Cognitive Dysfunction in Depression – Pathophysiology and Novel Targets

Chronic inflammation is associated with worsening working memory performance: Preliminary evidence from a diverse, longitudinal cohort of adolescents and young adults

Many depressed individuals experience cognitive difficulties that persist when depression is in remission. Inflammation is hypothesized to play a role in cognitive dysfunction in depression; however, many aspects of this relationship are not well characterized. The current study examined whether inflammation is associated with specific cognitive deficits in individuals with a history of depression and with progressively worsening working memory over time. Adolescents who participated in a prospective, longitudinal study of adolescent-onset depression were recruited to complete a follow-up cognitive assessment. The sample was comprised of 82 participants (52.4% female; 37.8% white; 42.7% low socioeconomic status) who were aged 22.61 years (SD = 1.50) at the time of the follow-up cognitive assessment. Prior to the follow-up cognitive assessment, they had completed an average of 6.24 (SD = 1.80) prior annual assessments over 6.24 years (SD = 2.08) as part of the parent longitudinal study in which C-reactive protein (CRP), depressive symptoms, and working memory were assessed repeatedly. First, using linear regression, we tested whether individuals exhibiting inflammation (CRP ≥3 mg/L) at multiple timepoints and a history of likely depression (Children's Depression Inventory ≥19) exhibited differentially worse executive functioning, episodic memory, or psychomotor speed. Second, using hierarchical linear modeling, we tested whether the combination of inflammation and likely past depression was associated with poorer working memory over time. Chronic inflammation was associated with worsening working memory over time, but no significant associations were observed in cross-sectional analyses. These preliminary data indicate that chronic inflammation may lead to progressive decline in working memory over time.

Psilocybin for dementia prevention? The potential role of psilocybin to alter mechanisms associated with major depression and neurodegenerative diseases

Major depression is an established risk factor for subsequent dementia, and depression in late life may also represent a prodromal state of dementia. Considering current challenges in the clinical development of disease modifying therapies for dementia, the focus of research is shifting towards prevention and modification of risk factors to alter the neurodegenerative disease trajectory. Understanding mechanistic commonalities underlying affective symptoms and cognitive decline may reveal biomarkers to aid early identification of those at risk of progressing to dementia during the preclinical phase of disease, thus allowing for timely intervention. Adult hippocampal neurogenesis (AHN) is a phenomenon that describes the birth of new neurons in the dentate gyrus throughout life and it is associated with spatial learning, memory and mood regulation. Microglia are innate immune system macrophages in the central nervous system that carefully regulate AHN via multiple mechanisms. Disruption in AHN is associated with both dementia and major depression and microgliosis is a hallmark of several neurodegenerative diseases. Emerging evidence suggests that psychedelics promote neuroplasticity, including neurogenesis, and may also be immunomodulatory. In this context, psilocybin, a serotonergic agonist with rapid-acting antidepressant properties has the potential to ameliorate intersecting pathophysiological processes relevant for both major depression and neurodegenerative diseases. In this narrative review, we focus on the evidence base for the effects of psilocybin on adult hippocampal neurogenesis and microglial form and function; which may suggest that psilocybin has the potential to modulate multiple mechanisms of action, and may have implications in altering the progression from major depression to dementia in those at risk.

A novel dual serotonin transporter and M-channel inhibitor D01 for antidepression and cognitive improvement

Cognitive dysfunction is a core symptom common in psychiatric disorders including depression that is primarily managed by antidepressants lacking efficacy in improving cognition. In this study, we report a novel dual serotonin transporter and voltage-gated potassium Kv7/KCNQ/M-channel inhibitor D01 (a 2-methyl-3-aryloxy-3-heteroarylpropylamines derivative) that exhibits both anti-depression effects and improvements in cognition. D01 inhibits serotonin transporters (Ki = 30.1 ± 6.9 nmol/L) and M channels (IC50 = 10.1 ± 2.4 μmol/L). D01 also reduces the immobility duration in the mouse FST and TST assays in a dose-dependent manner without a stimulatory effect on locomotion. Intragastric administrations of D01 (20 and 40 mg/kg) can significantly shorten the immobility time in a mouse model of chronic restraint stress (CRS)-induced depression-like behavior. Additionally, D01 dose-dependently improves the cognitive deficit induced by CRS in Morris water maze test and increases the exploration time with novel objects in normal or scopolamine-induced cognitive deficits in mice, but not fluoxetine. Furthermore, D01 reverses the long-term potentiation (LTP) inhibition induced by scopolamine. Taken together, our findings demonstrate that D01, a dual-target serotonin reuptake and M channel inhibitor, is highly effective in the treatment-resistant depression and cognitive deficits, thus holding potential for development as therapy of depression with cognitive deficits.

Individuals with depression exhibiting a pro-inflammatory phenotype receiving omega-3 polyunsaturated fatty acids experience improved motivation-related cognitive function: Preliminary results from a randomized controlled trial

Cognitive impairment related to major depressive disorder (MDD) is highly prevalent, debilitating and is lacking in effective treatments; dysregulated inflammatory physiology is a putative mechanism and may represent a therapeutic target. In depressed individuals exhibiting a pro-inflammatory phenotype who were enrolled in a 12-week randomized placebo-controlled trial of 3 doses of omega-3 polyunsaturated fatty acids (ω-3-FA), we examined: (i) the relationship between dysregulated inflammatory physiology and baseline cognitive impairment; (ii) improvement in cognitive impairment following treatment; and (iii) the association between baseline inflammatory biomarkers and change in cognitive impairment for those receiving treatment. We randomized 61 unmedicated adults aged 45.50 years (75% female) with DSM-5 MDD, body mass index >25 kg/m², and C-reactive protein (CRP) ≥3.0 mg/L to three doses of ω-3-FA (1, 2, or 4 g daily) or matching placebo. Analyses focused on 45 study completers who had inflammatory biomarkers assessed [circulating CRP, interleukin-6 (IL-6) and tumor necrosis factor-α (TNFα) as well as lipopolysaccharide (LPS)-stimulated concentrations of IL-6 and TNFα in peripheral blood mononuclear cells (PBMC)] and on the highest dose ω-3-FA (4 g daily; n = 11) compared to placebo (n = 10). Impairment in motivational symptoms (e.g., alertness, energy, enthusiasm) and higher-order cognitive functions (e.g., word-finding, memory) were assessed by a validated self-report measure. Among all 45 participants at baseline, lower concentrations of IL-6 in LPS-stimulated PBMC were associated with greater impairment in higher-order cognitive functions (r = -0.35, p = .02). Based on hierarchical linear modeling, individuals receiving 4 g/day of ω-3-FA reported significant improvement in motivational symptoms compared to placebo (B = -0.07, p = .03); in the 4 g/day group, lower baseline concentrations of TNFα in LPS-stimulated PBMC were associated with significant improvement in motivational symptoms (Ρ = .71, p = .02) following treatment. In this exploratory clinical trial, daily supplementation with 4 g of ω-3-FA improves motivational symptoms in depressed individuals exhibiting an inflammatory phenotype.

Comparison of online and in-person cognitive behavioral therapy in individuals diagnosed with major depressive disorder: a non-randomized controlled trial

Objective

The increased prevalence of major depressive disorder (MDD) amid the COVID-19 pandemic has resulted in substantial growth in online mental health care delivery. Compared to its in-person counterpart, online cognitive behavioral therapy (e-CBT) is a time-flexible and cost-effective method of improving MDD symptoms. However, how its efficacy compares to in-person CBT is yet to be explored. Therefore, the current study compared the efficacy of a therapist-supported, electronically delivered e-CBT program to in-person therapy in individuals diagnosed with MDD.

