Systematic review of randomized controlled trials of candidate treatments for cognitive impairment in depression and methodological challenges in the field

Effects of erythropoietin on cognitive impairment and prefrontal cortex activity across affective disorders: A randomized, double-blinded, placebo-controlled trial

BACKGROUND

Persistent cognitive impairment is frequent across bipolar disorder (BD) and major depressive disorder (MDD), highlighting an urgent need for pro-cognitive treatments.

AIM

This study investigated effects of erythropoietin (EPO) on cognitive impairment and dorsal prefrontal cortex (dPFC) activity in affective disorders.

METHODS

In this randomized, double-blinded, placebo-controlled trial, cognitively impaired patients with remitted BD or MDD received 1 weekly recombinant human EPO (40,000 IU/mL) or saline infusion for a 12-week period. Assessments were conducted at baseline, after 2 weeks of treatment (week 3), immediately after treatment (week 13) and at 6-months follow-up. Participants underwent functional MRI during performance on a n-back working memory (WM) task at baseline and week 3, and for a subgroup 6 weeks post-treatment (week 18). The primary outcome was a cognitive composite score at week 13, whereas secondary outcomes comprised sustained attention and functioning. WM-related dPFC activity was a tertiary outcome.

RESULTS

Data were analysed for 101 of the 103 included patients (EPO, n = 58; saline, n = 43). There were no effects of EPO over saline on any cognitive or functional outcomes or on WM-related dPFC activity.

CONCLUSIONS

The absence of treatment-related changes in cognition and neural activity was unexpected and contrasts with multiple previous preclinical and clinical studies. It is possible that the lack of effects resulted from a recent change in the manufacturing process for EPO. Nevertheless, the findings support the validity of dPFC target engagement as a biomarker model for pro-cognitive effects, according to which treatments that do not improve cognition should not modulate dPFC activity.

TRIAL REGISTRATIONS

EudraCT no.: 2016-004023-24; ClinicalTrials.gov identifier: NCT03315897.

Tolerability of vortioxetine compared to selective serotonin reuptake inhibitors in older adults with major depressive disorder (VESPA): a randomised, assessor-blinded and statistician-blinded, multicentre, superiority trial

Background

Major depressive disorder (MDD) is prevalent and disabling among older adults. Standing on its tolerability profile, vortioxetine might be a promising alternative to selective serotonin reuptake inhibitors (SSRIs) in such a vulnerable population.

Methods

We conducted a randomised, assessor- and statistician-blinded, superiority trial including older adults with MDD. The study was conducted between 02/02/2019 and 02/22/2023 in 11 Italian Psychiatric Services. Participants were randomised to vortioxetine or one of the SSRIs, selected according to common practice. Treatment discontinuation due to adverse events after six months was the primary outcome, for which we aimed to detect a 12% difference in favour of vortioxetine. The study was registered in the online repository clinicaltrials.gov (NCT03779789).

Findings

The intention-to-treat population included 179 individuals randomised to vortioxetine and 178 to SSRIs. Mean age was 73.7 years (standard deviation 6.1), and 264 participants (69%) were female. Of those on vortioxetine, 78 (44%) discontinued the treatment due to adverse events at six months, compared to 59 (33%) of those on SSRIs (odds ratio 1.56; 95% confidence interval 1.01-2.39). Adjusted and per-protocol analyses confirmed point estimates in favour of SSRIs, but without a significant difference. With the exception of the unadjusted survival analysis showing SSRIs to outperform vortioxetine, secondary outcomes provided results consistent with a lack of substantial safety and tolerability differences between the two arms. Overall, no significant differences emerged in terms of response rates, depressive symptoms and quality of life, while SSRIs outperformed vortioxetine in terms of cognitive performance.

Interpretation

As opposed to what was previously hypothesised, vortioxetine did not show a better tolerability profile compared to SSRIs in older adults with MDD in this study. Additionally, hypothetical advantages of vortioxetine on depression-related cognitive symptoms might be questioned. The study's statistical power and highly pragmatic design allow for generalisability to real-world practice.

Funding

The study was funded by the Italian Medicines Agency within the "2016 Call for Independent Drug Research".

Targeting Nociceptin/Orphanin FQ receptor to rescue cognitive symptoms in a mouse neuroendocrine model of chronic stress

Chronic stress causes cognitive deficits, such as impairments in episodic-like hippocampus-dependent memory. Stress regulates an opioid-related neuropeptide named Nociceptin/Orphanin FQ (N/OFQ), the ligand of the G protein-coupled receptor NOP. Since this peptide has deleterious effects on memory, we hypothesized that the N/OFQ system could be a mediator of the negative effects of stress on memory. Chronic stress was mimicked by chronic exposure to corticosterone (CORT). The NOP receptor was either acutely blocked using selective antagonists, or knocked-down specifically in the hippocampus using genetic tools. Long-term memory was assessed in the object recognition (OR) and object location (OL) paradigms. Acute injection of NOP antagonists before learning had a negative impact on memory in naive mice whereas it restored memory performances in the chronic stress model. This rescue was associated with a normalization of neuronal cell activity in the CA3 part of the hippocampus. Chronic CORT induced an upregulation of the N/OFQ precursor in the hippocampus. Knock-down of the NOP receptor in the CA3/Dentate Gyrus region prevented memory deficits in the CORT model. These data demonstrate that blocking the N/OFQ system can be beneficial for long-term memory in a neuroendocrine model of chronic stress. We therefore suggest that NOP antagonists could be useful for the treatment of memory deficits in stress-related disorders.

Aberrant resting-state functional connectivity underlies cognitive and functional impairments in remitted patients with bipolar disorder

BACKGROUND

Bipolar disorder (BD) is commonly associated with cognitive impairments, that directly contribute to patients' functional disability. However, there is no effective treatment targeting cognition in BD. A key reason for the lack of pro-cognitive interventions is the limited insight into the brain correlates of cognitive impairments in these patients. This is the first study investigating the resting-state neural underpinnings of cognitive impairments in different neurocognitive subgroups of patients with BD.

METHOD

Patients with BD in full or partial remission and healthy controls (final sample of n = 144 and n = 50, respectively) underwent neuropsychological assessment and resting-state functional magnetic resonance imaging. We classified the patients into cognitively impaired (n = 83) and cognitively normal (n = 61) subgroups using hierarchical cluster analysis of the four cognitive domains. We used independent component analysis (ICA) to investigate the differences between the neurocognitive subgroups and healthy controls in resting-state functional connectivity (rsFC) in the default mode network (DMN), executive central network (ECN), and frontoparietal network (FPN).

RESULTS

Cognitively impaired patients displayed greater positive rsFC within the DMN and less negative rsFC within the ECN than healthy controls. Across cognitively impaired patients, lower positive connectivity within DMN and lower negative rsFC within ECN correlated with worse global cognitive performance.

CONCLUSION

Cognitive impairments in BD seem to be associated with a hyper-connectivity within the DMN, which may explain the failure to suppress task-irrelevant DMN activity during the cognitive performance, and blunted anticorrelation in the ECN. Thus, aberrant connectivity within the DMN and ECN may serve as brain targets for pro-cognitive interventions.

Serotonin 4 Receptor Brain Binding in Major Depressive Disorder and Association With Memory Dysfunction

Importance

The cerebral serotonin 4 (5-HT4) receptor is a promising novel target for treatment of major depressive disorder (MDD), and pharmacological stimulation of the 5-HT4 receptor has been associated with improved learning and memory in healthy individuals.

Objective

To map the neurobiological signatures of patients with untreated MDD compared with healthy controls and to examine the association between cerebral 5-HT4 receptor binding and cognitive functions in the depressed state.

Design, Setting, and Participants

This case-control study used baseline data from the NeuroPharm clinical depression trial in Denmark. Adult participants included antidepressant-free outpatients with a current moderate to severe depressive episode and healthy controls. All participants completed positron emission tomography (PET) scanning with [11C]SB207145 for quantification of brain 5-HT4 receptor binding, but only the patients underwent cognitive testing. Data analyses were performed from January 21, 2020, to April 22, 2022.

Main Outcomes and Measures

The main study outcome was the group difference in cerebral 5-HT4 receptor binding between patients with MDD and healthy controls. In addition, the association between 5-HT4 receptor binding and verbal memory performance in the patient group was tested. Other cognitive domains (working memory, reaction time, emotion recognition bias, and negative social emotions) were assessed as secondary outcomes.

