Cognitive predictors of treatment response to bupropion and cognitive effects of bupropion in patients with major depressive disorder

Electrophysiological predictors of early response to antidepressants in major depressive disorder

BACKGROUND

Psychomotor retardation (PMR) is a core feature of major depressive disorder (MDD), which is characterized by abnormalities in motor control and cognitive processes. PMR in MDD can predict a poor antidepressant response, suggesting that PMR may serve as a marker of the antidepressant response. However, the neuropathological relationship between treatment outcomes and PMR remains uncertain. Thus, this study examined electrophysiological biomarkers associated with poor antidepressant response in MDD.

METHODS

A total of 142 subjects were enrolled in this study, including 49 healthy controls (HCs) and 93 MDD patients. All participants performed a simple right-hand visuomotor task during magnetoencephalography (MEG) scanning. Patients who exhibited at least a 50 % reduction in disorder severity at the endpoint (>2 weeks) were considered to be responders. Motor-related beta desynchronization (MRBD) and inter- and intra-hemispheric functional connectivity were measured in the bilateral motor network.

RESULTS

An increased MRBD and decreased inter- and intra-hemispheric functional connectivity in the motor network during movement were observed in non-responders, relative to responders and HCs. This dysregulation predicted the potential antidepressant response.

CONCLUSION

Abnormal local activity and functional connectivity in the motor network indicate poor psychomotor function, which might cause insensitivity to antidepressant treatment. This could be regarded as a potential neural mechanism for the prediction of a patient's treatment response.

Oral ketamine effects on dynamics of functional network connectivity in patients treated for chronic suicidality

The underlying brain mechanisms of ketamine in treating chronic suicidality and the characteristics of patients who will benefit from ketamine treatment remain unclear. To address these gaps, we investigated temporal variations of brain functional synchronisation in patients with suicidality treated with ketamine in a 6-week open-label oral ketamine trial. The trial's primary endpoint was the Beck Scale for Suicide Ideation (BSS). Patients who experienced greater than 50% improvement in BSS scores or had a BSS score less than 6 at the post-treatment and follow-up (10 weeks) visits were considered responders and persistent responders, respectively. The reoccurring and transient connectivity pattern (termed brain state) from 29 patients (45.6 years ± 14.5, 15 females) were investigated by dynamic functional connectivity analysis of resting-state functional MRI at the baseline, post-treatment, and follow-up. Post-treatment patients showed significantly more (FDR-Q = 0.03) transitions among whole brain states than at baseline. We also observed increased dwelling time (FDR-Q = 0.04) and frequency (FDR-Q = 0.04) of highly synchronised brain state at follow-up, which were significantly correlated with BSS scores (both FDR-Q = 0.008). At baseline, persistent responders had higher fractions (FDR-Q = 0.03, Cohen's d = 1.39) of a cognitive control network state with high connectivities than non-responders. These findings suggested that ketamine enhanced brain changes among different synchronisation patterns and enabled high synchronisation patterns in the long term, providing a possible biological pathway for its suicide-prevention effects. Moreover, differences in cognitive control states at baseline may be used for precise ketamine treatment planning.

Relations between clinical characteristics and cognitive deficits among adult patients diagnosed with major depressive disorder

OBJECTIVE

The present study examined the relations between clinical characteristics and cognitive deficits in adult patients with major depressive disorder (MDD) from a local outpatient psychiatric clinic in Malaysia.

METHODS

The present sample included 110 participants aged 20-60 years old. Participants were invited to provide their information on sociodemographic variables (age, gender, and educational level) and clinical characteristics (age at onset of depression and duration of illness) and to complete a series of cognitive performance measures including the Trail Making Tests A (psychomotor speed) and B (executive function), the Digit Symbol Substitution Test (attention), and the Auditory Verbal Learning Test (immediate free recall, acquisition phase, and delayed recall). The Mini International Neuropsychiatric Interview Version 6.0 was used to confirm the diagnosis of MDD and the Montgomery-Åsberg Depression Rating Scale was used to assess illness severity.

RESULTS

At the bivariate level, relations of age and educational level to all cognitive deficit domains were significant. At the multivariate level, only educational level and illness severity consistently and significantly predicted all cognitive deficits domains.

CONCLUSIONS

Therapeutic modalities should be individualised whilst considering the impacts of cognitive deficits in an attempt to prevent further deterioration in psychosocial functioning of MDD patients.KEY POINTSCognitive deficits are an elemental component of Major Depressive Disorder (MDD) persisting during a current major depressive episode or during remission, altering individuals' ability to process information and changes the way they perceive and interact with the environment.Cognitive deficits in MDD are evident among the upper-middle income groups in South-Eastern Asian countries warranting more local research as such deficits could lead to functional decline and work performance such as absenteeism and presenteeism.Therapeutic modalities should be individualised by taking the impacts of cognitive deficits into consideration to promote psychosocial functioning of MDD patients.

Pharmacological targeting of cognitive impairment in depression: recent developments and challenges in human clinical research

Impaired cognition is often overlooked in the clinical management of depression, despite its association with poor psychosocial functioning and reduced clinical engagement. There is an outstanding need for new treatments to address this unmet clinical need, highlighted by our consultations with individuals with lived experience of depression. Here we consider the evidence to support different pharmacological approaches for the treatment of impaired cognition in individuals with depression, including treatments that influence primary neurotransmission directly as well as novel targets such as neurosteroid modulation. We also consider potential methodological challenges in establishing a strong evidence base in this area, including the need to disentangle direct effects of treatment on cognition from more generalised symptomatic improvement and the identification of sensitive, reliable and objective measures of cognition.

Exploration of baseline and early changes in neurocognitive characteristics as predictors of treatment response to bupropion, sertraline, and placebo in the EMBARC clinical trial

BACKGROUND

Treatment for major depressive disorder (MDD) is imprecise and often involves trial-and-error to determine the most effective approach. To facilitate optimal treatment selection and inform timely adjustment, the current study investigated whether neurocognitive variables could predict an antidepressant response in a treatment-specific manner.

METHODS

In the two-stage Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care (EMBARC) trial, outpatients with non-psychotic recurrent MDD were first randomized to an 8-week course of sertraline selective serotonin reuptake inhibitor or placebo. Behavioral measures of reward responsiveness, cognitive control, verbal fluency, psychomotor, and cognitive processing speeds were collected at baseline and week 1. Treatment responders then continued on another 8-week course of the same medication, whereas non-responders to sertraline or placebo were crossed-over under double-blinded conditions to bupropion noradrenaline/dopamine reuptake inhibitor or sertraline, respectively. Hamilton Rating for Depression scores were also assessed at baseline, weeks 8, and 16.

RESULTS

Greater improvements in psychomotor and cognitive processing speeds within the first week, as well as better pretreatment performance in these domains, were specifically associated with higher likelihood of response to placebo. Moreover, better reward responsiveness, poorer cognitive control and greater verbal fluency were associated with greater likelihood of response to bupropion in patients who previously failed to respond to sertraline.

CONCLUSION

These exploratory results warrant further scrutiny, but demonstrate that quick and non-invasive behavioral tests may have substantial clinical value in predicting antidepressant treatment response.

Cold Cognition as Predictor of Treatment Response to rTMS; A Retrospective Study on Patients With Unipolar and Bipolar Depression

Background

Cognitive impairments are prevalent in patients with unipolar and bipolar depressive disorder (UDD and BDD, respectively). Considering the fact assessing cognitive functions is increasingly feasible for clinicians and researchers, targeting these problems in treatment and using them at baseline as predictors of response to treatment can be very informative.

Method

In a naturalistic, retrospective study, data from 120 patients (Mean age: 33.58) with UDD (n = 56) and BDD (n = 64) were analyzed. Patients received 20 sessions of bilateral rTMS (10 Hz over LDLPFC and 1 HZ over RDLPFC) and were assessed regarding their depressive symptoms, sustained attention, working memory, and executive functions, using the Beck Depression Inventory (BDI-II) and Neuropsychological Test Automated Battery Cambridge, at baseline and after the end of rTMS treatment course. Generalized estimating equations (GEE) and logistic regression were used as the main statistical methods to test the hypotheses.

Results

Fifty-three percentage of all patients (n = 64) responded to treatment. In particular, 53.1% of UDD patients (n = 34) and 46.9% of BDD patients (n = 30) responded to treatment. Bilateral rTMS improved all cognitive functions (attention, working memory, and executive function) except for visual memory and resulted in more modulations in the working memory of UDD compared to BDD patients. More improvements in working memory were observed in responded patients and visual memory, age, and sex were determined as treatment response predictors. Working memory, visual memory, and age were identified as treatment response predictors in BDD and UDD patients, respectively.

Conclusion

Bilateral rTMS improved cold cognition and depressive symptoms in UDD and BDD patients, possibly by altering cognitive control mechanisms (top-down), and processing negative emotional bias.

Machine learning to predict clinical remission in depressed patients after acute phase selective serotonin reuptake inhibitor treatment

OBJECTIVE

Selective serotonin reuptake inhibitors (SSRIs) are suggested as the first-line treatment for patients with major depressive disorder (MDD), but the remission rate is unsatisfactory. We aimed to establish machine learning models and explore variables available at baseline to predict the 8-week outcome among patients taking SSRIs.

