Persistence of neuropsychologic deficits in the remitted state of late-life depression

Frontal-executive and corticolimbic structural brain circuitry in older people with remitted depression, mild cognitive impairment, Alzheimer's dementia, and normal cognition

A history of depression is a risk factor for dementia. Despite strong epidemiologic evidence, the pathways linking depression and dementia remain unclear. We assessed structural brain alterations in white and gray matter of frontal-executive and corticolimbic circuitries in five groups of older adults putatively at-risk for developing dementia- remitted depression (MDD), non-amnestic MCI (naMCI), MDD+naMCI, amnestic MCI (aMCI), and MDD+aMCI. We also examined two other groups: non-psychiatric ("healthy") controls (HC) and individuals with Alzheimer's dementia (AD). Magnetic resonance imaging (MRI) data were acquired on the same 3T scanner. Following quality control in these seven groups, from diffusion-weighted imaging (n = 300), we compared white matter fractional anisotropy (FA), mean diffusivity (MD), and from T1-weighted imaging (n = 333), subcortical volumes and cortical thickness in frontal-executive and corticolimbic regions of interest (ROIs). We also used exploratory graph theory analysis to compare topological properties of structural covariance networks and hub regions. We found main effects for diagnostic group in FA, MD, subcortical volume, and cortical thickness. These differences were largely due to greater deficits in the AD group and to a lesser extent aMCI compared with other groups. Graph theory analysis revealed differences in several global measures among several groups. Older individuals with remitted MDD and naMCI did not have the same white or gray matter changes in the frontal-executive and corticolimbic circuitries as those with aMCI or AD, suggesting distinct neural mechanisms in these disorders. Structural covariance global metrics suggested a potential difference in brain reserve among groups.

Transcranial sonography imaging of brainstem raphe, substantia nigra and cerebral ventricles in patients with geriatric depression

OBJECTIVES

Geriatric depression is a special condition associated with a chronic course, treatment resistance and vascular processes. However, its neurobiology has not been fully elucidated. There is no study in geriatric depression evaluating deep brain structures with transcranial sonography (TCS) which is a low-cost, non-invasive and practical tool. The present study aimed to evaluate the changes in the echogenicity of brainstem raphe (BR), substantia nigra (SN) and ventricular diameters by TCS in association with cognitive dysfunctions in patients with geriatric depression.

METHODS

Echogenicity of BR and SN were assessed and transverse diameters of the third ventricle and frontal horns of the lateral ventricles were measured by TCS in 34 patients with DSM-5 major depression and 31 healthy volunteers aged 60 and older. Cognitive functions were evaluated by using Mini Mental State Examination, Montreal Cognitive Assessment Tool, Clock Drawing Test and Subjective Memory Complaints Questionnaire.

RESULTS

Although depressed patients had more subjective memory complaints than controls, they had similar cognitive performances. Reduced echogenicity (interrupted/invisible echogenic line) of BR was found to be significantly higher and the ventricular diameters were larger in the depressed group. There was no difference between the groups in terms of SN echogenicity. There was no correlation between ventricular diameters and depression severity or cognitive functions.

CONCLUSIONS

Results of the present study are important in terms of pointing out neurobiological changes related to geriatric depression which are in parallel with the results of the studies in younger patients with depression. However, long-term follow-up studies are required for accurate differentiation of neurocognitive disorders.

Clinical factors associated with progression to dementia in people with late-life depression: a cohort study of patients in secondary care

OBJECTIVES

Depression can be a prodromal feature or a risk factor for dementia. We aimed to investigate which clinical factors in patients with late-life depression are associated with a higher risk of developing dementia and a more rapid conversion.

DESIGN

Retrospective cohort study.

SETTING

South London and Maudsley NHS Foundation Trust (SLaM) secondary mental healthcare services.

PARTICIPANTS

The SLaM Clinical Record Interactive Search was used to retrieve anonymised data on 3659 patients aged 65 years or older who had received a diagnosis of depression in mental health services and had been followed up for at least 3 months.

OUTCOME MEASURES

Predictors of development of incident dementia were investigated, including demographic factors, health status rated on the Health of the National Outcome scale for older people (HoNOS65+), depression recurrence and treatments including psychotropic drugs and cognitive behavioural therapy (CBT).

RESULTS

In total, 806 (22.0%) patients developed dementia over a mean follow-up time of 2.7 years. Significant predictors of receiving a dementia diagnosis in fully adjusted models and after accounting for multiple comparisons were older age (adjusted HR=1.04, 95% CI 1.03 to 1.06 per year difference from sample mean) and the HoNOS65+ subscale measuring cognitive problems (HR=4.72, 95% CI 3.67 to 6.06 for scores in the problematic range). Recurrent depressive disorder or past depression (HR=0.65, 95% CI 0.55 to 0.77) and the receipt of CBT (HR=0.73 95% CI 0.61 to 0.87) were associated with a lower dementia risk. Over time, hazards related to age increased and hazards related to cognitive problems decreased.

CONCLUSIONS

In older adults with depression, a higher risk of being subsequently diagnosed with dementia was predicted by higher age, new onset depression, severity of cognitive symptoms and not receiving CBT. Further exploration is needed to determine whether the latter risk factors are responsive to interventions.

Depression could modulate neuropsychological status in epilepsy

While cognition and depression have often been studied in patients with epilepsy, only a few studies have so far attempted to link these two domains, and more specifically to investigate the specific impact of depression on cognition in epilepsy. In this review, we performed an extensive search of the literature database to provide a better understanding of this subject. Using several inclusion criteria (adult population, quantitative depression/neuropsychological assessment, statistical analyses of the impact of depression on cognitive scores, patients with epilepsy (PWE) and no other neurological disease, and studies including at least 20 patients), we identified 20 articles (out of 712 search results) that investigated both depression and cognition in PWE. Their results were summarized using a narrative and descriptive approach. This review highlights a variable impact of depression on cognition in PWE, depending on the laterality of the seizure onset zone, the type of epilepsy and the surgical context. We emphasize the need for a systematic depression assessment in these patients, especially since depressed PWE will benefit from prompt and appropriate care to help them avoid cognitive decline, particularly in a surgical context.

Evidence for Structural and Functional Alterations of Frontal-Executive and Corticolimbic Circuits in Late-Life Depression and Relationship to Mild Cognitive Impairment and Dementia: A Systematic Review

Depression is a risk factor for developing Alzheimer's disease and Related Dementia (ADRD). We conducted a systematic review between 2008 and October 2018, to evaluate the evidence for a conceptual mechanistic model linking depression and ADRD, focusing on frontal-executive and corticolimbic circuits. We focused on two neuroimaging modalities: diffusion-weighted imaging measuring white matter tract disruptions and resting-state functional MRI measuring alterations in network dynamics in late-life depression (LLD), mild cognitive impairment (MCI), and LLD+MCI vs. healthy control (HC) individuals. Our data synthesis revealed that in some but not all studies, impairment of both frontal-executive and corticolimbic circuits, as well as impairment of global brain topology was present in LLD, MCI, and LLD+MCI vs. HC groups. Further, posterior midline regions (posterior cingulate cortex and precuneus) appeared to have the most structural and functional alterations in all patient groups. Future cohort and longitudinal studies are required to address the heterogeneity of findings, and to clarify which subgroups of people with LLD are at highest risk for developing MCI and ADRD.

On the conundrum of cognitive impairment due to depressive disorder in older patients

Objectives

Depressive symptoms and cognitive impairment often concur in older persons. Differentiating the cause of cognitive impairment in older persons with Depressive Disorder (DD) from other diseases such as Alzheimer’s Disease (AD) is challenging. The goal of this study was to characterize cognitive impairment in older persons with DD.

Design

Cross-sectional retrospective observational clinical cohort study using patient records from 2014 to 2018.

Setting

Gerontopsychiatric services of Ulm University at Bezirkskrankenhaus Günzburg serving as primary psychiatric care institution and tertiary referral center for psychiatric care for older persons.

Partcipants

DD was diagnosed according to ICD-10 criteria. When indicated by the medical history or neuropsychological assessment further diagnostic procedures were initiated. Cerebrospinal fluid (CSF) tap was routinely the first additional procedure. If patients did not consent to CSF tap or contraindications were present, ¹⁸F-fluordesoxyglucose-PET (FDG-PET) or Amyloid-PET (Am-PET) were performed.