Results

A total of 90 patients with untreated MDD (mean [SD] age, 27.1 [8.2] years; 64 women [71.1%]) and 91 healthy controls (mean [SD] age, 27.1 [8.0] years; 55 women [60.4%]) were included in the analysis. Patients with current MDD had significantly lower cerebral 5-HT4 receptor binding than healthy controls (-7.0%; 95% CI, -11.2 to -2.7; P = .002). In patients with MDD, there was a correlation between cerebral 5-HT4 receptor binding and verbal memory (r = 0.29; P = .02).

Conclusions and Relevance

Results of this study show that cerebral 5-HT4 receptor binding was lower in patients with MDD than in healthy controls and that the memory dysfunction in patients with MDD was associated with lower cerebral 5-HT4 receptor binding. The cerebral 5-HT4 receptor is a promising treatment target for memory dysfunction in patients with MDD.

Is suboptimal effort an issue? A systematic review on neuropsychological performance validity in major depressive disorder

BACKGROUND

In Major Depressive Disorder (MDD), emotion- and motivation related symptoms may affect effort during neuropsychological testing. Performance Validity Tests (PVT's) are therefore essential, but are rarely mentioned in research on cognitive functioning in MDD. We aimed to assess the proportion of MDD patients with demonstrated valid performance and determine cognitive functioning in patients with valid performance. This is the first systematic review on neuropsychological performance validity in MDD.

METHODS

Databases PubMed, PsycINFO, Embase, and Cochrane Library were searched for studies reporting on PVT results of adult MDD patients. We meta-analyzed the proportion of MDD patients with PVT scores indicative of valid performance.

RESULTS

Seven studies with a total of 409 MDD patients fulfilled inclusion criteria. Six studies reported the exact proportion of patients with PVT scores indicative of valid performance, which ranged from 60 to 100 % with a proportion estimate of 94 %. Four studies reported on cognitive functioning in MDD patients with valid performance. Two out of these studies found memory impairment in a minority of MDD patients and two out of these studies found no cognitive impairment.

LIMITATIONS

Small number of studies and small sample sizes.

CONCLUSIONS

A surprisingly small number of studies reported on PVT in MDD. About 94 % of MDD patients in studies using PVT's had valid neuropsychological test performance. Concessive information regarding cognitive functioning in MDD patients with valid performance was lacking. Neuropsychological performance validity should be taken into account since this may alter conclusions regarding cognitive functioning.

The trajectory of emotional and non-emotional cognitive function in newly diagnosed patients with bipolar disorder and their unaffected relatives: A 16-month follow-up study

Cognitive impairments are evident in remitted patients with bipolar disorder (BD) and their unaffected relatives (UR) compared to healthy controls (HC). However, the temporal course of cognition, and whether cognition is marked by neuroprogressive changes, remain unclear. In a large prospective study of newly diagnosed patients with BD, we assessed patients with BD (n = 266), UR (n = 105) and HC (n = 190) using an extensive cognitive battery of non-emotional and emotional cognition at baseline and 16-months follow-up. Cognitive change across groups was examined with linear mixed-model analyses. Results showed no evidence of trajectory differences between patients with BD, UR, and HC in neurocognition and emotional cognition (ps≥.10). Patients with BD showed stable impairments in global neurocognitive functioning over time, as well as within the domains of 'working memory and executive function' and 'attention and psychomotor speed', compared to HC. Patients who relapsed during the follow-up time were less successful at down-regulating emotions in positive social scenarios compared to HC. Unaffected relatives also displayed stable deficits in 'working memory and executive function' over time, with performance at intermediate levels between BD probands and HC. Finally, poorer neurocognition and positive emotion regulation were associated with more subsyndromal symptoms and functional impairments. In conclusion, we found no evidence of a neuroprogressive origin of cognitive impairments in the newly diagnosed BD or in their UR. Patients' and UR's impairments in working memory and executive function may reflect a stable cognitive trait-marker of familial risk. Difficulties with positive emotion regulation may be associated with illness progression in BD.

A pilot study of accelerated deep transcranial magnetic stimulation effects on cognitive functioning in patients diagnosed with treatment resistant major depressive disorder

The purpose of this study was to assess cognitive functioning in patients diagnosed with major depressive disorder (MDD) treated with two different accelerated deep transcranial magnetic stimulation (dTMS) modalities as an add-on to stable pharmacotherapy.A total of 32 adult psychiatric inpatients diagnosed with treatment resistant MDD were allocated by stratified randomization into two groups: a group treated with dTMS twice a day during 2 weeks, and a group treated with dTMS twice a day during 3 weeks. Clinical psychologists assessed participants´ cognitive functions (memory, visuospatial functioning, executive functions, psychomotor speed, verbal fluency) via a battery of instruments, after the inclusion, and by the end of treatment.Our findings showed mild to moderate improvements in the majority of administered tests measuring different cognitive functions, meaning that patients achieved significantly better results by the end of the treatment compared to baseline, regardless of the duration of the treatment (2 or 3 weeks). No adverse effects on cognition were observed. The results seem promising in the context of treating the cognitive symptoms associated with functional recovery of patients suffering from depression.

In pursuit of full recovery in major depressive disorder

Many individuals with major depression disorder (MDD) who achieve remission of depressive symptoms, do not perceive themselves as fully recovered. This study explores whether clinical remission is related to functional remission and to patient's perception of recovery, as well as, which factors are associated with their functional and subjective remission. 148 patients with MDD in partial clinical remission were included. Demographics and clinical variables were collected through semi-structured interviews. Objective cognition was evaluated through a neuropsychological battery and subjective cognition through a specific questionnaire. The patient's psychosocial functioning and the perception of their remission were also assessed. Apart from descriptive analysis, Pearson correlations and backward stepwise regression models explored the relationship between demographic, clinical, and cognitive factors with patients' functional and self-perceived remission. From the whole sample, 57 patients (38.5%) were considered to achieve full clinical remission, 38 patients (25.7%) showed functional remission, and 55 patients (37.2%) perceived themselves as remitted. Depressive symptoms and objective and subjective executive function were the factors associated with psychosocial functioning. Besides, depressive symptoms, objective and subjective attention, and subjective executive function were the significant explanatory variables for self-perception of remission. The concept of full recovery from an episode of MDD should not only include the clinician's perspective but also the patient's psychosocial functioning along with their self-perceived remission. As residual depressive symptoms and cognition (objective and subjective) are factors with great contribution to a full recovery, clinicians should specifically address them when choosing therapeutic strategies.

Associations of cognitive impairment in patients with schizophrenia with genetic features and with schizophrenia-related structural and functional brain changes

Cognitive impairment is highly prevalent in patients with major psychiatric disorders (MPDs), including schizophrenia (SCZ), bipolar disorder, major depressive disorder, in whom it can be highly disruptive to community functioning and worsen prognosis. Previously, genetic factors and cognitive impairments in MPD patients have been examined mostly in isolated circuits rather than in the whole brain. In the present study, genetic, neuroimaging, and psychometric approaches were combined to investigate the relationship among genetic factors, alterations throughout the brain, and cognitive impairments in a large cohort of patients diagnosed with SCZ, with a reference healthy control (HC) group. Single nucleotide polymorphisms (SNPs) in SCZ-risk genes were found to be strongly related to cognitive impairments as well as to gray matter volume (GMV) and functional connectivity (FC) alterations in the SCZ group. Annotating 136 high-ranking SNPs revealed 65 affected genes (including PPP1R16B, GBBR2, PDE4B, CANCNA1C, SLC12AB, SATB2, MAG12, and SATB2). Only one, a PDE4B SNP (rs1006737), correlated with GMV (r = 0:19 p = 0.015) and FC (r = 0.21, p = 0.0074) in SCZ patients. GMV and FC alterations correlated with one another broadly across brain regions. Moreover, the present data demonstrate three-way SNP-FC-GMV associations in patients with SCZ, thus providing clues regarding potential genetic bases of cognition impairments in SCZ. SNP-FC-GMV relationships correlated with visual learning and reasoning dimensions of cognition. These data provide evidence that SCZ-related cognitive impairments may reflect genetically underlain whole-brain structural and functional alterations.

Disentangling cognitive inflexibility in major depressive disorder: A transcranial direct current stimulation study

BACKGROUND

Cognitive dysfunction is a persistent residual symptom in major depressive disorders (MDDs) that hinders social and occupational recovery. Cognitive inflexibility is a typical cognitive dysfunction in MDD and refers to difficulty in switching tasks, which requires two subcomponents: forgetting an old task and adapting to a new one. Here, we aimed to disentangle the subcomponents of cognitive inflexibility in MDD and investigate whether they can be improved by transcranial direct current stimulation (tDCS) on the prefrontal cortex.

