Cognitive dysfunction in depression: neurocircuitry and new therapeutic strategies

Trajectories of Purpose in Life Across Diagnosis of Alzheimer's Disease or Related Dementias in Older Adulthood

Objectives: Sense of purpose serves as a psychological resource for late-life health. Limited research has examined how purpose changes across chronic illness diagnoses, including a diagnosis of Alzheimer's disease and related dementias (ADRD).Method: This study leverages data from the National Health and Aging Trends Study (NHATS; N = 831) to establish trajectories of purpose across ADRD diagnosis using three-year (pre-diagnosis, year of diagnosis, post-diagnosis) timespans and two comparison groups (heart disease diagnosis, no diagnosis). Results: We observed a longitudinal decrease in purpose in the ADRD diagnosis group, t = 3.85, p = .003, d = -0.258. This contrasts with heart disease diagnosis and no diagnosis groups, where purpose did not change over time. Discussion: Older adults who receive an ADRD diagnosis may be vulnerable to a decreasing sense of purpose across their diagnosis experience. We consider social, psychological, and clinical antecedents for this trend.

MM165 - A Small Hybrid Molecule Modulates the Kynurenine Pathway and Attenuates Lipopolysaccharide-Induced Memory Deficits and Inflammation

Cognitive dysfunctions are now recognized as core symptoms of various psychiatric disorders e.g., major depressive disorder. Sustained immune activation may leads to cognitive dysfunctions. Proinflammatory cytokines shunt the metabolism of tryptophan towards kynurenine and quinolinic acid may accumulate at toxic concentrations. This acid triggers an increase in neuronal nitric oxide synthase function and promotes oxidative stress. The searching for small molecules that can regulate tryptophan metabolites produced in the kynurenic pathway has become an important goal in developing treatments for various central nervous system diseases with an inflammatory component. Previously we have identified a small hybrid molecule - MM165 which significantly reduces depressive-like symptoms caused by inflammation induced by lipopolysaccharide administration. In the present study, we investigated whether this compound would mitigate cognitive deficits induced by lipopolysaccharide administration and whether treatment with it would affect the plasma or brain levels of quinolinic acid and kynurenic acid. Neuroinflammation was induced in rats by administering lipopolysaccharide at a dose of 0.5 mg/kg body weight for 10 days. We conducted two tests: novel object recognition and object location, to assess the effect on memory impairment in animals previously treated with lipopolysaccharide. In plasma collected from rats, the concentrations of C-reactive protein and tumor necrosis factor alfa were determined. The concentrations of kynurenic acid and quinolinic acid were determined in plasma and homogenates obtained from the cerebral cortex of rats. Interleukin 6 in the cerebral cortex of rats was determined. Additionally, the body and spleen mass and spontaneous activity were measured in rats. Our study shows that MM165 may mitigate cognitive deficits induced by inflammation after administration of lipopolysaccharide and alter the concentrations of tryptophan metabolites in the brain. Compounds exhibiting a mechanism of action analogous to that of MM165 may serve as foundational structures for the development of a new class of antidepressants.

Efficacy and Safety of Antidiabetic Agents for Major Depressive Disorder and Bipolar Depression: A Meta-Analysis of Randomized, Double-Blind, Placebo-Controlled Trials

BACKGROUND

This meta-analysis aimed to determine the efficacy and safety of antidiabetic agents in the treatment of major depressive disorder and bipolar depression.

METHODS

Randomized controlled trials (RCTs) of antidiabetic agents in major depressive disorder or bipolar depression were searched in three electronic databases and three clinical trial registry websites from their inception up to October 2023. The differences in changes in the depression rating scale scores from baseline to endpoint or pre-defined sessions, response rate, remission rate, rate of side effects and dropout rate between antidiabetic agents and placebo were meta-analyzed.

RESULTS

Six RCTs involving 399 participants were included in the final meta-analysis, which did not find that antidiabetics outperformed the placebo in reducing depressive symptoms. The standardized mean difference (SMD) in the depression scores from baseline to endpoint was 0.25 (95% CI -0.1, 0.61). However, a subgroup analysis found a significant difference between antidiabetics and placebos in reducing depressive symptoms in Middle Eastern populations, with an SMD of 0.89 (95% CI 0.44, 1.34).

CONCLUSIONS

The current meta-analysis does not support the efficacy of antidiabetics being superior to the placebo in the treatment of unipolar and bipolar depression. However, a subgroup analysis indicates that patients from the Middle East may benefit from adding an antidiabetic medication to their ongoing medication(s) for their depression. Larger studies with good-quality study designs are warranted.

Indoor air pollution and cognitive function among older adults in India: a multiple mediation approach through depression and sleep disorders

BACKGROUND

Studies across multiple countries reveal that depression and sleep disorders can lead to cognitive decline. This study aims to speculate on the effect of different sources of indoor air pollution on cognition and to explore the mediation effect of depression and sleep disorders on cognition when exposed to indoor air pollution. We hypothesize that an older adult experiences higher cognitive decline from indoor pollution when mediated by depression and sleep disorders.

METHODS

We use data from Longitudinal Aging Study in India (LASI), 2017-2018, and employ a multiple mediation model to understand the relationship between indoor air pollution and cognition through sleep disorders and depression while adjusting for possible confounders. Sensitivity analysis was applied to see the effect of different sources of indoor pollution (cooking fuel, indoor smoke products, and secondhand smoke) on cognitive performance.

RESULTS

The effect of three sources of indoor pollutants on cognition increased when combined, indicating stronger cognitive decline. Unclean cooking practices, indoor smoke (from incense sticks and mosquito coils), and secondhand smoke were strongly associated with sleep disorders and depression among older adults. Indoor air pollution was negatively associated with cognitive health (β= -0.38) while positively associated with depression (β= 0.18) and sleep disorders (β= 0.038) acting as mediators. Sensitivity analysis explained 45% variability while adjusting for confounders.

CONCLUSION

The study lays a foundation for future investigations into the nexus of indoor pollution and mental health. It is essential to formulate policies to reduce exposure to varying sources of indoor air pollutants and improve screening for mental health services as a public health priority.

Adult Neurogenesis, Context Encoding, and Pattern Separation: A Pathway for Treating Overgeneralization

In mammals, the subgranular zone of the dentate gyrus is one of two brain regions (with the subventricular zone of the olfactory bulb) that continues to generate new neurons throughout adulthood, a phenomenon known as adult hippocampal neurogenesis (AHN) (Eriksson et al., Nat Med 4:1313-1317, 1998; García-Verdugo et al., J Neurobiol 36:234-248, 1998). The integration of these new neurons into the dentate gyrus (DG) has implications for memory encoding, with unique firing and wiring properties of immature neurons that affect how the hippocampal network encodes and stores attributes of memory. In this chapter, we will describe the process of AHN and properties of adult-born cells as they integrate into the hippocampal circuit and mature. Then, we will discuss some methodological considerations before we review evidence for the role of AHN in two major processes supporting memory that are performed by the DG. First, we will discuss encoding of contextual information for episodic memories and how this is facilitated by AHN. Second, will discuss pattern separation, a major role of the DG that reduces interference for the formation of new memories. Finally, we will review clinical and translational considerations, suggesting that stimulation of AHN may help decrease overgeneralization-a common endophenotype of mood, anxiety, trauma-related, and age-related disorders.

Restorative effect of NitroSynapsin on synaptic plasticity in an animal model of depression

In the search for new options for the pharmacological treatment of major depressive disorder, compounds with a rapid onset of action and high efficacy but lacking a psychotomimetic effect are of particular interest. In the present study, we evaluated the antidepressant potential of NitroSynapsin (NS) at behavioural, structural, and functional levels. NS is a memantine derivative and a dual allosteric N-methyl-d-aspartate receptors (NMDAR) antagonist using targeted delivery by the aminoadamantane of a warhead nitro group to inhibitory redox sites on the NMDAR. In a chronic restraint stress (CRS) mouse model of depression, five doses of NS administered on three consecutive days evoked antidepressant-like activity in the chronically stressed male C57BL/6J mice, reversing CRS-induced behavioural disturbances in sucrose preference and tail suspension tests. CRS-induced changes in morphology and density of dendritic spines in cerebrocortical neurons in the medial prefrontal cortex (mPFC) were also reversed by NS. Moreover, CRS-induced reduction in long-term potentiation (LTP) in the mPFC was found to be prevented by NS based on the electrophysiological recordings. Our study showed that NS restores structural and functional synaptic plasticity and reduces depressive behaviour to the level found in naïve animals. These results preliminarily revealed an antidepressant-like potency of NS.