Methods

Participants (n = 108) diagnosed with MDD selected either a 12 week in-person CBT or an asynchronous therapist-supported e-CBT program. E-CBT participants (n = 55) completed weekly interactive online modules delivered through a secure cloud-based online platform (Online Psychotherapy Tool; OPTT). These modules were followed by homework in which participants received personalized feedback from a trained therapist. Participants in the in-person CBT group (n = 53) discussed sessions and homework with their therapists during one-hour weekly meetings. Program efficacy was evaluated using clinically validated symptomatology and quality of life questionnaires.

Results

Both treatments yielded significant improvements in depressive symptoms and quality of life from baseline to post-treatment. Participants who opted for in-person therapy presented significantly higher baseline symptomatology scores than the e-CBT group. However, both treatments demonstrated comparable significant improvements in depressive symptoms and quality of life from baseline to post-treatment. e-CBT seems to afford higher participant compliance as dropouts in the e-CBT group completed more sessions on average than those in the in-person CBT group.

Conclusion

The findings support e-CBT with therapist guidance as a suitable option to treat MDD. Future studies should investigate how treatment accessibility is related to program completion rates in the e-CBT vs. in-person group.

Clinical Trial Registration

ClinicalTrials.Gov Protocol Registration and Results System (NCT04478058); clinicaltrials.gov/ct2/show/NCT04478058.

"Severe Anemia: A Case Report of an Uncommon Precipitant of Schizophrenia Relapse"

A 48-year-old patient with stable residual schizophrenia experienced a syndromic psychosis relapse following an episode of severe combined immunohemolytic and pure red cell aplastic anemia, with a hemoglobin level of 4.7 g/dl. The anemia was attributed to her anti-HIV medication zidovudine. Her HIV infection had been well-controlled; no other organic precipitant of the psychosis was found. Following transfusion of 2 units of leukocyte-poor packed red cells, schizophrenia symptoms promptly recovered to her baseline. This was maintained at 3- and 6-month follow-ups without any need for antipsychotic dose adjustment. Following zidovudine discontinuation and a short course of oral prednisolone, her anemia gradually recovered.

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

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

Prefrontal cortex activities during verbal fluency and emotional words tasks in major depressive, adjustment, and bipolar disorders with depressive states

BACKGROUND

It can be difficult to differentiate psychiatric disorders from depressive states, with little knowledge on how to differentiate them. This study aimed to evaluate changes in brain activity during cognitive and emotional tasks in patients with depressive state to help with differential diagnoses.

METHODS

Sixty-two patients with depressive states [17 with adjustment disorder (AD), 27 with major depressive disorder (MDD), and 18 with bipolar disorder (BD)] and 34 healthy controls (HC) were recruited. We used a verbal fluency task (VFT) and emotional word tasks with happy and threat words. Functional near-infrared spectroscopy measured the relative change in oxygenated hemoglobin in the frontotemporal areas.

RESULTS

During the VFT, patients with AD or MDD showed significantly reduced activation in the bilateral frontotemporal region (all p < 0.01), whereas patients with BD demonstrated significantly reduced activation in the right frontotemporal areas compared to HC (p < 0.01). During the emotional words task with happy words, patients with MDD showed significantly increased activity in the frontopolar area compared to HC (p = 0.023). Binary logistic regression analysis showed that MDD or BD was significantly associated with brain activity during the happy word task. In distinguishing MDD or BD from HC, the happy words task performed equally well, with an area under the curve of 0.70.

LIMITATIONS

All study patients were taking psychotropic drugs.

CONCLUSIONS

Brain activation in response to a combination of cognitive or emotional stimuli could assist in distinguishing patients with depressive states from healthy controls.

A Multi-Center Study for the Development of the Taiwan Cognition Questionnaire (TCQ) in Major Depressive Disorder

Cognitive dysfunction is associated with functional impairment of patients with Major Depressive Disorder (MDD). The goals were to explore the associated factors of cognitive impairment in MDD and to develop and validate a brief and culture-relevant questionnaire, the Taiwan Cognition Questionnaire (TCQ), among patients with MDD. This was a cross-sectional, multi-center observational study of MDD patients in Taiwan. Participants of Group 1 from 10 centers contributed to the validation of the TCQ by their response and sociodemographics. The participants of Group 2 from one center received an objective cognitive assessment for clarification of the relationship between the TCQ score and its associated factors. In Group 1, 493 participants were recruited. As for Group 2, an extra 100 participants were recruited. The global Cronbach’s alpha for the TCQ was 0.908. According to the coordinates of the ROC curve, 9/10 was the ideal cut-off point. With the criteria, the sensitivity/specificity of the TCQ was 0.610/0.689. The TCQ score was positively associated with a history of being admitted to acute psychiatric care and the severity of depression and negatively associated with objective cognitive measures. The TCQ provides a reliable, valid, and convenient measure of subjective cognitive dysfunction in patients with MDD.

Deep brain stimulation improved depressive-like behaviors and hippocampal synapse deficits by activating the BDNF/mTOR signaling pathway

Our previous study demonstrated that acute deep brain stimulation (DBS) in the ventromedial prefrontal cortex (vmPFC) remarkably improved the depressive-like behaviors in a rat model of chronic unpredictable mild stress (CUS rats). However, the mechanisms by which chronic DBS altered depressive-like behaviors and reversed cognitive impairment have not been clarified. Recent work has shown that deficits in brain-derived neurotrophic factor (BDNF) and its downstream proteins, including mammalian target of rapamycin (mTOR), might be involved in the pathogenesis of depression. Therefore, we hypothesized that the antidepressant-like and cognitive improvement effects of DBS were achieved by activating the BDNF/mTOR pathway. CUS rats received vmPFC DBS at 20 Hz for 1 h once a day for 28 days. After four weeks of stimulation, the rats were assessed for the presence of depressive-like behaviors and euthanized to detect BDNF/mTOR signaling using immunoblots. DBS at the vmPFC significantly ameliorated depressive-like behaviors and spatial learning and memory deficits in the CUS rats. Furthermore, DBS restored the reduced synaptic density in the hippocampus induced by CUS and increased the expression or activity of BDNF, Akt, and mTOR in the hippocampus. Thus, the antidepressant-like effects and cognitive improvement produced by vmPFC DBS might be mediated through increased activity of the BDNF/mTOR signaling pathway.

Neurobiological Highlights of Cognitive Impairment in Psychiatric Disorders

This review is focused on several psychiatric disorders in which cognitive impairment is a major component of the disease, influencing life quality. There are plenty of data proving that cognitive impairment accompanies and even underlies some psychiatric disorders. In addition, sources provide information on the biological background of cognitive problems associated with mental illness. This scientific review aims to summarize the current knowledge about neurobiological mechanisms of cognitive impairment in people with schizophrenia, depression, mild cognitive impairment and dementia (including Alzheimer's disease).The review provides data about the prevalence of cognitive impairment in people with mental illness and associated biological markers.