METHODS

Data from 400 patients were used to build machine learnings. The last observation carried forward approach was used to determine the remitter/non-remitter status of the patients at week 8. Using least absolute shrinkage and selection operator (LASSO) to select features, we built 4 different machine learning algorithms including gradient boosting decision tree, support vector machine (SVM), random forests, and logistic regression with five-fold cross-validation. Then, we adopted Shapley additive explanations (SHAP) values to interpret the model output.

RESULTS

The remission rate is 67.8%. We obtained 78 features from the baseline characteristics, including 25 sociodemographic characteristics, 31 clinical features, 15 psychological traits and 7 neurocognitive functions, and 13 of these features were selected to establish SVM. The accuracy of the SVM prediction is 74.49%, reaching an average area under the curve of 0.734±0.043. The sensitivity is 0.899±0.038 with a positive predictive value of 0.776±0.028. The specificity is 0.422±0.091 with a negative predictive value of 0.674±0.086. According to the SHAP values, neurocognitive functions and anxiety and hypochondriasis symptoms were important predictors.

CONCLUSION

Our study supports the utilization of machine learning approaches with inexpensive and highly accessible variables to accurately predict the 8-week treatment outcome of SSRIs in patients with MDD.

Pretreatment Reward Sensitivity and Frontostriatal Resting-State Functional Connectivity Are Associated With Response to Bupropion After Sertraline Nonresponse

BACKGROUND

Standard guidelines recommend selective serotonin reuptake inhibitors as first-line antidepressants for adults with major depressive disorder, but success is limited and patients who fail to benefit are often switched to non-selective serotonin reuptake inhibitor agents. This study investigated whether brain- and behavior-based markers of reward processing might be associated with response to bupropion after sertraline nonresponse.

METHODS

In a two-stage, double-blinded clinical trial, 296 participants were randomized to receive 8 weeks of sertraline or placebo in stage 1. Individuals who responded continued on another 8-week course of the same intervention in stage 2, while sertraline and placebo nonresponders crossed over to bupropion and sertraline, respectively. Data from 241 participants were analyzed. The stage 2 sample comprised 87 patients with major depressive disorder who switched medication and 38 healthy control subjects. A total of 116 participants with major depressive disorder treated with sertraline in stage 1 served as an independent replication sample. The probabilistic reward task and resting-state functional magnetic resonance imaging were administered at baseline.

RESULTS

Greater pretreatment reward sensitivity and higher resting-state functional connectivity between bilateral nucleus accumbens and rostral anterior cingulate cortex were associated with positive response to bupropion but not sertraline. Null findings for sertraline were replicated in the stage 1 sample.

CONCLUSIONS

Pretreatment reward sensitivity and frontostriatal connectivity may identify patients likely to benefit from bupropion following selective serotonin reuptake inhibitor failures. Results call for a prospective replication based on these biomarkers to advance clinical care.

The Effect of Second-Generation Antidepressant Treatment on the Memory of Patients With Major Depressive Disorder: A Meta-analysis Study With Structural Equation Models

BACKGROUND

Major depressive disorder (MDD) has been linked to episodic memory deficits that may be improved after pharmacological treatment, but it is unclear whether there is a class of antidepressants that is more effective than others to ameliorate these deficits in MDD. In addition, the possible effects of clinical and sociodemographic variables on the improvement of MDD memory deficits after pharmacological treatment are currently unknown. Our aims are to study the possible neuropsychological effects of second-generation antidepressant classes on the episodic memory of MDD patients and to study the potential effects of clinical and demographic variables as moderators of the effects of antidepressants on the memory of depressed patients through a meta-analysis approach.

PROCEDURES

Nine articles were included in our study. A structural equation model meta-analysis was performed.

RESULTS

Our results suggest that selective serotonin reuptake inhibitors and serotonine-noradrenaline reuptake inhibitors would bring about a substantial improvement in the memory of depressed patients, whereas other antidepressant classes would cause rather modest effects. Our results also suggest that clinical and demographic variables play a very important role as mediators of memory improvement after MDD treatment. Thus, a relatively low level of symptom severity, a high degree of clinical improvement, a younger age, and more years of education were positively related to memory improvement after MDD treatment.

CONCLUSIONS

Although antidepressant class is an important variable linked to memory improvement in MDD, overall, the degree of memory amelioration in depression is very closely related to clinical and demographic variables of patients with depression.

Evaluating the severity of depressive symptoms using upper body motion captured by RGB-depth sensors and machine learning in a clinical interview setting: A preliminary study

BACKGROUND

Mood disorders have long been known to affect motor function. While methods to objectively assess such symptoms have been used in experiments, those same methods have not yet been applied in clinical practice because the methods are time-consuming, labor-intensive, or invasive.

METHODS

We videotaped the upper body of each subject using a Red-Green-Blue-Depth (RGB-D) sensor during a clinical interview setting. We then examined the relationship between depressive symptoms and body motion by comparing the head motion of patients with major depressive disorders (MDD) and bipolar disorders (BD) to the motion of healthy controls (HC). Furthermore, we attempted to predict the severity of depressive symptoms by using machine learning.

RESULTS

A total of 47 participants (HC, n = 16; MDD, n = 17; BD, n = 14) participated in the study, contributing to 144 data sets. It was found that patients with depression move significantly slower compared to HC in the 5th percentile and 50th percentile of motion speed. In addition, Hamilton Depression Rating Scale (HAMD)-17 scores correlated with 5th percentile, 50th percentile, and mean speed of motion. Moreover, using machine learning, the presence and/or severity of depressive symptoms based on HAMD-17 scores were distinguished by a kappa coefficient of 0.37 to 0.43.

LIMITATIONS

Limitations include the small number of subjects, especially the number of severe cases and young people.

CONCLUSIONS

The RGB-D sensor captured some differences in upper body motion between depressed patients and controls. If much larger samples are accumulated, machine learning may be useful in identifying objective measures for depression in the future.

Bupropion increases activation in nucleus accumbens during anticipation of monetary reward

RATIONALE

Bupropion is used for major depressive disorder, smoking cessation aid, and obesity. It blocks reuptake of dopamine and noradrenaline and antagonizes nicotinic acetylcholine receptor. Animal studies showed that bupropion enhanced rewarding effects. In addition, bupropion has the potential to treat patients with reward processing dysfunction. However, neural substrates underlying the bupropion effects on reward function in human subjects are not fully understood.

OBJECTIVES

We investigated single-dose administration of bupropion on neural response of reward anticipation in healthy subjects using a monetary incentive delay (MID) task by functional magnetic resonance imaging (fMRI), especially focusing on nucleus accumbens (NAc) activity to non-drug reward stimuli under bupropion treatment.

METHODS

We used a randomized placebo-controlled within-subject crossover design. Fifteen healthy adults participated in two series of an fMRI study, taking either placebo or bupropion. The participants performed the MID task during the fMRI scanning. The effects of bupropion on behavioral performance and blood oxygenation level-dependent (BOLD) signal in NAc during anticipation of monetary gain were analyzed.

RESULTS

We found that bupropion significantly increased BOLD responses in NAc during monetary reward anticipation. The increased BOLD responses in NAc were observed with both low and high reward incentive cues. There was no significant difference between placebo and bupropion in behavioral performance.

CONCLUSIONS

Our findings provide support for the notion that bupropion enhances non-drug rewarding effects, suggesting a possible mechanism underlying therapeutic effects for patients with motivational deficit.

Neurocognitive Predictors of Clinical Improvement in Selective Serotonin Reuptake Inhibitor-Treated Adolescents with Major Depressive Disorder

OBJECTIVES

Numerous studies have suggested cognitive deficits as consistently associated with adolescent depression. No study to date, however, has assessed neurocognitive predictors of selective serotonin reuptake inhibitor (SSRI) treatment response in adolescents with depression. This study examined neurocognitive tasks at baseline as predictors of clinical improvement with SSRI treatment (fluoxetine) at week 6 and 12 in an adolescent population.

METHODS

Adolescents with depression were recruited from a child and adolescent psychiatry outpatient clinic at a university medical center. Twenty-four adolescents (mean age 14.8 years) with Major Depressive Disorder completed tasks of the Cambridge Neuropsychological Test Automated Battery, including visual memory, executive functioning, sustained attention, and impulsivity. Depression severity, measured by the Children's Depression Rating Scale-Revised (CDRS-R), was assessed at week 6 and 12 and clinical improvement was defined as percentage (%) change in CDRS-R from baseline.

RESULTS

Clinical improvement is noted at both week 6 (mean % change in CDRS-R [M] = 46.8, standard deviation [SD] = 51.9) and week 12 (M = 87.9, SD = 57.2). Results reveal that less difficulty in sustained attention (p = 0.02), lower impulsivity (p = 0.00), and better planning (p = 0.04) at baseline were predictors of greater clinical improvement at week 6. Lower impulsivity at baseline remained significantly predictive of clinical improvement at week 12 (p = 0.01).

CONCLUSION

Neurocognitive assessments could potentially help identify a subset of depressed adolescents who may not respond to conventional SSRI treatment and who may be better candidates for alternative or augmentation treatments.

How to choose an antidepressant medication

OBJECTIVE

We consider how to choose an antidepressant (AD) medication for the treatment of clinical depression.