Psilocybin as a lead candidate molecule in preclinical therapeutic studies of psychiatric disorders: A systematic review

Psilocybin is the main psychoactive compound found in hallucinogenic/magic mushrooms and can bind to both serotonergic and tropomyosin receptor kinase b (TrkB) receptors. Psilocybin has begun to show efficacy for a range of neuropsychiatric conditions, including treatment-resistant depression and anxiety disorders; however, neurobiological mechanisms are still being elucidated. Clinical research has found that psilocybin can alter functional connectivity patterns in human brains, which is often associated with therapeutic outcomes. However, preclinical research affords the opportunity to assess the potential cellular mechanisms by which psilocybin may exert its therapeutic effects. Preclinical rodent models can also facilitate a more tightly controlled experimental context and minimise placebo effects. Furthermore, where there is a rationale, preclinical researchers can investigate psilocybin administration in neuropsychiatric conditions that have not yet been researched clinically. As a result, we have systematically reviewed the knowledge base, identifying 82 preclinical studies which were screened based on specific criteria. This resulted in the exclusion of 44 articles, with 34 articles being included in the main review and another 2 articles included as Supporting Information materials. We found that psilocybin shows promise as a lead candidate molecule for treating a variety of neuropsychiatric conditions, albeit showing the most efficacy for depression. We discuss the experimental findings, and identify possible mechanisms whereby psilocybin could invoke therapeutic changes. Furthermore, we critically evaluate the between-study heterogeneity and possible future research avenues. Our review suggests that preclinical rodent models can provide valid and translatable tools for researching novel psilocybin-induced molecular and cellular mechanisms, and therapeutic outcomes.

Strain-level structure of gut microbiome showed potential association with cognitive function in major depressive disorder: A pilot study

BACKGROUND

Although the association between gut microbiota and the pathogenesis of major depressive disorder (MDD) has been well studied, it is unclear whether gut microbiota affects cognitive function in patients with MDD. In this study, we explored the association between gut microbiota and cognitive function in MDD and its possible mechanisms.

METHODS

We enrolled 57 patients with MDD and 30 healthy controls (HCs) and used 16S rRNA gene sequencing analysis and shotgun metagenomic sequencing analysis to determine gut microbial composition.

RESULTS

The richness and diversity of gut microbiota in patients with MDD were the same as those in HCs, but there were differences in the abundance of Bifidobacterium and Blautia. Compared with HCs, two strains (bin_32 and bin_55) were significantly increased, and one strain (bin_31) was significantly decreased in patients with MDD based on the strain-level meta-analysis. Time to complete the Stroop-C had significant negative correlations with bin_31 and bin_32. Bin_55 had significant negative correlations with time to complete the Stroop-C, time to complete the Stroop-CW, and repeated animal words in 60 s but significant positive correlations with correct answers in 120 s on the Stroop-CW.

LIMITATIONS

This study only tested the cognitive function of MDD in a small sample, which may have caused some bias.

CONCLUSIONS

Based on our strain-level analysis, we found that gut microbiota may be associated with the pathogenesis of MDD and may have potential effects on cognitive function.

Ventral Hippocampal Input to Infralimbic Cortex Is Necessary for the Therapeutic-Like Effects of Extinction in Stressed Rats

BACKGROUND

Posttraumatic stress disorder is characterized by deficits in cognitive flexibility related to dysfunction of the medial prefrontal cortex (mPFC). Exposure therapy can effectively reverse these deficits. Fear extinction in rodents bears similarity to exposure therapy. Extinction reverses chronic stress-induced deficits in cognitive flexibility on the attentional set-shifting test (AST), an mPFC-mediated process. This therapeutic effect requires activity of pyramidal neurons and brain derived neurotrophic factor (BDNF) signaling in infralimbic cortex (IL). However, the circuit mechanisms governing BDNF-mediated plasticity initiated by extinction in IL are unknown. The ventral hippocampus (vHipp) plays a role in regulating IL activity during extinction, and plasticity in vHipp is necessary for extinction memory consolidation. Therefore, we investigated the role of vHipp input to IL in the effects of extinction in reversing stress-induced cognitive deficits.

METHODS

vHipp input to IL was silenced using a Gi-Designer Receptors Exclusively Activated by Designer Drugs (DREADD) via local infusion of clozapine-N-oxide (CNO) into IL before extinction. A day later, rats were tested on AST. In a separate experiment, we tested whether vHipp input to the IL induces BDNF signaling to exert therapeutic effects. We activated the vHipp using a Gq-DREADD, and injected an anti-BDNF neutralizing antibody into IL. Rats were tested on the AST 24 hours later.

RESULTS

Silencing the vHipp input to IL prevented the beneficial effects of extinction in reversing stress-induced cognitive deficits. Activating vHipp input to IL in the absence of extinction was sufficient to reverse stress-induced deficits in set-shifting. The beneficial effects were blocked by local infusion of a neutralizing anti-BDNF antibody into IL.

CONCLUSIONS

vHipp-driven BDNF signaling in IL is critical for extinction to counteract the deleterious cognitive effects of chronic stress.

Linkage of premature and early menopause with psychosocial well-being: a moderated multiple mediation approach

PURPOSE

Menopause occurring before the age of 40 is premature and between 40 and 44 years age is early, since the natural age of menopause lies between 45 and 50. The endocrine changes that come with menopause include an erratic decline in estrogen levels which affects the brain. Thus, leading to changes in cognitive function in the longer term due to the menopausal transition. The study aims to explore the effect of premature and early menopause on cognitive health, and psychosocial well-being. The moderated multiple mediation hypothesis of the study is that the effect of premature or early menopause is mediated by depression and insomnia, while all the pathways are moderated by smoking habits.

DATA AND METHODS

The study utilized Longitudinal Aging Study in India (LASI), 2017-2018, Wave 1 data. The sample of 31,435 women were aged 45 and above and did not undergo hysterectomy. A moderated multiple mediation model was used to understand the association between premature or early menopause (X), insomnia (M1), depression (M2), moderator (W), and cognitive health (Y), while controlling for possible confounders.

RESULTS

Premature menopause was negatively associated with cognition (β:-0.33; SE:0.12; p < 0.05), whereas positively associated with insomnia (β:0.18; SE:0.03; p < 0.001) and depression (β:0.25; SE:0.04; p < 0.001). There is a moderating effect of smoking or tobacco consumption has a significant moderating effect on the pathways among premature menopause, depression, insomnia and cognition. When the same model was carried out for early menopause (40-44 years), the results were not significant.

CONCLUSIONS

The findings emphasize the fact that smoking is associated with premature menopause, depression and insomnia. Women who experienced premature menopause has lower cognitive scores, depressive symptoms and insomnia symptoms, which were higher among those who consumed tobacco. The study, strongly recommends the dissemination of information on the negative effects of tobacco consumption and making more informed choices to maintain a healthy life. More research into various methods and therapy is needed to determine the relationship between the age of early menopause and their psychosocial well-being.

Delirium, depression, and long-term cognition

OBJECTIVES

We examined whether preadmission history of depression is associated with less delirium/coma-free (DCF) days, worse 1-year depression severity and cognitive impairment.

DESIGN AND MEASUREMENTS

A health proxy reported history of depression. Separate models examined the effect of preadmission history of depression on: (a) intensive care unit (ICU) course, measured as DCF days; (b) depression symptom severity at 3 and 12 months, measured by the Beck Depression Inventory-II (BDI-II); and (c) cognitive performance at 3 and 12 months, measured by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) global score.

SETTING AND PARTICIPANTS

Patients admitted to the medical/surgical ICU services were eligible.

RESULTS

Of 821 subjects eligible at enrollment, 261 (33%) had preadmission history of depression. After adjusting for covariates, preadmission history of depression was not associated with less DCF days (OR 0.78, 95% CI, 0.59-1.03 p = 0.077). A prior history of depression was associated with higher BDI-II scores at 3 and 12 months (3 months OR 2.15, 95% CI, 1.42-3.24 p = <0.001; 12 months OR 1.89, 95% CI, 1.24-2.87 p = 0.003). We did not observe an association between preadmission history of depression and cognitive performance at either 3 or 12 months (3 months beta coefficient -0.04, 95% CI, -2.70-2.62 p = 0.97; 12 months 1.5, 95% CI, -1.26-4.26 p = 0.28).

CONCLUSION

Patients with a depression history prior to ICU stay exhibit a greater severity of depressive symptoms in the year after hospitalization.

Psychiatric symptoms and intentions to quit smoking: How regularity and volume of cigarette consumption moderate the relationship

INTRODUCTION

Smoking prevalence is disproportionately higher in those with psychiatric symptoms. Smokers with psychiatric symptoms are less likely to have an intention to quit smoking and attain eventual smoking abstinence. This study presents the relationship between depressive/anxiety symptoms and the intention to quit smoking and related influencing factors.

METHODS

A cross-sectional study recruited 931 current smoking individuals covering two provinces in China in July 2022. The online survey comprised questions concerning sociodemographic characteristics, smoking conditions and psychiatric symptoms. Chi-squared analyses and moderation analyses were applied.