METHODS

The current study included 20 patients with MDD (seven females) and 22 age-matched healthy controls (HCs) (seven females). The participants received anodal tDCS on either the dorsomedial prefrontal cortex (DMPFC) or dorsolateral prefrontal cortex (DLPFC) in a crossover design. Before and after the application of tDCS, the participants performed a modified Wisconsin Card Sorting Test, in which the task-switching rules were explicitly described and proactive interference from a previous task rule was occasionally released.

RESULTS

We found that the behavioral cost of a task switch was increased in patients with MDD, but that of proactive interference was comparable between patients with MDD and HCs. The response time for anodal DMPFC tDCS was decreased compared with that for anodal tDCS on the DLPFC in MDD.

CONCLUSIONS

These findings suggest that cognitive inflexibility in MDD is primarily explained by the difficulty to adapt to a new task and environment, and that tDCS on the DMPFC improves behavioral performance during cognitively demanding tasks that require conflict resolution.

Randomised controlled cognition trials in remitted patients with mood disorders published between 2015 and 2021: A systematic review by the International Society for Bipolar Disorders Targeting Cognition Task Force

BACKGROUND

Cognitive impairments are an emerging treatment target in mood disorders, but currently there are no evidence-based pro-cognitive treatments indicated for patients in remission. With this systematic review of randomised controlled trials (RCTs), the International Society for Bipolar Disorders (ISBD) Targeting Cognition Task force provides an update of the most promising treatments and methodological recommendations.

METHODS

The review included RCTs of candidate pro-cognitive interventions in fully or partially remitted patients with major depressive disorder or bipolar disorder. We followed the procedures of the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) 2020 statement. Searches were conducted on PubMed/MEDLINE, PsycInfo, EMBASE and Cochrane Library from January 2015, when two prior systematic reviews were conducted, until February 2021. Two independent authors reviewed the studies with the Revised Cochrane Collaboration's Risk of Bias tool for Randomised trials.

RESULTS

We identified 16 RCTs (N = 859) investigating cognitive remediation (CR; k = 6; N = 311), direct current or repetitive magnetic stimulation (k = 3; N = 127), or pharmacological interventions (k = 7; N = 421). CR showed most consistent cognitive benefits, with two trials showing improvements on primary outcomes. Neuromodulatory interventions revealed no clear efficacy. Among pharmacological interventions, modafinil and lurasidone showed early positive results. Sources of bias included small samples, lack of pre-screening for objective cognitive impairment, no primary outcome and no information on allocation sequence masking.

CONCLUSIONS

Evidence for pro-cognitive treatments in mood disorders is emerging. Recommendations are to increase sample sizes, pre-screen for impairment in targeted domain(s), select one primary outcome, aid transfer to real-world functioning, investigate multimodal interventions and include neuroimaging.

Mechanisms of Cognitive Impairment in Depression. May Probiotics Help?

Depression is the major cause of disability globally. Apart from lowered mood and accompanying symptoms, it leads to cognitive impairment that altogether predicts disadvantaged social functioning. Reduced cognitive function in depression appears a bit neglected in the field of clinical and molecular psychiatry, while it is estimated to occur in two-thirds of depressed patients and persist in at least one third of remitted patients. This problem, therefore, requires elucidation at the biomolecular and system levels and calls for improvement in therapeutic approach. In this review study, we address the above-mentioned issues by discussing putative mechanisms of cognitive decline in depression: (1) increased oxidative stress and (2) inflammation, (3) disturbed hypothalamus-pituitary-adrenals axis, and (4) reduced monoamines functionality. Moreover, we acknowledge additional underpinnings of cognitive impairment in depressed elderly: (5) vascular-originated brain ischemia and (6) amyloid-beta plaque accumulation. Additionally, by reviewing molecular, pre-clinical and clinical evidence, we propose gut microbiota-targeted strategies as potential adjuvant therapeutics. The study provides a consolidated source of knowledge regarding mechanisms of cognitive impairment in depression and may path the way toward improved treatment options.

Affective episodes in recently diagnosed patients with bipolar disorder associated with altered working memory-related prefrontal cortex activity: A longitudinal fMRI study

INTRODUCTION

Bipolar disorder (BD) is often accompanied by trait-related cognitive impairments, but it is unclear which neurocircuitry abnormalities give rise to these impairments and whether neurocircuitry differences are exacerbated with illness progression. This longitudinal fMRI study of recently diagnosed BD patients investigates whether aberrant working memory (WM) related activity in the cognitive control network is accentuated by new affective episodes.

METHODS

Forty-seven recently diagnosed BD patients in full or partial remission and 38 healthy controls were assessed with neurocognitive tests and fMRI during the performance of a verbal n-back WM task at baseline and follow-up (15.4 months in average).

RESULTS

Patients showed WM-related hypo-activity in dorsal prefrontal cortex (dPFC) and impaired cognitive function within attention and psychomotor speed, WM and executive function, and verbal learning and memory compared to controls at baseline. During the follow-up period, 26 patients experienced at least one affective episode (BD+), while 21 remained in remission (BD-). There was no deterioration in cognitive performance in BD+ compared to BD- patients. Nevertheless, BD+ displayed increased WM-related dPFC activity at follow-up compared with BD- patients. This change in dPFC response was independent of mood symptoms and medication.

LIMITATIONS

The study did not account for type or frequency of affective episodes.

CONCLUSION

The study identifies cognitive impairment and WM-related hypo-activity in dPFC early during the course of BD. Increased high-load WM related dPFC activity over the follow-up period in BD+ versus BD- patients in the absence of changes in cognitive performance may reflect an episode-related reduction in PFC efficiency.

The potential pro-cognitive effects with intravenous subanesthetic ketamine in adults with treatment-resistant major depressive or bipolar disorders and suicidality

BACKGROUND

Ketamine has rapid and robust antidepressant effects in depression, while its effects on cognitive measures are less clearly understood. This aim of the study herein is to determine whether ketamine has direct pro-cognitive effects in real-world treatment depression and/or suicidality.

METHODS

Subjects with unipolar (n = 84) and bipolar (n = 27) depression suffering treatment resistance or suicidality received six infusions of ketamine (0.5 mg/kg) during a 12-day period. Depression symptoms were assessed using the Montgomery-Asberg Depression Rating Scale at baseline, day 13 and day 26. Cognitive domains, including processing speed, working memory, visual learning and verbal learning were also measured using the MATRICS Consensus Cognitive Battery at the same time-points.

RESULTS

Significant improvement was observed in processing speed at day 13 (effect size [ES] = 0.501) and day 26 (ES = 0.654), and verbal learning at day 13 (ES = 0.362). Path analysis showed significant direct (β = 2.444, P = 0.017) and indirect (β = 1.220, P = 0.048) effect of ketamine on processing speed, indicating its improvement was partly independent of improvement in depressive symptoms. The direct effect (β = -1.963, P = 0.052) of ketamine on verbal learning was not significant, whereas the indirect effect (β = 1.386, P = 0.024) was significant, indicating treatment with ketamine indirectly improved verbal learning performance, via changes in depressive symptom.

CONCLUSION

Six infusions of ketamine have a potential mood independent pro-cognitive effect on processing speed in adults with treatment depression and/or suicidality. The potential pro-cognitive effects of ketamine provide the basis for hypothesizing that other clinical outcomes (e.g., suicidality, functional impairment) reported with ketamine treatment may be in part mediated by improvement in cognition.

Evaluation of cognitive impairment in patients with major depressive disorder in remission

Background

Cognitive symptoms are one of the core symptoms of depressive disorders with a bearing effect on functional outcomes. Cognitive symptoms, including poor concentration and difficulty making decisions, are one of the DSM-IV diagnostic criteria for major depressive disorder. This study was designed to evaluate cognitive deficits in a sample of adult patients with major depressive disorder (MDD) in remission. A cross-sectional study was done on 60 patients fulfilling the diagnostic criteria of MDD in remission state. In addition, 60 normal subjects with matched age, sex, and educational level were compared with the patients group. Participants in both patients and control groups were subjected to clinical assessment using Mini-International Neuropsychiatric Interview plus (MINI-plus), assessment of cognitive functions using Wechsler Memory Scale-Revised (WMS-R) short form, and Wisconsin Card Sorting Test (WCST).

Results

There were statistically significant differences between patients and control groups regarding cognitive function. The patients group scored less in visual memory, verbal memory, attention/concentration, and psychomotor speed. They also performed poorly regarding executive functions. But there was no statistically significant difference between the patients and control groups regarding sustained attention and visuospatial function. No significant correlations did exist between age at onset of MDD and the duration of illness with different domains of cognitive function except for figural memory of WMS-R and categories completed of Wisconsin card sorting test.

Conclusion

Patients with MDD in remission experienced deficits in several cognitive functions when compared to matched control subjects. The cognitive functions do not reach normal levels of performance, particularly in visual memory and executive functioning with remission of depressive symptoms.