METHOD

A narrative review was undertaken addressing antidepressant 'choice' considering a range of parameters either weighted by patients and clinicians or suggested in the scientific literature. Findings were synthesised and incorporated with clinical experience into a model to assist AD choice.

RESULTS

Efficacy studies comparing ADs offer indicative guidance, while precision psychiatry prediction based on genetics, developmental trauma, neuroimaging, behavioural and cognitive biomarkers, currently has limited clinical utility. Our model offers guidance for AD choice by assessing first for the presence of a depressive subtype or symptom cluster and matching choice of AD class accordingly. Failing this, an AD can be chosen based on depression severity. Within-class choice can be determined by reference to personality style, patient preference, medical or psychiatric comorbidities and side-effect profile.

CONCLUSION

Clarification of AD choice would occur if medications are trialled in specific depressive subtypes rather than using the generic diagnosis of major depressive disorder (MDD). Such 'top-down' methods could be enhanced by 'bottom-up' studies to classify individuals according to symptom clusters and biomarkers with AD efficacy tested in these categories. Both methods could be utilised for personalised AD choice.

Do baseline WAIS-III subtests predict treatment outcomes for depressed inpatients receiving fluoxetine?

This study aimed to determine whether baseline WAIS-III subtests could be associated with treatment outcomes for patients with major depressive disorder (MDD) receiving a 6-week fluoxetine treatment. A total of 131 acutely ill MDD inpatients were enrolled to receive 20 mg of fluoxetine daily for 6 weeks. Eight WAIS-III subtests were administered at baseline. Symptom severity and functional impairment were assessed at baseline, and again at weeks 1, 2, 3, 4, and 6 using the 17-item Hamilton Depression Rating Scale (HAMD-17) and the Modified Work and Social Adjustment Scale (MWSAS), respectively. The generalized estimating equations method was used to analyze the influence of potential predictors over time on the HAMD-17 and MWSAS, after adjusting for covariates. Of the 131 participants, 104 (79.4%) who completed 8 WAIS-III subtests at baseline and had at least one post-baseline assessment were included in the analysis. Patients with lower forward digit span scores were more likely to have poor treatment outcomes, both measured by HAMD-17, and by MWSAS. Forward digit span may be clinically useful in identifying MDD patients with greater treatment difficulty in symptoms and functioning. Other neurocognitive tests to predict treatment outcome require further exploration.

Bilateral Transcranial Magnetic Stimulation on DLPFC Changes Resting State Networks and Cognitive Function in Patients With Bipolar Depression

Introduction: Bipolar patients have abnormalities in cognitive functions and emotional processing. Two resting state networks (RSNs), the default mode network (DMN) and the sensorimotor network (SMN), play a decisive role in these two functions. Dorsolateral prefrontal cortex (DLPFC) is one of the main areas in the central executive network (CEN), which is linked to the activities of each of the two networks. Studies have found DLPFC abnormalities in both hemispheres of patients with bipolar depression. We hypothesized that the bilateral repetitive transcranial magnetic stimulation (rTMS) of DLPFC would produce changes in the activity of both the SMN and DMN as well as relevant cognitive function in patients with bipolar depression that responded to treatment.

Methods: 20 patients with bipolar depression underwent 10 sessions of 1 Hz rTMS on right DLPFC with subsequent 10 Hz rTMS on left DLPFC. Changes in electroencephalography resting networks between pre and post rTMS were evaluated utilizing low-resolution electromagnetic tomography (eLORETA). Depression symptom was assessed using the Beck Depression Inventory (BDI-II) and cognitive function was assessed by Verbal Fluency Test (VFT), Rey Auditory Verbal Learning Test (RAVLT), Stroop Test, and Wisconsin Card Sorting Test (WCST).

Results: Responders to rTMS showed significantly lower DMN activity at baseline and a significant decrease in SMN connectivity after treatment. Non-responders did not significantly differ from the control group at the baseline and they showed higher activity in the SMN, visual network, and visual perception network compared to control group following treatment. Bilateral rTMS resulted in significant changes in the executive functions, verbal memory, and depression symptoms. No significant changes were observed in selective attention and verbal fluency.

Conclusion: Bilateral stimulation of DLPFC, as the main node of CEN, results in changes in the activity of the SMN and consequently improves verbal memory and executive functions in patients with bipolar depression.

Progress in Elucidating Biomarkers of Antidepressant Pharmacological Treatment Response: A Systematic Review and Meta-analysis of the Last 15 Years

BACKGROUND

Antidepressant drugs are widely prescribed, but response rates after 3 months are only around one-third, explaining the importance of the search of objectively measurable markers predicting positive treatment response. These markers are being developed in different fields, with different techniques, sample sizes, costs, and efficiency. It is therefore difficult to know which ones are the most promising.

OBJECTIVE

Our purpose was to compute comparable (i.e., standardized) effect sizes, at study level but also at marker level, in order to conclude on the efficacy of each technique used and all analyzed markers.

METHODS

We conducted a systematic search on the PubMed database to gather all articles published since 2000 using objectively measurable markers to predict antidepressant response from five domains, namely cognition, electrophysiology, imaging, genetics, and transcriptomics/proteomics/epigenetics. A manual screening of the abstracts and the reference lists of these articles completed the search process.

RESULTS

Executive functioning, theta activity in the rostral Anterior Cingular Cortex (rACC), and polysomnographic sleep measures could be considered as belonging to the best objectively measured markers, with a combined d around 1 and at least four positive studies. For inter-category comparisons, the approaches that showed the highest effect sizes are, in descending order, imaging (combined d between 0.703 and 1.353), electrophysiology (0.294-1.138), cognition (0.929-1.022), proteins/nucleotides (0.520-1.18), and genetics (0.021-0.515).

CONCLUSION

Markers of antidepressant treatment outcome are numerous, but with a discrepant level of accuracy. Many biomarkers and cognitions have sufficient predictive value (d ≥ 1) to be potentially useful for clinicians to predict outcome and personalize antidepressant treatment.

Neural and Behavioral Predictors of Treatment Efficacy on Mood Symptoms and Cognition in Mood Disorders: A Systematic Review

Background: The clinical and etiological heterogeneity of mood disorders impede identification of effective treatments for the individual patient. This highlights a need for early neuronal and behavioral biomarkers for treatment efficacy, which can provide a basis for more personalized treatments. The present systematic review aimed to identify the most consistent neuronal and behavioral predictors of treatment efficacy on mood symptoms and cognitive impairment in mood disorders. Methods: We identified and included 60 original peer-reviewed studies investigating neuroimaging and behavioral predictors of treatment efficacy within the domains of emotional and non-emotional cognition, structural neuroimaging, and resting state functional connectivity in patients with unipolar or bipolar disorder. Results: Lower baseline responsivity in limbic regions coupled with heightened medial and dorsal prefrontal responses to emotional stimuli were the most consistent predictors of response to pharmacotherapy for depression. In contrast, heightened limbic and ventral prefrontal reactivity to emotional stimuli seemed to predict efficacy of psychological interventions. Early modulation of fronto-limbic activity and reduction in negative bias were also associated with treatment response. Better performance on non-emotional tests at baseline was relatively consistently associated with efficacy on mood symptoms, whereas the association between neural activity during non-emotional tests and treatment response was less clear. Other baseline factors associated with treatment response were greater white matter integrity, resting state functional connectivity, more prefrontal gray matter volume as well as an early increase following short administered treatment. Finally, emerging evidence indicates that baseline cognitive deficits are associated with greater chances of achieving treatment efficacy on cognition. Conclusions: Patients' profile of emotional and non-emotional cognition and neural activity-and the early treatment-associated changes in neural and cognitive function-may be useful for guiding treatments for depression. While cognitive deficits at baseline seem to improve chances of treatment efficacy on cognition, more studies of this association are urgently needed.

A Systematic Review of Cognitive Predictors of Treatment Outcome in Major Depression

Background: Research suggests that only 50% of patients with major depression respond to psychotherapy or pharmacological treatment, and relapse is common. Therefore, there is interest in elucidating factors that help predict clinical response. Cognitive impairment is a key feature of depression, which often persists beyond remission; thus, the aim of this systematic review was to determine whether baseline cognitive functioning can predict treatment outcomes in individuals with depression. Method: Studies examining cognitive predictors of treatment response in depression were identified using Pub Med and Web of Science databases. Given the heterogeneity of outcome measures, the variety of treatment protocols, and the differing ways in which data was presented and analyzed, a narrative rather than meta-analytic review technique was used. Results: 39 studies met inclusion criteria. Findings in younger adult samples were inconclusive. There was some evidence for a predictive effect of executive function and to a lesser extent, psychomotor speed, on treatment response. There was no evidence of learning or memory being associated with treatment response. In older-aged samples, the evidence was much more consistent, suggesting that poor executive function predicts poor response to SSRIs. Conclusions: Findings from the present review suggest that certain aspects of cognitive functioning, particularly executive function, may be useful in predicting treatment response in depression. This is certainly the case in elderly samples, with evidence suggesting that poor executive functioning predicts poor response to SSRIs. With further research, baseline cognitive functioning may serve as a factor which helps guide clinical decision making. Moreover, cognitive deficits may become targets for specific pharmacological or psychological treatments, with the hope of improving overall outcome.