Materials and methods

Extensive neuropsychological test battery to assess cognitive profile.

Results

457 subjects were diagnosed with DD (DD-all; age 50–94; 159 males, 298 females). Biomarkers were assessed in 176 persons; in 90 of these subjects AD-biomarkers were negative (DD-BM-; age 54–89; 40 males, 50 females), and in 86 subjects at least one biomarker was compatible with AD (DD-BM+; age 60–90; 31 males, 55 females). Cognitive performance was below healthy controls (HC; n = 56; age 50–80; 30 males, 26 females) for all groups of patients with DD. With case-control matching of HC and DD-BM- we find that executive functions are impaired in about one out of three and delayed recall in about two out of three patients with DD.

Conclusion

Cognitive impairment is frequent in older persons with DD. Cognitive profile in older patients with DD without and with biomarkers of AD is not distinguishable. Therefore, cognitive impairment due to DD should be diagnosed after exclusion of comorbid AD.

Late life depressive symptoms and cognitive function among older Mexican adults: the past and the present

Objective: To evaluate associations between depression and individual cognitive domains and how changes in depressive symptoms relate to cognition three years later in the context of Mexico, a developing country experiencing rapid aging.Method: Data comes from the 2012 and 2015 waves of the Mexican Health and Aging Study (n = 12,898, age 50+). Depression is ascertained using a modified Center for Epidemiologic Studies - Depression Scale. Cognition is assessed using verbal learning, verbal memory, visual scanning, verbal fluency, visuospatial ability, visual memory, and orientation tasks. Depressive symptoms and cognitive functioning were both measured in 2012 and 2015. Scores across cognitive domains are modeled using ordinary least squares regression, adjusting for demographic, health, and economic covariates.Results: When depression and cognition were measured concurrently in 2015, depression exhibited associations with all cognitive domains. When considering a respondent's history of depression, individuals who had elevated depressive symptoms in 2012 and recovered by 2015 continued to exhibit poorer cognitive function in 2015 in verbal learning, verbal memory, visual scanning, and verbal fluency tasks compared to individuals who were neither depressed in 2012 nor 2015.Conclusions: Depression was associated with cognition across cognitive domains among older Mexican adults. Despite improvements in depressive symptomatology, formerly depressed respondents continued to perform worse than their counterparts without a history of depression on several cognitive tasks. In addition to current mental health status, researchers should consider an individual's history of depression when assessing the cognitive functioning of older adults.

Association between Changes in Depressive State and Cognitive Function

Dementia is defined as a severe form of cognitive impairment. Research concerning the two-way relationship between depression and cognitive impairment has been conducted; however, there has been little analysis of cognitive function following changes in depressive status. This study describes the association between changes in depressive state and cognitive function in a Korean geriatric population sample. Using the Korean Longitudinal Study of Aging (KLoSA) database, Mini-Mental State Examination (MMSE) scores and Center for Epidemiologic Studies Depression Scale (CESD-10) indexes were used for measuring cognitive function and depression, respectively. The survey population was divided into four case categories by change in depressive status: normal to normal (Group A), normal to depressive (Group B), depressive to normal (Group C), and depressive to depressive (Group D). Analysis of variance, multiple regression analysis, and subgroup analysis were used for statistical examination. In the multiple regression analysis between MMSE values and depressive status change groups, with Group A as the reference, β in all other groups was negative, and its absolute value was large in the order of D, B, and C in both men (B: −0.717, C: −0.416, D: −1.539) and women (B: −0.629, C: −0.430, D: −1.143). There were also significant results in the subgroup analysis in terms of age, working status, participation in social activities, regular physical activities, and number of chronic medical conditions. In conclusion, both cases—those suffering from depression and those having suffered from it before—experience cognitive impairment. The degree of cognitive function being impaired is greater in the case of depression-onset than that of depression-remission. Age, stimulating activities, and chronic conditions are also strongly relevant to cognitive decline accompanied by changes in depressive state.

Disruption of Neural Homeostasis as a Model of Relapse and Recurrence in Late-Life Depression

The significant public health burden associated with late-life depression (LLD) is magnified by the high rates of recurrence. In this manuscript, we review what is known about recurrence risk factors, conceptualize recurrence within a model of homeostatic disequilibrium, and discuss the potential significance and challenges of new research into LLD recurrence. The proposed model is anchored in the allostatic load theory of stress. We review the allostatic response characterized by neural changes in network function and connectivity and physiologic changes in the hypothalamic-pituitary-adrenal axis, autonomic nervous system, immune system, and circadian rhythm. We discuss the role of neural networks' instability following treatment response as a source of downstream disequilibrium, triggering and/or amplifying abnormal stress response, cognitive dysfunction and behavioral changes, ultimately precipitating a full-blown recurrent episode of depression. We propose strategies to identify and capture early change points that signal recurrence risk through mobile technology to collect ecologically measured symptoms, accompanied by automated algorithms that monitor for state shifts (persistent worsening) and variance shifts (increased variability) relative to a patient's baseline. Identifying such change points in relevant sensor data could potentially provide an automated tool that could alert clinicians to at-risk individuals or relevant symptom changes even in a large practice.

Cognitive Deficits in Older Adults With Psychotic Depression: A Meta-Analysis

A major depressive disorder with psychotic features, that is, psychotic depression (PD), is often accompanied by cognitive deficits, particularly in older patients. We aimed to assess to what extent various cognitive domains are affected in older patients with PD compared to those with nonpsychotic depression (NPD). Therefore, a systematic search was conducted in Medline, Embase, Web of Science, the Cumulative Index to Nursing and Allied Literature (CINAHL), Google Scholar, and Cochrane for all relevant studies. Hereafter, we conducted a meta-analysis of seven studies on cognitive deficits in older adults (55+ years), comparing patients with PD and patients with NPD. Compared to patients with NPD, those with PD not only showed a significantly poorer performance on overall cognitive function, with a Hedges' g effect size of -0.34 (95% confidence interval: -0.56; -0.12; p = 0.003), but also on nearly all separate cognitive domains, with Hedges' g effect sizes ranging from -0.26 to -0.64 (all p's <0.003), of which attention was most adversely affected. Verbal fluency showed no significant effect, although this analysis may have been underpowered. The funnel plot suggested no significant publication bias (Egger test intercept: -2.47; 95% confidence interval: -5.50; 0.55; p = 0.09). We conclude that older patients with PD show more cognitive deficits on all cognitive domains, except for verbal fluency, compared to patients with NPD. It is crucial that clinicians and researchers take cognitive deficits into consideration in older adults with PD.

Cognitive function following a major depressive episode: a systematic review and meta-analysis

BACKGROUND

Substantial evidence suggests that cognitive deficits might persist after remission of a major depressive episode. However, results are inconsistent relative to the importance, pattern, severity, and moderating factors of this impairment. We aimed to determine how cognitive function following a major depressive episode compares with normal function, to specify the pattern and severity of persistent cognitive dysfunctions, and to examine the potential moderator effect of ten prespecified clinical and demographic variables.

METHODS

We did a systematic review and meta-analysis of the published research. We searched systematically MEDLINE, Embase, PsycARTICLES, PsycINFO, the Cochrane Library, and relevant reviews identified by our database search, for research published from Jan 1, 1972, up to Jan 31, 2018, for studies of patients with past depression. We included all independent studies of patients who were assessed while in remission from a major depressive episode with at least one cognitive test, with inclusion of a healthy control group assessed with either the same test(s) as the major depressive episode group or with a standardised test with published age-stratified normative data. The main outcome was the difference in cognitive performance between major depressive episode remitters and healthy controls. Effect sizes were calculated using random-effects models for cognitive outcomes classified into 18 standard domains. Moderators of between-study variability were assessed using mixed-effects subgroup analyses and meta-regressions.