A neural network approach to optimising treatments for depression using data from specialist and community psychiatric services in Australia, New Zealand and Japan

This study investigated the application of a recurrent neural network for optimising pharmacological treatment for depression. A clinical dataset of 458 participants from specialist and community psychiatric services in Australia, New Zealand and Japan were extracted from an existing custom-built, web-based tool called Psynary . This data, which included baseline and self-completed reviews, was used to train and refine a novel algorithm which was a fully connected network feature extractor and long short-term memory algorithm was firstly trained in isolation and then integrated and annealed using slow learning rates due to the low dimensionality of the data. The accuracy of predicting depression remission before processing patient review data was 49.8%. After processing only 2 reviews, the accuracy was 76.5%. When considering a change in medication, the precision of changing medications was 97.4% and the recall was 71.4% . The medications with predicted best results were antipsychotics (88%) and selective serotonin reuptake inhibitors (87.9%). This is the first study that has created an all-in-one algorithm for optimising treatments for all subtypes of depression. Reducing treatment optimisation time for patients suffering with depression may lead to earlier remission and hence reduce the high levels of disability associated with the condition. Furthermore, in a setting where mental health conditions are increasing strain on mental health services, the utilisation of web-based tools for remote monitoring and machine/deep learning algorithms may assist clinicians in both specialist and primary care in extending specialist mental healthcare to a larger patient community.

Inflammatory Markers in Substance Use and Mood Disorders: A Neuroimaging Perspective

Chronic exposure to addictive drugs in substance use disorders and stressors in mood disorders render the brain more vulnerable to inflammation. Inflammation in the brain, or neuroinflammation, is characterized by gliosis, microglial activation, and sustained release of cytokines, chemokines, and pro-inflammatory factors compromising the permeability of the blood-brain barrier. There is increased curiosity in understanding how substance misuse and/or repeated stress exposure affect inflammation and contribute to abnormal neuronal activity, altered neuroplasticity, and impaired cognitive control, which eventually promote compulsive drug-use behaviors and worsen mood disorders. This review will emphasize human imaging studies to explore the link between brain function and peripheral markers of inflammation in substance use disorders and mood disorders.

Neural activity in adults with major depressive disorder differs from that in healthy individuals: A resting-state functional magnetic resonance imaging study

OBJECTIVE

Currently, findings regarding resting-state functional magnetic resonance imaging studies of major depressive disorder (MDD) are inconsistent. In contrast to the previously used a priori seed-based functional connectivity analyses, this study employed whole-brain exploratory analyses and aimed to explore neural activity patterns in Chinese adults with MDD.

MATERIALS AND METHODS

Specifically, this study examined the amplitude of low-frequency fluctuations within the whole brain and adopted a large-scale brain network template to explore the core dysfunctional brain regions in individuals with MDD.

RESULTS

Overall, 32 individuals with MDD and 32 healthy controls were evaluated. Compared to healthy controls, individuals with MDD showed more profound alterations in the amplitude of low-frequency fluctuations in the temporolimbic affective circuit (e.g., middle temporal gyrus and parahippocampus) and default mode network (e.g., precuneus and thalamus). Moreover, functional connectivity between the left mid-insula and parietal regions within the sensorimotor network was weaker in individuals with MDD than in healthy controls.

CONCLUSION

In conclusion, the neural characteristics of MDD correspond to cognitive deficits in self-referential processing and emotional processing and are related to a risk of sensory disorders or psychomotor retardation. These findings present neural markers that may be used to identify MDD, contributing to clinical diagnosis.

Transcriptomic signatures of psychomotor slowing in peripheral blood of depressed patients: evidence for immunometabolic reprogramming

Inflammation impacts basal ganglia motor circuitry in association with psychomotor retardation, a key symptom of major depression (MD). We previously reported associations between circulating protein inflammatory biomarkers and psychomotor slowing as measured by neuropsychological tests probing psychomotor speed in patients with MD. To discover novel transcriptional signatures in peripheral blood immune cells related to psychomotor slowing, microarray data were analyzed in a primary cohort of 88 medically-stable, unmedicated, ambulatory MD patients. Results were confirmed and extended in a second cohort of 57 patients with treatment resistant depression (TRD) before and after anti-inflammatory challenge with the tumor necrosis factor antagonist infliximab versus placebo. Composite scores reflecting pure motor and cognitive-motor processing speed were linearly associated with 403 and 266 gene transcripts in each cohort, respectively (|R| > 0.30, p < 0.01), that were enriched for cytokine signaling and glycolysis-related pathways (p < 0.05). Unsupervised clustering in the primary cohort revealed two psychomotor slowing-associated gene co-expression modules that were enriched for interferon, interleukin-6, aerobic glycolysis, and oxidative phosphorylation pathways (p < 0.05, q < 0.1). Transcripts were predominantly derived from monocytes, plasmacytoid dendritic cells, and natural killer cells (p's < 0.05). In infliximab-treated TRD patients with high plasma C-reactive protein concentrations (>5 mg/L), two differential co-expression modules enriched for oxidative stress and mitochondrial degradation were associated with improvements in psychomotor reaction time (p < 0.05). These results indicate that inflammatory signaling and associated metabolic reprogramming in peripheral blood immune cells are associated with systemic inflammation in depression and may affect relevant brain circuits to promote psychomotor slowing.

Inflammation and depression: Research designs to better understand the mechanistic relationships between depression, inflammation, cognitive dysfunction, and their shared risk factors

There is convergent evidence that the immune system is dysregulated in some depressed individuals. A psychoneuroimmunology-based understanding of depression is advancing rapidly; however, a question of fundamental importance is poorly understood: does inflammation play a causal role in the etiology of depression or are elevated inflammatory biomarkers a downstream effect of depressive behaviors? Although longitudinal studies suggest that the relationship between depression and inflammation is characterized by complex bidirectional associations, existing prospective, longitudinal research designs are poorly equipped to investigate the dynamic interplay of depression and inflammation that unfolds over a relatively short time period. In addition, the precise role played by multiple, shared, and overlapping risk factors (e.g., diet, adiposity, stress, sleep dysregulation) in the etiology of depression and a pro-inflammatory phenotype (or both) is poorly understood. In this manuscript, I highlight the benefits of research designs that (i) manipulate constructs of interest (depression/inflammation) using intervention or treatment designs and (ii) use intensive sampling approaches with an ultimate goal of better understanding the temporal sequence and causal relationships of depression, inflammation, cognitive dysfunction, and their shared risk factors. For instance, are improved depressive symptoms a downstream effect of changes in inflammatory activity caused by increases in exercise or, alternatively, are changes in inflammatory activity and depression sequelae of improvements in sleep quality caused by increases in exercise? Potential benefits of these research designs are discussed in terms of their contribution to a better understanding of the etiology of depression and a pro-inflammatory phenotype, their relevance to structural health inequalities, and better characterizing the heterogeneous clinical presentation of depression, particularly relating to the etiology of cognitive dysfunction in depression.

Investigating whether a combination of higher CRP and depression is differentially associated with worse executive functioning in a cohort of 43,896 adults

Many depressed individuals experience difficulties in executive functioning that contribute substantially to functional impairment. It is unknown whether a subtype of depression characterized by chronic inflammation is differentially associated with worse executive functioning. This study examined whether the combination of depression and higher C reactive protein (CRP) is differentially associated with worse executive functioning and whether this association is stronger in older adults. This cross-sectional study analyzed data collected from a population-representative sample of 43,896 adults aged 44.13 years (SD = 13.52) who participated in the baseline assessment of the Lifelines cohort study. Multivariate regression models tested whether depressed individuals (established via structured interview) exhibiting higher levels of inflammation (indexed via high-sensitivity CRP assay following an overnight fast) performed worse on a behavioral test of executive functioning. Depression (B = -3.66, 95% CI: -4.82, -2.49, p < .001) and higher log-transformed CRP (B = -0.67, 95% CI: -0.87,-0.47, p < .001) were associated with worse executive functioning, after adjustment for age, sex, educational attainment, body mass index, smoking status, exposure to stressful life events and chronic stressors, sedentary behavior, and number of chronic medical conditions. Depressed individuals with higher log-transformed CRP exhibited differentially poorer executive functioning (B = -1.09, 95% CI: -2.07,-0.11, p < .001). This association did not differ based on age (B = 0.01, 95% CI: -0.08, 0.10, p = .82). Executive functioning is poorer in depressed individuals with higher CRP, even in early adulthood. Interventions that reduce inflammation may improve cognitive functioning in depression.