Improvement in neurocognitive functions and serum brain-derived neurotrophic factor levels in patients with depression treated with antidepressants and yoga

CONTEXT AND AIMS

Impairment in cognition is well-known in patients with major depressive disorder. This study examined the effect of yoga therapy with or without antidepressants and antidepressants alone on certain neuropsychological functions in patients with depression. Correlation between changes in neuropsychological test performance and serum brain-derived neurotrophic factor (BDNF) levels was also explored.

MATERIALS AND METHODS

Antidepressant-naïve/antidepressant-free outpatients with depression received antidepressant medication alone (n = 23) or yoga therapy with (n = 26) or without (n = 16) antidepressants. Depression was assessed using the Hamilton Depression Rating Scale. Neuropsychological tests included digit-span forward and backward, Rey Auditory Verbal Learning Test, and Trail Making Tests (TMT-A and B). These tests were administered before and 3 months after the treatment in patients, and once in healthy comparison subjects (n = 19).

STATISTICAL ANALYSIS

Baseline differences were analyzed using independent sample t-test, Chi-square, and one-way ANOVA. Paired t-test was used to analyze the change from baseline to follow-up. Pearson's correlation was used to explore the association of change between 2 variables.

RESULTS

Patients had impaired performance on most neuropsychological tests. After 3 months, there was significant improvement - patients' performance was comparable to that of healthy controls on majority of the tests. Significant inverse correlation was observed between increase in BDNF levels and improvement in TMT "A" duration in Yoga-alone group (r = -0.647; P = 0.009).

CONCLUSIONS

To conclude that, Yoga therapy, alone or in combination with medications, is associated with improved neuropsychological functions and neuroplastic effects in patients with depression.

Treatment of neurocognitive symptoms in unipolar depression: A systematic review and future perspectives

BACKGROUND

Cognitive symptoms in Major Depressive Disorder (MDD) are persistent and commonly entail neurocognitive impairment and a decline in quality of life. This systematic review gathers the current scientific evidence on therapeutic strategies for neuropsychological impairment in MDD.

METHOD

A systematic search on PubMed, PsycINFO and Clinicaltrials.gov was carried out on December 2016 according to PRISMA using Boolean terms to identify interventions for the treatment of cognitive dysfunction in MDD. Only English-written articles providing original data and focusing in adults with MDD were included with no time restrictions.

RESULTS

A total of 95 studies reporting data on 40 pharmacological and non-pharmacological interventions were included. Interventions were grouped into the following categories: 1) Pharmacological Therapies (antidepressants, stimulants, compounds acting on NMDA receptors, compounds acting on the cholinergic system, compounds showing anti-inflammatory or antioxidant properties, other mechanisms of action), 2) Physical Therapies and 3) Psychological Therapies, 4) Exercise. There are some promising compounds showing a positive impact on cognitive symptoms including vortioxetine, lisdexamfetamine or erythropoietin.

LIMITATIONS

The studies included showed significant methodological differences in heterogeneous samples. The lack of a standardized neuropsychological battery makes comparisons between studies difficult.

CONCLUSION

Current evidence is not sufficient to widely recommend the use of procognitive treatments in MDD although promising results are coming to light.

Bupropion for attention deficit hyperactivity disorder (ADHD) in adults

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a prevalent neurobiological condition, characterised by behavioral and cognitive symptoms such as inattention, impulsivity and/or excessive activity. The syndrome is commonly accompanied by psychiatric comorbidities and is associated with educational and occupational underachievement.Although psychostimulant medications are the mainstay of treatment for ADHD, not all adults respond optimally to, or can tolerate, these medicines. Thus, alternative non-stimulant treatment approaches for ADHD have been explored. One of these alternatives is bupropion, an aminoketone antidepressant and non-competitive antagonism of nicotinic acetylcholine receptors. Bupropion is registered for the treatment of depression and smoking cessation, but is also used off-label to treat ADHD.

OBJECTIVES

To assess the effects and safety of bupropion for the treatment of adults with ADHD.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and seven other databases in February 2017. We also searched three trials registers and three online theses portals. In addition, we checked references of included studies and contacted study authors to identify potentially relevant studies that were missed by our search.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that evaluated the effects (including adverse effects) of bupropion compared to placebo in adults with ADHD.

DATA COLLECTION AND ANALYSIS

Two review authors (WV, GB) independently screened records and extracted data using a data extraction sheet that we tested in a pilot study. We extracted all relevant data on study characteristics and results. We assessed risks of bias using the Cochrane 'Risk of bias' tool, and assessed the overall quality of evidence using the GRADE approach. We used a fixed-effect model to pool the results across studies.

MAIN RESULTS

We included six studies with a total of 438 participants. Five studies were conducted in the USA, and one in Iran. All studies evaluated a long-acting version of bupropion, with the dosage ranging from 150 mg up to 450 mg daily. Study intervention length varied from six to 10 weeks. Four studies explicitly excluded participants with psychiatric comorbidity and one study included only participants with opioid dependency. Four studies were funded by industry, but the impact of this on study results is unknown. Two studies were publicly funded and in one of these studies, the lead author was a consultant for several pharmaceutical companies and also received investigator-driven funding from two companies, however none of these companies manufacture bupropion. We judged none of the studies to be free of bias because for most risk of bias domains the study reports failed to provide sufficient details. Using the GRADE approach, we rated the overall quality of evidence as low. We downgraded the quality of the evidence because of serious risk of bias and serious imprecision due to small sample sizes.We found low-quality evidence that bupropion decreased the severity of ADHD symptoms (standardised mean difference -0.50, 95% confidence interval (CI) -0.86 to -0.15, 3 studies, 129 participants), and increased the proportion of participants achieving clinical improvement (risk ratio (RR) 1.50, 95% CI 1.13 to 1.99, 4 studies, 315 participants), and reporting an improvement on the Clinical Global Impression - Improvement scale (RR 1.78, 95% CI 1.27 to 2.50, 5 studies, 337 participants). There was low-quality evidence that the proportion of participants who withdrew due to any adverse effect was similar in the bupropion and placebo groups (RR 1.20, 95% CI 0.35 to 4.10, 3 studies, 253 participants). The results were very similar when using a random-effects model and when we analysed only studies that excluded participants with a psychiatric comorbidity.

AUTHORS' CONCLUSIONS

The findings of this review, which compared bupropion to placebo for adult ADHD, indicate a possible benefit of bupropion. We found low-quality evidence that bupropion decreased the severity of ADHD symptoms and moderately increased the proportion of participants achieving a significant clinical improvement in ADHD symptoms. Furthermore, we found low-quality evidence that the tolerability of bupropion is similar to that of placebo. In the pharmacological treatment of adults with ADHD, extended- or sustained-release bupropion may be an alternative to stimulants. The low-quality evidence indicates uncertainty with respect to the pooled effect estimates. Further research is very likely to change these estimates. More research is needed to reach more definite conclusions as well as clarifying the optimal target population for this medicine. Treatment response remains to be reported in a DSM5-diagnosed population. There is also a lack of knowledge on long-term outcomes.

Neurocognitive Predictors of Response in Treatment Resistant Depression to Subcallosal Cingulate Gyrus Deep Brain Stimulation

Background: Deep brain stimulation (DBS) is a neurosurgical intervention with demonstrated effectiveness for treatment resistant depression (TRD), but longitudinal studies on the stability of cognitive parameters following treatment are limited. The objectives of this study are to (i) identify baseline cognitive predictors of treatment response to subcallosal cingulate gyrus (SCG) DBS for unipolar TRD and (ii) compare neurocognitive performance prior to and 12 months after DBS implantation.

Methods: Twenty unipolar TRD patients received SCG DBS for 12 months. A standardized neuropsychological battery was used to assess a range of neurocognitive abilities at baseline and after 12 months. Severity of depression was evaluated using the 17 item Hamilton Rating Scale for Depression.

Results: Finger Tap-Dominant Hand Test and total number of errors made on the Wisconsin Card Sorting Test predicted classification of patients as treatment responders or non-responders, and were independent of improvement in mood. Change in verbal fluency was the only neuropsychological test that correlated with change in mood from baseline to the follow up period. None of the neuropsychological measures displayed deterioration in cognitive functioning from baseline to repeat testing at 12 months.

Limitations: This was an open label study with a small sample size which limits predictive analysis. Practice effects of the neuropsychological testing could explain the improvement from baseline to follow up on some tasks. Replication using a larger sample of subjects who received neuropsychological testing before and at least 12 months after DBS surgery is required.

