Cognitive Dysfunction In Major Depressive Disorder Research Articles

The interplay between polygenic score for tumor necrosis factor-α, brain structural connectivity, and processing speed in major depression.

Reduced processing speed is a core deficit in major depressive disorder (MDD) and has been linked to altered structural brain network connectivity. Ample evidence highlights the involvement of genetic-immunological processes in MDD and specific depressive symptoms. Here, we extended these findings by examining associations between polygenic scores for tumor necrosis factor-α blood levels (TNF-α PGS), structural brain connectivity, and processing speed in a large sample of MDD patients. Processing speed performance of n = 284 acutely depressed, n = 177 partially and n = 198 fully remitted patients, and n = 743 healthy controls (HC) was estimated based on five neuropsychological tests. Network-based statistic was used to identify a brain network associated with processing speed. We employed general linear models to examine the association between TNF-α PGS and processing speed. We investigated whether network connectivity mediates the association between TNF-α PGS and processing speed. We identified a structural network positively associated with processing speed in the whole sample. We observed a significant negative association between TNF-α PGS and processing speed in acutely depressed patients, whereas no association was found in remitted patients and HC. The mediation analysis revealed that brain connectivity partially mediated the association between TNF-α PGS and processing speed in acute MDD. The present study provides evidence that TNF-α PGS is associated with decreased processing speed exclusively in patients with acute depression. This association was partially mediated by structural brain connectivity. Using multimodal data, the current findings advance our understanding of cognitive dysfunction in MDD and highlight the involvement of genetic-immunological processes in its pathomechanisms.

A Pilot Study Assessing the Effects of Goal Management Training on Cognitive Functions among Individuals with Major Depressive Disorder and the Effect of Post-Traumatic Symptoms on Response to Intervention

Recent meta-analyses highlight alterations in cognitive functioning among individuals with major depressive disorder (MDD), with performance deficits observed across multiple cognitive domains including executive functioning, memory, and attention. Moreover, impaired concentration is a formal diagnostic criterion for a major depressive episode. Notably, cognitive impairment is reported frequently in MDD and is associated with poor treatment response. Despite this knowledge, research examining the effectiveness of top-down, adjunctive treatments for cognitive dysfunction in MDD remains in its infancy. The primary aim of the present study was to perform a pilot investigation of the implementation of a standardized cognitive remediation program, Goal Management Training (GMT), among individuals with a primary diagnosis of MDD. A secondary aim was to explore how comorbid symptoms of post-traumatic stress disorder (PTSD) among those MDD patients exposed to trauma may affect treatment response. A final sample of thirty individuals were randomized to either participate in the nine-week GMT program (active group; n = 16) or to complete a nine-week waiting period (waitlist control; n = 14). One participant was excluded from the GMT group analysis following study completion due to meeting an exclusion criteria. In total, 60% of the individuals allocated to the GMT program were trauma exposed (n = 9). Groups were assessed at baseline, post-treatment, and at three-month follow-up. The assessment comprised neuropsychological tasks assessing a variety of cognitive domains, subjective measures of functioning and symptom severity, as well as a clinical interview to establish a primary diagnosis of MDD. Significant gains in processing speed, attention/concentration, and response inhibition were observed for the participants in the GMT condition relative to participants in the waitlist control condition. Individuals in the GMT condition also reported improvements in subjective cognitive functioning from baseline to post-treatment. Heightened PTSD symptom severity was associated with reduced response to treatment with respect to the domain of processing speed. The results of this pilot investigation highlight not only the potential utility of GMT as an augmentative treatment in MDD, but also highlight the contribution of comorbid symptoms of PTSD to diminished treatment response among trauma-exposed individuals with MDD. The study is limited primarily by its small pilot sample and the absence of a program evaluation component to gauge participant opinions and feedback of the treatment protocol.

Correlation between Aβ1-42, Dnmt3a2, urinary AD7c-NTP and cognitive dysfunction in first-episode and recurrent MDD: A case-control study.