RESULTS

The proportion of smokers who had the intention to quit smoking within six months was 46.1%. In comparison with subjects without depressive/anxiety symptoms, individuals who had both psychiatric symptoms were less likely to have the intention to quit smoking (39.3% vs 49.8%, χ²=9.130, p=0.028). As for the moderating model of depression, the interaction term of depressive symptoms and smoking regularly was significant (β=0.554, t=3.260, p=0.001). For those who were occasional smokers, depressive symptoms significantly lowered their quitting intentions. The regularity of smoking similarly moderated the effect of anxiety symptoms on quitting intentions. When the number of cigarettes used weekly served as the moderator, the interaction of this number and depressive symptoms was significant, as well as for anxiety (p<0.001), indicating that the volume of cigarette consumption moderated the relationship between depressive/anxiety symptoms and intention to quit smoking.

CONCLUSIONS

Psychiatric symptoms were significant factors in reducing the willingness of smokers to quit smoking, and the effects were moderated by smokers' cigarette consumption conditions. Interventions are urged to enhance quitting intentions of these vulnerable smokers.

Allergen induces depression-like behavior in association with altered prefrontal-hippocampal circuit in male rats

Allergic asthma is a common chronic inflammatory condition associated with psychiatric comorbidities. Notably depression, correlated with adverse outcomes in asthmatic patients. Peripheral inflammation's role in depression has been shown previously. However, evidence regarding the effects of allergic asthma on the medial prefrontal cortex (mPFC)-ventral hippocampus (vHipp) interactions, an important neurocircuitry in affective regulation, is yet to be demonstrated. Herein, we investigated the effects of allergen exposure in sensitized rats on the immunoreactivity of glial cells, depression-like behavior, brain regions volume, as well as activity and connectivity of the mPFC-vHipp circuit. We found that allergen-induced depressive-like behavior was associated with more activated microglia and astrocytes in mPFC and vHipp, as well as reduced hippocampus volume. Intriguingly, depressive-like behavior was negatively correlated with mPFC and hippocampus volumes in the allergen-exposed group. Moreover, mPFC and vHipp activity were altered in asthmatic animals. Allergen disrupted the strength and direction of functional connectivity in the mPFC-vHipp circuit so that, unlike normal conditions, mPFC causes and modulates vHipp activity. Our results provide new insight into the underlying mechanism of allergic inflammation-induced psychiatric disorders, aiming to develop new interventions and therapeutic approaches for improving asthma complications.

Familial risk for depression is associated with reduced P300 and late positive potential to affective stimuli and prolonged cardiac deceleration to unpleasant stimuli

Despite evidence of abnormal affective processing as a key correlate of depression, specific attentional mechanisms underlying processing of emotions in familial risk for depression have yet to be investigated in a single study. To this end, the amplitude of the P300 and late positive potential (LPP) complex and cardiac deceleration were assessed during the passive viewing of affective pictures in 32 individuals who had family history of depression (without depressive symptoms) and in 30 controls (without depressive symptoms and family history of depression). Individuals with familial risk for depression revealed reduced P300-LPP amplitudes in response to pleasant and unpleasant stimuli relative to controls, and comparable P300-LPP amplitudes in response to pleasant and neutral stimuli. Controls, but not individuals with familial risk for depression, reported cardiac deceleration during the viewing of pleasant vs. neutral and unpleasant stimuli in the 0-3 s time window. Also, only individuals with familial risk for depression showed a prolonged cardiac deceleration in response to unpleasant vs. neutral stimuli. Overall, the present study provides new insights into the characterization of emotion-related attentional processes in familial risk for depression as potential vulnerability factors for the development of the disorder.

Ketamine as a therapeutic agent in major depressive disorder and posttraumatic stress disorder: Potential medicinal and deleterious effects

Major depressive disorder (MDD) and posttraumatic stress disorder (PTSD) are the most common causes of emotional distress that impair an individual's quality of life. MDD is a chronic mental illness that affects 300 million people across the world. Clinical manifestations of MDD include fatigue, loss of interest in routine tasks, psychomotor agitation, impaired ability to focus, suicidal ideation, hypersomnolence, altered psychosocial functioning, and appetite loss. Individuals with depression also demonstrate a reduced behavioral response while experiencing pleasure, a symptom known as anhedonia. Like MDD, PTSD is a prevalent and debilitating psychiatric disorder resulting from a traumatic incident such as sexual assault, war, severe accident, or natural disaster. Symptoms such as recalling event phases, hypervigilance, irritability, and anhedonia are common in PTSD. Both MDD and PTSD pose enormous socioeconomic burdens across the globe. The search for effective treatment with minimal side effects is still ongoing. Ketamine is known for its anesthetic and analgesic properties. Psychedelic and psychotropic effects of ketamine have been found on the nervous system, which highlights its toxicity. In this article, the effectiveness of ketamine as a potential therapeutic for PTSD and MDD along with its mechanisms of action, clinical trials, and possible side effects have been discussed.

Linguistic Analysis for Identifying Depression and Subsequent Suicidal Ideation on Weibo: Machine Learning Approaches

Depression is one of the most common mental illnesses but remains underdiagnosed. Suicide, as a core symptom of depression, urgently needs to be monitored at an early stage, i.e., the suicidal ideation (SI) stage. Depression and subsequent suicidal ideation should be supervised on social media. In this research, we investigated depression and concomitant suicidal ideation by identifying individuals' linguistic characteristics through machine learning approaches. On Weibo, we sampled 487,251 posts from 3196 users from the depression super topic community (DSTC) as the depression group and 357,939 posts from 5167 active users on Weibo as the control group. The results of the logistic regression model showed that the SCLIWC (simplified Chinese version of LIWC) features such as affection, positive emotion, negative emotion, sadness, health, and death significantly predicted depression (Nagelkerke's R2 = 0.64). For model performance: F-measure = 0.78, area under the curve (AUC) = 0.82. The independent samples' t-test showed that SI was significantly different between the depression (0.28 ± 0.5) and control groups (-0.29 ± 0.72) (t = 24.71, p < 0.001). The results of the linear regression model showed that the SCLIWC features, such as social, family, affection, positive emotion, negative emotion, sadness, health, work, achieve, and death, significantly predicted suicidal ideation. The adjusted R2 was 0.42. For model performance, the correlation between the actual SI and predicted SI on the test set was significant (r = 0.65, p < 0.001). The topic modeling results were in accordance with the machine learning results. This study systematically investigated depression and subsequent SI-related linguistic characteristics based on a large-scale Weibo dataset. The findings suggest that analyzing the linguistic characteristics on online depression communities serves as an efficient approach to identify depression and subsequent suicidal ideation, assisting further prevention and intervention.

Cerebello-cerebral Functional Connectivity Networks in Major Depressive Disorder: a CAN-BIND-1 Study Report

Neuroimaging studies have demonstrated aberrant structure and function of the "cognitive-affective cerebellum" in major depressive disorder (MDD), although the specific role of the cerebello-cerebral circuitry in this population remains largely uninvestigated. The objective of this study was to delineate the role of cerebellar functional networks in depression. A total of 308 unmedicated participants completed resting-state functional magnetic resonance imaging scans, of which 247 (148 MDD; 99 healthy controls, HC) were suitable for this study. Seed-based resting-state functional connectivity (RsFc) analysis was performed using three cerebellar regions of interest (ROIs): ROI₁ corresponded to default mode network (DMN)/inattentive processing; ROI₂ corresponded to attentional networks, including frontoparietal, dorsal attention, and ventral attention; ROI₃ corresponded to motor processing. These ROIs were delineated based on prior functional gradient analyses of the cerebellum. A general linear model was used to perform within-group and between-group comparisons. In comparison to HC, participants with MDD displayed increased RsFc within the cerebello-cerebral DMN (ROI₁) and significantly elevated RsFc between the cerebellar ROI₁ and bilateral angular gyrus at a voxel threshold (p < 0.001, two-tailed) and at a cluster level (p < 0.05, FDR-corrected). Group differences were non-significant for ROI₂ and ROI₃. These results contribute to the development of a systems neuroscience approach to the diagnosis and treatment of MDD. Specifically, our findings confirm previously reported associations between MDD, DMN, and cerebellum, and highlight the promising role of these functional and anatomical locations for the development of novel imaging-based biomarkers and targets for neuromodulation therapies. ClinicalTrials.gov TRN: NCT01655706; Date of Registration: August 2nd, 2012.

Cognitive bias modification for adult's depression: A systematic review and meta-analysis

Objects

This study aimed to elucidate the effect of cognitive bias modification on depression.

Methods

This research included 10 randomized studies searching four major databases: PubMed, Embase, PsycINFO, and Cochrane Library, with a total sample size of 467. Moreover, they were examined for quality and possible publication bias.

Results

Cognitive bias modification (CBM) had statistically significant results, g = -0.64, 95% CI = [-0.97-0.32]. The interpretation of cognitive bias modification shows the highest effect size, g = -1.45, 95% CI = [-2.05-0.88]. When the training place is located in the laboratory, the training effect is significant, g = -1.11, 95% CI = [-1.62-0.61]. The difference is statistically significant when the training environment was changed to home, g = -0.28, 95% CI = [-0.51-0.05]. CBM has a statistical effect on moderate-to-severe depression, g = -0.70, 95% CI = [-1.04-0.36].

