients with mood disorders and healthy controls (HC). Methods: The study sample included 161 participants aged 18-65 years - 34 HC, 72 patients with bipolar disorder and 55 with major depressive disorder (in depressive episode or remission). Reliability of the Polish adaptation of the DARS was assessed using Cronbach's α and the average inter-item correlation (AIC). Convergent and divergent validity was established by Pearson's correlations between the DARS and the Snaith-Hamilton Pleasure Scale (SHAPS), the Quick Inventory of Depressive Symptomatology- self-report (QIDS-SR), the Hospital Anxiety and Depression Scale (HADS). The structure of the scale was examined by factor analysis. Results: The factor structure was consistent with the original scale. Strong internal consistency for the DARS total score (Cronbach's α = 0.95) and all subscales (0.86-0.93) was observed. The DARS demonstrated good convergent (moderate to strong correlations with measures of anhedonia and depression) and divergent validity (weak correlations with anxiety level). Conclusion: The Polish DARS demonstrated excellent internal consistency and very good validity. The scale is a valuable contribution to the psychometrics of anhedonia measures in patients with mood disorders.

Risk-Sensitive Decision-Making and Self-Harm in Youth Bipolar Disorder.

Background: Youth with bipolar disorder (BD) are at high risk for suicide and have high rates of self-harm, which includes both suicide attempts and non-suicidal self-injury. Greater risk-taking has been associated with suicide attempts in youth with major depression, although there are no studies examining the relationship between risk-related decision-making and self-harm in youth with BD. We aimed to examine the association of suicide risk with risk-sensitive decision-making in a controlled sample of youth with BD.Methods: Eighty-one youth with BD (based on DSM-IV criteria; 52 youth with a history of self-harm [BDSH+]; 29 without a history of self-harm [BDSH-]) and 82 age- and sex-matched control youth aged 13-20 years were recruited between 2012 and 2020. Decision-making and risk-taking performance were assessed via the Cambridge Gambling Task within the Cambridge Neuropsychological Test Automated Battery (CANTAB). General linear models were used to examine differences between groups with control for age, sex, and IQ.Results: There was a significant difference in the overall proportion of points bet (F2,157 = 3.87, P = .02, η2 = 0.23) such that BDSH- youth performed better than both BDSH+ (P = .02) and control youth (P = .04). Mean latency was significant (F3,156 = 4.12, P = .017, η2 = 0.03), with BDSH- youth deliberating longer than controls (P = .03). Risk-taking significantly differed between groups (F2,157 = 3.83, P = .02, η2 = 0.23), with BDSH- youth showing greater self-control compared to BDSH+ (P = .01) and control youth (P = .01).Conclusions: BDSH- youth had greater self-control and lower risk-taking. We speculate this finding may be reflective of a compensatory process among BDSH- youth serving a protective role in suicide risk. Future longitudinal studies are needed to examine the temporal association of neurocognition and self-harm among youth with BD.

Resting-state neural mechanisms of capability for suicide and their interaction with pain - A CAN-BIND-05 Study.

BACKGROUND: Suicidal ideation is highly prevalent in Major Depressive Disorder (MDD). However, the factors determining who will transition from ideation to attempt are not established. Emerging research points to suicide capability (SC), which reflects fearlessness of death and increased pain tolerance, as a construct mediating this transition. This Canadian Biomarker Integration Network in Depression study (CANBIND-5) aimed to identify the neural basis of SC and its interaction with pain as a marker of suicide attempt. METHODS: MDD patients (n = 20) with suicide risk and healthy controls (n = 21) completed a self-report SC scale and a cold pressor task measuring pain threshold, tolerance, endurance, and intensity at threshold and tolerance. All participants underwent a resting-state brain scan and functional connectivity was examined for 4 regions: anterior insula (aIC), posterior insula (pIC), anterior mid-cingulate cortex (aMCC) and subgenual anterior cingulate cortex (sgACC). RESULTS: In MDD, SC correlated positively with pain endurance and negatively with threshold intensity. Furthermore, SC correlated with the connectivity of aIC to the supramarginal gyrus, pIC to the paracingulate gyrus, aMCC to the paracingulate gyrus, and sgACC to the dorsolateral prefrontal cortex. These correlations were stronger in MDD compared to controls. Only threshold intensity mediated the correlation between SC and connectivity strength. LIMITATIONS: Resting-state scans provided an indirect assessment of SC and the pain network. CONCLUSIONS: These findings highlight point to a neural network underlying SC that is associated with pain processing. This supports the potential clinical utility of pain response measurement as a method to investigate markers of suicide risk.