Conclusion: These preliminary results (i) suggest that psychomotor speed may be a useful baseline predictor of response to SCG DBS treatment and (ii) support previous suggestions that SCG DBS has no deleterious effects on cognition.

p,p'-Methoxyl-diphenyl diselenide elicits an antidepressant-like effect in mice without discontinuation anxiety phenotype

Major depressive disorder is the most severe and debilitating disease among psychiatric illnesses. The abrupt interruption of antidepressant treatment may lead to a complex physiological and neuropsychiatric syndrome. The organoselenium compound (MeOPhSe)₂ has been reported to have neuroprotective properties in animal models. The study aimed to investigate the effects of single or repeated administration of (MeOPhSe)₂ on depressive-like behavior and if the compound administration, and its discontinuation, may affect the anxiolytic-like phenotype in Swiss mice. The results showed that repeated intragastric administration of (MeOPhSe)₂ (dose range: 0.1-5mg/kg), different from a single administration, reduced the immobility time in the mouse tail suspension test. A single administration of (MeOPhSe)₂ at a dose of 5mg/kg decreased the immobility time, increased the swimming time and did not alter the climbing behavior in the modified forced swimming test (mFST). Repeated administration of (MeOPhSe)₂ decreased the immobility time, did not alter the swimming time and increased the climbing behavior in the mouse mFST. Repeated administration of (MeOPhSe)₂ at a dose of 5mg/kg elicited a mouse anxiolytic-like phenotype in the elevated plus maze and light-dark tests. Markers of hepatic and renal function tests were not altered by repeated administration of (MeOPhSe)₂ to mice. The findings indicate that a single or repeated administration of (MeOPhSe)₂ elicited an antidepressant-like action in mice. Moreover, repeated treatment with (MeOPhSe)₂ produced an anxiolytic-like action in mice and its profile remained stable after discontinuation.

Establishing moderators and biosignatures of antidepressant response in clinical care (EMBARC): Rationale and design

Remission rates for Major Depressive Disorder (MDD) are low and unpredictable for any given antidepressant. No biological or clinical marker has demonstrated sufficient ability to match individuals to efficacious treatment. Biosignatures developed from the systematic exploration of multiple biological markers, which optimize treatment selection for individuals (moderators) and provide early indication of ultimate treatment response (mediators) are needed. The rationale and design of a multi-site, placebo-controlled randomized clinical trial of sertraline examining moderators and mediators of treatment response is described. The target sample is 300 participants with early onset (≤30 years) recurrent MDD. Non-responders to an 8-week trial are switched double blind to either bupropion (for sertraline non-responders) or sertraline (for placebo non-responders) for an additional 8 weeks. Clinical moderators include anxious depression, early trauma, gender, melancholic and atypical depression, anger attacks, Axis II disorder, hypersomnia/fatigue, and chronicity of depression. Biological moderator and mediators include cerebral cortical thickness, task-based fMRI (reward and emotion conflict), resting connectivity, diffusion tensor imaging (DTI), arterial spin labeling (ASL), electroencephalograpy (EEG), cortical evoked potentials, and behavioral/cognitive tasks evaluated at baseline and week 1, except DTI, assessed only at baseline. The study is designed to standardize assessment of biomarkers across multiple sites as well as institute replicable quality control methods, and to use advanced data analytic methods to integrate these markers. A Differential Depression Treatment Response Index (DTRI) will be developed. The data, including biological samples (DNA, RNA, and plasma collected before and during treatment), will become available in a public scientific repository.

CLINICAL TRIAL REGISTRATION

Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care for Depression (EMBARC). Identifier: NCT01407094. URL: http://clinicaltrials.gov/show/NCT01407094.

Cognitive Dysfunction in Major Depressive Disorder: Assessment, Impact, and Management

Cognitive dysfunction is increasingly being recognized as an important clinical dimension in major depressive disorder. This review summarizes the existing data on the epidemiology, assessment, and treatment of cognitive dysfunction among nonelderly adults with the disorder. Overall, cognitive dysfunction is prevalent, persists through periods of symptom remission, and may be independently associated with functional outcomes. However, although the evidence increasingly suggests that clinicians should be heedful of their patients' cognitive functioning, there is as yet no consensus on how best to monitor cognition clinically. In addition, although most studies have reported improved cognition with antidepressant medications, psychotherapy, and neuromodulation, the clinical significance of these improvements is unclear, and high-level evidence to guide decision making is limited. Nonetheless, given the important functional implications, clinicians should assess and monitor cognition and optimize both medication and psychological treatments to mitigate cognitive dysfunction among patients with major depressive disorder.

Cognitive remission: a novel objective for the treatment of major depression?

BACKGROUND

Cognitive dysfunction in major depressive disorder (MDD) encompasses several domains, including but not limited to executive function, verbal memory, and attention. Furthermore, cognitive dysfunction is a frequent residual manifestation in depression and may persist during the remitted phase. Cognitive deficits may also impede functional recovery, including workforce performance, in patients with MDD. The overarching aims of this opinion article are to critically evaluate the effects of available antidepressants as well as novel therapeutic targets on neurocognitive dysfunction in MDD.

DISCUSSION

Conventional antidepressant drugs mitigate cognitive dysfunction in some people with MDD. However, a significant proportion of MDD patients continue to experience significant cognitive impairment. Two multicenter randomized controlled trials (RCTs) reported that vortioxetine, a multimodal antidepressant, has significant precognitive effects in MDD unrelated to mood improvement. Lisdexamfetamine dimesylate was shown to alleviate executive dysfunction in an RCT of adults after full or partial remission of MDD. Preliminary evidence also indicates that erythropoietin may alleviate cognitive dysfunction in MDD. Several other novel agents may be repurposed as cognitive enhancers for MDD treatment, including minocycline, insulin, antidiabetic agents, angiotensin-converting enzyme inhibitors, S-adenosyl methionine, acetyl-L-carnitine, alpha lipoic acid, omega-3 fatty acids, melatonin, modafinil, galantamine, scopolamine, N-acetylcysteine, curcumin, statins, and coenzyme Q10. The management of cognitive dysfunction remains an unmet need in the treatment of MDD. However, it is hoped that the development of novel therapeutic targets will contribute to 'cognitive remission', which may aid functional recovery in MDD.

Differential effects of bupropion on acquisition and performance of an active avoidance task in male mice

Bupropion is an antidepressant drug that is known to aid smoking cessation, although little experimental evidence exists about its actions on active avoidance learning tasks. Our aim was to evaluate the effects of this drug on two-way active avoidance conditioning. In this study, NMRI mice received bupropion (10, 20 and 40mg/kg) or saline before a daily training session (learning phase, days 1-4) in the active avoidance task. Performance was evaluated on the fifth day (retention phase): in each bupropion-treated group half of the mice continued with the same dose of bupropion, and the other half received saline. Among the vehicle-treated mice, different sub-groups were challenged with different doses of bupropion. Results indicated that mice treated with 10 and 20mg/kg bupropion exhibited more number of avoidances during acquisition. The response latency confirmed this learning improvement, since this parameter decreased after bupropion administration. No differences between groups were observed in the retention phase. In conclusion, our data show that bupropion influences the learning process during active avoidance conditioning, suggesting that this drug can improve the control of emotional responses.

A computational analysis of flanker interference in depression

BACKGROUND

Depression is characterized by poor executive function, but - counterintuitively - in some studies, it has been associated with highly accurate performance on certain cognitively demanding tasks. The psychological mechanisms responsible for this paradoxical finding are unclear. To address this issue, we applied a drift diffusion model (DDM) to flanker task data from depressed and healthy adults participating in the multi-site Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care for Depression (EMBARC) study.

METHOD

One hundred unmedicated, depressed adults and 40 healthy controls completed a flanker task. We investigated the effect of flanker interference on accuracy and response time, and used the DDM to examine group differences in three cognitive processes: prepotent response bias (tendency to respond to the distracting flankers), response inhibition (necessary to resist prepotency), and executive control (required for execution of correct response on incongruent trials).

RESULTS

Consistent with prior reports, depressed participants responded more slowly and accurately than controls on incongruent trials. The DDM indicated that although executive control was sluggish in depressed participants, this was more than offset by decreased prepotent response bias. Among the depressed participants, anhedonia was negatively correlated with a parameter indexing the speed of executive control (r = -0.28, p = 0.007).

CONCLUSIONS

Executive control was delayed in depression but this was counterbalanced by reduced prepotent response bias, demonstrating how participants with executive function deficits can nevertheless perform accurately in a cognitive control task. Drawing on data from neural network simulations, we speculate that these results may reflect tonically reduced striatal dopamine in depression.

Treatment-related improvement in neuropsychological functioning in suicidal depressed patients: paroxetine vs. bupropion

Neuropsychological dysfunction is associated with risk for suicidal behavior, but it is unknown if antidepressant medication treatment is effective in reducing this dysfunction, or if specific medications might be more beneficial. A comprehensive neuropsychological battery was administered at baseline and after 8 weeks of treatment within a randomized, double-blind clinical trial comparing paroxetine and bupropion in patients with DSM-IV Major Depressive Disorder and either past suicide attempt or current suicidal thoughts. Change in neurocognitive performance was compared between assessments and between medication groups. Treatment effects on the Hamilton Depression Rating Scale and Scale for Suicide Ideation were compared with neurocognitive improvement. Neurocognitive functioning improved after treatment in all patients, without clear advantage for either medication. Improvement in memory performance was associated with a reduction in suicidal ideation independent of the improvement of depression severity. Overall, antidepressant medication improved neurocognitive performance in patients with major depression and suicide risk. Reduced suicidal ideation was best predicted by a combination of the independent improvements in both depression symptomatology and verbal memory. Targeted treatment of neurocognitive dysfunction in these patients may augment standard medication treatment for reducing suicidal behavior risk.

Toward an online cognitive and emotional battery to predict treatment remission in depression

PURPOSE

To evaluate the performance of a cognitive and emotional test battery in a representative sample of depressed outpatients to inform likelihood of remission over 8 weeks of treatment with each of three common antidepressant medications.