Major depressive disorder (MDD) is one of the most prevalent mental illnesses worldwide and involves cognitive dysfunction that may negatively impact clinical and social outcomes. Previous studies have suggested that beta-amyloid peptide (Aβ1-42), DNA methyltransferase (Dnmt3a2), and urinary Alzheimer-associated neuronal thread protein (AD7c-NTP) are associated with cognitive impairment. However, there are no relevant studies in MDD. The aim of this study was to assess the correlation between serum Aβ1-42, Dnmt3a2, and urinary AD7c-NTP and cognitive dysfunction in MDD. A total of 59 eligible patients were included in the study, including 29 patients with first-episode MDD (FEDs) and 30 patients with recurrent MDD (RMDDs), and 30 matched healthy controls (HCs) were selected. Participants' cognitive functioning was evaluated using the MATRICS consensus cognitive battery (MCCB). The enzyme-linked immunosorbent assay (ELISA) method was used to measure the concentrations of the three proteins. Statistical analysis was completed using Statistical Package for the Social Sciences (SPSS) 20.0. The statistical significance was set as P < 0.05. Serum Dnmt3a2 and urinary AD7c-NTP showed significant differences among the three groups (both P < 0.001), but there were no significant differences in Aβ1-42 levels. Upon examining the results of cognitive testing, we found that serum Aβ1-42 was negatively associated with working memory scores in RMDDs (P = 0.020), but Dnmt3a2 was positively associated with working memory and verbal learning scores in the same cohort (P = 0.012 and P = 0.037, respectively). In contrast, urinary AD7c-NTP was negatively correlated with verbal learning scores in FEDs (P = 0.013). Serum Dnmt3a2 and Aβ1-42 levels may be associated with cognitive impairment in RMDDs and may act as potential biomarkers of cognitive impairment. Although urinary AD7c-NTP was closely related to cognitive dysfunction in FEDs, this relationship did not hold in RMDDs.

Anomalous functional connectivity of amygdala subregional networks in major depressive disorder.

Amygdala-based network dysfunction has been found to be centrally implicated in major depressive disorder (MDD). However, relatively little is known about how different forms of effective or cognitive dysfunction are modulated in MDD. Therefore, in the current study, we aimed to examine the alteration of amygdala subregional networks in adult patients with MDD to explore whether different parts of the amygdala that are functionally connected to different regions contribute differently to the cerebral network mechanism of depression. Resting-state fMRI scans were obtained from 70 medication-free adults with MDD and 70 age- and sex-matched healthy controls (HC). Functional connectivity maps of four distinct regions of the amygdala, including the amygdalostriatal transition area (AStr) and the basolateral (BLA), centromedial (CM) and superficial (SF) amygdala, were generated and compared between the two groups. Compared with HC, patients with MDD showed hypoconnectivity between the AStr/BLA and the orbitofrontal cortex (OFC), between the CM/SF and the brainstem/cerebellum, and within AStr/CM/SF-thalamic/striatal networks. Hyperconnectivity was observed between the left AStr/BLA and the fusiform gyrus. There was no difference in the gray matter volume of the amygdala or any of its subregions between the two groups. These findings suggest that amygdala subregional-network dysfunction in MDD is independent of structural changes and, more important, that hypoconnectivity and hyperconnectivity in different subregional networks may reflect imbalanced network function, which may modulate different forms of emotional and cognitive dysfunction in MDD.

Patient Perspective of Cognitive Symptoms in Major Depressive Disorder: Retrospective Database and Prospective Survey Analyses.

BackgroundMajor depressive disorder (MDD) is a common and burdensome condition. The clinical understanding of MDD is shaped by current research, which lacks insight into the patient perspective.ObjectiveThis two-part study aimed to generate data from PatientsLikeMe, an online patient network, on the perception of cognitive symptoms and their prioritization in MDD.MethodsA retrospective data analysis (study 1) was used to analyze data from the PatientsLikeMe community with self-reported MDD. Information on patient demographics, comorbidities, self-rated severity of MDD, treatment effectiveness, and specific symptoms of MDD was analyzed. A prospective electronic survey (study 2) was emailed to longstanding and recently active members of the PatientsLikeMe MDD community. Study 1 analysis informed the objectives of the study 2 survey, which were to determine symptom perception and prioritization, cognitive symptoms of MDD, residual symptoms, and medication effectiveness.ResultsIn study 1 (N=17,166), cognitive symptoms were frequently reported, including “severe” difficulty in concentrating (28%). Difficulty in concentrating was reported even among patients with no/mild depression (80%) and those who considered their treatment successful (17%). In study 2 (N=2525), 23% (118/508) of patients cited cognitive symptoms as a treatment priority. Cognitive symptoms correlated with depression severity, including difficulty in making decisions, concentrating, and thinking clearly (rs=0.32, 0.36, and 0.34, respectively). Cognitive symptoms interfered with meaningful relationships and daily life tasks and had a profound impact on patients’ ability to work and recover from depression.ConclusionsPatients acknowledge that cognitive dysfunction in MDD limits their ability to recover fully and return to a normal level of social and occupational functioning. Further clinical understanding and characterization of MDD for symptom prioritization and relapse risk due to residual cognitive impairment are required to help patients return to normal cognitive function and aid their overall recovery.

