Late-onset depressive symptoms increase the risk of dementia in small vessel disease

Depression as a Risk Factor for Dementia: A Meta-Analysis

Dementia is a syndrome characterized by the deterioration of cognitive function beyond what is expected. The increased risk of developing this syndrome resulting from established modifiable risk factors, such as depressive episodes, is currently a subject of interest. The aim of this study was to review the scientific evidence that addresses the relationship between depression and dementia. A bibliographic search of the PubMed and PsycInfo databases for articles published over the past 20 years was conducted with the following medical subject heading terms: depression or depressive, dementia, and incidence or cohort studies. After articles meeting the inclusion criteria were selected, relevant moderating variables were grouped as sample characteristics, methodological characteristics, extrinsic characteristics, and outcome variables. The 26 selected studies resulted in a sample comprising 1,760,262 individuals. Statistical analysis revealed a pooled relative risk for the development of dementia of 1.82 (95% CI=1.62-2.06). The primary variables evaluated were the diagnostic methods for depression and dementia and the presence of depression. Other variables, such as mean age, methodological quality of each study, follow-up time, and publication year, were also evaluated. Age was statistically but not clinically significant. No relevant publication bias or alterations in the results were found when accounting for the quality of the studies. It is recommended that new moderating variables be evaluated or that existing variables be reformulated in future studies.

Cognitive Performance Deficits Are Associated with Clinically Significant Depression Symptoms in Older US Adults

Accumulating research has described cognitive impairment in adults with depression, however, few studies have focused on this relationship during older adulthood. Our cross-sectional study investigated the association between cognitive function performance and clinically significant depression symptoms in older adults. We analysed the data from the 2011 to 2014 National Health and Nutrition Examination Survey on older (aged 60 years and above) US adults. Cognitive function was assessed as a composite score and on a test-by-test basis based on the Consortium to Establish a Registry for Alzheimer's Disease Word List Learning Test, the Word List Recall Test, and Intrusion Word Count Test, the Animal Fluency Test, and the Digit Symbol Substitution Test (DSST). Depression was defined as clinically significant depression symptoms based on the standard cut-off point of the Patient Health Questionnaire-9 (PHQ-9) score of 10 or greater. Adjusted-logistic regression analysis was employed using survey weights to examine the former relationships. Sociodemographic factors, in addition to medical history and status in terms of self-reported chronic illness and the incidence of stroke or memory-cognitive function loss, were considered as covariates. Among 1622 participants of a survey-weighted 860,400 US older adults, cognitive performance was associated with clinically significant depression symptoms (p = 0.003) after adjustment. Most prominently, older adults with significant cognitive deficits had approximately two and a half times (OR: 2.457 [1.219-4.953]) higher odds for a PHQ-9 score above threshold compared to those with the highest performance. Particularly, those with lowest DSST score had increased odds of almost four times (OR: 3.824 [1.069-13.678]). Efforts to decipher the underlying aetiology of these negative disparities may help create opportunities and interventions that could alleviate the risks from depression, cognitive impairment, and associated consequences in older adults at a population level.

Competing risk analysis of the association between dementia and major depressive disorder: a nationwide population-based study in Taiwan

Objectives: To investigate the association between major depressive disorder (MDD) and the competing risk of Alzheimer's dementia (AD) and non-Alzheimer's dementia (NAD) using a nationwide population-based health insurance database.Methods: From Taiwan's National Health Insurance Research Database, we extracted claims data of 13,067 patients with MDD and 52,268 non-MDD controls matched by index date, age, sex, geographical area, monthly income, and selected comorbidities through propensity score matching. Follow-up durations in person-years were calculated for each person until dementia diagnosis, death, or the end of 2013. Competing incident risks of AD and NAD between patients with MDD and non-MDD.Results: In this study, 335 (2.6%) of the 13,067 MDD patients and 313 (0.6%) of the 52,268 non-MDDs developed AD. During the follow-up period, 73 (0.59%) of the 13,067 MDD patients developed NAD and 80 (0.15%) of the 52,268 non-MDD developed NAD. The patients with MDD had 4.73 and 3.69 times higher risks of AD (adjusted subdistribution hazard ratio [SHR] 4.73; 95% confidence interval [CI] 4.05-5.52) and NAD (adjusted SHR 3.69; 95% CI 2.68-5.08), respectively, than the controls.Conclusions: The patients with MDD had significantly higher incidence rates of AD and NAD than the controls, in particular among aged 65 and above. Additional studies are required to clarify the underlying pathophysiology between the MDD-dementia association and investigate whether prompt intervention in MDD can reduce the risk of dementia.