PATIENTS AND METHODS

Outpatients 18-65 years old with nonpsychotic major depressive disorder (17 sites) were randomized to escitalopram, sertraline or venlafaxine-XR (extended release). Participants scored ≥12 on the baseline 16-item Quick Inventory of Depressive Symptomatology - Self-Report and completed 8 weeks of treatment. The baseline test battery measured cognitive and emotional status. Exploratory multivariate logistic regression models predicting remission (16-item Quick Inventory of Depressive Symptomatology - Self-Report score ≤5 at 8 weeks) were developed independently for each medication in subgroups stratified by age, sex, or cognitive and emotional test performance. The model with the highest cross-validated accuracy determined the participant proportion in each arm for whom remission could be predicted with an accuracy ≥10% above chance. The proportion for whom a prediction could be made with very high certainty (positive predictive value and negative predictive value exceeding 80%) was calculated by incrementally increasing test battery thresholds to predict remission/non-remission.

RESULTS

The test battery, individually developed for each medication, improved identification of remitting and non-remitting participants by ≥10% beyond chance for 243 of 467 participants. The overall remission rates were escitalopram: 40.8%, sertraline: 30.3%, and venlafaxine-XR: 31.1%. Within this subset for whom prediction exceeded chance, test battery thresholds established a negative predictive value of ≥80%, which identified 40.9% of participants not remitting on escitalopram, 77.1% of participants not remitting on sertraline, and 38.7% of participants not remitting on venlafaxine-XR (all including 20% false negatives).

CONCLUSION

The test battery identified about 50% of each medication group as being ≥10% more or less likely to remit than by chance, and identified about 38% of individuals who did not remit with ≥80% certainty. Clinicians might choose to avoid this specific medication in these particular patients.

Neuropsychological performance in melancholic, atypical and undifferentiated major depression during depressed and remitted states: a prospective longitudinal study

BACKGROUND

Considerable evidence has demonstrated that melancholic and atypical major depression have distinct biological correlates relative to undifferentiated major depression, but few studies have specifically delineated neuropsychological performance for them.

METHOD

In a six-week prospective longitudinal study, we simultaneously compared neuropsychological performance among melancholic depression (n=142), atypical depression (n=76), undifferentiated major depression (n=91), and healthy controls (n=200) during a major depressive episode and a clinically remitted state, respectively. We administered neuropsychological tests assessing processing speed, attention, shifting, planning, verbal fluency, visual spatial memory, and verbal working memory to all participants.

RESULTS

During the depressive state, the three subtypes displayed extensive cognitive impairment, except for attention, when compared with the healthy controls. Melancholic depression significantly differed from atypical depression in processing speed and verbal fluency. In the remitted state, the three subtypes recovered their visual spatial memory and verbal working memory functions to the healthy control level. The recovery of the other domains (processing speed, set shifting, planning, and verbal fluency), however, was different across the subtypes. No predictive relationship existed between neuropsychological performance and the treatment outcome.

LIMITATIONS

The drop-out rate in the six-week longitudinal study was relatively high.

CONCLUSION

Our data provide preliminary evidence that during depressed states the three major depressive subtypes display similar cognitive deficits in some domains but differ in such domains as processing speed and verbal fluency. The recovery of the cognitive deficits following clinical remission from depression may be associated with subtypes of major depressive disorder.

Pharmacological and non-pharmacological interventions to improve cognitive dysfunction and functional ability in clinical depression--a systematic review

Cognitive dysfunction is of clinical significance and exerts longstanding implication on patients׳ function. Pharmacological and non-pharmacological treatments of cognitive dysfunction are emerging. This review evaluates pharmacological and non-pharmacological treatments of cognitive impairment primarily in the domains of memory, attention, processing speed and executive function in clinical depression. A total of 35 studies were retrieved from Pubmed, PsycInfo and Scopus after applying inclusion and exclusion criteria. Results show that various classes of antidepressants exert improving effects on cognitive function across several cognitive domains. Specifically, studies suggest that SSRIs, the SSRE tianeptine, the SNRI duloxetine, vortioxetine and other antidepressants such as bupropion and moclobemide may exert certain improving effects on cognitive function in depression, such as in learning and memory and executive function. Class-specific cognitive domains or specific dose-response relationships were not identified yet. The few non-pharmacological studies conducted employing cognitive orientated treatments and cognitive remediation therapy show promising results for the improvement of cognitive impairment in depression. However, several methodological constraints of studies limit generalizability of the results and caution the interpretation. Future direction should consider the development of a neuropsychological consensus cognitive battery to support the discovery, clinical assessment, comparison of studies and registration of new agents in clinical depression.

Neurocognitive predictors of antidepressant clinical response

BACKGROUND

Executive dysfunction and psychomotor slowing in depressed patients have been associated with poor antidepressant clinical response, but little is known about the value of neurocognitive tests for differential prediction of response.

METHODS

This report presents new findings for 70 depressed patients tested on neurocogntive tests before receiving treatment with a SSRI (escitalopram or citalopram), NDRI (bupropion) or dual mechanism therapy including a serotonergic agent, and for 57 healthy controls.

RESULTS

As predicted from previous research, patients who did not respond to a SSRI or dual therapy showed poorer word fluency than responders, whereas this was not seen for patients treated with bupropion alone. Longer choice reaction time (RT) was also found in nonresponders to a SSRI or dual therapy, but the opposite trend was seen for bupropion. Using a combined index of word fluency and RT (with normative performance as a cutoff) yielded differential predictions of response. Equal to or above normal performance predicted good response to a SSRI or dual therapy, with high positive predictive value (90%) and specificity (78%) but lower sensitivity (53%). In contrast, less than normal performance predicted good response to bupropion alone (positive predictive value=82%; specificity=67%; sensitivity=90%).

LIMITATIONS

Relatively small sample size, no placebo control, and combining across SSRI alone and dual treatments.

CONCLUSIONS

Although findings are preliminary due to small sample size, brief tests of word fluency and psychomotor speed may help identify depressed patients who are unresponsive to a serotonergic agent, but who may respond to bupropion alone.

Neuropsychological function before and after subcallosal cingulate deep brain stimulation in patients with treatment-resistant depression

BACKGROUND

Treatment-resistant depression (TRD) is a pervasive and difficult to treat condition for which deep brain stimulation (DBS) of the subcallosal cingulate white matter (SCCwm) is an emerging therapeutic option. However, neuropsychological safety data for this novel treatment have only been published for a small number of subjects. Moreover, little is known regarding the neuropsychological profile present in TRD patients at baseline, prior to initiation of DBS therapy. This report describes the neuropsychological effects of TRD and acute and chronic DBS of the SCCwm in patients with unipolar and bipolar TRD.

METHODS

Patients with TRD (N = 17) were compared to a healthy control group (N = 15) on subtests from the Cambridge Neuropsychological Test Automated Battery and the Stroop Task. Patients were then tested again at subsequent time points of 1 and 6 months following the initiation of chronic DBS of the SCCwm.

RESULTS

Patients with TRD showed similar levels of performance to healthy controls on most neuropsychological measures, with the exception that the TRD group had slower processing speed. Patients with bipolar TRD, relative to those with unipolar TRD, obtained lower scores on measures of executive function and memory only at baseline. With acute and chronic SCCwm DBS, neuropsychological function improved in multiple domains including processing speed and executive function (planning, set shifting, response inhibition), and memory remained stable.

CONCLUSIONS

Patients with TRD show slowed processing speed but otherwise largely preserved neuropsychological functioning. DBS of the SCCwm does not result in worsening of any aspect of neuropsychological function and may improve certain domains. Future research is warranted to better understand the effects of TRD and DBS on neuropsychological function.

Cognitive dysfunction in unipolar depression: implications for treatment

OBJECTIVE

The primary objective of this review is to examine the literature assessing abnormalities in neural circuitry and cognition early in the course of major depressive disorder (MDD) and the impact of these features on treatment selection and long-term outcomes.

DATA SOURCES

English language and peer-reviewed publications were obtained by PubMed/Medline (www.pubmed.org) searches using combinations of major depressive disorder, major depression, or unipolar depression and "first episode", early, cognition, cognitive, executive function and memory. The terms bipolar and psychosis were excluded from the searches. These searches yielded 409 records.

STUDY SELECTION

A total of 12 studies, systematic reviews and meta-analyses were selected that evaluated learning, memory and executive function in individuals with major depressive disorder. Additional publications meeting these criteria were identified from the bibliographies of the 12 selected articles and from the "related citations" section of PubMed.

RESULTS

Difficulty in concentrating and indecisiveness are reported as among the most troubling symptoms by patients with MDD and may limit functional recovery. Cognitive deficits in memory and decision-making are present early in the course of MDD and may be accompanied by structural abnormalities in the hippocampus and prefrontal cortex involved in cognitive functions. Although resolution of cognitive symptoms of depression lags behind recovery from mood symptoms in many patients, preliminary evidence suggests they may improve with antidepressant therapy, but can also persist residually.

CONCLUSIONS

New strategies that target cognitive symptoms of depression in addition to mood symptoms are needed to improve long-term outcomes, particularly functional recovery.