The Efficacy of Vortioxetine on Anhedonia in Patients With Major Depressive Disorder.

Background: Anhedonia is a common, persistent, and disabling phenomenon in treated adults with Major Depressive Disorder (MDD). Hitherto, relatively few antidepressant agents have been evaluated with respect to their effect on anhedonia in MDD.Methods: This is a post-hoc analysis of a primary study that sought to evaluate the sensitivity to change of the THINC-integrated tool (THINC-it) in MDD (ClinicalTrials.gov Identifier: NCT03053362). Adults meeting DSM-5 criteria for MDD with at least moderate depressive symptom severity [i.e., Montgomery Åsberg Depression Rating Scale (MADRS) total score ≥20] were eligible. Subjects were recruited between October 2017 and August 2018 in Toronto, Ontario at the Brain and Cognition Discovery Foundation. All subjects received open-label vortioxetine (10–20 mg/day, flexibly-dosed) for 8 weeks. Herein, the primary outcome of interest was the change from baseline to endpoint in the Snaith-Hamilton Pleasure Scale (SHAPS) total score, as well as the MADRS anhedonia factor. The mediational effects of improvements in anhedonia on general function and quality of life, as measured by the Sheehan Disability Scale (SDS) and the 5-Item World Health Organization Well-Being Index (WHO-5), were secondarily assessed.Results: A total of 100 subjects with MDD were enrolled in the primary study and began treatment with vortioxetine. Vortioxetine significantly improved anhedonia as evidenced by significant baseline to endpoint improvements in SHAPS and MADRS anhedonia factor scores (p < 0.0001). Improvements in the SHAPS and the MADRS anhedonia factor correlated with improvements in general function (i.e., SDS) and quality of life (i.e., WHO-5) (p < 0.0001). Notably, improvements in anhedonia were found to mediate the association between improvements in overall depressive symptom severity (i.e., MADRS total score) and social functioning (i.e., social life component of the SDS) (p = 0.026).Conclusion: The unmet need in depression is to improve patient functioning and other patient-reported outcomes (e.g., quality of life). Antidepressant interventions capable of attenuating anhedonia as well as cognitive dysfunction in MDD may help in this regard, as improvement in these domains have been associated with improvement in psychosocial function and quality of life.

Cognitive Dysfunction in Major Depressive Disorder: Cause and Effect

Major depressive disorder (MDD) is a pervasive and debilitating mental illness, associated with significant emotional, social, and functional deficits. Growing evidence suggests that cognitive dysfunction is a core feature of MDD and may negatively interact with other clinical features of the illness (e.g., psychosocial dysfunction, illness onset). We review recent advances in our understanding of cognitive dysfunction in MDD and highlight the putative causes and effects of cognitive deficits in depressed patients. Recent findings in this domain point to a multifaceted pathology of cognitive deficits in MDD, with behavioural disengagement and chronic low-grade inflammation likely playing an antecedent role. Emerging evidence suggests an independent role for cognitive deficits in the development of psychosocial dysfunction, particularly in domains of occupational function, interpersonal relationships, and quality of life. While the pathology of cognitive deficits in MDD is complex and multifaceted, recent advances provide clarity in select areas. Executive functioning stands out as a cognitive domain crucial to adaptive psychosocial status, highlighting the importance of remediating executive deficits with cognitive treatment. Low-grade inflammation may indicate a predisposition to severe, treatment-resistant depression and associated cognitive deficits. Screening for specific cognitive deficits and inflammatory markers in depressed patients may therefore prove crucial in the advancement of our detection and treatment of major depression.

Characterizing, Assessing, and Treating Cognitive Dysfunction in Major Depressive Disorder.