Conclusion

We found that CBM had a moderate therapeutic effect on depression, whether the setting was at home or in the lab. Especially when the interpretation of cognitive bias modification (CBM-I) was used, we got the highest effect value. Furthermore, CBM has a statistical effect on moderate-to-severe depression.

"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.

The relationship between psychological resilience, neuroticism, attentional bias, and depressive symptoms in college Chinese students

In recent years, the incidence of depressive symptoms among Chinese college students has been increasing. Studies have shown that depressive symptoms are related to a variety of psychosocial factors, among which neuroticism, resilience, and attention bias are most notably related, but the correlation among the three is not clear. This study aimed to investigate the influence mechanisms of different degrees of resilience, attentional bias, and neuroticism in the formation of depressive symptoms. The college freshmen of this study were selected through stratified multi-stage cluster sampling. Students provided informed consent and then completed a general situation questionnaire and four scales: the Chinese version of the Connor–Davidson Resilience Scale, the Attention to Positive and Negative Information Scale, the Eysenck Personality Questionnaire, and the Zung Self-Rating Depressive Symptoms Scale. In total, 1,493 freshmen participated in the research group. Our results showed that low resilience, negative attention bias, and high neuroticism jointly increased the risk of depressive symptoms. There is a significant correlation between these three factors and depressive symptoms. Additionally, strength, tenacity, and attention bias all had more significant effects on the occurrence of depressive symptoms. These findings indicate that there may be an important psychological mechanism for the occurrence, development, and poor prognosis of depressive symptoms.

Early indicators of vulnerability to depression: The role of rumination and heart rate variability

BACKGROUND

Despite the evidence of increased levels of rumination and reduced heart rate variability (HRV) in depression, whether these measures can be considered early indicators of vulnerability to depression has yet to be investigated. Therefore, the present study aimed to investigate both levels of rumination and resting HRV in individuals with familial risk for depression that is the most reliable risk factor for the disorder.

METHODS

Rumination and vagally-mediated HRV were assessed using the Ruminative Response Scale and a smartphone-based photoelectric volumetric pulse wave assay, respectively, in 25 individuals who had family history of depression (but did not report current depressive symptoms), 15 individuals who reported depressive symptoms (but had no family history of depression), and 25 controls (without depressive symptoms and family history of depression).

RESULTS

Individuals with depressive symptoms and those with a family history of depression were characterized by higher levels of rumination and lower cardiac vagal control than controls.

LIMITATIONS

Given the small sample size, this study should be used to design larger confirmatory studies; the cross-sectional nature of the study does not allow discussing the results in terms of cause-effect relationships.

CONCLUSIONS

Our findings suggested that individuals at risk of developing depression, also in absence of depressive symptoms, are defined by defective self-regulation capacity that may lead to future depression episodes. Increased ruminative thoughts and reduced HRV may represent early indicators of vulnerability to depression. Effective prevention programs designed to reduce rumination and/or increase HRV may reduce the risk of developing a full-blown depressive episode.

Molecular changes in nucleus accumbens due to amelioration of depressive-like behavior by housing with companion

Social support are positively and causally related to mental health. Higher levels of perceived social support and group memberships are shown to be associated with lower depression symptomatology and recovery from depression, but the molecular biological mechanism behind its remains largely unknown. Here, we report that accompanying with companion ameliorated chronic unpredictable mild stress (CUMS) induced depression-like behaviors in mice. Accompanying with companion altered RNA expression profiles of nucleus accumbens (NAc) in CUMS-induced susceptible and resilience mice. 117 differentially expressed genes (DEGs) were found to be associated with depression-like behaviors, 17 DEGs associated with resilient behaviors, 43 DEGs associated with accompanying with companion. Importantly, 234 differentially expressed miRNAs that associated with accompanying with companion were obtained, and the miRNA-mRNA network associated with companion was established in NAc, based on the miRNA and mRNA profiles. Taken together, our findings revealed a potential new approach to improve depression-like behaviors, as well as many potential drug targets for the prevention or treatment of depression.

The effect of second-generation antidepressant treatment on the attention and mental processing speed of patients with major depressive disorder: A meta-analysis study with structural equation models

Major depressive disorder (MDD) has been linked to attention and mental processing speed deficits that can be improved after pharmacological treatment. However, it is unclear whether a class of antidepressants is more effective than others to ameliorate these deficits in MDD. Additionally, the possible effects of clinical and demographic variables on improving MDD attention and processing speed deficits after antidepressant treatment are unknown. We aimed to study the possible neuropsychological effects of second-generation antidepressant classes on the attention and processing speed of MDD patients and the potential influences of clinical and demographic variables as moderators of these effects using a meta-analytic approach. Twenty-five papers were included in our study. A structural equation model meta-analysis was performed. The improvement of attention and processing speed after pharmacological treatment is clinically relevant but incomplete. Selective serotonin reuptake inhibitors (SSRIs) and dual inhibitors are the drugs causing the greatest improvement in the processing speed of MDD patients. Antidepressant class is an important variable linked to processing speed improvement after MDD treatment. However, the degree of improvement in both cognitive functions is strongly influenced by some clinical and demographic variables of depressed patients, such are age and education of the MDD patients, the duration of the antidepressant treatment, and the depression status of the patients.

Suicide Ideation and Neurocognition Among 9- and 10-Year Old Children in the Adolescent Brain Cognitive Development (ABCD) Study

OBJECTIVE

During the past decade, the pediatric suicide rate has nearly tripled. Yet, little is known about suicide behavior (SB) in children. Identification of risk factors associated with SB during childhood may be critical to preventing future attempts. The purpose of this study was to examine the relationship between neurocognitive performance and suicide ideation (SI) in children.

METHOD

The present study utilized baseline data from 11,875 participants in the Adolescent Brain Cognitive Development (ABCD) study, a longitudinal study that follows 9- and 10-year-old children through late adolescence to examine factors that influence developmental trajectories. Suicidality was assessed by the Kiddie Schedule for Affective Disorder and Schizophrenia (KSADS) suicide module completed by the parent. Neurocognitive ability was assessed using the NIH Toolbox Cognition measures administered to the youth.

RESULTS

Children with a history of SI reported by their parent or concordant parent and youth report of SI demonstrated lower performance on the NIH Toolbox Picture Sequence Memory Test compared to children without SI. The difference in performance on the memory task remained significant when including demographic characteristics, family history of suicide, and internalizing symptoms in the model as covariates.

CONCLUSIONS

To our knowledge, this is the first study to identify decreased episodic memory in children with SI. These findings are similar to results from adult and adolescent studies which have reported decreased memory performance among suicide attempters. Deficits in episodic memory may impact a child's ability to problem-solve and generate potential future outcomes, which may increase the risk for SB. Early identification of memory deficits in children may inform suicide prevention and intervention efforts.Highlights6% of parents and children reported a history of active suicide ideation in children.Children with a history of suicide ideation had lower episodic memory performance.Early identification of memory deficits may inform suicide intervention efforts.

Assessment of Mental Workload by Visual Motor Activity among Control Group and Patient Suffering from Depressive Disorder

Major depressive disorder (MDD) is a mood state that is not usually associated with vision problems. Recent research has found that the inhibitory neurotransmitter GABA levels in the occipital brain have dropped. Aim. The aim of the research is to evaluate mental workload by single channel electroencephalogram (EEG) approach through visual-motor activity and comparison of parameter among depressive disorder patient and in control group. Method. Two tests of a visual-motor task similar to reflect drawings were performed in this study to compare the visual information processing of patients with depression to that of a placebo group. The current study looks into the accuracy of monitoring cognitive burden with single-channel portable EEG equipment. Results. The alteration of frontal brain movement in reaction to fluctuations in cognitive burden stages generated through various vasomotor function was examined. By applying a computerised oculomotor activity analogous to reflector image diagram, we found that the complexity of the path to be drawn was more important than the real time required accomplishing the job in determining perceived difficulty in depressive disorder patients. The overall perceived difficulty of the exercise is positively linked with EEG activity measured from the motor cortex region at the start of every experiment test. The average rating for task completion for depression patients and in control group observed and no statistical significance association reported between rating scale and time spent on each trial (p=1.43) for control group while the normalised perceived difficulty rating had 0.512, 0.623, and 0.821 correlations with the length of the pathway, the integer of inclination in the pathway, and the time spent to complete every experiment test, respectively (p < 0.0001) among depression patients. The findings imply that alterations in comparative cognitive burden levels during an oculomotor activity considerably modify frontal EEG spectrum. Conclusion. Patients with depression perceived the optical illusion in the arrays as weaker, resulting in a little bigger disparity than individuals who were not diagnosed with depression. This discovery provided light on the prospect of adopting a user-friendly mobile EEG technology to assess mental workload in everyday life.