The effects of glucagon-like peptide 1 receptor agonist (exenatide) on memory impairment, and anxiety- and depression-like behavior induced by REM sleep deprivation

Previous investigations have shown that REM sleep deprivation impairs the hippocampus-dependent memory, long-term potentiation and causing mood changes. The aim of the present study was to explore the effects of exenatide on memory performance, anxiety- and depression like behavior, oxidative stress markers, and synaptic protein levels in REM sleep deprived rats. A total of 40 male Wistar rats were randomly divided to control, exenatide-treated control, sleep deprivation (SD), wide platform (WP) and exenatide-treated SD groups. During experiments, exenatide treatment (0.5 μg/kg, subcutaneously) was applied daily in a single dose for 9 days. Modified multiple platform method was employed to generate REM sleep deprivation for 72 h. The Morris water maze test was used to assess memory performance. Anxiety- and depression-like behaviors were evaluated by open field test (OFT), elevated plus maze (EPM) forced swimming test (FST), respectively 72 h after REMSD. The levels of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and postsynaptic density proteins 95 (PSD95) were measured in tissues of hippocampus and prefrontal cortex. The content of malondialdehyde (MDA) and reduced glutathione (GSH) were also measured. In the present study, an impairment in memory was observed in SD rats at the 24th hour of SD in compare to those of other groups. REMSD increased depression-like behavior in FST as well as the number of rearing and crossing square in OFT. Anxiety is the most common comorbid condition with depressive disorders. Contents of CaMKII and PSD95 decreased in hippocampus of SD rats. Exenatide treatment improved the impaired memory of SD rats and increased CaMKII content in hippocampus There was no difference in MDA and GSH levels among groups. Exenatide treatment also diminished locomotor activity in OFT. In conclusion, treatment with exenatide, at least in part, prevented from these cognitive and behavioral changes possibly through normalizing CaMKII levels in the hippocampus.

Investigating whether depressed youth exhibiting elevated C reactive protein perform worse on measures of executive functioning, verbal fluency and episodic memory in a large, population based sample of Dutch adolescents

Cognitive functioning is disrupted during a depressive episode and cognitive dysfunction persists when depression is in remission. A subtype of depressed individuals who exhibit elevated inflammatory biomarkers may be at particular risk for cognitive dysfunction. We examined whether an elevated inflammatory biomarker (C-reactive protein: CRP) in acute and/or remitted depression was associated with specific deficits in executive functioning, episodic memory, and verbal fluency. Data were drawn from a population-based sample of Dutch adolescents (N = 1066; 46% male) recruited at the age of 11 and followed over the course of eight years. We tested whether adolescents with either, (i) a history of depression (Wave 1-3) or (ii) current depression (Wave 4), and elevated levels of C-reactive protein measured in blood at Wave 3 performed worse on cognitive assessments at Wave 4. Eight measures of cognitive functioning were hypothesized to load on to one of three dimensions of cognitive functioning (executive functioning, episodic memory, and verbal fluency) within a structural equation model framework. Higher levels of CRP were associated with worse future executive functioning in adolescents with and without current/prior depression. A current depression diagnosis also was associated with worse executive functioning. There was consistent evidence linking low socioeconomic status and health-related covariates (high body mass index/sedentary behavior) with worse performance across multiple measures of cognitive functioning and, importantly, the association of depression/CRP and executive functioning was no longer significant when controlling for these covariates. Future studies may benefit from investigating whether specific depressogenic behaviors (e.g., sedentary behavior/substance use) mediate a relationship between depression and worse executive functioning, potentially via a prospective pathway through elevated inflammation.

Severe sleep disturbance is associated with executive function impairment in patients with first-episode, treatment-naïve major depressive disorders

BACKGROUND

Sleep disturbance and executive function impairment are common in patients with major depressive disorder (MDD), though the relationship between the two remains unclear. We investigated this association in first-episode, treatment-naïve patients with MDD.

METHODS

We analyzed data from 242 patients with MDD. We divided the patients into 2 groups based on sleep disturbance severity and compared the executive function odds ratios between the groups.

RESULTS

A total of 121 pairs of patients were matched (age 39.4 ± 10.1, 70.2% female). After propensity score matching, the odds ratios for cognitive impairment in patients with MDD and severe sleep disturbance were 1.922 (1.068-3.459, P = 0.029, q = 0.044) in executive functioning; 2.023 (1.211-3.379, P = 0.007, q = 0.021) in executive shifting.

CONCLUSIONS

Sleep disturbance is associated with executive functioning impairment in first-episode, treatment-naïve patients with MDD. Severe sleep disturbance can be a marker and aid in recognizing executive function impairment in patients with first-episode treatment-naïve MDD. Severe sleep disturbance can be a potential modifiable factor to improve executive function in MDD, as well as an effective measurement to improve cognition for sleep symptom management that should be enforced at initial treatment of first-episode MDD. Further study is required to confirm our results.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02023567 ; registration date: December 2013.

Factors associated with recurrent transient global amnesia: systematic review and pathophysiological insights

The examination of the risk factors that affect the recurrence of transient global amnesia (TGA) may shed light on the pathophysiological substrate of the disease. A systematic review was performed to identify the factors associated with the recurrence of TGA. MEDLINE, EMBASE, CENTRAL and PsycINFO were meticulously searched. Observational controlled studies involving patients with single (s-TGA) and recurrent TGA (r-TGA) according to Hodges and Warlow's criteria were retrieved. Differences in the demographic characteristics, personal and family medical history, previous exposure to precipitating events and laboratory findings were examined. Retrieved evidence was assessed in the context of the individual article validity, based on the numerical power and methodological quality of each study. Nine cohort studies with retrospective, prospective or mixed design were retrieved. In total, 1989 patients with TGA were included, 269 of whom suffered from r-TGA (13.5%). R-TGA presented an earlier age of onset. Evidence was suggestive of a relationship between recurrence and a family or personal history of migraine, as well as a personal history of depression. There was weaker evidence that associated recurrence with a positive family history of dementia, a personal history of head injury and hippocampal lesions in diffusion-weighted MRI. On the other hand, no connection was found between recurrence and electroencephalographic abnormalities, impaired jugular venous drainage, cardiovascular risk factors, atrial fibrillation, previous cerebrovascular events, exposure to precipitating events, a positive family history of TGA and hypothyroidism. Important pathophysiological insights that arised from these findings were discussed.

Cognitive effects of the GSK-3 inhibitor "lithium" in LPS/chronic mild stress rat model of depression: Hippocampal and cortical neuroinflammation and tauopathy

Low-dose repeated lipopolysaccharide pre-challenge followed by chronic mild stress (LPS/CMS) protocol has been introduced as a rodent model of depression combining the roles of immune activation and chronic psychological stress. However, the impact of this paradigm on cognitive functioning has not been investigated hitherto.