After participating in this activity, learners should be better able to:• Characterize cognitive dysfunction in patients with major depressive disorder.• Evaluate approaches to treating cognitive dysfunction in patients with major depressive disorder. Cognitive dysfunction is a core psychopathological domain in major depressive disorder (MDD) and is no longer considered to be a pseudo-specific phenomenon. Cognitive dysfunction in MDD is a principal determinant of patient-reported outcomes, which, hitherto, have been insufficiently targeted with existing multimodal treatments for MDD. The neural structures and substructures subserving cognitive function in MDD overlap with, yet are discrete from, those subserving emotion processing and affect regulation. Several modifiable factors influence the presence and extent of cognitive dysfunction in MDD, including clinical features (e.g., episode frequency and illness duration), comorbidity (e.g., obesity and diabetes), and iatrogenic artefact. Screening and measurement tools that comport with the clinical ecosystem are available to detect and measure cognitive function in MDD. Notwithstanding the availability of select antidepressants capable of exerting procognitive effects, most have not been sufficiently studied or rigorously evaluated. Promising pharmacological avenues, as well as psychosocial, behavioral, chronotherapeutic, and complementary alternative approaches, are currently being investigated.

Targeted proteomic analysis of cognitive dysfunction in remitted major depressive disorder: Opportunities of multi-omics approaches towards predictive, preventive, and personalized psychiatry

In order to accelerate the understanding of pathophysiological mechanisms and clinical biomarker discovery and in psychiatry, approaches that integrate multiple –omics platforms are needed. We introduce a workflow that investigates a narrowly defined psychiatric phenotype, makes use of the potent and cost-effective discovery technology of gene expression microarrays, applies Weighted Gene Co-Expression Network Analysis (WGCNA) to better capture complex and polygenic traits, and finally explores gene expression findings on the proteomic level using targeted mass-spectrometry (MS) technologies. To illustrate the effectiveness of the workflow, we present a proteomic analysis of peripheral blood plasma from patient's remitted major depressive disorder (MDD) who experience ongoing cognitive deficits. We show that co-expression patterns previous detected on the transcript level could be replicated for plasma proteins, as could the module eigengene correlation with cognitive performance. Further, we demonstrate that functional analysis of multi-omics data has the potential to point to cellular mechanisms and candidate biomarkers for cognitive dysfunction in MDD, implicating cell cycle regulation by cyclin D3 (CCND3), regulation of protein processing in the endoplasmatic reticulum by Thioredoxin domain-containing protein 5 (TXND5), and modulation of inflammatory cytokines by Tripartite Motif Containing 26 (TRI26). SignificanceThis paper discusses how data from multiple –omics platforms can be integrated to accelerate biomarker discovery in psychiatry. Using the phenotype of cognitive impairment in remitted major depressive disorder (MDD) as an example, we show that the application of a systems biology approach - weighted gene co-expression network analysis (WGCNA) - in the discovery phase, and targeted proteomic follow-up of results, provides a structured avenue towards uncovering novel candidate markers and pathways for personalized clinical psychiatry.

Pharmacological Treatment of Cognitive Symptoms in Major Depressive Disorder.

Cognitive dysfunction is a core transdiagnostic domain of Major Depressive Disorder (MDD) and is a principal determinant of functional recovery. However, it has been insufficiently targeted within the current therapeutic framework for MDD. To highlight these unmet cognitive needs in MDD. An article search was conducted using PubMed from inception to November 2016: Major Depressive Disorder (and/or variant) was cross-referenced with the following terms: antidepressants, augmentation, cognition, cognitive deficits, cognitive dysfunction, functional outcomes, mechanism of action, and treatment. Articles informed by observational studies, clinical trials, and review articles relevant to the discussion of cognition and cognitive impairment in MDD were included for review. Additional terms and citations previously not identified in the initial search were obtained from a manual review of article reference lists. Cognitive deficits in MDD are replicable, non-specific, and clinically significant. Abnormalities in the domains of learning/memory, executive function, attention, concentration, and processing speed are consistently reported. Only two antidepressants (i.e., duloxetine and vortioxetine) have established procognitive effects utilizing rigorous methodology in MDD. Most antidepressants improve cognitive function(s), but the extent to which they directly exert pro-cognitive effects is not yet understood. Cognitive dysfunction in MDD is a principal determinant of patient-reported outcomes (e.g., psychosocial function). Healthcare providers are encouraged to screen for cognitive dysfunction in MDD and familiarize themselves with the efficacy profiles of antidepressants on disparate cognitive domains.