FINDINGS

Of 10 126 citations identified by our search, 75 cognitive variables from 252 eligible studies (11 882 major depressive episode remitters and 8533 healthy controls) were included in our meta-analysis. Significant deficits following major depressive episode remission were observed in 55 (73%) of the 75 cognitive variables. These deficits (in the domains of processing speed, visual selective attention, working memory, verbal learning, and executive functioning), were generally small (30 [40%] of the 75 variables) or medium (22 [29%]) in size, although three long-term memory variables showed large deficits: g=-0·81 [95% CI -1·01 to -0·61] for logical memory immediate recall, g=-0·88 [-1·19 to -0·57] for logical memory delayed recall, and g=-0·84 [-1·18 to -0·50] for Cambridge Neuropsychological Test Automated Battery pattern recognition latency. Auditory attention, general autobiographical memory, inhibition ability unconstrained by speed, and intellectual functioning unconstrained by speed were equivalent between major depressive episode remitters and matched controls. The number of previous depressive episodes explained heterogeneity in the majority of variables (z=-2·06 [p=0·039] to z=-4·26 [p<0·0001]).

INTERPRETATION

Deficits in selective attention, working memory, and long-term memory persist in remission from a major depressive episode and worsen with repeated episodes. Depression treatments, including relapse prevention, need to target these cognitive functions to optimise prognosis.

FUNDING

None.

Cardiovascular diseases and related risk factors accelerated cognitive deterioration in patients with late-life depression: a one-year prospective study

OBJECTIVES

Cognitive impairment in late-life depression is common and associated with a higher risk of all-cause dementia. Late-life depression patients with comorbid cardiovascular diseases (CVDs) or related risk factors may experience higher risks of cognitive deterioration in the short term. We aim to investigate the effect of CVDs and their related risk factors on the cognitive function of patients with late-life depression.

METHODS

A total of 148 participants were recruited (67 individuals with late-life depression and 81 normal controls). The presence of hypertension, coronary heart disease, diabetes mellitus, or hyperlipidemia was defined as the presence of comorbid CVDs or related risk factors. Global cognitive functions were assessed at baseline and after a one-year follow-up by the Mini-Mental State Examination (MMSE). Global cognitive deterioration was defined by the reliable change index (RCI) of the MMSE.

RESULTS

Late-life depression patients with CVDs or related risk factors were associated with 6.8 times higher risk of global cognitive deterioration than those without any of these comorbidities at a one-year follow-up. This result remained robust after adjusting for age, gender, and changes in the Hamilton Depression Rating Scale (HAMD) scores.

CONCLUSIONS

This study suggests that late-life depression patients with comorbid CVDs or their related risk factors showed a higher risk of cognitive deterioration in the short-term (one-year follow up). Given that CVDs and their related risk factors are currently modifiable, active treatment of these comorbidities may delay rapid cognitive deterioration in patients with late-life depression.

Cognitive profiles in major depressive disorder: Comparing remitters and non-remitters to rTMS treatment

Major Depressive Disorder (MDD) is typically accompanied by cognitive impairment. Repetitive Transcranial Magnetic Stimulation (rTMS) treatment for MDD involves stimulation of the dorsolateral prefrontal cortex which plays an important role in cognition. This study aimed to identify differences in cognitive profiles between remitters and non-remitters to rTMS at baseline and across treatment. 25 patients with MDD performed cognitive tasks at baseline and after 6, 12 and 30 sessions of rTMS. At baseline, there was no difference in simple reaction time (RT) between groups, but remitters (n = 13) showed faster RTs than non-remitters (n = 12) in the Switch and No-Switch conditions of Task Switching. Across sessions, remitters showed a decrease in 3-Back omission errors and RTs to 3-Back, Stroop's Congruent and Incongruent, and Task Switching's Switch and No-Switch conditions, whereas non-remitters only showed improvements in Stroop Congruent and Incongruent RTs. Baseline and final scores on the Hamilton Depression Rating Scale were positively correlated with Switch and No-Switch RTs. This study demonstrates that eventual remitters to rTMS treatment for MDD perform better in cognitive tasks requiring shifting attention, and this difference is observable prior to the start of treatment. Remitters also show improvement in both their mood and cognitive performance.

Management of Late-Life Depression in the Context of Cognitive Impairment: a Review of the Recent Literature

PURPOSE OF REVIEW

Evidence regarding the treatment of late-life depression is not necessarily generalizable to persons with a neurocognitive disorder and comorbid depression. Thus, this article reviews recent evidence that pertains to the treatment of depression in older adults with neurocognitive disorders, and synthesizes and critically analyzes this literature to identify methodological issues and gaps for the purpose of future research.

RECENT FINDINGS

Controlled trials and meta-analyses examining depression treatment in neurocognitive disorders, published between 2015 and 2019 (N = 16 reports), can be divided into those addressing pharmacotherapy, psychological and behavioral therapy, and somatic therapy. The evidence generally does not support benefit of antidepressant medication over placebo in treating depressive disorders in dementia. No pharmacological studies since 2015 have examined antidepressant medication in participants with mild cognitive impairment (MCI). Problem adaptation therapy demonstrates efficacy for depression in MCI and mild dementia. Other psychological and behavioral interventions for depressive symptoms in dementia demonstrate mixed findings. The only somatic treatment trials published since 2015 have assessed bright light therapy, with positive findings but methodological limitations. Psychological, behavioral, and somatic treatments represent promising treatment options for depression in neurocognitive disorders, but further studies are needed, particularly in participants with depressive disorders rather than subclinical depressive symptoms. Little is known about the treatment of depression in patients with MCI, and rigorous identification of MCI in late-life depression treatment trials will help to advance knowledge in this area. Addressing methodological issues, particularly the diagnosis and measurement of clinically significant depression in dementia, will help to move the field forward.

ASSOCIATION OF DEPRESSIVE SYMPTOMS AND SUBJECTIVE MEMORY COMPLAINTS WITH THE INCIDENCE OF COGNITIVE IMPAIRMENT IN OLDER ADULTS WITH HIGH BLOOD PRESSURE

PURPOSE

High blood pressure is a relevant risk factor for vascular damage, leading to development of depressive symptoms and dementia in older adults. Moreover, subjective memory complaints are recognized as an early marker of cognitive impairment. However, it has been established that subjective memory complaints could also be a reflection of depressive symptoms. The objective of this paper is to assess the impact of depressive symptoms and subjective memory complaints on the incidence of cognitive impairment in older adults with high blood pressure.

METHODS

This is a secondary analysis of the Mexican Health and Aging Study, a representative cohort composed by individuals aged ≥ 50 years. Participants with cognitive impairment in 2012 were excluded since the outcome was incident cognitive impairment in 2015. Four groups were created according to depressive symptomatology and subjective memory complaints status, analyses were stratified according to blood pressure status. The odds incident cognitive impairment was estimated through logistic regression models.

RESULTS

A total of 6,327 participants were included, from which 6.44% developed cognitive impairment. No differences were seen regarding the development of cognitive impairment in participants without high blood pressure. However, increased risk was evident in those with both high blood pressure and depressive symptoms (OR=2.1, 95% CI 1.09 - 4.09, p =0.026) as with high blood pressure, depressive symptoms and subjective memory complaints (OR=1.91, 9% CI 1.4 - 3.2, p= 0.001).

CONCLUSION

Individuals with high blood pressure have a higher risk of developing incident cognitive impairment when depressive symptoms and/or subjective memory complaints are present. Our results suggest that a sequence of events related to altered cerebral vascular dynamics is possible.

The impact of white matter hyperintensities on the structural connectome in late-life depression: Relationship to executive functions

BACKGROUND

White matter hyperintensities (WMH) represent ischemic white matter damage in late-life depression (LLD) and are associated with cognitive control dysfunction. Understanding the impact of WMH on the structural connectivity of gray matter and the cognitive control correlates of WMH-related structural dysconnectivity can provide insight into the pathophysiology of LLD.

METHODS

We compared WMH burden and performance on clinical measures of cognitive control in patients with LLD (N = 44) and a control group of non-depressed older adults (N = 59). We used the Network Modification (NeMo) Tool to investigate the impact of WMH on structural dysconnectivity in specific gray matter regions, and how such connectivity was related to cognitive control functions.