Chronic Social Defeat During Adolescence Induces Short- and Long-Term Behavioral and Neuroendocrine Effects in Male Swiss-Webster Mice

Chronic stress exposure during adolescence is a significant risk factor for the development of depression. Chronic social defeat (CSD) in rodents is an animal model of depression with excellent ethological, predictive, discriminative, and face validity. Because the CSD model has not been thoroughly examined as a model of stress-induced depression within the adolescence stage, the present study analyzed the short- and long-term behavioral and neuroendocrine effects of CSD during early adolescence. Therefore, adolescent male Swiss-Webster (SW) mice were exposed to the CSD model from postnatal day (PND) 28 to PND37. Twenty-four hours (mid-adolescence) or 4 weeks (early adulthood) later, mice were tested in two models of depression; the social interaction test (SIT) and forced swimming test (FST); cognitive deficits were evaluated in the Barnes maze (BM). Finally, corticosterone and testosterone content was measured before, during, and after CSD exposure, and serotonin transporter (SERT) autoradiography was studied after CSD in adolescent and adult mice. CSD during early adolescence induced enduring depression-like behaviors as inferred from increased social avoidance and immobility behavior in the SIT and FST, respectively, which correlated in an age-dependent manner with SERT binding in the hippocampus; CSD during early adolescence also induced long-lasting learning and memory impairments in the Barnes maze (BM). Finally, CSD during early adolescence increased serum corticosterone levels in mid-adolescence and early adulthood and delayed the expected increase in serum testosterone levels observed at this age. In conclusion: (1) CSD during early adolescence induced long-lasting depression-like behaviors, (2) sensitivity of SERT density during normal brain development was revealed, (3) CSD during early adolescence induced enduring cognitive deficits, and (4) results highlight the vulnerability of the adolescent brain to social stressors on the adrenal and gonadal axes, which emphasizes the importance of an adequate interaction between both axes during adolescence for normal development of brain and behavior.

The Relevance and Added Value of Geriatric Medicine (GM): Introducing GM to Non-Geriatricians

Geriatric Medicine (GM) holds a crucial role in promoting health and managing the complex medical, cognitive, social, and psychological issues of older people. However, basic principles of GM, essential for optimizing the care of older people, are commonly unknown or undermined, especially in countries where GM is still under development. This narrative review aims at providing insights into the role of GM to non-geriatrician readers and summarizing the main aspects of the added value of a geriatric approach across the spectrum of healthcare. Health practitioners of all specialties are frequently encountered with clinical conditions, common in older patients (such as cancer, hypertension, delirium, major neurocognitive and mental health disorders, malnutrition, and peri-operative complications), which could be more appropriately managed under the light of the approach of GM. The role of allied health professionals with specialized knowledge and skills in dealing with older people's issues is essential, and a multidisciplinary team is required for the delivery of optimal care in response to the needs and aspirations of older people. Thus, countries should assure the educational background of all health care providers and the specialized health and social care services required to meet the demands of a rapidly aging society.

Role of trace amine‑associated receptor 1 in the medial prefrontal cortex in chronic social stress-induced cognitive deficits in mice

Emerging evidence supports an essential role of trace amine-associated receptor 1 (TAAR1) in neuropsychiatric disorders such as depression and schizophrenia. Stressful events are critical contributors to various neuropsychiatric disorders. This study examined the role of TAAR1 in mediating the negative outcomes of stressful events. In mice that experienced chronic social defeat stress but not acute stress, a significant reduction in the TAAR1 mRNA level was found in the medial prefrontal cortex (mPFC), a brain region that is known to be vulnerable to stress experience. Conditional TAAR1 knockout in the mPFC mimicked the cognitive deficits induced by chronic stress. In addition, chronic treatment with the selective TAAR1 partial agonist RO5263397 ameliorated chronic stress-induced changes in cognitive function, dendritic arborization, and the synapse number of pyramidal neurons in the mPFC but did not affect chronic stress-induced anxiety-like behaviors. Biochemically, chronic stress reduced the ratio of vesicular transporters of glutamate-1 (VGluT1) / vesicular GABA transporter (VGAT) in the mPFC，most prominently in the prelimbic cortex, and RO5263397 restored the excitatory-inhibitory (E/I) imbalance. Together, the results of this study reveal an essential role of TAAR1 in mediating chronic stress-induced cognitive impairments and suggest that TAAR1 agonists may be uniquely useful to treat MDD-related cognitive impairments.

Tolerability and efficacy of vortioxetine versus SSRIs in elderly with major depression. Study protocol of the VESPA study: a pragmatic, multicentre, open-label, parallel-group, superiority, randomized trial

Introduction

Depression is a highly prevalent condition in the elderly, with a vast impact on quality of life, life expectancy, and medical outcomes. Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed agents in this condition and, although generally safe, tolerability issues cannot be overlooked. Vortioxetine is an antidepressant with a novel mechanism of action. Based on studies to date, it may have a promising tolerability profile in the elderly, as it does not adversely affect psychomotor or cognitive performance and does not alter cardiovascular and endocrine parameters. The present study aims to assess the tolerability profile of vortioxetine in comparison with the SSRIs considered as a single group in elderly participants with depression. The rate of participants withdrawing from treatment due to adverse events after 6 months of follow up will be the primary outcome.

Methods and analysis

This is a pragmatic, multicentre, open-label, parallel-group, superiority, randomized trial funded by the Italian Medicines Agency (AIFA - Agenzia Italiana del Farmaco). Thirteen Italian Community Psychiatric Services will consecutively enrol elderly participants suffering from an episode of major depression over a period of 12 months. Participants will be assessed at baseline and after 1, 3 and 6 months of follow up. At each time point, the following validated rating scales will be administered: Montgomery–Åsberg Depression Rating Scale (MADRS), Antidepressant Side-Effect Checklist (ASEC), EuroQual 5 Dimensions (EQ-5D), Short Blessed Test (SBT), and Charlson Age-Comorbidity Index (CACI). Outcome assessors and the statistician will be masked to treatment allocation. A total of 358 participants (179 in each group) will be enrolled.

Ethics and dissemination

This study will fully adhere to the ICH E6 Guideline for Good Clinical Practice. Participants’ data will be managed and safeguarded according to the European Data Protection Regulation 2016/679. An external Ethical Advisory Board will help guarantee high ethical standards.

Trial registration

Clinicaltrials.gov: NCT03779789, Registered on 19 December 2018. Submitted on 19 December. EudraCT number: 2018–001444-66.

Trial status

Protocol version 1.5; 09/06/2018. Recruitment started In February 2019 and it is ongoing. It is expected to end approximately on 30 September 2021.

Impaired Cognitive Flexibility and Working Memory Precedes Depression: A Rat Model to Study Depression

INTRODUCTION

Depressive disorders are the 4th leading cause of health problems and the 2nd leading cause of burden among all diseases. Almost all depressive disorder patients have cognitive impairments to a certain extend. Studies about cognitive impairments in depression had been conducted, but whether cognitive dysfunctions are the cause or the effect is still not clear.

OBJECTIVES

To analyze the process of working memory and cognitive flexibility impairments in a rat model of depression.

METHODS

In this experimental study, chronic unpredictable mild stress (CUMS) was used as a model of depression in 30 rats (Rattus novergicus). Cognitive function was assessed with the Morris water maze and attentional set shifting test.

RESULTS

This study found a significant difference on day 21 in working memory (p = 0.002) and cognitive flexibility (p = 0.036), which continued to day 41 in working memory (p = 0.001) and cognitive flexibility (p = 0.020). In the CUMS model of depression, parameters peak on day 41 and reveal parameter changes in weight gain (p = 0.018), food intake (p < 0.001), changes in food intake (p = 0.001), and the sucrose preference (p = 0.005), elevated plus maze (p = 0.001), and light dark box tests (p = 0.020).

CONCLUSION

In a rat model of depression, cognitive impairment preceded depression, but it might be caused by anxiety-like behavior that occurred in early stimulation of chronic unpredictable mild stress.

Clinical and methodological considerations for psychological treatment of cognitive impairment in major depressive disorder

BACKGROUND

Cognitive impairment is considered a core feature of major depressive disorder (MDD) and research into psychological treatments aiming to address cognitive impairment are gaining momentum. Compared with the well-established research base of cognitive treatment trials in schizophrenia, including meta-analyses, mood disorder research is much more preliminary.

AIMS

To focus on identifying the important factors to consider in developing larger-scale psychological treatment trials targeting cognitive impairment in mood disorders. Trial design recommendations have been published for cognitive treatment trials in bipolar disorder.

METHOD

An in-depth discussion of methodological considerations in the development of cognitive treatment trials for MDD.