Late-life depression and increased risk of dementia: a longitudinal cohort study

Late-life depression (LLD) is associated with an increased risk of developing dementia; however, it is not known whether individuals with a history of LLD exhibit a more rapid rate of cognitive decline. We aimed to determine whether those with LLD experienced faster cognitive decline compared with never-depressed control (NDC) participants from the community and whether stratification of LLD into early-onset depression (EOD) and late-onset depression (LOD) subtypes revealed differing rates and domain-specific expression of cognitive decline. We conducted a prospective, longitudinal study where 185 participants with LLD (remitted) and 114 NDC were followed for 5 years on average. EOD was defined as having first lifetime depressive episode at <60years and LOD at ≥60years. Every year, participants underwent comprehensive neuropsychological assessment. Composite scores for each cognitive domain were calculated through averaging standardized scores across tests. LLD compared to NDC demonstrated significant baseline impairment but did not decline more rapidly. EOD were significantly impaired in attention/processing speed and global cognitive function at baseline but did not experience more rapid decline as compared to NDC. Those with LOD compared to both NDC and EOD performed worse in all domains at baseline and experienced more rapid decline in verbal skills and delayed memory ability. Our findings suggest that baseline impairment may lower the threshold for those with LLD to develop dementia. EOD and LOD may represent distinct phenotypes of cognitive impairment with differing neural substrates. LOD may represent a distinct phenotype with a more rapid decline in verbal skills and delayed memory.

Depression in Alzheimer's Disease: A Delphi Consensus on Etiology, Risk Factors, and Clinical Management

Background: Alzheimer's disease (AD) and other forms of dementia are among the most common causes of disability in the elderly. Dementia is often accompanied by depression, but specific diagnostic criteria and treatment approaches are still lacking. This study aimed to gather expert opinions on dementia and depressed patient management to reduce heterogeneity in everyday practice. Methods: Prospective, multicenter, 2-round Modified Delphi survey with 53 questions regarding risk factors (11), signs and symptoms (7), diagnosis (8), and treatment (27) of depression in dementia, with a particular focus on AD. The questionnaire was completed by a panel of 37 expert physicians in neurodegenerative diseases (19 neurologists, 17 psychiatrists, and 1 geriatrician). Results: Consensus was achieved in 40 (75.5%) of the items: agreement in 33 (62.3%) and disagreement in 7 (13.2%) of them. Among the most relevant findings, depression in the elderly was considered an early sign (prodromal) and/or a dementia risk factor, so routine cognitive check-ups in depressed patients should be adopted, aided by clinical scales and information from relatives. Careful interpretation of neuropsychological assessment must be carried out in patients with depression as it can undermine cognitive outcomes. As agreed, depression in early AD is characterized by somatic symptoms and can be differentiated from apathy by the presence of sadness, depressive thoughts and early-morning awakening. In later-phases, symptoms of depression would include sleep-wake cycle reversal, aggressive behavior, and agitation. Regardless of the stage of dementia, depression would accelerate its course, whereas antidepressants would have the opposite effect. Those that improve cognitive function and/or have a dual or multimodal mode of action were preferred: Duloxetine, venlafaxine/desvenlafaxine, vortioxetine, tianeptine, and mirtazapine. Although antidepressants may be less effective than in cognitively healthy patients, neither dosage nor treatment duration should differ. Anti-dementia cholinesterase inhibitors may have a synergistic effect with antidepressants. Exercise and psychological interventions should not be applied alone before any pharmacological treatment, yet they do play a part in improving depressive symptoms in demented patients. Conclusions: This study sheds light on several unresolved clinical challenges regarding depression in dementia patients. Further studies and specific recommendations for this comorbid patient population are still needed.

Neuropsychiatric Symptoms in Mild Cognitive Impairment and Dementia Due to AD: Relation With Disease Stage and Cognitive Deficits

Background: The interaction between neuropsychiatric symptoms, mild cognitive impairment (MCI), and dementia is complex and remains to be elucidated. An additive or multiplicative effect of neuropsychiatric symptoms such as apathy or depression on cognitive decline has been suggested. Unraveling these interactions may allow the development of better prevention and treatment strategies. In the absence of available treatments for neurodegeneration, a timely and adequate identification of neuropsychiatric symptom changes in cognitive decline is highly relevant and can help identify treatment targets. Methods: An existing memory clinic-based research database of 476 individuals with MCI and 978 individuals with dementia due to Alzheimer's disease (AD) was reanalyzed. Neuropsychiatric symptoms were assessed in a prospective fashion using a battery of neuropsychiatric assessment scales: Middelheim Frontality Score, Behavioral Pathology in Alzheimer's Disease Rating Scale (Behave-AD), Cohen-Mansfield Agitation Inventory, Cornell Scale for Depression in Dementia (CSDD), and Geriatric Depression Scale (30 items). We subtyped subjects suffering from dementia as mild, moderate, or severe according to their Mini-Mental State Examination (MMSE) score and compared neuropsychiatric scores across these groups. A group of 126 subjects suffering from AD with a significant cerebrovascular component was examined separately as well. We compared the prevalence, nature, and severity of neuropsychiatric symptoms between subgroups of patients with MCI and dementia due to AD in a cross-sectional analysis. Results: Affective and sleep-related symptoms are common in MCI and remain constant in prevalence and severity across dementia groups. Depressive symptoms as assessed by the CSDD further increase in severe dementia. Most other neuropsychiatric symptoms (such as agitation and activity disturbances) progress in parallel with severity of cognitive decline. There are no significant differences in neuropsychiatric symptoms when comparing "pure" AD to AD with a significant vascular component. Conclusion: Neuropsychiatric symptoms such as frontal lobe symptoms, psychosis, agitation, aggression, and activity disturbances increase as dementia progresses. Affective symptoms such as anxiety and depressive symptoms, however, are more frequent in MCI than mild dementia but otherwise remain stable throughout the cognitive spectrum, except for an increase in CSDD score in severe dementia. There is no difference in neuropsychiatric symptoms when comparing mixed dementia (defined here as AD + significant cerebrovascular disease) to pure AD.