RESULTS

Compared to the control group, LLD participants had greater WMH burden, poorer performance on Trail Making Test (TMT) A & B, and greater self-reported dysexecutive behavior on the Frosntal Systems Behavior Scale-Executive Function subscale (FrSBe-EF). Within the LLD group, disrupted connectivity in the left supramarginal gyrus, paracentral lobule, thalamus, and pallidum was associated with psychomotor slowing (TMT-A). Altered connectivity in the left supramarginal gyrus, paracentral lobule, precentral gyrus, postcentral gyrus, thalamus, and pallidum was associated with poor attentional set-shifting (TMT-B). A follow-up analysis that isolated set-shifting ability (TMT-B/A ratio) confirmed the association with dysconnectivity in the bilateral paracentral lobule, right thalamus, left precentral gyrus, postcentral gyrus, and pallidum; additionally, it revealed associations with dysconnectivity in the right posterior cingulate, and left anterior cingulate, middle frontal cortex, and putamen.

CONCLUSIONS

In LLD, WMH are associated with region-specific disruptions in cortical and subcortical gray matter areas involved in attentional aspects of cognitive control systems and sensorimotor processing, which in turn are associated with slower processing speed, and reduced attentional set-shifting.

CLINICAL TRIALS REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT01728194.

Depressive symptoms in relation to clinical symptom onset of mild cognitive impairment

ABSTRACTObjective:There is increasing evidence of an association between depressive symptoms and mild cognitive impairment (MCI) in cross-sectional studies, but the longitudinal association between depressive symptoms and risk of MCI onset is less clear. The authors investigated whether baseline symptom severity of depression was predictive of time to onset of symptoms of MCI.

METHOD

These analyses included 300 participants from the BIOCARD study, a cohort of individuals who were cognitively normal at baseline (mean age = 57.4 years) and followed for up to 20 years (mean follow-up = 2.5 years). Depression symptom severity was measured using the Hamilton Depression Scale (HAM-D). The authors assessed the association between dichotomous and continuous HAM-D and time to onset of MCI within 7 years versus after 7 years from baseline (reflecting the mean time from baseline to onset of clinical symptoms in the cohort) using Cox regression models adjusted for gender, age, and education.

RESULTS

At baseline, subjects had a mean HAM-D score of 2.2 (SD = 2.8). Higher baseline HAM-D scores were associated with an increased risk of progression from normal cognition to clinical symptom onset ≤ 7 years from baseline (p = 0.043), but not with progression > 7 years from baseline (p = 0.194). These findings remained significant after adjustment for baseline cognition.

CONCLUSIONS

These results suggest that low levels of depressive symptoms may be predictive of clinical symptom onset within approximately 7 years among cognitively normal individuals and may be useful in identifying persons at risk for MCI due to Alzheimer's disease.

Immunological Aspects of Depressive Disorder – The Review

Depression represents a mood disorder and is considered to be one of the most common mental disorders in general. World Health Organization estimates that depression will be the leading cause of disability-adjusted life years, until 2030. Depression is a complex heterogeneous disorder where immune system and its regulation play an important role. Innate and adaptive immunity mecha nisms are included, along with processes of immune activation and suppression. The expression of humoral factors of innate immunity, especially pro-inflammatory cytokines, is increased, whereas the intensity of cellular immune mechanisms, primarily T cells and NK cells, are impaired. The influence of pro-inflammatory cytokines on depression is reflected in their effect on certain enzymes and ensuing reduction of neurotransmitters serotonin and dopamine. They also affect the neuroendocrine function in central nervous system, resulting in increase of cortisol levels and inactivation of glucocorticoid receptors in the periphery, which leads to neurodegeneration and decrease in neurotransmitter production. Certain cytokines affect neuroplasticity through the decreasing of concentration of neurotrophic brain factor and induction of brain cell apoptosis. The results are often contradictory talking about mechanisms of adaptive immunity. On one hand, an increased activity of Tlymphocytes is observed, while on the other, there are evidence of spontaneous apoptosis and impaired function of these cells in depression. In addition, neuroprotective role of autoreactive and regulatory T cells in prevention of depression has also been demonstrated. The aim of this paper is to analyze the current knowledge on the role of immune mechanisms in the pathogenesis of depression.

Toward Prevention of Mild Cognitive Impairment in Older Adults With Depression: An Observational Study of Potentially Modifiable Risk Factors

OBJECTIVE

Late-life depression has been associated with increased risk of mild cognitive impairment (MCI) and dementia. Predictors of increased risk are incompletely understood. Identification of potentially modifiable risk factors could facilitate prevention of MCI and dementia. This study aimed to determine which clinical characteristics are associated with increased risk of MCI among older adults with depression and normal cognition at baseline.

METHODS

Data from the National Alzheimer's Coordinating Center dataset were used. Study participants who attended a participating Alzheimer's Disease Center from September 2005 through September 2017 with normal cognition and a history of clinically defined depression (broadly based on DSM criteria) were followed until first diagnosis of MCI (or dementia when MCI was not diagnosed).

RESULTS

A total of 2,655 study participants were followed for a median duration of 41.8 months. Of these, 586 (22.1%) developed either MCI (n = 509, 19.2%) or dementia (n = 77, 2.9%). In survival analyses, cognitive decline was associated with age, sex, education, baseline cognition, and several potentially modifiable risk factors including vascular risk factors, hearing impairment, vitamin B₁₂ deficiency, active depression within the last 2 years, and increased severity of depression. In an adjusted survival analysis, the only variables that remained significantly associated with development of MCI or dementia were female sex (HR = 0.72; 95% CI, 0.59-0.88), higher education (HR = 0.96; 95% CI, 0.93-0.99), and higher baseline cognition (HR = 0.87; 95% CI, 0.82-0.93), which were associated with reduced risk, and older age (HR = 1.07; 95% CI, 1.05-1.08), active depression within the last 2 years (HR = 1.41; 95% CI, 1.15-1.74), and increased severity of depression (HR = 1.05; 95% CI, 1.02-1.09), which were associated with increased risk.

CONCLUSIONS

Development of MCI is associated with several potentially modifiable risk factors in older adults with depression. Future studies should determine whether active management of risk factors could reduce incidence of MCI in this vulnerable population.

A reliable global cognitive decline and cortisol as an associated risk factor for patients with late-life depression in the short term: A 1-year prospective study

BACKGROUND

Late-life depression is a risk factor of dementia. It may increase the risk of reliable cognitive decline in the short term, and its associated risk factors remain unclear. Cortisol level may be one of the important predictors.

OBJECTIVES

To estimate whether patients with late-life depression are at an increased risk for reliable global cognitive declines in 1 year, and explore associated risk factors predicting cognitive declines.

METHODS

This prospective 1-year follow-up study involved 148 participants (67 with late-life depression and 81 normal elderly). Global cognitive function was assessed by the Mini-Mental State Examination (MMSE). The reliable global cognitive decline was defined by the reliable change index (RCI) of the MMSE. Factors related to cognitive function (e.g., age, gender, education, duration of depression and severity of depression) were obtained. Serum cortisol levels were measured at baseline.

RESULTS

At the 1-year follow-up assessment, 19 patients with late-life depression (28.4%) showed reliable global cognitive declines, a risk that was 6.4 times (95% CIs = 1.3-31.1, p = 0.021) higher than that of normal elderly. Elevated serum cortisol levels and older age were associated with the risk of cognitive decline that was 1.6- and 1.2-times higher (95% CIs = 1.07-2.5, p = 0.02, and 95% CIs = 1.04-1.4, p = 0.01 respectively).

LIMITATIONS

Serum cortisol levels were measured only in the morning.

CONCLUSIONS

Late-life depression is associated with a greatly increased risk of reliable cognitive decline in short term. Cortisol dysregulation may contribute to the pathology of cognitive decline.

Aberrant Default Mode Network Underlying the Cognitive Deficits in the Patients With Late-Onset Depression

Late-onset depression (LOD) is regarded as a risk factor or a prodrome of Alzheimer’s disease (AD). Moreover, LOD patients with cognitive deficits have the higher risk of subsequent AD. Thus, it is necessary to understand the neural underpinnings of cognitive deficits and its pathological implications in LOD. Consistent findings show that the default mode network (DMN) is an important and potentially useful brain network for the cognitive deficits in LOD patients. In recent years, genetics has been actively researched as a possible risk factor in the pathogenesis of LOD. So, in this review, we discuss the current research progress on the cognitive deficits and DMN in LOD through a combined view of brain network and genetics. We find that different structural and functional impairments of the DMN might be involved in the etiological mechanisms of different cognitive impairments in LOD patients.