METHODS

This study evaluated LPS/CMS-induced cognitive effects and the role of glycogen synthase kinase-3β (GSK-3β) activation with subsequent neuroinflammation and pathological tau deposition in the pathogenesis of these effects using lithium (Li) as a tool for GSK-3 inhibition.

RESULTS

LPS pre-challenge reduced CMS-induced neuroinflammation, depressive-like behavior and cognitive inflexibility. It also improved spatial learning but increased GSK-3β expression and exaggerated hyperphosphorylated tau accumulation in hippocampus and prefrontal cortex. Li ameliorated CMS and LPS/CMS-induced depressive and cognitive deficits, reduced GSK-3β over-expression and tau hyperphosphorylation, impeded neuroinflammation and enhanced neuronal survival.

CONCLUSION

This study draws attention to LPS/CMS-triggered cognitive changes and highlights how prior low-dose immune challenge could develop an adaptive capacity to buffer inflammatory damage and maintain the cognitive abilities necessary to withstand threats. This work also underscores the favorable effect of Li (as a GSK-3β inhibitor) in impeding exaggerated tauopathy and neuroinflammation, rescuing neuronal survival and preserving cognitive functions. Yet, further in-depth studies utilizing different low-dose LPS challenge schedules are needed to elucidate the complex interactions between immune activation and chronic stress exposure.

Altered GABA-mediated information processing and cognitive dysfunctions in depression and other brain disorders

Cognitive dysfunctions, including impaired attention, learning, memory, planning and problem solving, occur in depressive episodes, often persist during remission, predict relapse, worsen with recurrent episodes, and are not treated by current antidepressants or other medications. Cognitive symptoms are also present in other psychiatric disorders, are a hallmark of aging, and define several late-life disorders, including Alzheimer's disease. This pervasive occurrence suggests either a non-specific outcome of a diseased brain, or a shared underlying pathology contributing to this symptom dimension. Recent findings suggest a role for altered GABAergic inhibition in cognitive symptoms. Cellular, molecular and biochemical studies in human subjects report changes affecting the gamma-amino butyric acid (GABA) system, specifically somatostatin-expressing (SST+) GABAergic interneurons, across brain disorders and during aging. SST+ neurons gate excitatory input onto pyramidal neurons within cortical microcircuits. Experimentally reducing the function of these neurons affects excitatory signal-to-noise ratio, reduces synchronized cellular and neural activity, and leads to cognitive dysfunctions. Conversely, augmenting SST+ cell post-synaptic α5-GABA-A receptor activity has pro-cognitive efficacy in stress and aging models. Together, this suggests that reduced signaling of the SST+ neuron/α5-GABA-A receptor pathway contributes to cognitive dysfunctions, and that it represents a novel therapeutic target for remediating mood and cognitive symptoms in depression, other psychiatric disorders and during aging.

AMPA receptors mediate the pro-cognitive effects of electrical and optogenetic stimulation of the medial prefrontal cortex in antidepressant non-responsive Wistar-Kyoto rats

BACKGROUND

The chronic mild stress (CMS) procedure is a widely used animal model of depression, and its application in Wistar-Kyoto (WKY) rats has been validated as a model of antidepressant-refractory depression. While not responding to chronic treatment with antidepressant drugs, WKY rats do respond to acute deep brain stimulation (DBS) of the medial prefrontal cortex (mPFC). In antidepressant-responsive strains there is evidence suggesting a role for AMPA subtype of glutamate receptor in the action mechanism of both antidepressants and DBS.

METHODS

Animals were subjected to CMS for 6 to 8 weeks; sucrose intake was monitored weekly and novel object recognition (NOR) test was conducted following recovery from CMS. Wistars were treated chronically with venlafaxine (VEN), while WKY were treated acutely with either DBS, optogenetic stimulation (OGS) of virally-transduced (AAV5-hSyn-ChR2-EYFP) mPFC or ventral hippocampus, or acute intra-mPFC injection of the AMPA receptor positive allosteric modulator CX-516. The AMPA receptor antagonist NBQX was administered, at identical sites in mPFC, immediately following the exposure trial in the NOR.

RESULTS

Sucrose intake and NOR were suppressed by CMS, and restored by VEN in Wistars and by DBS, OGS, or CX-516 in WKY. However, OGS of the ventral hippocampal afferents to mPFC was ineffective. A low dose of NBQX selectively blocked the procognitive effect of VEN, DBS and OGS.

CONCLUSIONS

These results suggest that activation of AMPA receptors in the mPFC represents a common pathway for the antidepressant effects of both conventional (VEN) and novel (DBS, OGS) antidepressant modalities, in both antidepressant responsive (Wistar) and antidepressant-resistant (WKY) rats.

Potential therapeutic target for aging and age-related neurodegenerative diseases: the role of acid sphingomyelinase

Aging, which is associated with age-related changes in physiological processes, is the most significant risk factor for the development and progression of neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Accumulating evidence has indicated that sphingolipids are significant regulators that are associated with pathogenesis in aging and several age-related neurodegenerative diseases. In particular, abnormal levels of acid sphingomyelinase (ASM), one of the significant sphingolipid-metabolizing enzymes, have been found in the blood and some tissues under various neuropathological conditions. Moreover, recent studies have reported the importance of ASM as a critical mediator that contributes to pathologies in aging and age-related neurodegenerative diseases. In this review, we describe the pathophysiological processes that are regulated by ASM, focusing on the age-related neurodegenerative environment. Furthermore, we discuss novel insights into how new therapeutics targeting ASM may potentially lead to effective strategies to combat aging and age-related neurodegenerative diseases.

Executive dysfunction in depression in adolescence: the role of inflammation and higher body mass

BACKGROUND

There is substantial evidence that many depressed individuals experience impaired executive functioning. Understanding the causes of executive dysfunction in depression is clinically important because cognitive impairment is a substantial contributor to functional impairment. This study investigated whether elevated levels of an inflammatory cytokine [interleukin-6 (IL-6)] and/or higher body mass index (BMI) concurrently and/or prospectively accounted for the relationship between depressive symptoms and impaired executive functioning in adolescents.

METHODS

A diverse, community sample of adolescents (N = 288; mean age = 16.33; 51.4% female; 59.0% African-American) completed assessments of height and weight, IL-6, depressive symptoms, and self-report/behavioral measures of executive functioning (selective attention, switching attention) and future orientation annually over 3 years. Adolescents experiencing acute illness or medical conditions that affect inflammation were excluded from analyses. Path analysis within a structural equation modeling framework simultaneously examined the concurrent and prospective relationships between BMI, IL-6, depressive symptoms, and the measures of cognitive functioning across three timepoints.

RESULTS

Across all timepoints, higher BMI was prospectively associated with higher levels of IL-6 and depressive symptoms, while higher levels of IL-6 were associated with worse performance on three behavioral and self-report measures of cognitive functioning. Higher depressive symptoms also were prospectively associated with elevated IL-6 and both higher depressive symptoms and a higher BMI predicted worse future executive functioning via increased IL-6.

CONCLUSIONS

More severe depressive symptoms and increased BMI may disrupt executive functioning via elevated IL-6.