Latent anxiety in clinical depression is associated with worse recognition of emotional stimuli

BACKGROUND

Major Depressive Disorder, characterized by cognitive affective biases, is a considerable public health challenge. Past work has shown that higher depressive symptoms are associated with augmented memory of negative stimuli. In contrast, anxiety symptoms have been associated with overgeneralization of emotional memories. Given the high comorbidity of depression and anxiety, it is critical to understand how cognitive affective biases are differentially associated with clinical symptoms.

METHOD

We used continuous measures of depression (Beck Depression Inventory [BDI-II]) and anxiety (Beck Anxiety Inventory [BAI]) to evaluate an adult sample (N = 79; 18-41 years old, 58 female). Emotional memory discrimination and recognition memory were tested using an emotional discrimination task. We applied exploratory factor analysis to questions from the BAI and BDI-II to uncover latent constructs consisting of negative affect, anhedonia, somatic anxiety, and cognitive anxiety.

RESULTS

We report evidence that anxious symptoms were associated with impaired recognition of negative items after accounting for age and sex. Our exploratory factor analysis revealed that impaired negative item recognition is largely associated with somatic and cognitive anxiety factors.

LIMITATIONS

Interpretations in a mixed pathology sample, especially given collinearity among factors, may be difficult.

CONCLUSIONS

We provide evidence that somatic and cognitive anxiety are related to impaired recognition memory for negative stimuli. Future clinical investigations should uncover the neurobiological basis supporting the link between recognition of negative stimuli and somatic/cognitive symptoms of anxiety.

Cognitive Adverse Effects of Electroconvulsive Therapy: A Discrepancy Between Subjective and Objective Measures?

OBJECTIVES

The character and duration of cognitive adverse effects of electroconvulsive therapy (ECT) are unclear. This study investigated (1) the sensitivity of a short cognitive test battery to cognitive adverse effects of ECT, (2) the relation between subjective and objective cognitive adverse effects, and (3) patient characteristics associated with more subjective than objective adverse effects.

METHODS

Forty-one patients with unipolar or bipolar depression referred to ECT underwent assessments at baseline, 5 to 7 days post-ECT, and 3 months post-ECT. Patients rated their fear of various aspects of ECT on a visual analog scale. At each assessment, patients were evaluated for depressive symptoms, completed the Screen for Cognitive Impairment in Psychiatry (SCIP) and Trail Making Test-Part B (TMT-B), and rated their cognitive difficulties.

RESULTS

Patients feared cognitive adverse effects and lack of treatment efficacy more than other aspects of ECT. The SCIP and TMT-B revealed transient decline in objective cognition after ECT, which was reversed after 3 months. Patients presented with more subjective than objective cognitive difficulties at baseline and more subjective than objective cognitive adverse effects of ECT. This discrepancy was significantly reduced at follow-up. Younger age and poorer objective cognition pretreatment were associated with more subjective than objective cognitive adverse effects 5 to 7 days after ECT.

CONCLUSIONS

The SCIP and TMT-B are sensitive to cognitive adverse effects of ECT. Patients show more subjective than objective cognitive adverse effects of ECT. These insights can be used clinically to inform patients of treatment choice and expected cognitive consequences.

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.

HINT1 deficiency in aged mice reduces anxiety-like and depression-like behaviours and enhances cognitive performances

Histidine triad nucleotide-binding protein 1 (HINT1) is regarded as a haplo-insufficient tumour suppressor and is closely associated with many neuropsychiatric disorders, including major depressive disorders. In addition, HINT1 knockout (KO) mice exhibit anxiolytic-like behaviour, antidepression-like behaviour, and enhanced cognitive performance in several studies. However, it is still unclear whether aging contributes to these changes in the emotion and cognition of HINT1 KO mice. This study examined the role of aging in anxiety-like and depression-like behaviours and cognition behaviours in aged HINT1 KO mice compared with young HINT1 KO mice and their wild-type littermates, along with a number of molecular biological methods. In a battery of behavioural tests, aged wild-type mice showed increased anxiety-like and depression-like behaviours and decreased cognitive performance, along with lower expression levels of glutathione peroxidase, enhanced amount of malondialdehyde, and decreased expression levels of brain-derived neurotrophic factor and tyrosine kinase B in the hippocampus and PFC compared to young wild-type mice. HINT1 KO mice showed reduced anxiety-like and depression-like behaviours and enhanced cognitive performance compared to age-matched wild-type mice. In addition, HINT1 KO mice also showed increased GSH-Px and superoxide dismutase, and decreased malondialdehyde, together with enhanced BDNF and Trk-B expression in the hippocampus and PFC. However, when compared with young HINT1 KO mice, aged HINT1 KO mice did not show increased anxiety-like and depression-like behaviours. And there are no differences in the expression level of superoxide dismutase, malondialdehyde, BDNF, and Trk-B between aged and young HINT1 KO mice. In summary, HINT1 deficiency can counteract age-related emotion and cognition dysfunction.

Differential Role of mGluR5 in Cognitive Processes in Posttraumatic Stress Disorder and Major Depression

Background

A robust literature supports the role of the metabotropic glutamate receptor type 5 (mGluR5) in cognitive functioning. mGluR5 is also implicated in the pathophysiology of posttraumatic stress disorder (PTSD) and major depressive disorder (MDD), which are characterized by cognitive alterations. However, the relationship between mGluR5 and cognition in MDD and PTSD has not yet been directly investigated. To address this gap, we examined the relationship between in vivo mGluR5 availability and cognition in PTSD, MDD, and matched healthy adults (HA).

Methods

Individuals with PTSD (N = 28) and MDD (N = 21), and HA (N = 28) were matched for age, gender, and smoking status. Participants completed 18F-FPEB positron emission tomography (PET) scan, psychiatric and cognitive assessments.

Results

Across models examining the relationship between mGluR5 availability and different domains of cognition across diagnostic groups, only the interaction of diagnosis*attention was significant (F 4,64 = 3.011, P = .024). Higher mGluR5 availability was associated with poorer attention in PTSD in 4 frontolimbic regions of interests (ROI's: OFC (r = -.441, P = .016), vmPFC (r = -.408, P = .028), dlPFC (r = -.421, P = .023), hippocampus (r = -.422, P = .025). By contrast, mGluR5 availability in the MDD group was positively related to Attention (ATTN) in the OFC (r = .590, P = .006), vmPFC (r = .653, P = .002), and dlPFC (r = .620, P = .004). Findings in the hippocampus for MDD followed the same pattern but did not survive correction for multiple comparisons (r = .480, P = .036). ATTN and mGluR5 availability were not significantly related in the HA group. Of note, in MANOVA analyses group*ATTN interaction results in the OFC did not survive multiple comparisons (P = .046). All other findings survived correction for multiple comparisons and remained significant when covarying for potential confounds (eg, depressed mood).

Conclusions

We observed a significant relationship between frontolimbic mGluR5 availability and performance on tests of attention in individuals with MDD and PTSD. This finding aligns with animal work showing dysregulation in mGluR5 in cognitive functioning, and differed as a function of diagnosis. Results suggest interventions targeting mGluR5 may help bolster cognitive difficulties, highlighting the importance of employing different mGluR5 directed treatment strategies in MDD and PTSD.

Rodrigues K, Pinz MP, Biondi JV, Becker NP, Blodorn E, Domingues WB, Larroza A, Campos VF, Alves D, Wilhelm EA, Luchese C. Prospecting for a quinoline containing selenium for comorbidities depression and memory impairment induced by restriction stress in mice

RATIONALE

Depression is often associated with memory impairment, a clinical feature of Alzheimer's disease (AD), but no effective treatment is available. 7-Chloro-4-(phenylselanyl) quinoline (4-PSQ) has been studied in experimental models of diseases that affect the central nervous system.

OBJECTIVES

The pharmacological activity of 4-PSQ in depressive-like behavior associated with memory impairment induced by acute restraint stress (ARS) in male Swiss mice was evaluated.

METHODS

ARS is an unavoidable stress model that was applied for a period of 240 min. Ten minutes after ARS, animals were intragastrically treated with canola oil (10 ml/kg) or 4-PSQ (10 mg/kg) or positive controls (paroxetine or donepezil) (10 mg/kg). Then, after 30 min, mice were submitted to behavioral tests. Corticosterone levels were evaluated in plasma and oxidative stress parameters; monoamine oxidase (MAO)-A and MAO -B isoform activity; mRNA expression levels of kappa nuclear factor B (NF-κB); interleukin (IL)-1β, IL-18, and IL-33; phosphatidylinositol-se-kinase (PI3K); protein kinase B (AKT2), as well as acetylcholinesterase activity were evaluated in the prefrontal cortex and hippocampus.

RESULTS

4-PSQ attenuated the depressive-like behavior, self-care, and memory impairment caused by ARS. Based on the evidence, we believe that effects of 4-PSQ may be associated, at least in part, with the attenuation of HPA axis activation, attenuation of alterations in the monoaminergic system, modulation of oxidative stress, reestablishment of AChE activity, modulation of the PI3K/AKT2 pathway, and reduction of neuroinflammation.