RESULTS

Methodological considerations include: screening for, and defining, cognitive impairment; mood state when cognitive intervention begins; medication monitoring during cognitive interventions; use of concomitant therapy; level of therapist involvement; duration and dose of treatment; choice of specific cognitive training exercises; home practice; improving adherence; appropriate comparison therapies in clinical trials; and choice of primary outcomes.

CONCLUSIONS

As well as guidance for clinical trial development, this review may be helpful for clinicians wanting to provide cognitive interventions for individuals with MDD.

Impact of pretreatment interhemispheric hippocampal asymmetry on improvement in verbal learning following erythropoietin treatment in mood disorders: a randomized controlled trial

BACKGROUND

Treatment development that targets cognitive impairment is hampered by a lack of biomarkers that can predict treatment efficacy. Erythropoietin (EPO) improves verbal learning and memory in mood disorders, and this scales with an increase in left hippocampal volume. This study investigated whether pretreatment left hippocampal volume, interhemisphere hippocampal asymmetry or both influenced EPO treatment response with respect to verbal learning.

METHODS

Data were available for 76 of 83 patients with mood disorders from our previous EPO trials (EPO = 37 patients; placebo = 39 patients). We performed cortical reconstruction and volumetric segmentation using FreeSurfer. We conducted multiple linear regression and logistic regression to assess the influence of left hippocampal volume and hippocampal asymmetry on EPO-related memory improvement, as reflected by change in Rey Auditory Verbal Learning Test total recall from baseline to post-treatment. We set up a corresponding exploratory general linear model in FreeSurfer to assess the influence of prefrontal cortex volume on verbal learning improvement, controlling for age, sex and total intracranial volume.

RESULTS

At baseline, more rightward (left < right) hippocampal asymmetry — but not left hippocampal volume per se — was associated with greater effects of EPO versus placebo on verbal learning (p ≤ 0.05). Exploratory analysis indicated that a larger left precentral gyrus surface area was also associated with improvement of verbal learning in the EPO group compared to the placebo group (p = 0.002).

LIMITATIONS

This was a secondary analysis of our original EPO trials.

CONCLUSION

Rightward hippocampal asymmetry may convey a positive effect of EPO treatment efficacy on verbal learning.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov NCT00916552

Diet and Neurocognition in Mood Disorders - An Overview of the Overlooked

Bipolar disorder and major depression are associated with significant disability, morbidity, and reduced life expectancy. People with mood disorders have shown higher ratios of unhealthy lifestyle choices, including poor diet quality and suboptimal nutrition. Diet and nutrition impact on brain /mental health, but cognitive outcomes have been less researched in psychiatric disorders. Neurocognitive dysfunction is a major driver of social dysfunction and a therapeutic target in mood disorders, although effective cognitive-enhancers are currently lacking. This narrative review aimed to assess the potential cognitive benefits of dietary and nutritional interventions in subjects diagnosed with mood disorders. Eight clinical trials with nutrients were identified, whereas none involved dietary interventions. Efficacy to improve select cognitive deficits has been reported, but results are either preliminary or inconsistent. Methodological recommendations for future cognition trials in the field are advanced. Current evidence and future views are discussed from the perspectives of precision medicine, clinical staging, nutritional psychiatry, and the brain-gut-microbiota axis.

Enhanced Functional Connectivity Within Executive Function Network in Remitted or Partially Remitted MDD Patients

Background: Impaired executive function (EF) is associated with a range of typical clinical characteristics and psychosocial dysfunction in major depressive disorder (MDD). However, because of the lack of objective cognitive tests, inconsistencies in research results, and improvement in patients' subjective experience, few clinicians are concerned with the persistent impairment of EF in euthymia. The study makes a further investigation for EF in remitted and partially remitted MDD patients via multiple EF tests and fMRI, so as to explore the executive function of patients in euthymia. Methods: We recruited 19 MDD patients and 17 age-, gender-, and education-matched healthy controls (HCs). All participants completed EF tests and fMRI scanning. Bilateral dorsolateral prefrontal cortex (dlPFC) regions were selected as the region of interests (ROIs) to conduct seed-based functional connectivity (FC). We conducted fractional amplitude of low-frequency fluctuations (fALFF) analysis for all ROIs and whole brain. Results: All MDD patients were in remission or partial remission, and they were comparable with HCs on all the EF tests. MDD group showed increased positive FC between left dlPFC and cerebellar Crus I, right dlPFC and supramarginal gyrus after 8-weeks treatment, even taking residual depressive symptoms into account. We did not find group difference of fALFF value. Conclusion: MDD patients persisted with EF impairment despite the remission or partially remission of depressive symptoms. Clinicians should focus on residual cognitive symptoms, which may contribute to maximize the efficacy of routine therapy.

Clinical characteristics associated with the discrepancy between subjective and objective cognitive impairment in depression

BACKGROUND

Patients with unipolar disorder (UD) commonly experience cognitive dysfunction during symptomatic and remitted phases. However, it is not necessarily the patients with the greatest subjective complaints, who display the largest objectively-measured deficits on neuropsychological tests.

OBJECTIVE

This report investigated the demographic and clinical factors associated with the discrepancy between subjective and objective measures of cognition in two separate depressed patient populations in Denmark and New Zealand, respectively, using a new methodology.

METHODS

Data from 137 depressed patients and 103 healthy controls including neuropsychological test scores, self-reported cognitive difficulties, and ratings of mood were pooled from two studies conducted in Copenhagen, Denmark, and Christchurch, New Zealand, respectively. Cognitive discrepancy scores were calculated using a novel methodology, with positive values indicating disproportionately more subjective than objective difficulties (i.e., "sensitivity") and negative values indicating more objective than subjective impairments (i.e., "stoicism").

RESULTS

In the Danish partially remitted patient sample, greater 'sensitivity' was associated with more subsyndromal depression severity (standardized Beta (std. β )= 0.4, p < 0.01)), illness duration (std. β = 0.4, p < 0.01), and younger age (std. β = 0.6, p < 0.001). This association was replicated in the New Zealand sample of more symptomatic patients (p-values ≤ 0.05).

LIMITATIONS

The cross-sectional design hampered causal inferences. We had obtained different measures of objective and subjective cognition from the two studies.

CONCLUSIONS

Patients with more depressive symptoms and younger age overreported cognitive impairments across all illness states. The use of an objective cognition screener thus seems particularly relevant for these patients to assess whether subjective complaints are accompanied by measurable cognitive deficits.

Structural changes in the hippocampus as a biomarker for cognitive improvements in neuropsychiatric disorders: A systematic review

Cognitive impairments are a core feature of several neuropsychiatric disorders. A common biomarker for pro-cognitive effects may provide a much-needed tool to select amongst candidate treatments targeting cognition. The hippocampus is a promising biomarker for target-engagement due to the illness-associated morphological hippocampal changes across unipolar disorder (UD), bipolar disorder (BD) and schizophrenia (SCZ). Following the PRISMA guidelines, we searched PubMed and Embase, for clinical trials targeting cognition across neuropsychiatric disorders, with longitudinal structural magnetic resonance imaging (MRI) measures of the hippocampus. Five randomized and three open-label trials were included. Hippocampal volume increases were associated with treatment-related cognitive improvement following treatment with erythropoietin across UD, BD and SCZ, lithium treatment in BD and aerobic exercise in SCZ. Conversely, an exercise intervention in UD showed no effect on hippocampal volume or cognition. Together, these observations point to hippocampal volume change as a putative biomarker-model for cognitive improvement. Future cognition trials are encouraged to include MRI assessments pre- and post-treatment to assess the validity of hippocampal changes as a biomarker for pro-cognitive effects.

Identifying cognitive subgroups in bipolar disorder: A cluster analysis

BACKGROUND

Evidence has shown heterogeneity of cognitive function among patients with bipolar disorder (BD). Our study aims to replicate recent findings of cognitive subgroups, as well as we assessed subjective cognitive difficulties and functioning in each cluster.

METHODS

Hierarchical cluster analysis was conducted to examine whether there were distinct neurocognitive subgroups based on neurocognitive battery. Cognitive Complaints in Bipolar Disorder Rating Assessment (COBRA) and Functioning Assessment Short Test (FAST) were used to assess subjective cognitive difficulties and functional impairment.

RESULTS

We found three distinct subgroups: a first cluster with intact cognition (n = 30, 43.5%), a second cluster with selective cognitive impairment (n = 23, 33.3%), and a third cluster with globally cognitive impairment (n = 16, 23.3%). The intact group had more years of education (p < .001) and higher estimated IQ (p < .001) than globally and selectively impaired subgroups. Additionally, they were younger (p = .011), had an earlier age at bipolar diagnosis (p < .037) and earlier age of first hospitalization (p < .035) compared to individuals with globally cognitive impairment.