Clinical and Preclinical Assessments of Anhedonia in Psychiatric Disorders.

Anhedonia is a prevalent symptom across many psychiatric disorders. The contemporary scope of anhedonia across various models includes interest, reward anticipation, motivation, effort expenditure, reward valuation, expectation, pleasure, satiation, and learning. In order to further elucidate the impact of anhedonia on treatment outcomes, quality of life, as well as brain function, validated tools to probe the various facets of anhedonia are necessary. This chapter evaluates assessment tools for anhedonia in clinical populations and in animals. Subjective clinical scales have been in use for decades, and as the construct of anhedonia evolved, contemporary scales were developed to integrate these new concepts. Clinical scales are useful for understanding the subjective experience of anhedonia but do not account for objective aspects of anhedonia, including implicit learning. Behavioral tasks that probe responses to rewarding stimuli have been useful to fill this gap and to delineate the specific brain processes underlying facets of anhedonia. Although there have been translational challenges in the assessments of anhedonia and reward deficits from preclinical to clinical (and vice versa), the multifaceted clinical scales and reward tasks provide valuable insights into the conceptualization of anhedonia and its neural basis across psychiatric disorders.

A qualitative systematic review of neurocognition in suicide ideators and attempters: Implications for cognitive-based psychotherapeutic interventions.

BACKGROUND: Growing evidence suggests cognitive deficits may represent neurocognitive markers with predictive utility in identifying those at risk for suicide. Characterizing these deficits may offer the opportunity to develop targeted interventions. AIM: The aim of this systematic qualitative review is to provide a synthesis of the published data on neurocognition in suicide ideators and attempters in order to clarify which neurocognitive targets may be most relevant to address using cognitive-based psychotherapeutic strategies in patients at risk for suicide. RESULTS: A total of 63 studies met criteria for inclusion. The most consistent findings were in depressed suicide attempters, where deficits in executive subdomains of inhibition, selective attention and decision-making, as well as in working memory, were identified. In contrast, no clear pattern of neurocognitive deficits emerged from studies in suicide ideators across diagnoses. CONCLUSIONS: More studies are needed to clarify the role of cognitive deficits in specific subtypes of individuals at risk for suicide. The findings are discussed in the context of promising research on cognitive remediation and other psychological interventions.

Define and characterize the anhedonia in major depressive disorder: An explorative study.

BACKGROUND: Although anhedonia is a key symptom of major depressive disorder (MDD), there is neither a concise nor effective method to distinguish and define anhedonia in MDD. The current study attempts to answer two questions based on validating the Dimensional Anhedonia Rating Scale (DARS) in Chinese MDD patients: 1) whether anhedonia subgroup can be identified? 2) whether patients with anhedonia display unique psychosocial and clinical features? METHODS: In the discovery sample, 533 MDD patients and 124 healthy controls were recruited into a multicenter study. For replication, a further 112 first-episode, drug-naïve MDD patients were recruited. Latent profile analysis (LPA) was used to identify the latent subgroups based on their hedonic function measured by the DARS. According to the categorization, ROC curves were applied to find the cut-off value. Lasso regression was performed to characterize psychological and clinical features linked to anhedonia. RESULTS: The data-driven approach identified and validated the anhedonia subgroup, and proposed that the cut-off value for distinguishing anhedonia was 28.5 based on the total score of DARS. Lasso regression demonstrated that melancholia, lower levels of positive affect and education, more severe depressive symptoms, older age were associated with anhedonia in MDD patients. CONCLUSION: This study used a data-driven approach to propose a new and convenient method for distinguishing the anhedonia of MDD patients with unique psychological and clinical features. Identifying the subtype may contribute to pinpointing more specific biomarkers in shedding light on the mechanisms of anhedonia in MDD. TRIAL REGISTRATION: TNDTAD study, NCT03294525; TOSD study, NCT03148522.

The BEACON study: an update to the protocol for a cohort study as part of an evaluation of the effectiveness of smartphone-assisted problem-solving therapy in men who present with intentional self-harm to emergency departments in Ontario.