Psychomotor retardation in depression: a systematic review of diagnostic, pathophysiologic, and therapeutic implications

Psychomotor retardation is a central feature of depression which includes motor and cognitive impairments. Effective management may be useful to improve the classification of depressive subtypes and treatment selection, as well as prediction of outcome in patients with depression. The aim of this paper was to review the current status of knowledge regarding psychomotor retardation in depression, in order to clarify its role in the diagnostic management of mood disorders. Retardation modifies all the actions of the individual, including motility, mental activity, and speech. Objective assessments can highlight the diagnostic importance of psychomotor retardation, especially in melancholic and bipolar depression. Psychomotor retardation is also related to depression severity and therapeutic change and could be considered a good criterion for the prediction of therapeutic effect. The neurobiological process underlying the inhibition of activity includes functional deficits in the prefrontal cortex and abnormalities in dopamine neurotransmission. Future investigations of psychomotor retardation should help improve the understanding of the pathophysiological mechanisms underlying mood disorders and contribute to improving their therapeutic management.

Psychomotor retardation in depression: a systematic review of diagnostic, pathophysiologic, and therapeutic implications

Psychomotor retardation is a central feature of depression which includes motor and cognitive impairments. Effective management may be useful to improve the classification of depressive subtypes and treatment selection, as well as prediction of outcome in patients with depression. The aim of this paper was to review the current status of knowledge regarding psychomotor retardation in depression, in order to clarify its role in the diagnostic management of mood disorders. Retardation modifies all the actions of the individual, including motility, mental activity, and speech. Objective assessments can highlight the diagnostic importance of psychomotor retardation, especially in melancholic and bipolar depression. Psychomotor retardation is also related to depression severity and therapeutic change and could be considered a good criterion for the prediction of therapeutic effect. The neurobiological process underlying the inhibition of activity includes functional deficits in the prefrontal cortex and abnormalities in dopamine neurotransmission. Future investigations of psychomotor retardation should help improve the understanding of the pathophysiological mechanisms underlying mood disorders and contribute to improving their therapeutic management.

The role of serotonin in cognitive function: evidence from recent studies and implications for understanding depression

BACKGROUND

Symptoms of cognitive impairment such as poor concentration, memory loss and difficulty with decision making are prevalent in patients with depression, but currently are not specific targets for treatment. However, patients can continue to demonstrate cognitive impairments even when apparently clinically recovered. Drugs that potentiate serotonin (5-HT) function, such as selective serotonin reuptake inhibitors (SSRIs), are the mainstay of treatment for depression. Nevertheless, our understanding of the effects of SSRIs and other conventional antidepressant therapy on cognitive function in healthy humans and depressed patients remains limited.

OBJECTIVE

The purpose of this article is to provide a concise overview for clinicians on the impact of pharmacological manipulation of 5-HT on cognitive function in healthy humans with additional reference to animal models where human data are lacking, particularly regarding specific 5-HT receptor subtype modulation.

FINDINGS

The most consistent observation following manipulation of serotonin levels in humans is that low extracellular 5-HT levels are associated with impaired memory consolidation. Preclinical data show that agonism and antagonism at specific 5-HT receptors can exert effects in animal models of cognition.

CONCLUSIONS

Larger, consistently designed studies are needed to understand the roles of 5-HT in cognition in healthy and depressed individuals. Efforts to target specific 5-HT receptors to improve cognitive outcomes are warranted.

Prediction of remission of depression with clinical variables, neuropsychological performance, and serotonergic/dopaminergic gene polymorphisms

OBJECTIVE

The aim of our work is to study the possible role of clinical variables, neuropsychological performance, and the 5HTTLPR, rs25531, and val108/58Met COMT polymorphisms on the prediction of depression remission after 12 weeks' treatment with fluoxetine. These variables have been studied as potential predictors of depression remission, but they present poor prognostic sensitivity and specificity by themselves.

METHODS

Seventy-two depressed patients were genotyped according to the aforementioned polymorphisms and were clinically and neuropsychologically assessed before a 12-week fluxetine treatment.

RESULTS

Only the La allele of rs25531 polymorphism and the GG and AA forms of the val 108/158 Met polymorphism predict major depressive disorder remission after 12 weeks' treatment with fluoxetine. None of the clinical and neuropsychological variables studied predicted remission.

CONCLUSIONS

Our results suggest that clinical and neuropsychological variables can initially predict early response to fluoxetine and mask the predictive role of genetic variables; but in remission, where clinical and neuropsychological symptoms associated with depression tend to disappear thanks to the treatment administered, the polymorphisms studied are the only variables in our model capable of predicting remission. However, placebo effects that are difficult to control require cautious interpretation of the results.

Bupropion and Citalopram in the APP23 Mouse Model of Alzheimer's Disease: A Study in a Dry-Land Maze

Background. Incipient Alzheimer's disease is often disguised as depressive disorder. Over the course of AD, depressive symptoms are even more frequent. Hence, treatment with antidepressants is common in AD. It was the goal of the present study to assess whether two common antidepressants with different mechanisms of action affect spatial learning in a transgenic animal model of Alzheimer's disease. Methods. We assessed spatial memory of male wild-type and B6C3-Tg(APPswe,PSEN1dE9)85Dbo (APP23) transgenic animals in a complex dry-land maze. Animals were treated with citalopram (10 mg/kg) and bupropion (20 mg/kg). Results. Moving and resting time until finding the goal zone decreased in 4.5-month-old sham-treated wild-type animals and, to a lesser extent, in APP23 animals. Compared with sham-treated APP23 animals, treatment with bupropion reduced resting time and increased speed. On treatment with citalopram, moving and resting time were unchanged but speed decreased. Length of the path to the goal zone did not change on either bupropion or citalopram. Conclusion. Bupropion increases psychomotor activity in APP23 transgenic animals, while citalopram slightly reduces psychomotor activity. Spatial learning per se is unaffected by treatment with either bupropion or citalopram.

Cognitive impairment in major depression and the mGlu2 receptor as a therapeutic target

Cognitive impairment, in particular of attention and memory, is often reported by patients suffering from major depressive disorder (MDD) and deficits in attention are part of the current diagnostic criteria of MDD. Objectively measured cognitive deficits associated with MDD have been described in many studies. They have been conceptualized as an integral facet and epiphenomenon of MDD. However, evidence accumulated in recent years has challenged this notion and demonstrated that in a subset of patients the degree of cognitive deficits cannot be accounted for by the severity of depression. In addition, in some patients cognitive deficits persist despite resolution of depressive symptomatology. It is plausible to assume that cognitive deficits contribute to functional impairment even though supportive data for such a relationship are lacking. However, the exact association between cognitive deficits and major depression and the clinical and neurobiological characteristics of patients with MDD in whom cognitive deficits seem partially or fully independent of the clinical manifestation of depressive symptoms remain poorly understood. This review focuses on objective measures of non-emotional cognitive deficits in MDD and discusses the presence of a subgroup of patients in whom these symptoms can be defined independently and in dissociation from the rest of the depressive symptomatology. The current understanding of brain circuits and molecular events implicated in cognitive impairment in MDD are discussed with an emphasis on the missing elements that could further define the specificity of cognitive impairment in MDD and lead to new therapeutics. Furthermore, this article presents in detail observations made in behavioral studies in rodents with potential novel therapeutic agents, such as negative allosteric modulators at the metabotropic glutamate receptor type 2/3 (mGlu2/3 NAM) which exhibit both cognitive enhancing and antidepressant properties. Such a compound, RO4432717, was tested in tests of short term memory (delayed match to position), cognitive flexibility (Morris water maze, reversal protocol), impulsivity and compulsivity (5-choice serial reaction time) and spontaneous object recognition in rodents, providing first evidence of a profile potentially relevant to address cognitive impairment in MDD. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

Cognitive enhancers for the treatment of ADHD

Attention-deficit hyperactivity disorder (ADHD) is associated with multiple cognition-related phenotypic features in both children and adults. This review aims to clarify the role of cognition in ADHD and how prevailing treatments, which are often highly effective at reducing the clinical symptoms of the disorder, fare in modulating ADHD-related cognitive processes. First, we consider how the broad construct of cognition can be conceptualized in the context of ADHD. Second, we review the available evidence for how a range of both pharmacological and non-pharmacological interventions have fared with respect to enhancing cognition in individuals affected by this pervasive disorder. Findings from the literature suggest that the effects across a broad range of pharmacological and non-pharmacological interventions on the characteristic symptoms of ADHD can be distinguished from their effects on cognitive impairments. As such the direct clinical relevance of cognition enhancing effects of different interventions is somewhat limited. Recommendations for future research are discussed, including the identification of cognition-related endophenotypes, the refinement of the ADHD clinical phenotype, and studying the difference between acute and chronic treatment regimens.