The role of prefrontal cortex dopamine D2 and D3 receptors in the mechanism of action of venlafaxine and deep brain stimulation in animal models of treatment-responsive and treatment-resistant depression

AIMS

The Wistar-Kyoto rat has been validated as an animal model of treatment-resistant depression. Here we investigated a role of dopamine D2 and D3 receptors in the ventro-medial prefrontal cortex in the mechanism of action of deep brain stimulation in Wistar-Kyoto rats and venlafaxine in Wistar rats.

METHODS

Wistar or Wistar-Kyoto rats were exposed chronically to chronic mild stress. Wistar rats were treated chronically with venlafaxine (10 mg/kg) beginning after two weeks of chronic mild stress; Wistar-Kyoto rats received two sessions of deep brain stimulation before behavioural tests. L-742,626 (1 µg), a D2 receptor agonist, or 7-OH DPAT (3 µg), a D3 receptor antagonist, were infused into the ventro-medial prefrontal cortex immediately following the exposure trial in the Novel Object Recognition Test, and discrimination between novel and familiar object was tested one hour later.

RESULTS

Chronic mild stress decreased sucrose intake and impaired memory consolidation; these effects were reversed by venlafaxine in Wistar rats and deep brain stimulation in Wistar-Kyoto rats. In control animals, L-742,626 and 7-OH DPAT also impaired memory consolidation. In Wistar rats, venlafaxine reversed the effect of L-742,626 in controls, but not in the chronic mild stress group, and venlafaxine did not reverse the effect of 7-OH DPAT in either group. In Wistar-Kyoto rats, deep brain stimulation reversed the effect of both L-742,626 and 7-OH DPAT in both control and chronic mild stress groups.

CONCLUSIONS

We conclude that the action of venlafaxine to reverse the impairment of memory consolidation caused by chronic mild stress in Wistar rats involves D2 receptors in the ventro-medial prefrontal cortex; but the effect of deep brain stimulation to reverse the same effect in Wistar-Kyoto rats does not.

The possible beneficial effects of creatine for the management of depression

Depression, a highly prevalent neuropsychiatric disorder worldwide, causes a heavy burden for the society and is associated with suicide risk. The treatment of this disorder remains a challenge, since currently available antidepressants provide a slow and, often, incomplete response and cause several side effects that contribute to diminish the adhesion of patients to treatment. In this context, several nutraceuticals have been investigated regarding their possible beneficial effects for the management of this neuropsychiatric disorder. Creatine stands out as a supplement frequently used for ergogenic purpose, but it also is a neuroprotective compound with potential to treat or mitigate a broad range of central nervous systems diseases, including depression. This review presents preclinical and clinical evidence that creatine may exhibit antidepressant properties. The focus is given on the possible molecular mechanisms underlying its effects based on the results obtained with different animal models of depression. Finally, evidence obtained in animal models of depression addressing the possibility that creatine may produce rapid antidepressant effect, similar to ketamine, are also presented and discussed.

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.

Cytokines in Relation to Motor Activity in an Acute Psychiatric Population

Background: Deviations in motor activity are important clinical features of several psychiatric disorders in an acute state. Immune activity is associated with several psychiatric disorders and may affect motor activity. We aimed to examine the association between immune activity measured as serum levels of cytokines and deviations in motor activity, in an acute psychiatric setting. Methods: Data on motor activity and immune markers were available on 277 patients admitted to an acute psychiatric inpatient department. The degree of increased or decreased motor activity was clinically assessed at admission. Serum concentrations of the following immune markers were measured: interleukin (IL) -1β, IL-4, IL-6, IL-10, tumor necrosis factor (TNF) -α, interferon (IFN) -γ, and transforming growth factor (TGF) -β. Results: Scores of increased motor activity were negatively correlated with IFN-γ (rho = -0.128, p = 0.033) in an acute psychiatric population. There was also a trend towards an association between motor activity and TGF-β (rho = 0.118, p = 0.050). In a multiple-linear-regression model correcting for age, gender, and body-mass index (BMI, kg/m²), the association did not remain significant. No significant correlations between motor retardation and circulating cytokines were found. Conclusions: After adjustment for potential confounders our study did not reveal any significant association between cytokines and motor activity. However, there is an indication of increased Th17 and decreased Th1 responses in relation to increased motor activity in line with the few previous reports in the field. The phenomenon however needs further exploration.

Altered Slc25 family gene expression as markers of mitochondrial dysfunction in brain regions under experimental mixed anxiety/depression-like disorder

BACKGROUND

Development of anxiety- and depression-like states under chronic social defeat stress in mice has been shown by many experimental studies. In this article, the differentially expressed Slc25* family genes encoding mitochondrial carrier proteins were analyzed in the brain of depressive (defeated) mice versus aggressive mice winning in everyday social confrontations. The collected samples of brain regions were sequenced at JSC Genoanalytica ( http://genoanalytica.ru/ , Moscow, Russia).

RESULTS

Changes in the expression of the 20 Slc25* genes in the male mice were brain region- and social experience (positive or negative)-specific. In particular, most Slc25* genes were up-regulated in the hypothalamus of defeated and aggressive mice and in the hippocampus of defeated mice. In the striatum of defeated mice and in the ventral tegmental area of aggressive mice expression of mitochondrial transporter genes changed specifically. Significant correlations between expression of most Slc25* genes and mitochondrial Mrps and Mrpl genes were found in the brain regions.

CONCLUSION

Altered expression of the Slc25* genes may serve as a marker of mitochondrial dysfunction in brain, which accompanies the development of many neurological and psychoemotional disorders.

Microglial markers in the frontal cortex are related to cognitive dysfunctions in major depressive disorder

BACKGROUND

Evidence suggests that microglia-mediated processes are implicated in the pathophysiology of major depressive disorder (MDD). The relationship between these processes and cognitive dysfunctions has not been explored.

METHODS

We recruited 50 never-medicated patients with MDD and 30 healthy control subjects. We used [¹⁸F]-FEPPA positron emission tomography (PET) to examine translocator protein total distribution volume (TSPO V_T), a marker of microglia. Cognitive functions were evaluated with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) (attention, immediate and delyed memory, language, and visuospatial functions).

RESULTS

Patients with MDD showed elevated TSPO V_T in all regions of interest (white matter, grey matter, frontal cortex, temporal cortex, and hippocampus) and were impaired on the attention and delayed memory domains of the RBANS. In the frontal cortex, increased TSPO V_T was associated with lower scores on the RBANS attention domain when the analysis was corrected for age, gender, education, and depressive symptoms.

LIMITATIONS

Affective functions were not investigated, the specificity of [¹⁸F]-FEPPA binding is limited, TSPO may reflect microglia/macrophage density rather than activation, and the sample was not balanced (more patients were included than controls).

CONCLUSIONS

Attentional dysfunctions may be associated with microglial pathology in the frontal cortex of untreated patients with MDD.

Chronic pain, depression and cognitive impairment: a close relationship

Over a half of chronic pain (CP) patients present with cognitive complaints, which increase their disability and impact quality of life. The paper reviews objective impairments in memory, attention, processing speed and executive function demonstrated in the CP population. The paper also reviews common pathology underlying cognitive impairment and CP: neuroplasticity in the shared brain areas, neurotransmitter and other molecular mechanisms. Common mechanisms in CP and depression precipitating cognitive impairment are also discussed. The paper also compares the potential of different antidepressants to improve cognitive functions in depression and CP.

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.