BACKGROUND: Men who present to the emergency department (ED) with self-harm are at high risk of dying by suicide, with 2.7% of men dying in the year following their presentation, more than double the rate for women (1.2%). Despite this, care received after an ED visit is highly variable and many are not assessed for psychological needs. Furthermore, the limited psychological care that is available is often not covered by provincial health insurance. Even when referrals for follow-up care are made, engagement rates are low. Previous recommendations to improve engagement include written discharge plans, caring contacts, and focused interventions targeting middle-aged men at elevated risk of dying by suicide. Blended care, the incorporation of technology into traditional care, has also been proposed as a method to increase engagement in and clinical benefits from psychotherapy. This project aims to determine whether the delivery of an evidence based treatment (problem-solving therapy (PST)) is enhanced by the addition of a custom smartphone application (BEACON) compared to usual care. Due to the impact of the COVID-19 pandemic on site participation and the planned implementation, we have made several changes to the study design, primary outcome, and implementation. METHOD: We originally proposed a cohort study nested within a larger cluster randomized trial wherein intervention sites would deliver the blended care, and control sites, whose personnel were not aware of their participation, would continue delivering usual care. The cohort study evaluated participant level outcomes as previously described by Hatcher et al. (2020). Due to pandemic-related constraints, our number of participating sites dropped to five potential sites which left the cohort study underpowered. As such, we changed the study design to a multi-site, individual randomized controlled trial (RCT) among the five remaining sites. Participants will be randomized to six sessions of therapy (PST) alone, or to the therapy plus BEACON, and followed up for 6 months. Our primary outcome was changed to evaluate feasibility and acceptability with the aim of designing a definitive RCT. Study implementation was reimagined to allow for completely virtual/online conduct to comply with local COVID-19 and institutional restrictions on in-person activities. CONCLUSION: This updated protocol will provide strong results for the planning of a definitive RCT of the blended care intervention in the future, addressing areas of difficulty and concern prior to its implementation. We will evaluate the feasibility of the study intervention, assess recruitment and retention of participants, and address challenges with implementing the protocol. Lastly, we will evaluate the appropriateness of our primary outcome measure and accurately determine a sample size for a definitive RCT. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03473535 . Registered on March 22, 2018.

The effects of agomelatine on sexual function in depressed patients and healthy volunteers.

BACKGROUND: Selective serotonin reuptake inhibitor (SSRI) and serotonin and norepinephrine reuptake inhibitor antidepressants are associated with high rates of treatment-emergent sexual dysfunction (TESD) due to stimulation of serotonin receptors. OBJECTIVE: The objective is to evaluate the effect of agomelatine on sexual function in depressed patients. METHODS: This paper reviews published and unpublished data on sexual function with agomelatine in depressed patients and healthy volunteers. RESULTS: Agomelatine, an agonist of melatonergic MT1 and MT2 receptors and antagonist of 5-HT2 receptors, is associated with similar rates of sexual dysfunction compared with placebo and lower rates compared with other antidepressants. Twice as many sexually active depressed patients (n = 193) reported a deterioration of sexual function during 12 weeks of treatment with venlafaxine compared with agomelatine (15.2% vs. 8.2%, p < 0.0001); however, no differences were found with respect to arousal. Using the Arizona Sexual Experience Scale in depressed patients (n = 399), the incidence of treatment-emergent sexual dysfunction (TESD) with agomelatine (3%) was significantly lower than placebo (8.6%) and selective serotonin reuptake inhibitors (10.1%). Among healthy male volunteers (n = 92), TESD was not increased compared with placebo in either agomelatine (25 and 50 mg/day) group over 8 weeks, and both were significantly lower than TESD with paroxetine (p < 0.0001). Moderate or severe TESD occurred in less than 5% of subjects receiving agomelatine versus 62% who received paroxetine (p < 0.001). CONCLUSION: Agomelatine demonstrates favorable sexual acceptability.

Neurostimulation therapies for treatment resistant depression: a focus on vagus nerve stimulation and deep brain stimulation.