LIMITATIONS

This is a cross-sectional design with a small sample including only patients from a tertiary hospital.

CONCLUSION

Our results give support to the existence of a continuum of severity from patients without impairment to those with poor cognitive functioning. Patients in the intact group seem to have higher cognitive reserve than other two groups. However, they also experienced cognitive complaints and some degree of functional impairment. These findings suggest the importance of using a combo of instruments (e.g., objective and subjective cognitive measures plus functioning instruments) for a complete assessment of patients with BD.

Neuronal underpinnings of cognitive impairment and - improvement in mood disorders

Neuropsychiatric illnesses including mood disorders are accompanied by cognitive impairment, which impairs work capacity and quality of life. However, there is a lack of treatment options that would lead to solid and lasting improvement of cognition. This is partially due to the absence of valid and reliable neurocircuitry-based biomarkers for pro-cognitive effects. This systematic review therefore examined the most consistent neural underpinnings of cognitive impairment and cognitive improvement in unipolar and bipolar disorders. We identified 100 studies of the neuronal underpinnings of working memory and executive skills, learning and memory, attention, and implicit learning and 9 studies of the neuronal basis for cognitive improvements. Impairments across several cognitive domains were consistently accompanied by abnormal activity in dorsal prefrontal (PFC) cognitive control regions-with the direction of this activity depending on patients' performance levels-and failure to suppress default mode network (DMN) activity. Candidate cognition treatments seemed to enhance task-related dorsal PFC and temporo-parietal activity when performance increases were observed, and to reduce their activity when performance levels were unchanged. These treatments also attenuated DMN hyper-activity. In contrast, nonspecific cognitive improvement following symptom reduction was typically accompanied by decreased limbic reactivity and reversal of pre-treatment fronto-parietal hyper-activity. Together, the findings highlight some common neural correlates of cognitive impairments and cognitive improvements. Based on this evidence, studies are warranted to examine the reliability and predictive validity of target engagement in the identified neurocircuitries as a biomarker model of pro-cognitive effects.

Cognitive impairment in depression: recent advances and novel treatments

In the past, little or no attention was paid to cognitive disorders associated with depression (a condition sometimes termed pseudodementia). However, recent years have seen a growing interest in these changes, not only because of their high frequency in acute-stage depression, but also because they have been found to persist, as residual symptoms (in addition to affective and psychomotor ones), in many patients who respond well to antidepressant treatment. These cognitive symptoms seem to impact significantly not only on patients' functioning and quality of life, but also on the risk of recurrence of depression. Therefore, over the past decade, pharmacological research in this field has focused on the development of new agents able to counteract not only depressive symptoms, but also cognitive and functional ones. In this context, novel antidepressants with multimodal activity have emerged. This review considers the different issues, in terms of disease evolution, raised by the presence of cognitive disorders associated with depression and considers, particularly from the neurologist's perspective, the ways in which the clinical approach to cognitive symptoms, and their interpretation to diagnostic and therapeutic ends, have changed in recent years. Finally, after outlining the pharmacodynamics and pharmacokinetics of the first multimodal antidepressant, vortioxetine, it reports the main results obtained with the drug in depressed patients, also in consideration of the ever-increasing evidence on its different mechanisms of action in animal models.

Effects of recombinant human erythropoietin on cognition and neural activity in remitted patients with mood disorders and first-degree relatives of patients with psychiatric disorders: a study protocol for a randomized controlled trial

Background

Bipolar disorder (BD) and unipolar disorder (UD) are associated with cognitive deficits and abnormal neural activity in a “cognitive control network.” There is an increased prevalence of cognitive dysfunction in psychiatric patients’ first-degree relatives, which constitutes a risk factor for psychiatric illness onset. However, there is no treatment with enduring pro-cognitive efficacy. We found preliminary evidence for beneficial effects of eight weekly doses of recombinant human erythropoietin (EPO) on cognition in BD in a recent randomized controlled trial (RCT). The present RCT consists of two sub-studies that extend our previous work by investigating important novel aspects: (1) the effects of 12 weekly doses of EPO on cognition in first-degree relatives of patients with BD, UD, or schizophrenia; and (2) the effects of extending the treatment schedule from 8 to 12 weeks in remitted patients with BD or UD; and (3) assessment of early treatment-associated neural activity changes that may predict cognitive improvement.

Methods

The trial comprises two parallel sub-studies with randomized, controlled, double-blinded, parallel group designs. First-degree relatives (sub-study 1; n = 52) and partially or fully remitted patients with BD or UD (sub-study 2; n = 52) with objectively verified cognitive dysfunction are randomized to receive weekly high-dose EPO (40,000 IU/mL) or placebo (saline) infusions for 12 weeks. Assessments of cognition and mood are conducted at baseline, after two weeks of treatment, after treatment completion, and at six-month follow-up. Functional magnetic resonance imaging (fMRI) is conducted at baseline and after two weeks of treatment. Psychosocial function is assessed at baseline, after treatment completion and six-month follow-up. The primary outcome is change in a cognitive composite score of attention, verbal memory, and executive functions. Statistical power of ≥ 80% is reached to detect a clinically relevant between-group difference by including 52 first-degree relatives and 52 patients with BD or UD, respectively. Behavioral data are analyzed with an intention-to-treat approach using mixed models. fMRI data are analyzed with the FMRIB Software Library.

Discussion

If this trial reveals pro-cognitive effects of EPO, this may influence future treatment of mood disorders and/or preventive strategies in at-risk populations. The fMRI analyses may unravel key neurobiological targets for pro-cognitive treatment.

Trial registration

ClinicalTrials.gov, NCT03315897. Registered on 20 October 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2995-7) contains supplementary material, which is available to authorized users.

GSK3β: a plausible mechanism of cognitive and hippocampal changes induced by erythropoietin treatment in mood disorders?

Mood disorders are associated with significant psychosocial and occupational disability. It is estimated that major depressive disorder (MDD) will become the second leading cause of disability worldwide by 2020. Existing pharmacological and psychological treatments are limited for targeting cognitive dysfunctions in mood disorders. However, growing evidence from human and animal studies has shown that treatment with erythropoietin (EPO) can improve cognitive function. A recent study involving EPO-treated patients with mood disorders showed that the neural basis for their cognitive improvements appeared to involve an increase in hippocampal volume. Molecular mechanisms underlying hippocampal changes have been proposed, including the activation of anti-apoptotic, antioxidant, pro-survival and anti-inflammatory signalling pathways. The aim of this review is to describe the potential importance of glycogen synthase kinase 3-beta (GSK3β) as a multi-potent molecular mechanism of EPO-induced hippocampal volume change in mood disorder patients. We first examine published associations between EPO administration, mood disorders, cognition and hippocampal volume. We then highlight evidence suggesting that GSK3β influences hippocampal volume in MDD patients, and how this could assist with targeting more precise treatments particularly for cognitive deficits in patients with mood disorders. We conclude by suggesting how this developing area of research can be further advanced, such as using pharmacogenetic studies of EPO treatment in patients with mood disorders.

Towards a biomarker model for cognitive improvement: No change in memory-related prefrontal engagement following a negative cognitive remediation trial in bipolar disorder

BACKGROUND

Cognitive deficits are prevalent in bipolar disorder during remission but effective cognition treatments are lacking due to insufficient insight into the neurobiological targets of cognitive improvement. Emerging data suggest that dorsal prefrontal cortex target engagement is a key neurocircuitry biomarker of pro-cognitive treatment effects.

AIMS

In this randomized controlled functional magnetic resonance imaging study, we test this hypothesis by investigating the effects of an ineffective cognitive remediation intervention on dorsal prefrontal response during strategic memory encoding and working memory engagement.

METHODS

Bipolar disorder patients in partial remission with subjective cognitive difficulties were randomized to receive 12-week group-based cognitive remediation ( n = 13) or to continue their standard treatment ( n = 14). The patients performed a strategic episodic picture encoding task and a spatial n-back working memory task under functional magnetic resonance imaging at baseline and following cognitive remediation or standard treatment.

RESULTS

The right dorsolateral prefrontal cortex was commonly activated by both strategic memory tasks across all patients. The task-related prefrontal engagement was not altered by cognitive remediation relative to standard treatment. The dorsolateral prefrontal cortex response was not significantly associated with recall accuracy or working memory performance.

CONCLUSIONS

As hypothesized, no task-related change in prefrontal activity was observed in a negative cognitive remediation trial in remitted bipolar disorder patients. By complementing previous findings linking cognitive improvement with increased dorsolateral prefrontal cortex engagement, our negative findings provide additional validity evidence to the dorsal prefrontal target engagement biomarker model of cognitive improvement by strengthening the proposed causality between modulation of dorsolateral prefrontal cortex engagement and pro-cognitive effects.