CONCLUSIONS

These results suggested that 4-PSQ exhibited an antidepressant-like effect and attenuated the memory impairment induced by ARS, and it is a promising molecule to treat these comorbidities.

Assessment of cognitive performances in major depressed patients: a 6-month follow-up study

OBJECTIVE

Our study aimed to assess the longitudinal change of cognitive functions in depressed patients after a 6-month interval free of mood symptoms.

METHODS

In a longitudinal study, 65 patients diagnosed with recurrent major depressive disorder were evaluated twice with neurocognitive tests, during an acute depressed episode and after 6 months of euthymia. The cognitive dimension was assessed with neuropsychological tests of attention and processing speed, memory, verbal fluency, psychomotor speed and executive functions. The severity of depression was evaluated through Hamilton Depression Rating Scale - 17 items. All the results were compared with the outcomes of 35 healthy controls, both in depression and euthymia.

RESULTS

Depressed patients compared to controls displayed significant statistical differences for most cognitive tests applied, verbal and working memory being the most severely impaired. They were still impaired at the second evaluation. Significant differences were noted between the euthymic and control group, too. Between the depression phase and euthymia, patients obtained significant improvement for attention and processing speed, verbal fluency, motor speed and executive functions.

CONCLUSIONS

Results from the current study indicate that cognitive impairment is more severe for depressed patients, decreases for euthymic subjects, and lasts longer after depressive symptoms remit.

Suppression of pyramidal neuron G protein-gated inwardly rectifying K+ channel signaling impairs prelimbic cortical function and underlies stress-induced deficits in cognitive flexibility in male, but not female, mice

Imbalance in prefrontal cortical (PFC) pyramidal neuron excitation:inhibition is thought to underlie symptomologies shared across stress-related disorders and neuropsychiatric disease, including dysregulation of emotion and cognitive function. G protein-gated inwardly rectifying K+ (GIRK/Kir3) channels mediate excitability of medial PFC pyramidal neurons, however, the functional role of these channels in mPFC-dependent regulation of affect, cognition, and cortical dynamics is unknown. We used a viral-cre approach in male and female mice harboring a "floxed" version of the kcnj3 (Girk1) gene, to disrupt GIRK1-containing channel expression in pyramidal neurons within the prelimbic cortex (PrL). In males, loss of pyramidal GIRK1-dependent signaling differentially impacted measures of affect and impaired working memory and cognitive flexibility. Unexpectedly, ablation of PrL GIRK1-dependent signaling did not impact affect or cognition in female mice. Additional studies used a model of chronic unpredictable stress (CUS) to determine the impact on PrL GIRK-dependent signaling and cognitive function. CUS exposure in male mice produced deficits in cognition that paralleled a reduction in PrL pyramidal GIRK-dependent signaling akin to viral approaches whereas CUS exposure in female mice did not alter cognitive flexibility performance. Stress-induced behavioral deficits in male mice were rescued by systemic injection of a novel, GIRK1-selective agonist, ML297. In conclusion, GIRK1-dependent signaling in male mice, but not females, is critical for maintaining optimal PrL function and behavioral control. Disruption of this inhibition may underlie stress-related dysfunction of the PrL and represent a therapeutic target for treating stress-induced deficits in affect regulation and impaired cognition that reduce quality of life.

Altered directed connectivity during processing of predictive stimuli in psychiatric patient populations

OBJECTIVES

The study investigated the role of top-down versus bottom-up connectivity, during the processing of predictive information, in three different psychiatric disorders.

METHODS

Electroencephalography (EEG) was recorded during the performance of a task, which evaluates the ability to use predictive information in order to facilitate predictable versus random target detection. We evaluated EEG event-related directed connectivity, in patients with schizophrenia (SZ), major depressive disorder (MDD), and autism spectrum disorder (ASD), compared with healthy age-matched controls. Directed connectivity was evaluated using phase transfer entropy.

RESULTS

We showed that top-down frontal-parietal connectivity was weaker in SZ (theta and beta bands) and ASD (alpha band) compared to control subjects, during the processing of stimuli consisting of the predictive sequence. In SZ patients, top-down connectivity was also attenuated, during the processing of predictive targets in the beta frequency band. In contrast, compared with controls, MDD patients displayed an increased top-down flow of information, during the processing of predicted targets (alpha band).

CONCLUSIONS

The findings suggest that top-down frontal-parietal connectivity is altered differentially across three major psychiatric disorders, specifically during the processing of predictive stimuli.

SIGNIFICANCE

Altered top-down connectivity may contribute to the specific prediction deficits observed in each of the patient populations.

A randomized, multicenter, crossover psychometric evaluation study of an iPad-administered cognitive test battery in participants with major depressive disorder who responded to treatment with oral antidepressants

BACKGROUND

Performance validity and test-retest reliability of ReVeRe.D, an iPad-administered cognitive test battery in major depressive disorder (MDD) were analyzed.

METHODS

Participants aged 18-59 years had DSM-5 diagnosis of MDD with adequate visual and hearing acuity. All had responded to oral antidepressant treatment for a major depressive episode within the most recent 24-months and were stable with no greater than mild depressive symptoms as evidenced by Montgomery Asberg Depression Rating Scale total score <17. Participants were randomly assigned to 1 of 2 test sequences (AABB or BBAA; A=ReVeRe.D; B=examiner-administered tests) in a crossover design.

RESULTS

244 randomized participants (AABB: n=123; BBAA: n=121) had mean age of 38.3 years; 54.9% had a college, baccalaureate, or higher education. At first administration, Pearson correlation coefficients (PCC) for 6/10 pairs of corresponding ReVeRe.D vs examiner-administered tests exceeded the pre-specified acceptance criterion (PCC=0.53) for the primary analysis; 8 test score pairs had PCC exceeding 0.40. At second administration, PCC for 9/10 test scores pairs exceeded PCC=0.53. Together, the series of PCCs supports the concurrent validity for ReVeRe.D. Test-retest reliability for ReVeRe.D test scores was generally moderate to high.

LIMITATIONS

The study included stable participants with MDD who had responded to oral antidepressant treatment, with most in at least partial remission. The sample was limited to English-speaking participants, and skewed towards white, college-educated women. Further studies in acutely ill MDD patients who represent a broader demographic, are warranted.

CONCLUSIONS

iPad-administered ReVeRe.D is a valid and reliable computerized test battery for assessment of cognitive performance in MDD.

Prefrontal inhibition drives formation and dynamic expression of probabilistic Pavlovian fear conditioning

The association between cause and effect is usually probabilistic. Memories triggered by ambiguous cues may be altered or biased into a more negative perception in psychiatric diseases. Understanding the formation and modulation of this probabilistic association is important for revealing the nature of aversive memory and alterations in brain diseases. We found that 50% conditioned and unconditioned stimuli (CS-US) association during Pavlovian fear conditioning results in reduced fear responses and neural spiking in the dorsomedial prefrontal cortex (dmPFC) due to enhanced inhibition from dmPFC parvalbumin (PV) neurons. Formation of probabilistic memory is associated with increased synaptic inputs to PV-neurons and requires activation of ventral hippocampus, which detects CS-US mismatch during conditioning. Stress prior to conditioning impairs the formation of probabilistic memory by abolishing PV-neuronal plasticity, while stress prior to memory retrieval reverts enhanced PV-neuron activity. In conclusion, PV-neurons tailor learned responses to fit brain state at the moment of retrieval.

Quercetin and/or Ascorbic Acid Modulatory Effect on Phenobarbital-Induced Sleeping Mice Possibly through GABAA and GABAB Receptor Interaction Pathway

Depressive disorder is a recurrent illness that affects large numbers of the general population worldwide. In recent years, the goal of depression treatment has moved from symptomatic response to that of full remission. However, treatment-resistant depression is a major challenge in the treatment of depression or depression-related disorders. Consensus opinion, therefore, suggests that effective combined aggressive initial treatment is the most appropriate strategy. This study aimed to evaluate the effects of quercetin (QUR) and/or ascorbic acid (AA) on Phenobarbital-induced sleeping mice. QUR (50 mg/kg) and/or AA (25 mg/kg) with or without intraperitoneally pre-treated with GABA receptor agonist (diazepam: 2 mg/kg, i.p.) or antagonist (Flumazenil: 2.5 mg/kg, i.p.) to underscore the effects, as well as the possible involvement of the GABA receptor in the modulatory action of QUR and AA in sleeping mice. Additionally, an in silico study was undertaken to predict the involvement of GABA receptors in the sleep mechanism. Findings suggest that the pretreatment of QUR and AA modulated the onset and duration of action of the standard drugs in experimental animals. The acute administration of QUR and/or AA significantly (p < 0.05) reversed the DZP-mediated onset of action and slightly reversed the duration of sleep time in comparison to the vehicle (control) group. A further combination of QUR or AA with the FLU resulted in an enhancement of the onset of action while reducing the duration of action, suggesting a FLU-like effect on the test animals. In in silico studies, AA and QUR showed good to moderate binding affinities with GABA_A and GABA_B receptors. Both QUR and AA produced a stimulatory-like effect on mice, possibly through the GABA_A and GABA_B receptor interaction pathways. Further studies are necessary to verify this activity and clarify the exact mechanism of action(s) involved.