Cognitive dysfunction in major depressive disorder.

The principal aim of this review is to highlight recent advances in our understanding of cognitive dysfunction in major depressive disorder (MDD). We review new assessment and treatment approaches, in which cognition and associated psychosocial dysfunction are considered primary outcomes. Current work suggests that cognitive dysfunction reduces occupational productivity, and interferes broadly with domains of day-to-day and social functioning. These findings imply that cognitive dysfunction interacts with emotional and social factors relevant to MDD. Recent advances in screening instruments enable standardized detection of cognitive symptoms in MDD. Clinical trials suggest that cognitive symptoms are suitable targets and primary outcomes of psychological and pharmacological treatments. A growing interest in cognitive dysfunction in MDD has improved our ability to assess and treat MDD. Future research will be strengthened by the use of consistent terminology, standardized cognitive screening, and treatments that target cognitive dysfunction in MDD. Integration of emotional and social treatment strategies may further advance clinical efficacy.

A randomized, double-blind, placebo-controlled, crossover trial evaluating the effect of intranasal insulin on cognition and mood in individuals with treatment-resistant major depressive disorder

BackgroundCognitive dysfunction in major depressive disorder (MDD) is identified as a primary therapeutic target; no current treatment is approved for the treatment of cognitive dysfunction in MDD. We examined whether intranasal insulin offered a beneficial effect across measures of cognitive function in adults with MDD. MethodsThirty-five adults (18–65 years of age: 47.09±9.89) meeting criteria for a major depressive episode as per the Diagnostic and Statistical Manual (DSM)-IV-Treatment Revised were included in this randomized, double blind, placebo-controlled, crossover design study. Subjects were not stratified based on baseline cognitive deficit. Subjects were randomized to 4 weeks of either intranasal insulin 40 International Units (IU) taken four times a day (i.e., morning, afternoon, evening, and before bed) (QID) (n=19) or placebo (n=16). ResultsNo between group differences were observed in change from baseline on total Montgomery Åsberg Depression Rating Scale (MADRS) score (25.98±2.81), in either of the Positive or Negative subscales of the Positive and Negative Affect Schedule (PANAS), or on a global index of neurocognition. The possibility of practice and/or carry over effect could not be excluded. Methodological refinement (e.g., stratification of subjects based on baseline cognitive deficit) may have augmented assay sensitivity. ConclusionIntranasal insulin did not demonstrate statistically significant improvements on overall mood, aspects of emotional processing, neurocognitive function, or self-reported quality of life patient reported outcomes.

Assessing and measuring cognitive function in major depressive disorder

Cognitive dysfunction is a major component of major depressive disorder (MDD). No ‘gold-standard’ tool exists for the assessment of cognitive dysfunction for adults with MDD. The use of measurement-based care...

Italian neurologists' perception on cognitive symptoms in major depressive disorder.

The assessment of cognition is an important part of major depressive disorder (MDD) evaluation and a crucial issue is the physicians' perception of cognitive dysfunction in MDD that remains nowadays a little known matter. The present study aims at investigating the understanding of neurologists' perception about cognitive dysfunction in MDD. An on-line survey addressed to 85 Italian neurologists in the period between May and June 2015 was performed. The questionnaire comprised three sections: the first section collecting information on neurologists' socio-demographic profile, the second investigating cognitive symptoms relevance in relation with different aspects and the third one explicitly focusing on cognitive symptoms in MDD. Cognitive symptoms are considered most significant among DSM-5 symptoms to define the presence of a Major Depressive Episode in a MDD, to improve antidepressant therapy adherence, patients' functionality and concurrent neurological condition, once resolved. Furthermore, an incongruity came to light from this survey: the neurologists considered cognitive symptoms a not relevant aspect to choose the antidepressant treatment in comparison with the other DSM-5 symptoms on one side, but they declared the opposite in the third part of the questionnaire focused on cognitive symptoms. Cognitive symptoms appeared to be a relevant aspect in MDD and neurologists have a clear understanding of this issue. Nevertheless, the discrepancy between neurologists' perception on cognitive symptoms and the antidepressant treatment highlights the feeling of an unmet need that could be filled increasing the awareness of existing drugs with pro-cognitive effects.