The neural correlates of perceived energy levels in older adults with late-life depression

Late-life depression is common among older adults. Although white-matter abnormality is highly implicated, the extent to which the corticospinal tract is associated with the pathophysiology of late-life depression is unclear. The current study aims to investigate the white-matter structural integrity of the corticospinal tract and determine its cognitive and functional correlates in older adults with late-life depression. Twenty-eight older adults with clinical depression and 23 healthy age-matched older adults participated in the study. The white matter volume and the white matter hyperintensities (WMHs) of the corticospinal tract, as well as the global WMHs, were measured. Psychomotor processing speed, severity of depression, perceived levels of energy and physical functioning were measured to examine the relationships among the correlates in the depressed participants. The right corticospinal tract volume was significantly higher in depressed older adults relative to healthy controls. Moreover, the right corticospinal tract volume was significantly associated with the overall severity of depression and accounted for 17% of its variance. It further attenuated the relationship between the severity of depression and perceived levels of energy. Our findings suggested that higher volume in the right corticospinal tract is implicated in LLD and may relate to lower perceived levels of energy experienced by older adults with depression.

The association between urinary Alzheimer-associated neuronal thread protein and cognitive impairment in late-life depression: a controlled pilot study

Accumulation of tau protein is associated with both Alzheimer's disease (AD) and late-life depression (LLD). Alzheimer-associated neuronal thread protein (AD7c-NTP), which is closely linked with the tau protein, is elevated in the cerebrospinal fluid and urine of AD patients. This study examined the association between urinary AD7c-NTP and late-life depression with cognitive impairment. One hundred and thirty-eight subjects were recruited into late-life depression with cognitive impairment (LLD-CI, n=52), late-life depression without cognitive impairment (LLD-NCI, n=29), AD (n=27), and healthy control (HC, n=30) groups. The level of urinary AD7c-NTP was measured using the enzyme-linked immunosorbent assay method. The Montreal Cognitive Assessment scale (MoCA), Hamilton Rating Scale for Depression (HRSD) and Hamilton Anxiety Rating Scale (HAMA) were used to assess cognitive functions and depressive and anxiety symptoms in the AD and LLD groups. Urinary levels of AD7c-NTP in the LLD-CI group (1.0±0.7ng/ml) were significantly higher than both the LLD-NCI (0.5±0.3ng/ml) and HC groups (0.5±0.3ng/ml), but lower than in the AD group (1.6±1.7 ng/ml). No significant associations were found in the level of urinary AD7c-NTP in relation to age, gender, education and MoCA in the LLD-CI group. The level of urinary AD7c-NTP appears to be associated with cognitive impairment in late-life depression and may be a potential biomarker for early identification of cognitive impairment in LLD.

Cognitive performance in antidepressant-free recurrent major depressive disorder

BACKGROUND

Cognitive complaints are common in depression, and cognition may be an important treatment target as cognitive problems often remain during remission and may contribute to recurrence risk. Previous studies of cognitive performance in depression have mainly examined late-life depression, with a focus on older adults, or assessed performance in specific cognitive tasks rather than cognitive domains.

METHODS

This study examined cognitive performance across multiple cognitive domains in antidepressant-free depressed adults with early onset recurrent depression compared to never-depressed controls. Domain scores were calculated for episodic memory, executive function, processing speed, and working memory, and the effect of depression diagnosis, depression severity, and depression duration on each domain score was examined, including interactions with age, sex, and education.

RESULTS

Currently depressed adults (n = 91) exhibited poorer performance in the processing speed domain compared with never-depressed adults (n = 105). Additionally, there was an interactive effect of depression duration and age on processing speed and executive function domain performance, such that performance was worse with older age and longer duration of depression. There were no effects of depression severity on performance across the cognitive domains.

CONCLUSIONS

These findings support that processing speed deficits appear in young adults with early onset depression that may not be related to current mood. Additionally, the effects of cumulative depressive episodes may interact with aging such that cognitive performance deficits worsen with recurrence over the lifespan.

Diversity of neurodegenerative pathophysiology in nondemented patients with major depressive disorder: Evidence of cerebral amyloidosis and hippocampal atrophy

BACKGROUND

Patients with late-life depression may be at the preclinical stage of dementia. However, the neurodegenerative processes in late-life depression are poorly understood. This study aimed to investigate the distribution patterns of amyloid pathology and neurodegeneration in a depressive population without dementia.

METHODS

The study recruited 63 middle-aged and elderly patients with major depressive disorder (MDD) and 22 control subjects. The MDD patients were further subdivided into those with mild cognitive impairment (MCI) (n = 24) and non-MCI (n = 39) patients. We used the global standardized uptake value ratio of ¹⁸ F-florbetapir (AV-45/Amyvid) positron emission tomography imaging as a biomarker of cerebral amyloidosis and the hippocampal volume as a biomarker for neurodegeneration. Cutoff points of brain amyloid positivity and hippocampal atrophy were determined using independent data obtained from clinically diagnosed Alzheimer's disease (AD) patients in a previous study.

RESULTS

Most of the control subjects (81.8%) were biomarker-negative, in contrast to the MCI MDD patients (37.5%). A relatively high proportion of the MCI MDD patients (12.5%) exhibited both amyloid positivity and hippocampal atrophy as compared to the control subjects (4.5%) and non-MCI patients (5.1%). However, a considerable proportion of the MCI MDD patients (29.2%) were categorized into the group with hippocampal atrophy alone, and negative amyloid deposition, as compared to the control subjects (0%) and non-MCI patients (5.1%).

CONCLUSIONS

This study highlights the expected heterogeneity of the processes of neurodegeneration in MDD patients. The diverse neurodegenerative processes may have important etiologic and therapeutic implications regarding neurodegenerative pathophysiology in late-life depression.

Aberrant topographical organization in default-mode network in first-episode remitted geriatric depression: a graph-theoretical analysis

ABSTRACTBackground:Neuroimaging studies have shown that major depressive disorder is associated with altered activity patterns of the default-mode network (DMN). In this study, we sought to investigate the topological organization of the DMN in patients with remitted geriatric depression (RGD) and whether RGD patients would be more likely to show disrupted topological configuration of the DMN during the resting-state.

METHODS

Thirty-three RGD patients and thirty-one healthy control participants underwent clinical and cognitive evaluations as well as resting-state functional magnetic resonance imaging scans. The functional connectivity (FC) networks were constructed by thresholding Pearson correlation metrics of the DMN regions defined by group independent component analysis, and their topological properties (e.g. small-world and network efficiency) were analyzed using graph theory-based approaches.

RESULTS

Relative to the healthy controls, the RGD patients showed decreased FC in the posterior regions of the DMN (i.e. the posterior cingulate cortex/precuneus, angular gyrus, and middle temporal gyrus). Furthermore, the RGD patients showed abnormal global topology of the DMN (i.e. increased characteristic path length and reduced global efficiency) when compared with healthy controls. Importantly, significant correlations between these network measures and cognitive performance indicated their potential use as biomarkers of cognitive dysfunction in RGD.

CONCLUSIONS

The present study indicated disrupted FC and topological organization of the DMN in the context of RGD, and further implied their contribution to cognitive deficits in RGD patients.

Severity of Depression Impacts Imminent Conversion from Mild Cognitive Impairment to Alzheimer's Disease

BACKGROUND

Mild cognitive impairment (MCI) has been suggested to represent a prodromal stage of dementia and to confer a high risk for conversion to dementia Alzheimer's type (DAT).

OBJECTIVES

In this study, we examined the predictive value of depressive symptoms and neuropsychological variables on conversion of MCI to DAT.

METHODS

Neuropsychological and clinical follow-up data of 260 MCI patients seen at the Psychiatric Memory Clinic of the Medical University of Innsbruck between 2005 and 2015 were analyzed retrospectively. Depression was assessed using the Geriatric Depression Scale (GDS). Potential predictors of conversion from MCI to DAT were analyzed by logistic regression analyses and additional survival-analytic methods.