Prevalence of cognitive impairment in major depression and bipolar disorder

OBJECTIVES

The current study examines prevalence of cognitive impairment in four mood disorder samples, using four definitions of impairment. The impact of premorbid IQ on prevalence was examined, and the influence of treatment response.

METHODS

Samples were: (i) 58 inpatients in a current severe depressive episode (unipolar or bipolar), (ii) 69 unmedicated outpatients in a mild to moderate depressive episode (unipolar or bipolar), (iii) 56 outpatients with bipolar disorder, in a depressive episode, and (iv) 63 outpatients with bipolar disorder, currently euthymic. Cognitive assessment was conducted after treatment in Studies 1 (6 weeks of antidepressant treatment commenced on admission) and 2 (16-week course of cognitive behaviour therapy or schema therapy), allowing the impact of treatment response to be assessed. All mood disorder samples were compared with healthy control groups.

RESULTS

The prevalence of cognitive impairment was highest for the inpatient depression sample (Study 1), and lowest for the outpatient depression sample (Study 2). Substantial variability in rates was observed depending on the definition of impairment used. Correcting cognitive performance for premorbid IQ had a significant impact on the prevalence of cognitive impairment in the inpatient depression sample. There was minimal evidence that treatment response impacted on prevalence of cognitive impairment, except in the domain of psychomotor speed in inpatients.

CONCLUSIONS

As interventions aiming to improve cognitive outcomes in mood disorders receive increasing research focus, the issue of setting a cut-off level of cognitive impairment for screening purposes becomes a priority. This analysis demonstrates important differences in samples likely to be recruited depending on the definition of cognitive impairment and begins to examine the importance of premorbid IQ in determining who is impaired.

Assessing and addressing cognitive impairment in bipolar disorder: the International Society for Bipolar Disorders Targeting Cognition Task Force recommendations for clinicians

OBJECTIVES

Cognition is a new treatment target to aid functional recovery and enhance quality of life for patients with bipolar disorder. The International Society for Bipolar Disorders (ISBD) Targeting Cognition Task Force aimed to develop consensus-based clinical recommendations on whether, when and how to assess and address cognitive impairment.

METHODS

The task force, consisting of 19 international experts from nine countries, discussed the challenges and recommendations in a face-to-face meeting, telephone conference call and email exchanges. Consensus-based recommendations were achieved through these exchanges with no need for formal consensus methods.

RESULTS

The identified questions were: (I) Should cognitive screening assessments be routinely conducted in clinical settings? (II) What are the most feasible screening tools? (III) What are the implications if cognitive impairment is detected? (IV) What are the treatment perspectives? Key recommendations are that clinicians: (I) formally screen cognition in partially or fully remitted patients whenever possible, (II) use brief, easy-to-administer tools such as the Screen for Cognitive Impairment in Psychiatry and Cognitive Complaints in Bipolar Disorder Rating Assessment, and (III) evaluate the impact of medication and comorbidity, refer patients for comprehensive neuropsychological evaluation when clinically indicated, and encourage patients to build cognitive reserve. Regarding question (IV), there is limited evidence for current evidence-based treatments but intense research efforts are underway to identify new pharmacological and/or psychological cognition treatments.

CONCLUSIONS

This task force paper provides the first consensus-based recommendations for clinicians on whether, when, and how to assess and address cognition, which may aid patients' functional recovery and improve their quality of life.

The effects of vortioxetine on cognitive dysfunction in patients with inadequate response to current antidepressants in major depressive disorder: A short-term, randomized, double-blind, exploratory study versus escitalopram

BACKGROUND

Major Depressive Disorder (MDD) is a heterogeneous disease characterized by emotional, physical and cognitive symptoms. This study explored the effects of vortioxetine versus escitalopram on outcomes of cognition, functioning and mood symptoms in depressed patients with inadequate response to current antidepressant treatment.

METHODS

In this parallel-group, active-comparator study, adult patients (18-65 years, N = 101) with MDD, with inadequate response to current antidepressant monotherapy, were randomized 1:1 to 8 weeks' double-blind treatment with flexible doses (10-20mg/day) of either vortioxetine or escitalopram. Primary and key secondary efficacy measures were the Digit Symbol Substitution Test (DSST), analyzed using a mixed model for repeated measurements, and the University of San Diego Performance-based Skills Assessment - Brief (UPSA-B), analyzed using analysis of covariance (last observation carried forward method).

RESULTS

At week 8, DSST and UPSA-B performance had improved in both treatment groups, with no statistically significant treatment differences. Numerical improvements across measures of cognition, functioning and mood symptoms generally favored vortioxetine. Most adverse events were mild or moderate, with nausea being the most common adverse event.

LIMITATIONS

This was an exploratory study with small sample sizes implying limited statistical power.

CONCLUSION

Although this explorative study did not meet primary endpoints, the results confirm vortioxetine in doses of 10-20mg/day as an efficacious and well-tolerated antidepressant switch treatment. The overall direction of numerical effect sizes across cognition endpoints support previous findings that vortioxetine specifically benefits cognitive function in MDD.

Corticotropin-releasing factor 1 receptor haplotype and cognitive features of major depression

Corticotropin-releasing factor signaling through CRF receptor type 1 (CRF₁) has been shown to contribute to learning and memory function. A haplotype of alleles T-A-T in a set of common polymorphisms in the gene encoding for CRF₁ (CRHR1) has been associated with both depression vulnerability and alterations in cognitive functioning. The present study investigated the relations between the TAT haplotype and specific symptoms of depression, self-reported ruminative behaviors, and neuropsychological performance on a learning and memory task. Participants were adults with major depression with and without psychotic features (N = 406). Associations were examined between TAT haplotype and endorsement of depression symptoms from diagnostic interviews, scores on the rumination response scale (RRS), and verbal memory performance on the California Verbal Learning Test-II (CVLT-II). All analyses included depression subtype, age, and sex as covariates; CVLT-II analyses also included evening cortisol levels. Across the entire sample, carriers of more copies of the TAT haplotype reported greater endorsement of the symptom describing difficulty concentrating and making decisions. In separate subsamples, TAT homozygotes had higher rumination scores on the RRS, both brooding and reflection subscales, and more TAT copies were associated with poorer CVLT-II performance in both total learning and free recall trials. These data demonstrate that the CRHR1 TAT haplotype is associated with cognitive features of depression including difficulty with decision-making, higher rumination, and poorer learning and memory. It will be important in future research to identify the specific molecular mechanisms for CRF₁ signaling that contribute to depression-related cognitive dysfunction.

Does Cognitive Dysfunction in Bipolar Disorder Qualify as a Diagnostic Intermediate Phenotype?-A Perspective Paper

The present perspective paper addresses and discusses whether cognitive dysfunction in bipolar disorder qualifies as a diagnostic intermediate phenotype using the Robin and Guze criteria of diagnostic validity. The paper reviews current data within (1) delineation of the clinical intermediate phenotype, (2) associations of the intermediate phenotype with para-clinical data such as brain imaging and blood-based data, (3) associations to family history / genetics, (4) characteristics during long-term follow-up, and (5) treatment effects on cognition. In this way, the paper identifies knowledge gaps and suggests recommendations for future research within each of the five areas. Based on the current state of knowledge, we conclude that cognitive dysfunction does not qualify as a diagnostic intermediate phenotype or endophenotype for bipolar disorder, although promising new evidence points to emotion and reward processing abnormalities as possible putative endophenotypes.

Assessment and Management of Cognitive and Psychosocial Dysfunctions in Patients With Major Depressive Disorder: A Clinical Review

Background: Full functional recovery is defined as a state in which patients are again able to enjoy their usual activities, return to work, and take care of themselves, and it should represent the end goal of treatment in patients with major depressive disorder (MDD). Patients with MDD report many unmet needs, including residual cognitive symptoms, lack of improvement in psychosocial functioning and life satisfaction, even during mood symptom remission. In this paper, we aim to: (a) identify the available assessment tools for evaluating cognitive and psychosocial functioning in patients with MDD; (b) provide an overview of therapeutic options that can improve full functional recovery in MDD also by improving cognitive symptoms. Methods: The relevant databases MEDLINE, ISI Web of Knowledge - Web of Science Index, Cochrane Reviews Library and PsychoINFO were searched for identifying papers on validated tools for the assessment of cognitive and personal functioning in patients with MDD. Results: New assessment tools (such as the THINC-it TOOL, the COBRA, the SCIP-D, and the UPSA-D) have been developed for evaluating the cognitive dysfunction in MDD patients. Adopting these tools in the clinical routine practice is useful to evaluate the improvement in cognitive functioning and, therefore, the achievement of full functioning recovery. The optimal management of patients with MDD include the combination of pharmacological compounds and psychosocial interventions for achieving full functional recovery in patients with MDD. Conclusions: Full functional recovery must be the target of any treatment programme for patients with MDD. In order to achieve this goal, it is necessary to develop personalized treatment and integrate psychosocial and psychopharmacological interventions.