Prefrontal cortex executive processes affected by stress in health and disease

Prefrontal cortical executive functions comprise a number of cognitive capabilities necessary for goal directed behavior and adaptation to a changing environment. Executive dysfunction that leads to maladaptive behavior and is a symptom of psychiatric pathology can be instigated or exacerbated by stress. In this review we survey research addressing the impact of stress on executive function, with specific focus on working memory, attention, response inhibition, and cognitive flexibility. We then consider the neurochemical pathways underlying these cognitive capabilities and, where known, how stress alters them. Finally, we review work exploring potential pharmacological and non-pharmacological approaches that can ameliorate deficits in executive function. Both preclinical and clinical literature indicates that chronic stress negatively affects executive function. Although some of the circuitry and neurochemical processes underlying executive function have been characterized, a great deal is still unknown regarding how stress affects these processes. Additional work focusing on this question is needed in order to make progress on developing interventions that ameliorate executive dysfunction.

Increased Risk of Dementia in Patients with Antidepressants: A Meta-Analysis of Observational Studies

Antidepressants are the most commonly and widely used medication for its effectiveness in the treatment of anxiety and depression. A few epidemiological studies have documented that antidepressant is associated with increased risk of dementia so far. Here, our aim is to assess the association between antidepressant use and risk of dementia in elderly patients. We searched articles through MEDLINE, EMBASE, Google, and Google Scholar from inception to December 1, 2017, that reported on the association between antidepressant use and dementia risk. Data were collected from each study independently, and study duplication was checked by at least three senior researchers based on a standardized protocol. Summary relative risk (RR) with 95% CI was calculated by using a random-effects model. We selected 9 out of 754 unique abstracts for full-text review using our predetermined selection criteria, and 5 out of these 9 studies, comprising 53,955 participants, met all of our inclusion criteria. The overall pooled RR of dementia was 1.75 (95% CI: 1.033–2.964) for SSRIs whereas the overall pooled RR of dementia was 2.131 (95% CI: 1.427–3.184) for tricyclic use. Also, MAOIs showed a high rate of increase with significant heterogeneity. Our findings indicate that antidepressant use is significantly associated with an increased risk of developing dementia. Therefore, we suggest physicians to carefully prescribe antidepressants, especially in elder patients. Additionally, treatment should be stopped if any symptoms related to dementia are to be noticed.

Prospective Epidemiological Research on Functioning Outcomes Related to Major Depressive Disorder in Japan (PERFORM-J): Protocol for a Prospective Cohort Study

Background

Patients with major depressive disorder may exhibit cognitive dysfunction that can affect functional outcomes. However, the prevalence and burden of cognitive dysfunction in Japanese patients with MDD have not been thoroughly examined.

Objective

To investigate the time course (over 6 months) of several functional outcomes during treatment with antidepressants in Japanese patients with major depressive disorder. The primary objective is to assess longitudinal changes in cognitive function and depressive symptoms, using both clinician-rated and patient-rated scales. The study incorporates assessments of cognitive function and other functional outcomes (functional capacity, disability, work productivity and impairments of activity, and quality of life), as well as depressive symptoms.

Methods

PERFORM-J (Prospective Epidemiological Research on Functioning Outcomes Related to Major Depressive Disorder in Japan) is a 6-month, prospective, multi-center, epidemiological cohort study. Participants are Japanese outpatients aged 18-65 years with a recurrent or new diagnosis of a major depressive episode (according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision [DSM-IV-TR]), who are initiating a new antidepressant as monotherapy (either as first-line therapy or after switching from a previous antidepressant). Eligible patients are evaluated objectively during four visits (at baseline and at Months 1, 2, and 6) using physician-rated assessments of severity of depressive symptoms, cognitive function, and functional capacity. Subjective, patient-reported, outcomes are also assessed as indicators of depressive symptoms, disability, work productivity or impairments of activity, and perceived cognitive dysfunction.

Results

The study began in September 2016. Patient enrollment was completed on June 30, 2017, with 523 patients having been enrolled from 48 study sites. As of October, 2017, 279 patients had completed the study.

Conclusions

PERFORM-J is expected to provide valuable information on the longitudinal relationship between cognitive dysfunction, depressive symptoms, and other functional outcomes in Japanese patients with major depressive disorder who initiate monotherapy with antidepressants.

Trial Registration

UMIN Clinical Trials Registry UMIN000024320; https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi? recptno=R000028011 (Archived by WebCite at http://www.webcitation.org/70K7W9PgC).

Registered Report Identifier

RR1-10.2196/9682

The Endoplasmic Reticulum Stress Response in Neuroprogressive Diseases: Emerging Pathophysiological Role and Translational Implications

The endoplasmic reticulum (ER) is the main cellular organelle involved in protein synthesis, assembly and secretion. Accumulating evidence shows that across several neurodegenerative and neuroprogressive diseases, ER stress ensues, which is accompanied by over-activation of the unfolded protein response (UPR). Although the UPR could initially serve adaptive purposes in conditions associated with higher cellular demands and after exposure to a range of pathophysiological insults, over time the UPR may become detrimental, thus contributing to neuroprogression. Herein, we propose that immune-inflammatory, neuro-oxidative, neuro-nitrosative, as well as mitochondrial pathways may reciprocally interact with aberrations in UPR pathways. Furthermore, ER stress may contribute to a deregulation in calcium homoeostasis. The common denominator of these pathways is a decrease in neuronal resilience, synaptic dysfunction and even cell death. This review also discusses how mechanisms related to ER stress could be explored as a source for novel therapeutic targets for neurodegenerative and neuroprogressive diseases. The design of randomised controlled trials testing compounds that target aberrant UPR-related pathways within the emerging framework of precision psychiatry is warranted.

Recognition and Treatment of Cognitive Dysfunction in Major Depressive Disorder

Major Depressive Disorder (MDD) is a prevalent, chronic, disabling, and multidimensional mental disorder. Cognitive dysfunction represents a core diagnostic and symptomatic criterion of MDD, and is a principal determinant of functional non-recovery. Cognitive impairment has been observed to persist despite remission of mood symptoms, suggesting dissociability of mood and cognitive symptoms in MDD. Recurrent impairments in several domains including, but not limited to, executive function, learning and memory, processing speed, and attention and concentration, are associated with poor psychosocial and occupational outcomes. Attempts to restore premorbid functioning in individuals with MDD requires regular screenings and assessment of objective and subjective measures of cognition by clinicians. Easily accessible and cost-effective tools such as the THINC-integrated tool (THINC-it) are suitable for use in a busy clinical environment and appear to be promising for routine usage in clinical settings. However, antidepressant treatments targeting specific cognitive domains in MDD have been insufficiently studied. While select antidepressants, e.g., vortioxetine, have been demonstrated to have direct and independent pro-cognitive effects in adults with MDD, research on additional agents remains nascent. A comprehensive clinical approach to cognitive impairments in MDD is required. The current narrative review aims to delineate the importance and relevance of cognitive dysfunction as a symptomatic target for prevention and treatment in the phenomenology of MDD.