RESULTS

Of the 260 patients (mean age 71.5±7.7 years), 83 (32%) converted to DAT within a mean follow-up time of 3.2±2.2 years and estimated one-year conversion rate of 10.1%. The univariate analysis showed with few exceptions (gender, use of antidepressants, low GDS score) group differences at baseline in patients converted to DAT compared to stable MCI patients. Logistic regression analysis as well as survival analysis revealed moderate to severe depression together with higher age and specific cognitive deficits as predictors of conversion from MCI to DAT.

CONCLUSION

Our results support the predictive value of different neuropsychological measures on the progression of DAT. In addition, we found a strong negative influence of depression on conversion to DAT in MCI patients. These results emphasize the importance of assessing depressive symptoms in the early stages of DAT when evaluating the conversion from MCI to DAT.

Exercise for Cognitive Symptoms in Depression: A Systematic Review of Interventional Studies

OBJECTIVE

To explore the effect of exercise on cognition in depression as well as the impact of potential moderators and intervention type.

METHOD

Controlled and uncontrolled interventional studies that described an exercise intervention and cognitive outcomes in participants with major depressive disorder (MDD) were included following a search of Pubmed, Ovid Medline, PsycInfo and Embase from inception to January 2017. Meta-analyses were conducted to calculate Hedges' g using a random-effects model. Meta-regression explored the relationships among age, baseline cognition, frequency and duration of exercise, and cognitive outcomes. Subgroup analyses were also conducted according to type and intensity of exercise interventions.

RESULTS

Of 12 controlled studies and 3 uncontrolled studies that met inclusion criteria, 9 (642 patients) were included in the meta-analysis. No significant effect of exercise was found on global cognition (Hedges' g = 0.08, P = 0.33, I2 = 0%) or on individual cognitive domains. Meta-regression analyses failed to find significant relationships among participant age, baseline cognition, number of exercise sessions per wk, duration of exercise per wk, total duration of exercise during the intervention, or improvement in global cognition. Interventions combining physical with cognitive activity significantly improved global cognition ( P = 0.048), whereas low-intensity interventions were also positive ( P = 0.048).

CONCLUSIONS

No impact of physical exercise was found on cognition in MDD overall. However, we found that interventions combining physical and cognitive activities had a positive impact, and that lower-intensity interventions, where adherence was improved, also impacted positively. There remains a lack of high-quality data in this population.

Cytokine alterations and cognitive impairment in major depressive disorder: From putative mechanisms to novel treatment targets

Overwhelming evidence indicates the involvement of immune-inflammatory processes in the pathophysiology of major depressive disorder (MDD). Peripheral cytokine alterations serve as one of most consistently reported indices of subthreshold inflammatory state observed in MDD. Although cytokines cannot pass directly through the blood-brain barrier, a number of transport mechanisms have been reported. In addition, peripheral cytokines may impact central nervous system via downstream effectors of their biological activity. Animal model studies have provided evidence that cytokines might impact cognitive performance through direct and indirect effects on long-term potentiation, neurogenesis and synaptic plasticity. Therefore, it has been hypothesized that cytokine alterations might contribute to cognitive impairment that is widely observed in MDD and persists beyond episodes of acute relapse in the majority of patients. Although several studies have provided that peripheral cytokine alterations might be related to cognitive deficits in patients with MDD, the quality of evidence still leaves much to be desired due to methodological heterogeneity and limitations. In this article, we provide an overview of studies investigating the association between peripheral cytokine alterations and cognitive performance in MDD, discuss underlying mechanisms and neural substrates. Finally, we propose possible treatment targets related to cytokine alterations taking into account existing evidence for antidepressant efficacy of anti-inflammatory pharmacological treatment modalities.

Unlocking Neurocognitive Substrates of Late-Life Affective Symptoms Using the Research Domain Criteria: Worry Is an Essential Dimension

While investigations have sought to identify the distinct and shared contributions of anxiety and depression to neurocognitive processes in late life, less is known regarding the further contribution of worry, a unique and critical dimension of affective dysregulation. Capturing the full range of symptoms, as inspired by the NIH Research Domain Criteria (RDoC), may provide finer-grained information on inter-relationships among worry, anxiety and depression on neurocognitive processing in later life. The objective of this study was to determine if the dimensional trait of worry intensifies known negative associations of dimensional measures of anxiety and depressive symptoms with neurocognitive processes, specifically cognitive control and memory processes. Using a cross-sectional and observational design, this study was conducted within a translational research center located with a Veterans medical center in Northern California. One hundred and nineteen community-residing older adults ages 65-91 years participated, and were characterized with psychiatric and neurocognitive dimensional measures. Affective symptom severity was assessed with the Penn State Worry Questionnaire, the Beck Anxiety Inventory (BAI), and the Beck Depression Inventory-II. Primary neurocognitive outcomes were inhibitory control assessed using a Stroop paradigm and delayed verbal memory assessed with the Rey Auditory Verbal Learning Test. Secondary outcomes included other less frequently examined cognitive control mechanisms (working memory, information processing, and verbal fluency) and memory processes (visual delayed memory). Contrary to prediction, the dimensional trait of worry attenuated negative associations between anxiety and depressive symptoms and inhibitory control on the one hand, and between depressive symptoms and delayed verbal memory processes on the other. In the secondary models, symptom dimensions were not associated with other cognitive control or visual delayed memory processes. Our fine-grained approach, in line with the NIMH RDoC model, suggests the neurocognitive processes associated with dimensional measures of late-life affective symptoms are dissociable. Specifically, dimensional measures of worry operate independently from other anxiety and depression symptoms to reveal differential patterns of neurocognitive processes associated with affective dysregulation.

The effect of rat strain and stress exposure on performance in touchscreen tasks

Patients suffering from depression-associated cognitive impairments often recover incompletely after remission from the core symptoms of depression (lack of energy, depressed mood and anhedonia). This study aimed to set the basis for clinically relevant testing of cognitive impairments in a preclinical model of depression. Hence, we used the chronic mild stress (CMS) model of depression, which provokes the core symptom of anhedonia in a fraction of the stress exposed animals, while others remain resilient, and assessed the entire CMS groups' cognitive performance on the touchscreen operant platform. Specifically, we applied the pairwise discrimination (PD) and reversal task including a retention phase on Wistar and Long Evans controls and CMS exposed Long Evans rats. We observed differences between the albino Wistar and the pigmented Long Evans strain regarding performance in the PD and reversal task as well as in memory consolidation. CMS exposure did not alter learning and memory in the PD and reversal task, even though it altered affective behaviours in the elevated plus-maze and open field test. This is likely due to the heterogeneity of the CMS group, in which stress exposure elicited the expected range of phenotypes from anhedonic-like to resilient shown with the sucrose consumption test. Thus, our study suggests that pigmented rat strains, such as Long Evans, are superior to albino rats in the vision-based touchscreen studies. Furthermore, we propose investigation of the CMS subgroups in more complex, hippocampus-dependent tasks to refine a translational preclinical model of depression-induced cognitive impairments. Hence, this study increased awareness of strain-specific differences in touchscreen performance and added to the literature regarding the sensitivity of the PD and reversal task to stress-induced cognitive alterations.

Domain-specific impairment in cognitive control among remitted youth with a history of major depression

AIM

Impairment in neuropsychological functioning is common in major depressive disorder (MDD), but it is not clear to what degree these deficits are related to risk (e.g. trait), scar, burden or state effects of MDD. The objective of this study was to use neuropsychological measures, with factor scores in verbal fluency, processing speed, attention, set-shifting and cognitive control in a unique population of young, remitted, unmedicated, early course individuals with a history of MDD in hopes of identifying putative trait markers of MDD.

METHODS

Youth aged 18-23 in remission from MDD (rMDD; n = 62) and healthy controls (HC; n = 43) were assessed with neuropsychological tests at two time points. These were from four domains of executive functioning, consistent with previous literature as impaired in MDD: verbal fluency and processing speed, conceptual reasoning and set-shifting, processing speed with interference resolution, and cognitive control.

RESULTS

rMDD youth performed comparably to HCs on verbal fluency and processing speed, processing speed with interference resolution, and conceptual reasoning and set-shifting, reliably over time. Individuals with rMDD demonstrated relative decrements in cognitive control at Time 1, with greater stability than HC participants.