Toward Precision Psychiatry in Bipolar Disorder: Staging 2.0

Personalized treatment is defined as choosing the "right treatment for the right person at the right time." Although psychiatry has not yet reached this level of precision, we are on the way thanks to recent technological developments that may aid to detect plausible molecular and genetic markers. At the moment there are some models that are contributing to precision psychiatry through the concept of staging. While staging was initially presented as a way to categorize patients according to clinical presentation, course, and illness severity, current staging models integrate multiple levels of information that can help to define each patient's characteristics, severity, and prognosis in a more precise and individualized way. Moreover, staging might serve as the foundation to create a clinical decision-making algorithm on the basis of the patient's stage. In this review we will summarize the evolution of the bipolar disorder staging model in relation to the new discoveries on the neurobiology of bipolar disorder. Furthermore, we will discuss how the latest and future progress in psychiatry might transform current staging models into precision staging models.

Cognitive dysfunction in major depressive disorder

PURPOSE OF REVIEW

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.

RECENT FINDINGS

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.

SUMMARY

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.

HIV and Cognitive Impairment in Clinical Practice: The Evaluation of a Stepwise Screening Protocol in Relation to Clinical Outcomes and Management

Neurocognitive impairment (NCI) is an increasingly important comorbidity in an ageing HIV+ population. Despite the lack of available treatment modalities, screening for NCI is recommended. In the UMC Utrecht, yearly NCI screening is done using the Montreal Cognitive Assessment (MoCA) tool and the HIV Dementia Scale (HDS). The aim of this study was to evaluate this screening protocol in relation to clinical outcomes and management. A retrospective cohort study was performed in suppressed adult HIV+ patients. Apart from the MoCa and the HDS, the Utrecht Scale for Evaluation of Rehabilitation-Participation (USER-P) and the Hospital Anxiety and Depression Scale (HADS) were performed. Patients scoring below average on cognitive screening tests or with subjective cognitive complaints were further evaluated using a standardized protocol, including optimizing cART and checking for somatic disorders. In patients with cognitive complaints and participation restrictions, cognitive rehabilitation was proposed. Two hundred eighty-six patients were screened. The vast majority were MSM with an average age of 49 years. One hundred forty-four out of 286 patients (50%) had an abnormal test score and/or had subjective cognitive complaints. Restrictions in participation were present in 23% of patients. Six patients on Efavirenz switched their regimes, as this drug is known for its potential central nervous system (CNS) side effects. A depressive component was present in 58 patients (40%). Five patients had a clinical relevant laboratory abnormality. Moreover, six patients were referred for cognitive rehabilitation, which resulted in a 100% success rate in set goals in the five evaluable patients. Although the protocol was not fully adhered to in all patients, it did result in detectable underlying causes of NCI in 59% of patients, and 21% was referred for further treatment. Moreover, cognitive rehabilitation appears to be a very successful intervention for patients with NCI who experience subjective complaints and participation restrictions.

The 'cognitive footprint' of psychiatric and neurological conditions: cross-sectional study in the UK Biobank cohort

OBJECTIVE

We aimed to quantify the prevalence of cognitive impairment in adults with a history of mood disorder, schizophrenia, multiple sclerosis or Parkinson's disease, within a large general population cohort.

METHOD

Cross-sectional study using UK Biobank data (n = 502 642). Psychiatric and neurological exposure status was ascertained via self-reported diagnoses, hospital records and questionnaires. Impairment on reasoning, reaction time and memory tests was defined with reference to a single unexposed comparison group. Results were standardised for age and gender. Sensitivity analyses examined the influence of comorbidity, education, information sources and missing data.

RESULTS

Relative to the unexposed group, cognitive impairment was least common in major depression (standardised prevalence ratios across tests = 1.00 [95% CI 0.98, 1.02] to 1.49 [95% CI 1.24, 1.79]) and most common in schizophrenia (1.89 [95% CI 1.47, 2.42] to 3.92 [95% CI 2.34, 6.57]). Prevalence in mania/bipolar was similar to that in multiple sclerosis and Parkinson's disease. Estimated population attributable prevalence of cognitive impairment was higher for major depression (256 per 100 000 [95% CI 130, 381]) than for all other disorders.

CONCLUSION

Although the relative prevalence of cognitive impairment was lowest in major depression, the population attributable prevalence was highest overall for this group.

The catechol-O-methyltransferase (COMT) Val158Met genotype modulates working memory-related dorsolateral prefrontal response and performance in bipolar disorder

OBJECTIVES

Cognitive dysfunction affects a substantial proportion of patients with bipolar disorder (BD), and genetic-imaging paradigms may aid in the elucidation of mechanisms implicated in this symptomatic domain. The Val allele of the functional Val158Met polymorphism of the catechol-O-methyltransferase (COMT) gene is associated with reduced prefrontal cortex dopamine and exaggerated working memory-related prefrontal activity. This functional magnetic resonance imaging (fMRI) study investigated for the first time whether the COMT Val158Met genotype modulates prefrontal activity during spatial working memory in BD.

METHODS

Sixty-four outpatients with BD in full or partial remission were stratified according to COMT Val158Met genotype (ValVal [n=13], ValMet [n=34], and MetMet [n=17]). The patients completed a spatial n-back working memory task during fMRI and the Cambridge Neuropsychological Test Automated Battery (CANTAB) Spatial Working Memory test outside the scanner.

RESULTS

During high working memory load (2-back vs 1-back), Val homozygotes displayed decreased activity relative to ValMet individuals, with Met homozygotes displaying intermediate levels of activity in the right dorsolateral prefrontal cortex (dlPFC) (P=.016). Exploratory whole-brain analysis revealed a bilateral decrease in working memory-related dlPFC activity in the ValVal group vs the ValMet group which was not associated with differences in working memory performance during fMRI. Outside the MRI scanner, Val carriers performed worse in the CANTAB Spatial Working Memory task than Met homozygotes (P≤.006), with deficits being most pronounced in Val homozygotes.

CONCLUSIONS

The association between Val allelic load, dlPFC activity and WM impairment points to a putative role of aberrant PFC dopamine tonus in the cognitive impairments in BD.

[Not Available]

Zusammenfassung. Depressionen, leichte kognitive Störungen und Demenzen sind besonders bei älteren Menschen häufig assoziiert. Ähnliche neuropathologische Mechanismen scheinen diesen Zusammenhang und die gegenseitigen Einflüsse mindestens teilweise zu erklären. Wir schlagen hier eine Kurzreview der Rolle der Depression als Risikofaktor, Prodrom oder Folge der kognitiven Störungen vor und skizzieren kurz mögliche Behandlungsansätze.

Dopaminergic mechanisms in memory consolidation and antidepressant reversal of a chronic mild stress-induced cognitive impairment`

Cognitive deficits in depression can be modelled using the novel object recognition (NOR) test, performance in which is impaired by chronic mild stress (CMS). We aimed to examine the involvement of mesocorticolimbic DA terminal regions, and to establish the substrate for CMS-induced impairment of NOR and its reversal by chronic antidepressant treatment. In experiments 1 and 2, we examined the effect of infusions into medial PFC, dorsal hippocampus (HPC), and nucleus accumbens (NAc) shell of D1 and D2 antagonists and D3 agonist, which were predicted to impair NOR with a short (1 h) delay, and of D1 and D2 agonists and D3 antagonist, which were predicted to facilitate NOR with a long (24 h) delay. Using optimal doses identified in experiment 2, in experiments 3 and 4, we examined effects on drug-stimulated NOR of CMS and chronic treatment with venlafaxine (VFX) or risperidone (RSP). We found a wide involvement of DA systems in memory for NOR: D1 receptors in PFC, HPC, and NAc; D3 receptors in PFC and HPC; and D2 receptors in PFC. CMS impaired D2- and D3-mediated effects in PFC and HPC; antidepressants rescued those effects in PFC but not HPC. The involvement of DA in NOR is multifaceted, but the effects of CMS and antidepressants are more discrete, involving D2 and D3 receptors in PFC specifically. While raising many difficult questions, these results suggest that the D2 and D3 receptors in the medial PFC may be an important substrate for cognitive deficits in depression and their remediation.