Disturbance in Plasma Metabolic Profile in Different Types of Human Cytomegalovirus-Induced Liver Injury in Infants

Human cytomegalovirus (HCMV) infection in infants is a global problem and the liver is a target organ of HCMV invasion. However, the mechanism by which HCMV causes different types of liver injury is unclear, and there are many difficulties in the differential diagnosis of HCMV infantile cholestatic hepatopathy (ICH) and extrahepatic biliary atresia (EHBA). We established a non-targeted gas chromatography-mass spectrometry metabolomics method in conjunction with orthogonal partial least squares-discriminate analysis based on 127 plasma samples from healthy controls, and patients with HCMV infantile hepatitis, HCMV ICH, and HCMV EHBA to explore the metabolite profile of different types of HCMV-induced liver injury. Twenty-nine metabolites related to multiple amino acid metabolism disorder, nitrogen metabolism and energy metabolism were identified. Carbamic acid, glutamate, L-aspartic acid, L-homoserine, and noradrenaline for HCMV ICH vs. HCMV EHBA were screened as potential biomarkers and showed excellent discriminant performance. These results not only revealed the potential pathogenesis of HCMV-induced liver injury, but also provided a feasible diagnostic tool for distinguishing EHBA from ICH.

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

BACKGROUND

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

METHOD

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

RESULTS

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

LIMITATIONS

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

CONCLUSION

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

Systematic review and meta-analysis of the efficacy and safety of minocycline in schizophrenia

OBJECTIVE

Our aim was to perform an updated systematic review and meta-analysis on the efficacy and safety of adjunctive minocycline as a treatment of schizophrenia.

METHODS

We conducted a PubMed/Scopus database search from inception to 3 February 2016 for randomized, placebo-controlled trials (RCTs), open non-randomized studies, and case reports/series evaluating minocycline in patients with schizophrenia. Random-effects meta-analysis of positive, negative, depressive, and cognitive symptom rating scales, discontinuation and adverse effects rates calculating standardized mean difference (SMD), and risk ratios±95% confidence intervals (CI 95%) were calculated.

RESULTS

Six RCTs were eligible (minocycline n=215, placebo n=198) that demonstrated minocycline's superiority versus placebo for reducing endpoint Positive and Negative Syndrome Scale (PANSS) total scores (SMD=-0.59; CI 95%=[1.15, -0.03]; p=0.04), negative (SMD=-0.76; CI 95%=[-1.21, -0.31]; p=0.001); general subscale scores (SMD=-0.44; CI 95%=[-0.88, -0.00]; p=0.05), Clinical Global Impressions scores (SMD=-0.50; CI 95%=[-0.78, -0.22]; p<0.001); and executive functioning (SMD=0.22; CI 95%=[0.01, 0.44]; p=0.04). Endpoint PANSS positive symptom scores (p=0.13), depression rating scale scores (p=0.43), attention (p=0.47), memory (p=0.52), and motor speed processing (p=0.50) did not significantly differ from placebo, before execution of a trim-and-fill procedure. Minocycline did not differ compared to placebo on all-cause discontinuation (p=0.56), discontinuation due to inefficacy (p=0.99), and intolerability (p=0.51), and due to death (p=0.32). Data from one open-label study (N=22) and three case series (N=6) were consistent with the metaanalytic results.

CONCLUSIONS

Minocycline appears to be an effective adjunctive treatment option in schizophrenia, improving multiple relevant disease dimensions. Moreover, minocycline has an acceptable safety and tolerability profile. However, more methodologically sound and larger RCTs remain necessary to confirm and extend these results.

Antidepressants and risk of dementia in migraine patients: A population-based case-control study

To ascertain the relationship between receipt of antidepressant agents and the risk of subsequent dementia in migraine patients. A population-based case-control analysis, using the Taiwan National Health Insurance Research Database. We identified 1774 patients with dementia and 1774 matched nondementia controls from migraine patients enrolled in the Taiwan National Health Insurance program between 2005 and 2011. The proportional distributions of exposure to three classes of antidepressant were compared between dementia and nondementia groups. Univariable and multivariable logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of dementia based on antidepressant exposure. The proportions of subjects taking tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and new-generation antidepressants (NGAs) in dementia versus nondementia groups are 52.3 vs 51.2%, 25.5 vs 30.7%, and 18.8 vs 6.26%, respectively. The adjusted ORs of dementia were 1.02 (95% CI=0.89, 1.17; P=0.56) for TCAs, 0.58 (95% CI=0.50, 0.69; P<0.001) for SSRIs, and 4.23 (95% CI=3.34, 5.37; P<0.001) for NGAs. Treatment with SSRIs was associated with a decreased risk of dementia in migraine patients. TCAs showed no association with dementia risk, and NGAs showed increased risk. Given the possibility of confounding by indication, additional prospective trials and basic research are needed before drawing conclusions about the population-level risks for dementia onset conferred by antidepressant medications.

HBK-14 and HBK-15 with antidepressant-like and/or memory-enhancing properties increase serotonin levels in the hippocampus after chronic treatment in mice

5-HT_1A and 5-HT₇ receptor ligands might have antidepressant-like properties and improve cognitive function. We previously reported significant antidepressant- and anxiolytic-like effects of two dual 5-HT_1A and 5-HT₇ receptor antagonists in various behavioral tests in rodents. As a continuation of our previous experiments, in this study we aimed to investigate whether chronic administration of 1-[(2,6-dimethylphenoxy)ethoxyethyl]-4-(2-methoxyphenyl)piperazine hydrochloride (HBK-14) and 1-[(2-chloro-6-methylphenoxy)ethoxyethyl]-4-(2-methoxyphenyl)piperazine hydrochloride (HBK-15) caused antidepressant-like effects and elevated serotonin levels in the murine hippocampus. We also evaluated cholinolytic properties and the influence of acute administration of both compounds on cognitive function in mice. To assess antidepressant-like properties and the influence on learning and memory we used forced swim test and step-through passive avoidance task in mice, respectively. Both compounds showed antidepressant-like properties and significantly elevated serotonin levels in the hippocampus after chronic treatment (HBK-14 - 2.5 mg/kg; HBK-15 - 0.625 and 1.25 mg/kg). HBK-15 administered chronically antidepressant-like activity at lower dose (0.625 mg/kg) than the dose active after acute treatment (1.25 mg/kg). None of the compounds affected locomotor activity of mice. HBK-15 possessed very weak cholinolytic properties, whereas HBK-14 did not show any effect on muscarinic receptors. Only HBK-15 (0.625 mg/kg) presented memory-enhancing properties and ameliorated cognitive impairments caused by scopolamine (1 mg/kg). Our results indicate that 5-HT_1A and 5-HT₇ antagonists might have potential in the treatment of depression and possess positive influence on cognitive function.

Insulin-like growth factor-1: a possible marker for emotional and cognitive disturbances, and treatment effectiveness in major depressive disorder

Depression and cognitive dysfunction share a common neuropathological platform. Abnormal neural plasticity in the frontolimbic circuits has been linked to changes in the expression of neurotrophic factors, including IGF-1. These changes may result in clinical abnormalities observed over the course of major depressive disorder (MDD), including cognitive dysfunction. The present review aimed to summarize evidence regarding abnormalities of peripheral IGF-1 in MDD patients and assess a marker and predictive role of the neurotrophin for emotional and cognitive disturbances, and treatment effectiveness. A literature search of the PubMed database was conducted for studies, in which peripheral IGF-1 levels were evaluated. Our analysis revealed four main findings: (1) IGF-1 levels in MDD patients mismatch across the studies, which may arise from various factors, e.g., age, gender, the course of the disease, presence of cognitive impairment, ongoing therapy, or general health conditions; (2) the initial peripheral IGF-1 levels may predict the occurrence of depression in future; (3) peripheral IGF-1 levels may reflect cognitive dysfunction, although the data is limited; (4) it is difficult to evaluate the influence of treatment on IGF-1 levels as there is discrepancy of this growth factor among the studies at baseline, although most of them showed a decrease in IGF-1 levels after treatment.

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.