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

BackgroundCognitive 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.DiscussionConventional 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.SummaryThe 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.

Cognition in major depressive disorder: a 'Systemically Important Functional Index' (SIFI).

Cognitive dysfunction in major depressive disorder (MDD) is common, pervasive across multiple subdomains of cognitive function, and is a principle determinant of health outcomes from patient, provider, and societal perspectives. The overarching aim herein is to provide rationale for the evaluation, measurement, and specific treatment of cognitive function in adults with MDD. Evidence indicates that cognitive dysfunction in MDD is a critical mediator of workplace disability. Systematic evaluation and measurement of cognitive function is warranted. All individuals with MDD should be evaluated for both objective and subjective cognitive dysfunction. Although differences between antidepressants in overall antidepressant efficacy are not consistent, unequivocal differences in improving measures of cognitive function are noted with evidence indicating that vortioxetine has multidomain cognitive benefits, whereas duloxetine has replicated evidence of improving measures of acquisition and recall (i.e. memory). The probability of functional recovery in MDD is likely to increase with interventions that specifically target and improve measures of cognitive function. Clinicians are encouraged to evaluate patients using a validated measure (e.g. the THINC-it tool); prevention of cognitive impairment in MDD is a critical therapeutic priority. Vortioxetine and duloxetine benefit measures of cognitive function in MDD. Preliminary evidence of beneficial effects on cognitive emotional processing are reported with ketamine.

Italian psychiatrists’ perception on cognitive symptoms in major depressive disorder

Objective: Differently than Schizophrenia, the investigation of cognitive impairment in bipolar disorder and major depressive disorder (MDD) attracted the interest of research only recently. Therefore, it is worth understanding clinicians’ perception about cognitive dysfunction in MDD and raising awareness about this issue. Methods: Between December 2014 and January 2015, 128 Italian psychiatrists participated in an on-line survey aiming at understanding psychiatrists’ perception about cognitive symptoms in MDD. The questionnaire comprised three sections: the first investigating psychiatrists’ socio-demographic profile, the second assessing cognitive symptoms relevance without mentioning that they represented the study focus and the third explicitly investigating cognitive symptoms. Results: Cognitive symptoms were considered as a relevant dimension of MDD and appeared among the most frequently cited residual symptoms influencing patients’ work and relapse risk. About 70% of psychiatrists declared that cognitive symptoms significantly influence antidepressant choice. However, in the second questionnaire section cognitive symptoms appeared less frequently considered for antidepressant choice. Conclusions: Results revealed a clear understanding of cognitive symptoms relevance in MDD. Nevertheless, the discrepancy between psychiatrists’ perception and their therapeutical choices underlines the presence of an unmet-need that should be addressed increasing the awareness about the positive effects on cognitive symptoms of existing drugs, which could allow a more symptom-oriented therapeutical intervention.Key pointsMajor depressive disorder (MDD) is a common mental disorder often associated with deficits in cognitive function.Psychiatrists considered cognitive symptoms among the most relevant residual symptoms in MDD patients that compromise patients working and influence the relapse risk.The importance given to residual cognitive symptoms seemed not to be reflected by psychiatrists’ therapeutical choice.There is a gap between what psychiatrists know and what psychiatrists apply to their clinical practice reflecting the feeling of a therapeutical unmet need.

The prevalence, measurement, and treatment of the cognitive dimension/domain in major depressive disorder.