Psychomotor retardation in depression: biological underpinnings, measurement, and treatment

Psychomotor retardation is a long established component of depression that can have significant clinical and therapeutic implications for treatment. Due to its negative impact on overall function in depressed patients, we review its biological correlates, optimal methods of measurement, and relevance in the context of therapeutic interventions. The aim of the paper is to provide a synthesis of the literature on psychomotor retardation in depression with the goal of enhanced awareness for clinicians and researchers. Increased knowledge and understanding of psychomotor retardation in major depressive disorder may lead to further research and better informed diagnosis in regards to psychomotor retardation. Manifestations of psychomotor retardation include slowed speech, decreased movement, and impaired cognitive function. It is common in patients with melancholic depression and those with psychotic features. Biological correlates may include abnormalities in the basal ganglia and dopaminergic pathways. Neurophysiologic tools such as neuroimaging and transcranial magnetic stimulation may play a role in the study of this symptom in the future. At present, there are three objective scales to evaluate psychomotor retardation severity. Studies examining the impact of psychomotor retardation on clinical outcome have found differential results. However, available evidence suggests that depressed patients with psychomotor retardation may respond well to electroconvulsive therapy (ECT). Current literature regarding antidepressants is inconclusive, though tricyclic antidepressants may be considered for treatment of patients with psychomotor retardation. Future work examining this objective aspect of major depressive disorder (MDD) is essential. This could further elucidate the biological underpinnings of depression and optimize its treatment.

The role of clinical variables, neuropsychological performance and SLC6A4 and COMT gene polymorphisms on the prediction of early response to fluoxetine in major depressive disorder

INTRODUCTION

Major depressive disorder (MDD) is treated with antidepressants, but only between 50% and 70% of the patients respond to the initial treatment. Several authors suggested different factors that could predict antidepressant response, including clinical, psychophysiological, neuropsychological, neuroimaging, and genetic variables. However, these different predictors present poor prognostic sensitivity and specificity by themselves. The aim of our work is to study the possible role of clinical variables, neuropsychological performance, and the 5HTTLPR, rs25531, and val108/58Met COMT polymorphisms in the prediction of the response to fluoxetine after 4weeks of treatment in a sample of patient with MDD.

METHODS

64 patients with MDD were genotyped according to the above-mentioned polymorphisms, and were clinically and neuropsychologically assessed before a 4-week fluoxetine treatment. Fluoxetine response was assessed by using the Hamilton Depression Rating Scale. We carried out a binary logistic regression model for the potential predictive variables.

RESULTS

Out of the clinical variables studied, only the number of anxiety disorders comorbid with MDD have predicted a poor response to the treatment. A combination of a good performance in variables of attention and low performance in planning could predict a good response to fluoxetine in patients with MDD. None of the genetic variables studied had predictive value in our model.

LIMITATIONS

The possible placebo effect has not been controlled. Our study is focused on response prediction but not in remission prediction.

CONCLUSIONS

Our work suggests that the combination of the number of comorbid anxiety disorders, an attentional variable, and two planning variables makes it possible to correctly classify 82% of the depressed patients who responded to the treatment with fluoxetine, and 74% of the patients who did not respond to that treatment.

Major Depressive Disorder in recovery and neuropsychological functioning: effects of selective serotonin reuptake inhibitor and dual inhibitor depression treatments on residual cognitive deficits in patients with Major Depressive Disorder in recovery

INTRODUCTION

Cognitive disturbances in Major Depressive Disorder (MDD) could persist beyond the symptomatic phase of the illness. However, the works addressing this topic did not usually account for the possible impact of medication on the cognitive functions of depressed patients. The present study aims to investigate whether MDD patients in remission treated with selective serotonin reuptake inhibitors (SSRI) or dual serotonergic-noradrenergic reuptake inhibitors (SNRI) show cognitive deficits, to study whether the same patients suffer neuropsychological disturbances when they are unmedicated and in recovery phase, and if the previous pharmacological treatment used to achieve the remission of MDD clinical symptoms had any effect in the profile of these patients' cognitive performance in the recovery phase.

METHODS

Thirty-six subjects with MDD treated with escitalopram and 37 depressed patients with duloxetine were compared both in remission phase and 24 weeks later, when they were unmedicated and in recovery phase. They were also compared, in both moments, to 37 healthy subjects.

RESULTS

The control subjects showed a broader better cognitive performance than MDD patients in both measurement moments, but several cognitive functions improved over time. Also, the patients treated with SNRI performed better in memory tests than the SNRI-treated patients in remission phase, and in recovery phase.

LIMITATIONS

Our sample size is somewhat small, and we followed our patients only for 6months after treatment.

CONCLUSIONS

Cognitive functions improve over time in patients with MDD beyond the remission phase, and the antidepressant treatment class used in acute depressive phase could influence his/her memory improvement.

Neuropsychologic effects of neuromodulation techniques for treatment-resistant depression: a review

Electroconvulsive therapy (ECT) and ablative neurosurgical procedures are established interventions for treatment-resistant depression (TRD), but their use may be limited in part by neuropsychological adverse effects. Additional neuromodulation strategies are being developed that aim to match or exceed the efficacy of ECT/ablative surgery with a better neurocognitive side effect profile. In this review, we briefly discuss the neurocognitive effects of ECT and ablative neurosurgical procedures, then synthesize the available neurocognitive information for emerging neuromodulation therapies, including repetitive transcranial magnetic stimulation, magnetic seizure therapy, transcranial direct current stimulation, vagus nerve stimulation, and deep brain stimulation. The available evidence suggests these procedures may be more cognitively benign relative to ECT or ablative neurosurgical procedures, though further research is clearly needed to fully evaluate the neurocognitive effects, both positive and negative, of these novel neuromodulation interventions.

The effects of the adjunctive bupropion on male sexual dysfunction induced by a selective serotonin reuptake inhibitor: a double-blind placebo-controlled and randomized study

OBJECTIVE

To determine the safety and efficacy of adjunctive bupropion sustained-release (SR) on male sexual dysfunction (SD) induced by a selective serotonin reuptake inhibitor (SSRI), as SD is a common side-effect of SSRIs and the most effective treatments have yet to be determined.

PATIENTS AND METHODS

The randomized sample consisted of 234 euthymic men who were receiving some type of SSRI. The men were randomly assigned to bupropion SR (150 mg twice daily, 117) or placebo (twice daily, 117) for 12 weeks. Efficacy was evaluated using the Clinical Global Impression-Sexual Function (CGI-SF; the primary outcome measure), the International Index of Erectile Function (IIEF), Arizona Sexual Experience Scale (ASEX), and Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) (secondary outcome measures). Participants were followed biweekly during study period.

RESULTS

After 12 weeks of treatment, the mean (sd) scores for CGI-SF were significantly lower, i.e. better, in patients on bupropion SR, at 2.4 (1.2), than in the placebo group, at 3.9 (1.1) (P= 0.01). Men who received bupropion had a significant increase in the total IIEF score (54.4% vs 1.2%; P= 0.003), and in the five different domains of the IIEF. Total ASEX scores were significantly lower, i.e. better, among men who received bupropion than placebo, at 15.5 (4.3) vs 21.5 (4.7) (P= 0.002). The EDITS scores were 67.4 (10.2) for the bupropion and 36.3 (11.7) for the placebo group (P= 0.001). The ASEX score and CGI-SF score were correlated (P= 0.003). In linear regression analyses the CGI-SF score was not affected significantly by the duration of SD, type of SSRI used and age.

CONCLUSIONS

Bupropion is an effective treatment for male SD induced by SSRIs. These results provide empirical support for conducting a further study of bupropion.

The role of dopaminergic agents in improving quality of life in major depressive disorder

Quality of life (QOL) is greatly diminished in patients with major depressive disorder (MDD) before treatment. This deficit persists even when patients are in remission; thus, interventions are needed to improve QOL. This article reviews QOL impairment in MDD and the cost of impairment, then summarizes the empiric literature on the effects of dopaminergic agents on QOL in patients with MDD. Studies were identified through a MEDLINE search from the past 35 years (1974-2009) using key terms "quality of life," "major depression," and "major depressive disorder," and "dopaminergic," "bupropion," or "modafinil." A total of 47 studies were included in this review. A brief overview of the relationship between QOL and MDD is presented, followed by a review of dopaminergic agent chemistry, mechanism of action, use, and trials conducted to investigate agents' effects on QOL. Preliminary evidence suggests dopaminergic agents may have a positive effect on QOL for patients with MDD. Prospective, randomized, double-blind, placebo-controlled studies are needed to extend these findings.

Effects of selective serotonin reuptake and dual serotonergic-noradrenergic reuptake treatments on memory and mental processing speed in patients with major depressive disorder

Patients with major depressive disorder (MDD) usually suffer from altered cognitive functions of episodic memory, working memory, mental processing speed and motor response. Diverse studies suggest that different antidepressant agents may improve cognitive functions in patients with MDD. The aim of this work is to study the effects of serotonergic reuptake inhibitors (SSRIs) and serotonergic-noradrenergic reuptake inhibitors (SNRIs) treatments to improve the performance on memory tasks and mental processing speed in MDD. Seventy-three subjects meeting criteria for major depressive disorder were assessed with the Hamilton depression rating scale and a neuropsychological battery. The subjects were medicated with escitalopram (n=36) or duloxetine (n=37) for 24 weeks. At the end of the trial, the subjects were assessed again with the same neuropsychological battery used prior to the treatment. Both treatments improved importantly the episodic memory and to a lesser extent, working memory, mental processing speed and motor performance. Our results suggest that cognition is partially independent from improvement in clinical symptoms. Both groups achieved remission rates in the HAM-D-17 after 24 weeks of treatment, but SNRI was superior to SSRI at improving episodic and working memory. Our work indicates that the superiority of SNRI over the SSRI at episodic memory improvement is clinically relevant.