Over-representation of fundamental decision variables in the prefrontal cortex underlies decision bias

The brain is organized into anatomically distinct structures consisting of a variety of projection neurons. While such evolutionarily conserved neural circuit organization underlies the innate ability of animals to swiftly adapt to environments, they can cause biased cognition and behavior. Although recent studies have begun to address the causal importance of projection-neuron types as distinct computational units, it remains unclear how projection types are functionally organized in encoding variables during cognitive tasks. This review focuses on the neural computation of decision making in the prefrontal cortex and discusses what decision variables are encoded by single neurons, neuronal populations, and projection type, alongside how specific projection types constrain decision making. We focus particularly on "over-representations" of distinct decision variables in the prefrontal cortex that reflect the biological and subjective significance of the variables for the decision makers. We suggest that task-specific over-representation in the prefrontal cortex involves the refinement of the given decision making, while generalized over-representation of fundamental decision variables is associated with suboptimal decision biases, including pathological ones such as those in patients with psychiatric disorders. Such over-representation of the fundamental decision variables in the prefrontal cortex appear to be tightly constrained by afferent and efferent connections that can be optogenetically intervened on. These ideas may provide critical insights into potential therapeutic targets for psychiatric disorders, including addiction and depression.

Sense of Purpose Promotes Resilience to Cognitive Deficits Attributable to Depressive Symptoms

Objective

Individuals higher in depressive symptoms commonly present with neuropsychological deficits including poorer memory performance. Sense of purpose in life has been shown to promote resilience to cognitive impairment in older adulthood, but it is unclear whether it may also protect against cognitive deficits associated with higher depressive symptoms.

Method

Cognitive functioning among 4599 older American adults (M_age = 74.33 years, range = 65–104 years, 56.84% female) was examined across a 12-year follow-up period. Depressive symptomatology was assessed at each wave using the 8-item Center for Epidemiologic Studies Depression Scale. Multilevel models assessed the influence of depressive symptoms and the interaction with sense of purpose in life on changes in memory performance and mental status.

Results

Higher depressive symptoms were associated with poorer memory performance at baseline, but did not predict rate of change over time. A negative interaction was observed between sense of purpose in life and depressive symptoms such that individuals higher in purpose experienced a less negative association between depressive symptoms and baseline memory performance. No significant interaction of sense of purpose and depressive symptoms was observed on mental status.

Conclusion

Having a sense of purpose in life may help protect older adults from memory deficits associated with higher depressive symptoms. The present findings underscore the potential for sense of purpose to promote cognitive reserve in older adulthood, allowing individuals to maintain cognitive performance in the face of accruing neurological insults.

Functional Contribution of the Medial Prefrontal Circuitry in Major Depressive Disorder and Stress-Induced Depressive-Like Behaviors

Despite decades of research on the neurobiology of major depressive disorder (MDD), the mechanisms underlying its expression remain unknown. The medial prefrontal cortex (mPFC), a hub region involved in emotional processing and stress response elaboration, is highly impacted in MDD patients and animal models of chronic stress. Recent advances showed alterations in the morphology and activity of mPFC neurons along with profound changes in their transcriptional programs. Studies at the circuitry level highlighted the relevance of deciphering the contributions of the distinct prefrontal circuits in the elaboration of adapted and maladapted behavioral responses in the context of chronic stress. Interestingly, MDD presents a sexual dimorphism, a feature recognized in the molecular field but understudied on the circuit level. This review examines the recent literature and summarizes the contribution of the mPFC circuitry in the expression of MDD in males and females along with the morphological and functional alterations that change the activity of these neuronal circuits in human MDD and animal models of depressive-like behaviors.

Role of FMRP in rapid antidepressant effects and synapse regulation

Rapid antidepressants are novel treatments for major depressive disorder (MDD) and work by blocking N-methyl-D-aspartate receptors (NMDARs), which, in turn, activate the protein synthesis pathway regulated by mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Our recent work demonstrates that the RNA-binding protein Fragile X Mental Retardation Protein (FMRP) is downregulated in dendrites upon treatment with a rapid antidepressant. Here, we show that the behavioral effects of the rapid antidepressant Ro-25-6981 require FMRP expression, and treatment promotes differential mRNA binding to FMRP in an mTORC1-dependent manner. Further, these mRNAs are identified to regulate transsynaptic signaling. Using a novel technique, we show that synapse formation underlying the behavioral effects of Ro-25-6981 requires GABABR-mediated mTORC1 activity in WT animals. Finally, we demonstrate that in an animal model that lacks FMRP expression and has clinical relevance for Fragile X Syndrome (FXS), GABABR activity is detrimental to the effects of Ro-25-6981. These effects are rescued with the combined therapy of blocking GABABRs and NMDARs, indicating that rapid antidepressants alone may not be an effective treatment for people with comorbid FXS and MDD.

Subjective age, depressive symptoms, and cognitive functioning across five domains

Objective: Younger subjective age predicts better episodic memory and executive functioning performance independent of chronological age. This study examined whether subjective age is associated with performance in five cognitive domains, quantified the extent to which these relationships are mediated by depressive symptoms, and tested whether these associations are moderated by chronological age.Method: Participants in this cross-sectional study included 993 adults aged 65 and older from the Health and Retirement Study's 2016 Harmonized Cognitive Assessment Protocol. Moderated mediation models estimated direct and indirect effects of subjective age on factor scores representing episodic memory, executive functioning, language, visuoconstruction, and speed through depressive symptoms and tested whether associations differed according to chronological age.Results: Depressive symptoms explained 21-32% of the associations between subjective age and language, speed, episodic memory, and executive functioning. Chronological age moderated the indirect effect involving language, such that depressive symptoms were more strongly related to worse language performance at older chronological ages. After accounting for indirect effects, direct effects of younger subjective age remained for language and speed domains.Conclusions: This study extends research on the cognitive correlates of subjective age and demonstrates that depressive symptoms partly mediate these relationships. Subjective age may bemost strongly associated with language among individuals at older chronological ages not because they are more sensitive to the negative mental health impact of feeling older than they are but because they may be particularly vulnerable to the negative effects of depressive symptoms on language ability. Additional longitudinal research is needed to determine whether links between subjective age and cognition are causal versus predictive.

Cognitive and Affective Processes Associated with Social Biases

BACKGROUND

Our social activities are quite often erroneous and irrational, based on biased judgements and decision-making, known as social biases. However, the cognitive and affective processes that produce such biases remain largely unknown. In this study, we investigated associations between social schemas, such as social judgment and conformity, entailing social biases and psychological measurements relevant to cognitive and affective functions.

METHOD

This study recruited 42 healthy adult subjects. A psychological test and a questionnaire were administered to assess biased social judgements by superficial attributes and social conformity by adherence to social norms, respectively, along with additional questionnaires and psychological tests for cognitive and affective measurements, including negative affects, autistic traits, and Theory of Mind (ToM). Associations of social judgment and conformity with cognitive and affective functions were examined using a multiple regression analysis and structural equation modeling.

RESULTS

Anxiety and the cognitive realm of ToM were mutually associated with both social judgments and conformity, although social judgements and conformity were still independent processes. Social judgements were also associated with autistic traits and the affective realm of ToM, whereas social conformity was associated with negative affects other than anxiety and an intuitive decision-making style.

CONCLUSIONS

These results suggest that ToM and negative affects may play important roles in social judgements and conformity, and the social biases connoted in these social schemas.

Do Cardiovascular Risk Factors and Cardiovascular Disease Explain Sex Differences in Cognitive Functioning in Old Age?

Background:

Sex differences in cognitive functioning in old age are known to exist yet are still poorly understood.

Objective:

This study examines to what extent differences in cardiovascular risk factors and cardiovascular disease between men and women explain sex differences in cognitive functioning.

Methods:

Data from 2,724 older adults from the Longitudinal Aging Study Amsterdam were used. Information processing speed and episodic memory, measured three times during six years of follow-up, served as outcomes. The mediating role of cardiovascular risk factors and cardiovascular disease was examined in single and multiple mediator models. Determinant-mediator effects were estimated using linear or logistic regression, and determinant-outcome and mediator-outcome effects were estimated using linear mixed models. Indirect effects were estimated using the product-of-coefficients estimator.

Results:

Women scored 1.58 points higher on information processing speed and 1.53 points higher on episodic memory. Several cardiovascular risk factors had small mediating effects. The sex difference in information processing speed was mediated by smoking, depressive symptoms, obesity, and systolic blood pressure. The sex difference in episodic memory was mediated by smoking, physical activity, and depressive symptoms. Effects of smoking, LDL cholesterol, and diabetes mellitus on information processing speed differed between men and women.