CONCLUSION

MDD may be characterized by regulatory difficulties that do not pertain specifically to active mood state or fluctuations in symptoms. Deficient cognitive control may represent a trait vulnerability or early course scar of MDD that may prove a viable target for secondary prevention or early remediation.

Longitudinal Cognitive Outcomes of Clinical Phenotypes of Late-Life Depression

OBJECTIVE

Late-life depression is associated with cognitive deficits and increased risk for cognitive decline. The purpose of the study was to determine whether clinical characteristics could serve as phenotypes informative of subsequent cognitive decline. Age at depression onset and antidepressant remission at 3 months (acute response) and 12 months (chronic response) were examined.

METHODS

In a longitudinal study of late-life depression in an academic center, 273 depressed and 164 never-depressed community-dwelling elders aged 60 years or older were followed on average for over 5 years. Participants completed annual neuropsychological testing. Neuropsychological measures were converted to z-scores derived from the baseline performance of all participants. Cognitive domain scores at each time were then created by averaging z-scores across tests, grouped into domains of episodic memory, attention-working memory, verbal fluency, and executive function.

RESULTS

Depressed participants exhibited poorer performance at baseline and greater subsequent decline in all domains. Early-onset depressed individuals exhibited a greater decline in all domains than late-onset or nondepressed groups. For remission, remitters and nonremitters at both 3 and 12 month exhibited greater decline in episodic memory and attention-working memory than nondepressed subjects. Three-month remitters also exhibited a greater decline in verbal fluency and executive function, whereas 12-month nonremitters exhibited greater decline in executive function than other groups.

CONCLUSION

Consistent with past studies, depressed elders exhibit greater cognitive decline than nondepressed subjects, particularly individuals with early depression onset, supporting the theory that repeated depressive episodes may contribute to decline. Clinical remission is not associated with less cognitive decline.

Nicotine and networks: Potential for enhancement of mood and cognition in late-life depression

Late-life depression is characterized by both lower mood and poor cognitive performance, symptoms that often do not fully respond to current antidepressant medications. Nicotinic acetylcholine receptor (nAChR) agonists such as nicotine may serve as a novel therapeutic approach for this population. Both preclinical and preliminary clinical studies suggest that nAChR agonists can improve depressive behavior in animal models and improve mood in depressed individuals. Substantial literature also supports that nAChR agonists benefit cognitive performance, particularly in older populations. These potential benefits may be mediated by the effects of nAChR stimulation on neural network function and connectivity. Functional neuroimaging studies detail effects of nAChR agonists on the default mode network, central-executive network, and salience network that may oppose or reverse network changes seen in depression. We propose that, given the existent literature and the clinical presentation of late-life depression, nicotine or other nAChR agonists may have unique therapeutic benefits in this population and that clinical trials examining nicotine effects on mood, cognition, and network dynamics in late-life depression are justified.

Weight Rich-Club Analysis in the White Matter Network of Late-Life Depression with Memory Deficits

Patients with late-life depression (LLD) have a higher incident of developing dementia, especially individuals with memory deficits. However, little is known about the white matter characteristics of LLD with memory deficits (LLD-MD) in the human connectome, especially for the rich-club coefficient, which is an indicator that describes the organization pattern of hub in the network. To address this question, diffusion tensor imaging of 69 participants [15 LLD-MD patients; 24 patients with LLD with intact memory (LLD-IM); and 30 healthy controls (HC)] was applied to construct a brain network for each individual. A full-scale battery of neuropsychological tests were used for grouping, and evaluating executive function, processing speed and memory. Rich-club analysis and global network properties were utilized to describe the topological features in each group. Network-based statistics (NBS) were calculated to identify the impaired subnetwork in the LLD-MD group relative to that in the LLD-IM group. We found that compared with HC participants, patients with LLD (LLD-MD and LLD-IM) had relatively impaired rich-club organizations and rich-club connectivity. In addition, LLD-MD group exhibited lower feeder and local connective average strength than LLD-IM group. Furthermore, global network properties, such as the shortest path length, connective strength, efficiency and fault tolerant efficiency, were significantly decreased in the LLD-MD group relative to those in the LLD-IM and HC groups. According to NBS analysis, a subnetwork, including right cognitive control network (CCN) and corticostriatal circuits, were disrupted in LLD-MD patients. In conclusion, the disease effects of LLD were prevalent in rich-club organization. Feeder and local connections, especially in the subnetwork including right CCN and corticostriatal circuits, were further impaired in those with memory deficits. Global network properties were disrupted in LLD-MD patients relative to those in LLD-IM patients.

Relationship of Depression With Executive Functions and Visuospatial Memory in Elderly

Cognitive deficits are a potential part of the clinical picture of depression, especially when it comes to late-life depression. The present study was carried out to establish whether distinctive cognitive deficiencies can be linked with depression in the late-life period, especially in executive functioning, working memory, and visuospatial memory. Our sample consisted of 71 seniors in the age range between 69 and 85 years. A battery of neurocognitive tests was used, including tests of executive functioning (Trail Making Test [TMT], part B, Stroop color word test, semantic word fluency test, and partially Rey-Osterrieth Complex Figure test [ROCF]), tests of attention and working memory (TMT, part A and digit span), and test of visuospatil ability and memory (ROCF). Results demonstrated that depression scores were significantly negatively correlated with scores on Verbal Fluency test, Stroop test, and ROCF immediate copy and recall. Depression was also linked to slower functioning on Trail Making A and Trail Making B subtest. In general, higher depression scores were correlated with lower performance on neuropsychological tests. However, digit span showed no significant correlation with depression. In addition, results of regression analyses revealed that the strongest predictors of depression were performance on the Rey-Osterrieth test-immediate recall and Stroop test. Thus, we could ascertain that difficulties in executive functioning and visuospatial memory are the best predictors of depression in elderly.

Cognitive performance in unipolar old-age depression: a longitudinal study

OBJECTIVE

Previous studies on cognitive deficits in acute and remitted states of old-age depression have shown mixed findings. The episodic nature of depression makes repeated assessment of cognitive performance important in order to address reversibility and stability of cognitive deficits.

METHODS

Dementia-free older participants (≥60 years) from the population-based Swedish National Study on Aging and Care in Kungsholmen who completed neuropsychological testing at baseline (T1) and follow-up (T2) formed the basis of the study sample. Participants were grouped according to depression status at T1 and T2: depressed-remitted (n = 32), remitted-depressed (n = 45), and nondepressed-depressed (n = 29). These groups were compared with a group of randomly selected and matched (age, gender, education, and follow-up time) healthy controls (n = 106) over a period of maximum 6 years.

RESULTS

Mixed ANCOVAs, controlling for age and gender, revealed depression-related deficits for processing speed, attention, executive function, and category fluency. In remitted states, only processing speed and attention were affected. However, these deficits were attenuated after exclusion of persons using benzodiazepine medications. A general pattern of cognitive decline was observed across all groups for processing speed, executive function, category fluency, and episodic and semantic memory; persons transitioning from a nondepressed to depressed state tended to show exacerbated cognitive decline.

CONCLUSIONS

The results support the notion that cognitive deficits in depression may be more transient than stable. Consequently, cognitive deficits in depression might be regarded as potential treatment targets rather than stable vulnerabilities. As such, repeated assessment of cognitive functioning may provide an additional marker of treatment response.

Improvement in Depression is Associated with Improvement in Cognition in Late-Life Psychotic Depression

OBJECTIVE

To characterize cognitive function at baseline and investigate the relationship between change in cognition, depression, and psychosis after treatment among older adults with major depressive disorder with psychotic features.

METHODS

This was a secondary analysis of a double-blind, randomized, controlled treatment trial at inpatient and outpatient settings at four academic health centers on "Young Old" (aged 60-71 years, N = 71) and "Older" (aged 72-86 years, N = 71) participants diagnosed with psychotic depression. Olanzapine plus sertraline or olanzapine plus placebo were given until week 12 or termination.

RESULTS

At baseline, Young Old and Older participants did not differ on measures of depression severity or global cognition, information processing speed, and executive function. Improvement in depressive and psychotic symptoms from baseline to treatment end was similar in both the Young Old and Older groups. However, improvement in depressive symptoms was significantly associated with improvement in global cognitive function in Young Old participants but not in Older participants.