Antidepressant treatments, including pharmacotherapy and psychotherapy, do not result in remission for the majority of patients with major depressive disorder. The high prevalence of treatment resistant depression (TRD) poses a significant issue for patients as well as both societal and economic costs. Due to the limited efficacy of existing therapies in this sub-population, alternative somatic treatments are being explored. Both vagus nerve stimulation (VNS) and deep brain stimulation (DBS) are neurostimulation treatments for TRD. While VNS has Food Drug Administration approval as an adjunctive therapy for MDD, DBS is still in the experimental stages. This article will review the evidence supporting the clinical utility of these therapies.

Anhedonia as a central factor in depression: Neural mechanisms revealed from preclinical to clinical evidence.

Anhedonia is one of the core symptoms of major depressive disorder (MDD), which is often inadequately treated by traditional antidepressants. The modern framework of anhedonia extends the definition from impaired consummatory pleasure or interest in rewards to a broad spectrum of deficits that impact functions such as reward anticipation, approach motivation, effort expenditure, reward valuation, expectation, and reward-cue association learning. Substantial preclinical and clinical research has explored the neural basis of reward deficits in the context of depression, and has implicated mesocorticolimbic reward circuitry comprising the nucleus accumbens, ventral pallidum, ventral tegmental area, amygdala, hippocampus, anterior cingulate, insula, orbitofrontal cortex, and other prefrontal cortex regions. Dopamine modulates several reward facets including anticipation, motivation, effort, and learning. As well, serotonin, norepinephrine, opioids, glutamate, Gamma aminobutyric acid (GABA), and acetylcholine are also involved in anhedonia, and medications targeting these systems may also potentially normalize reward processing in depression. Unfortunately, whereas reward anticipation and reward outcome are extensively explored by both preclinical and clinical studies, translational gaps remain in reward motivation, effort, valuation, and learning, where clinical neuroimaging studies are in the early stages. This review aims to synthesize the neurobiological mechanisms underlying anhedonia in MDD uncovered by preclinical and clinical research. The translational difficulties in studying the neural basis of reward are also discussed.

Reward processing as a common diathesis for chronic pain and depression.

Pain disorders and psychiatric illness are strongly comorbid, particularly in the context of Major Depressive Disorder (MDD). While these disorders account for a significant amount of global disability, the mechanisms of their overlap remain unclear. Understanding these mechanisms is of vital importance to developing prevention strategies and interventions that target both disorders. Of note, brain reward processing may be relevant to explaining how the comorbidity arises, given pain disorders and MDD can result in maladaptive reward responsivity that limits reward learning, appetitive approach behaviours and consummatory response. In this review, we discuss this research and explore the possibility of reward processing deficits as a common diathesis to explain the manifestation of pain disorders and MDD. Specifically, we hypothesize that contextual physical or psychological events (e.g. surgery, divorce) in the presence of a reward impairment diathesis worsens symptoms and results in a negative feedback loop that increases the chronicity and probability of developing the other disorder. We also highlight the implications for treatment and provide a framework for future research.

The relationship between testosterone and sexual function in depressed and healthy men.

AIM: Men with Major Depressive Disorder (MDD) report high rates of sexual dysfunction, as do healthy males with low levels of testosterone. The objective of this study is to evaluate the effects of depression and low testosterone across various domains of sexual function. METHODS: Untreated depressed males (N = 44) and age-matched healthy controls (N = 50) had blood samples drawn to determine morning levels of total testosterone (TT) and bioavailable testosterone (BT). In addition, questionnaires regarding depressive symptoms as well as sexual function were administered. MAIN OUTCOME MEASURES: Sexual function outcomes were measured using the Sex Effects (SexFX) Scale and depression severity was assessed with the Hamilton Rating Scale for Depression-17 item (HAMD-17). RESULTS: Using TT criteria, 27.9% of men were categorically defined as hypogonadal compared to 19.3% using BT criteria. Within both TT and BT hypogonadal groups, men with MDD had lower scores on all domains of sexual function compared to healthy controls with hypogonadism. Testosterone levels interacted with MDD status to affect orgasm and desire, although not arousal. Multiple linear regression analyses revealed that depression status was the main factor influencing sexual function. Hypogonadal status was not a predictor of sexual function in this sample, although age did play a minor role in the domain of arousal. CONCLUSION: While testosterone levels appear to influence sexual function, specifically orgasm, the presence of MDD appears to be a stronger factor and has high predictive value for sexual outcomes.