Conclusion:

Differences in cardiovascular risk factors between women and men partially explained why women had better cognitive functioning. A healthy cardiovascular lifestyle seems beneficial for cognition and sex-specific strategies may be important to preserve cognitive functioning at older age.

Acute cognitive effects of single-dose intravenous ketamine in major depressive and posttraumatic stress disorder

Intravenous (IV) subanesthetic doses of ketamine have been shown to reduce psychiatric distress in both major depressive (MDD) and posttraumatic stress disorder (PTSD). However, the effect of ketamine on cognitive function in these disorders is not well understood. To address this gap, we examined the effect of a single dose of IV ketamine on cognition in individuals with MDD and/or PTSD relative to healthy controls (HC). Psychiatric (n = 29; 15 PTSD, 14 MDD) and sex- age- and IQ matched HC (n = 29) groups were recruited from the community. A single subanesthetic dose of IV ketamine was administered. Mood and cognitive measures were collected prior to, 2 h and 1 day post-ketamine administration. MDD/PTSD individuals evidenced a large-magnitude improvement in severity of depressive symptoms at both 2-hours and 1 day post-ketamine administration (p's < .001, Cohen d's = 0.80-1.02). Controlling for baseline performance and years of education, IV ketamine induced declines in attention (ATTN), executive function (EF), and verbal memory (VM) 2 h post-administration, all of which had resolved by 1 day post-ketamine across groups. The magnitude of cognitive decline was significantly larger in MDD/PTSD relative to HC on attention only (p = .012, d = 0.56). Ketamine did not affect working memory (WM) performance. Cognitive function (baseline, change from baseline to post-ketamine) was not associated with antidepressant response to ketamine. Results suggest that while ketamine may have an acute deleterious effect on some cognitive domains in both MDD/PTSD and HC individuals, most notably attention, this reduction is transient and there is no evidence of ketamine-related cognitive dysfunction at 1 day post-administration.

American Academy of Clinical Neuropsychology (AACN) 2021 consensus statement on validity assessment: Update of the 2009 AACN consensus conference statement on neuropsychological assessment of effort, response bias, and malingering

Objective: Citation and download data pertaining to the 2009 AACN consensus statement on validity assessment indicated that the topic maintained high interest in subsequent years, during which key terminology evolved and relevant empirical research proliferated. With a general goal of providing current guidance to the clinical neuropsychology community regarding this important topic, the specific update goals were to: identify current key definitions of terms relevant to validity assessment; learn what experts believe should be reaffirmed from the original consensus paper, as well as new consensus points; and incorporate the latest recommendations regarding the use of validity testing, as well as current application of the term 'malingering.' Methods: In the spring of 2019, four of the original 2009 work group chairs and additional experts for each work group were impaneled. A total of 20 individuals shared ideas and writing drafts until reaching consensus on January 21, 2021. Results: Consensus was reached regarding affirmation of prior salient points that continue to garner clinical and scientific support, as well as creation of new points. The resulting consensus statement addresses definitions and differential diagnosis, performance and symptom validity assessment, and research design and statistical issues. Conclusions/Importance: In order to provide bases for diagnoses and interpretations, the current consensus is that all clinical and forensic evaluations must proactively address the degree to which results of neuropsychological and psychological testing are valid. There is a strong and continually-growing evidence-based literature on which practitioners can confidently base their judgments regarding the selection and interpretation of validity measures.

Ketamine specifically reduces cognitive symptoms in depressed patients: An investigation of associated neural activation patterns

Major depressive disorder (MDD) is characterized by heterogeneous cognitive, affective and somatic symptoms. Hence, the investigation of differential treatment effects on these symptoms as well as the identification of symptom specific biomarkers might crucially contribute to the development of individualized treatment strategies. We here aimed to examine symptom specific responses to treatment with ketamine, which repeatedly demonstrated rapid antidepressant effects in severe MDD. Additionally, we investigated working memory (WM) related brain activity associated with changes in distinct symptoms in order to identify specific response predictors. In a sample of 47 MDD patients receiving a single sub-anesthetic dose of ketamine, we applied a three-factor solution of the Beck Depression Inventory (BDI) to detect symptom specific changes 24 h post-infusion. A subsample of 16 patients underwent additional fMRI scanning during an emotional working memory task prior to ketamine treatment. Since functional aberrations in the default mode network (DMN) as well as in the dorsolateral prefrontal cortex (DLPFC) have been associated with impaired cognitive and emotional processing in MDD, we investigated neural activity in these regions. Our results showed that ketamine differentially affects MDD symptoms, with the largest symptom reduction in the cognitive domain. WM related neuroimaging results indicated that a more pronounced effect of ketamine on cognitive symptoms is predicted by lower DMN deactivation and higher DLPFC activation. Findings thereby not only indicate that ketamine's antidepressant efficacy is driven by a pro-cognitive mechanism, but also suggest that this might be mediated by increased potential for adaptive adjustment in the circumscribed brain regions.

The role of neuropeptide somatostatin in the brain and its application in treating neurological disorders

Somatostatin (SST) is a well-known neuropeptide that is expressed throughout the brain. In the cortex, SST is expressed in a subset of GABAergic neurons and is known as a protein marker of inhibitory interneurons. Recent studies have identified the key functions of SST in modulating cortical circuits in the brain and cognitive function. Furthermore, reduced expression of SST is a hallmark of various neurological disorders, including Alzheimer's disease and depression. In this review, we summarize the current knowledge on SST expression and function in the brain. In particular, we describe the physiological roles of SST-positive interneurons in the cortex. We further describe the causal relationship between pathophysiological changes in SST function and various neurological disorders, such as Alzheimer's disease. Finally, we discuss potential treatments and possibility of novel drug developments for neurological disorders based on the current knowledge on the function of SST and SST analogs in the brain derived from experimental and clinical studies.

THE EFFECT OF SECOND-GENERATION ANTIDEPRESSANT TREATMENT ON THE EXECUTIVE FUNCTIONS OF PATIENTS WITH MAJOR DEPRESSIVE DISORDER: A META-ANALYSIS STUDY WITH STRUCTURAL EQUATION MODELS

Major depressive disorder (MDD) has been linked to executive functions (EF) deficits that can be improved after pharmacological treatment, but it is unclear whether there is a class of antidepressants that is more effective than others to ameliorate these deficits in MDD. Additionally, the possible effects of clinical and demographic variables on the improvement of MDD EF deficits after pharmacological treatment are currently unknown. Our aim was to study the possible neuropsychological effects of second-generation antidepressant classes on the EF of MDD patients and the potential influence of clinical and demographic variables as moderators of these effects through a meta-analytic approach. Twenty-one papers were included in our study. A structural equation model meta-analysis was performed. The improvement of EF after pharmacological treatment is clinically relevant, but it is incomplete. This effect is influenced by age and years of education of the patients. Selective serotonin reuptake inhibitors (SSRIs) and dual inhibitors are the drugs causing the greatest improvement in EF of MDD patients. Antidepressant class is an important variable linked to EF improvement after MDD treatment, but the degree of improvement in these cognitive functions is strongly influenced by some clinical and demographic variables of patients with depression.

Depression and Cognitive Impairment in Institutionalized Older Adults

BACKGROUND

In the last three decades, the relationship between depression and cognition in geriatric patients has been a popular topic among researchers and clinicians. Clinical and epidemiological research has focused on the identification of risk factors that could be modified in pre-dementia syndromes, at a preclinical and early clinical stage of dementia disorders, with specific attention to the role of depression. The objective of this work was to determine the relationship between depressive disorder and cognitive deterioration in institutionalized older adults.

METHODS

In this descriptive, correlational study, data were gathered from two nursing homes in the province of Jaen (Spain), from a random sample of 140 older adults (70 nondependent and 70 dependent). The variables were measured using comprehensive geriatric assessment, the Cambridge Cognitive Test (CAMCOG), and the Geriatric Depression Scale (GDS).

RESULTS

Depression was correlated with cognitive level in the nondependent older adult sample (r = -0.471, p = 0.004). Age was inversely associated with the score obtained in the CAMCOG of the nondependent older adult sample (r = -0.352, p = 0.038). The functional capacity in several activities of daily living was correlated with the score obtained in the CAMCOG in each of the two groups. Depression was more prevalent in the dependent than in the nondependent older adults (82.85 vs. 57.14%). No association was observed between institutionalization time and the score obtained on the cognitive and affective scales (GDS and CAMCOG) in both groups (GDS-nondependent, r = -0.209, p = 0.234; CAMCOG-nondependent, r = 0.007, p = 0.967; GDS-dependent, r = 0.251, p = 0.152; CAMCOG-dependent, r = -0.021, p = 0.907).

CONCLUSION

Depressive symptomatology is associated with cognitive deterioration. Depression is prevalent in institutions that care for older, more dependent adults.