CONCLUSION

Cognitive dysfunction was not a detriment to improvement in symptoms of psychotic major depression in our geriatric patients. Young Old and Older patients improved to a similar degree on measures of depression and delusions from baseline to treatment end. However, improvement in cognition over the course of treatment was more prominent in the Young Old group than in the Older group.

Depression and the risk of vascular dementia: a population-based retrospective cohort study

OBJECTIVE

To examine the association between the risks of depression and vascular dementia (VaD) based on Taiwan's National Health Insurance Research Database.

METHODS

This retrospective longitudinal matched-cohort study used National Health Insurance Research Database data from 49,955 participants (9,991 with new onset depression, 39,964 controls). A Cox regression analysis was performed on the whole sample and the subgroup of patients with depression. We further excluded patients who developed VaD within 3 or 5 years after enrollment to evaluate depression as an independent risk factor for or a prodrome of VaD.

RESULTS

During the 10-year follow-up period, the incidence rate ratio of VaD between patients with depression and controls was 4.24 [95% confidence interval (CI) 2.90-6.21, P < 0.001]. After adjustment for covariates, the hazard ratio (HR) of VaD in patients with depression was 3.10 (95% CI 2.13-4.52, P < 0.001). In the whole sample, risk factors for VaD besides depression were aged ≥60 years (HR = 20.08), hypertension (HR = 1.70), diabetes (HR = 1.61), coronary artery disease (HR = 2.26), head injury (HR = 2.20), and cerebrovascular disease (HR = 3.02). In patients with depression, aged ≥60 years (HR = 32.16), coronary artery disease (HR = 2.82), head injury (HR = 2.06), and cerebrovascular disease (HR = 2.37) remained risk factors for VaD. After excluding those who developed VaD within 3 or 5 years, HRs remained high (3.28, 95% CI 2.03-5.31, P < 0.001; 2.12, 95% CI 1.05-4.25, P = 0.035, respectively).

CONCLUSIONS

Our findings suggest that depression is an independent risk factor for subsequent VaD. Older age, cerebrovascular disease, head injury, and coronary artery disease might increase the risk of VaD among patients with depression.

Neuropsychiatric Symptoms in Mild Cognitive Impairment

OBJECTIVE

Neuropsychiatric symptoms (NPS) may be the first manifestation of an underlying neurocognitive disorder. We undertook a review to provide an update on the epidemiology and etiological mechanisms of NPS that occur in mild cognitive impairment (MCI) and just before the onset of MCI. We discuss common clinical presentations and the implications for diagnosis and care.

METHOD

The authors conducted a selective review of the literature regarding the emergence of NPS in late life, before and after the onset of MCI. We discuss recent publications that explore the epidemiology and etiological mechanisms of NPS in the earliest clinical stages of these disorders.

RESULTS

NPS have been reported in 35% to 85% of adults with MCI and also occur in advance of cognitive decline. The occurrence of NPS for the first time in later life should increase suspicion for an underlying neurocognitive disorder. The presenting symptom may provide a clue regarding the etiology of the underlying disorder, and the co-occurrence of NPS may herald a more accelerated cognitive decline.

CONCLUSIONS

NPS are prevalent in the early clinical stages of neurocognitive disorders and can serve as both useful diagnostic and prognostic indicators. Recognition of NPS as early manifestations of neurocognitive disorders will become increasingly important as we move towards preventative strategies and disease-modifying treatments that may be most effective when deployed in the earliest stages of disease.

Disrupted Interhemispheric Synchrony in Default Mode Network Underlying the Impairment of Cognitive Flexibility in Late-Onset Depression

The intuitive association between cognitive impairment and aberrant functional activity in the brain network has prompted interest in exploring the role of functional connectivity in late-onset depression (LOD). The relationship of altered voxel-mirrored homotopic connectivity (VMHC) and cognitive dysfunction in LOD is not yet well understood. This study was designed to examine the implicit relationship between the disruption of interhemispheric functional coordination and cognitive impairment in LOD. LOD patients (N = 31) and matched healthy controls (HCs; N = 37) underwent neuropsychological tests and functional magnetic resonance imaging (fMRI) in this study. The intergroup difference of interhemispheric coordination was determined by calculating VMHC value in the whole brain. The neuro-behavioral relevancy approach was applied to explore the association between disrupted VMHC and cognitive measures. Receiver operating characteristic (ROC) curve analysis was used to determine the capability of disrupted regional VMHC to distinguish LOD. Compared to the HC group, significantly attenuated VMHC in the superior frontal gyrus (SFG), superior temporal gyrus (STG), posterior cerebellar lobe (CePL) and post- and precentral gyri were observed in the bilateral brain of LOD patients. The interhemispheric asynchrony in bilateral CePLs was positively correlated with the performance of trail making test B (TMT-B) in LOD patients (r = 0.367, P = 0.040). ROC analysis revealed that regions with abnormal VMHC could efficiently distinguish LOD from HCs (Area Under Curve [AUC] = 0.90, P < 0.001). Altered linkage patterns of intrinsic homotopic connectivity and impaired cognitive flexibility was first investigated in LOD, and it would provide a novel clue for revealing the neural substrates underlying cognitive impairment in LOD.

Cognitive performance in depressed older persons: the impact of vascular burden and remission. A two-year follow-up study

OBJECTIVES

Depression is associated with an increased risk of cognitive decline. The present study compared two-year change in cognitive performance between depressed older persons and a non-depressed control group, between remitted and non-remitted patients, and evaluated whether vascular burden at baseline was associated with more cognitive decline in depressed older persons.

METHODS

Depressed patients (n = 378) aged ≥60 were recruited from mental healthcare institutes and general practices, and a non-depressed control group (n = 132) was recruited from general practices. A DSM-IV depressive episode was established with the Composite International Diagnostic Interview, and processing speed, working memory, verbal memory and interference control were evaluated with three neurocognitive tasks at baseline and 2 years later. A modified Framingham Risk Score, ankle-brachial index, and history of a vascular event defined vascular burden at baseline.

RESULTS

After adjusting for baseline cognitive performance, age, sex, and education level, depressed older persons had worse processing speed and verbal memory scores at follow-up than controls (regression coefficients: -0.172; p = 0.042 and -0.309; p = 0.001, respectively) but did not differ in the other two-cognitive outcomes. In the sample of depressed patients, remission status at 2 years follow-up and baseline vascular burden did not predict cognitive performance at follow-up, after adjustment for baseline cognitive performance, age, sex and education level.

CONCLUSIONS

Our findings suggest that cognitive deficits in depressed older persons are not just a manifestation of depression. In addition, vascular burden was not associated with worse cognitive decline in a sample of depressed older persons. Copyright © 2016 John Wiley & Sons, Ltd.

Predictors of neurocognitive impairment at 2years after a first-episode major depressive disorder

BACKGROUND

Neurocognitive impairment is a contributor to major depressive disorder (MDD). However, MDD patients show great variability in the level and course of deficits. The present longitudinal study was to identify predictors of neurocognitive impairment in first-episode MDD patients.

METHODS

Neurocognitive performance was analyzed in a cohort of 100 patients at 2years after a first-episode MDD. Subgroups, deficit type vs. non-deficit type, were compared on baseline clinical, neuropsychological, premorbid and sociodemographic characteristics. The analysis was performed using the multivariate logistic regression to obtain a model for neurocognitive impairment determination. The predicted probabilities of multivariate logistic regression were analyzed using receiver operating characteristic (ROC) curve.

RESULTS

Fifty-two percent of MDD participants presented general neurocognitive impairment. The regression analyses demonstrated that clinical and sociodemographic characteristics were not predictive variables. A model composed of processing speed, executive function, and attention, dexterity correctly classified 85.8% of the MDD patients with deficit type. ROC curve indicated that the changes of these three cognitions could identify MDD with deficit type from MDD with non-deficit type. In addition, ROC curve also indicated that processing speed and executive function could identify MDD from CN subjects. Finally, processing speed performance was negatively correlated with Hamilton Depression Scale scores in both MDD with deficit and non-deficit type.

CONCLUSION

The present study provides novel insights on frequency and neurocognitive profile of subtypes of patients showing impairment. Our results suggest that processing speed impairment is a trait dimension of the disorder related to specific cognitive dysfunctions and the severity of depression.