Insufficient outcomes amongst adults with major depressive disorder (MDD) provide the impetus to identify and refine therapeutic targets that are most critical to outcome from patient, provider, and societal perspectives. Towards this aim, a pivotal shift towards the transnosological domain, cognition, is occurring in the study of MDD and other brain disorders. This paper aims to provide a framework for conceptualizing and prioritizing cognitive function amongst adults with MDD with a particular view to provide a conceptual framework for research and clinical priorities. We also summarize extant data pertaining to psychotropic effects, notably antidepressants, on the cognitive dimension/domain. This narrative review was based on articles identified through a PubMed/MEDLINE search of all English-language articles published between January 1966 and October 2014. The search words were major depressive disorder, depression, unipolar depression, cognition, cognitive dysfunction, cognitive deficit, and cognitive function. The search was supplemented with a manual review of relevant references. The selection of articles for inclusion in this review was based on overall methodological quality as well as on their pertinence to informing the framework described herein. Cognitive dysfunction in MDD is a discrete domain subserved by discrete yet overlapping substrates. There is a need to provide a glossary of terms commonly employed in the cognition literature for consensus as to the appropriate screening, measurement, and monitoring tools. The guiding principle of measurement-based care should include systematic assessment and measurement of cognition in subpopulations with MDD, as a tactic to improve outcome. Relatively few treatment strategies have demonstrated efficacy specifically for the cognitive domain in MDD. The antidepressant vortioxetine has replicated evidence of specific pro-cognitive effects in adults with MDD across multiple subdomains of cognitive function. Vortioxetine is a novel antidepressant that is hypothesized to act through a combination of direct effects on receptor activity and serotonin receptor inhibition, as well as other systems. Pro-cognitive effects for other US FDA-approved agents are suggested, but pseudospecificity has not been excluded as a possible explanation of their beneficial effects on cognitive function. A disparate assortment of other agents are currently under investigation for possible benefit in mitigating cognitive deficits and improving cognitive performance (e.g., intranasal insulin, erythropoietin, anti-inflammatory agents). Non-pharmacological approaches including, but not limited to, cognitive remediation (CR), aerobic exercise, and neuromodulation are promising.

Cognitive dysfunction in major depressive disorder: a state-of-the-art clinical review.

Major depressive disorder (MDD) is a prevalent and recurring mental disorder often associated with high rates of non-recovery and substantial consequences on psychosocial outcome. Cognitive impairment is one of the most frequent residual symptoms of MDD. The persistence of cognitive impairment even in remitted phases of the disorder, notably in the domains of executive function and attention, suggests that it may serve as a mediational nexus between MDD and poor functional outcome, accounting for occupational and relational difficulties regardless of clinical improvement on depressive symptoms. The critical impact of cognitive deficits on psychosocial dysfunction invites clinicians to regularly screen and assess cognition across multiple domains, taking into account also clinical correlates of cognitive dysfunction in MDD. Despite the availability of several instruments for the screening and assessment of cognitive dysfunction, the lack of consensus guiding the choice of appropriate instruments increases the likelihood to underestimate cognitive dysfunction in MDD in clinical settings. On the other hand, the unsatisfactory effect of most antidepressant treatments on cognitive deficits for many individuals with MDD calls for the development of genuinely novel therapeutic agents with potential to target cognitive dysfunction. Notwithstanding the necessity of further investigations, this review indicates that neuropsychological deficits (e.g., impaired executive functions) are stable markers of MDD and underscores the need for the development of integrative and multi-modal strategies for the prevention and treatment of neuropsychological impairments in MDD.

Towards a "metabolic" subtype of major depressive disorder: shared pathophysiological mechanisms may contribute to cognitive dysfunction.

Major depressive disorder (MDD) is frequently associated with significant cognitive dysfunction. Furthermore, MDD is often co-morbid with obesity and metabolic disorders. The aim of this review is to evaluate the pathophysiological role obesity and co-morbid metabolic disorders may play in cognitive dysfunction associated with MDD. We conducted a PubMed search from December 1(st) 2013 to May 31(st) 2014 of all English language publications including the following keywords: cognition, working memory, attention, executive functioning, inflammation, insulin, brain-derived neurotrophic factor, neurotrophins, incretins, glucagon-like peptide-1, adipokines, diabetes, oxidative stress and glucocorticoids, cross- referenced with MDD and obesity, metabolic disorders, or metabolic syndrome. Clinical and epidemiological studies indicate that metabolic disturbances may contribute to cognitive dysfunction in MDD. There are several overlapping pathophysiological mechanisms linking obesity and metabolic abnormalities to MDD including disturbances in the hypothalamic pituitary adrenal axis, abnormalities in brain-derived neurotrophic factor signaling, adipose-derived hormones, insulin signalling, inflammatory cytokines, as well as oxidative and nitrosative stress pathways. Based on current research results, this article presents several putative mechanisms underlying the effects of obesity and metabolic abnormalities on cognitive dysfunction in MDD. Metabolic MDD may represent a depression subtype with unique patho-etiological mechanisms. The diverse shared pathophysiological mechanisms elucidated in this review may provide novel targets for the prevention and/or treatment of cognitive deficits in MDD.