Depressive Symptoms in the Elderly-An Early Symptom of Dementia? A Systematic Review

Background

Depression and dementia are common incapacitating diseases in old age. The exact nature of the relationship between these conditions remains unclear, and multiple explanations have been suggested: depressive symptoms may be a risk factor for, a prodromal symptom of, or a coincidental finding in dementia. They may even be unrelated or only connected through common risk factors. Multiple studies so far have provided conflicting results.

Objectives

To determine whether a systematic literature review can clarify the nature of the relation between depressive symptoms and dementia.

Methods

Using the Patient/Problem/Population, Intervention, Comparator, Outcome or PICO paradigm, a known framework for framing healthcare and evidence questions, we formulated the question “whether depressive symptoms in cognitively intact older adults are associated with a diagnosis of dementia later in life.” We performed a systematic literature review of MEDLINE and PsycINFO in November 2018, looking for prospective cohort studies examining the aforementioned question.

Results

We critically analyzed and listed 31 relevant papers out of 1,656 and grouped them according to the main hypothesis they support: depressive symptoms as a risk factor, not a risk factor, a prodromal symptom, both, or some specific other hypothesis. All but three studies used clinical diagnostic criteria for dementia alone (i.e., no biomarkers or autopsy confirmation). Several studies contain solid arguments for the hypotheses they support, yet they do not formally contradict other findings or suggested explanations and are heterogeneous.

Conclusions

The exact nature of the relationship between depressive symptoms and dementia in the elderly remains inconclusive, with multiple studies supporting both the risk factor and prodromal hypotheses. Some provide arguments for common risk factors. It seems unlikely that there is no connection at all. We conclude that at least in a significant part of the patients, depressive symptoms and dementia are related. This may be due to common risk factors and/or depressive symptoms being a prodromal symptom of dementia and/or depression being a risk factor for dementia. These causal associations possibly overlap in some patients. Further research is warranted to develop predictive biomarkers and to develop interventions that may attenuate the risk of “conversion” from depressive symptoms to dementia in the elderly.

Cross-sectional and prospective inter-relationships between depressive symptoms, vascular disease and cognition in older adults

BACKGROUND

It has been proposed that vascular disease is the mechanism linking depression and cognition, but prospective studies have not supported this hypothesis. This study aims to investigate the inter-relationships between depressive symptoms, cognition and cerebrovascular disease using a well-characterised prospective cohort.

METHOD

Data came from waves 1 (2005-2007) and 2 (2007-2009) of the Sydney Memory and Ageing Study (n = 462; mean age = 78.3 years).

RESULTS

At wave 1, there was an association between depressive symptoms and white matter hyperintensity (WMH) volume [b = 0.016, t(414) = 2.34, p = 0.020]. Both depressive symptoms [b = -0.058, t(413) = -2.64, p = 0.009] and WMH volume [b = -0.011, t(413) = -3.77, p < 0.001], but not stroke/transient ischaemic attack (TIA) [b = -0.328, t(413) = -1.90, p = 0.058], were independently associated with lower cognition. Prospectively, cerebrovascular disease was not found to predict increasing depressive symptoms [stroke/TIA: b = -0.349, t(374.7) = -0.76, p = 0.448; WMH volume: b = 0.007, t(376.3) = 0.875, p = 0.382]. Depressive symptoms predicted increasing WMH severity [b = 0.012, t(265.9) = -3.291, p = 0.001], but not incident stroke/TIA (odds ratio = 0.995; CI 0.949-1.043; p = 0.820). When examined in separate models, depressive symptoms [b = -0.027, t(373.5) = -2.16, p = 0.032] and a history of stroke/TIA [b = -0.460, t(361.2) = -4.45, p < 0.001], but not WMH volume [b = 0.001, t(362.3) = -0.520, p = 0.603], predicted declines in cognition. When investigated in a combined model, a history of stroke/TIA remained a predictor of cognitive decline [b = -0.443, t(360.6) = -4.28, p < 0.001], whilst depressive symptoms did not [b = -0.012, t(359.7) = -0.96, p = 0.336].

CONCLUSIONS

This study is contrasted with previous prospective studies which indicate that depressive symptoms predict cognitive decline independently of vascular disease. Future research should focus on further exploring the vascular mechanisms underpinning the relationship between depressive symptoms and cognition.

Late-life depression and cognitive function among older adults in the U.S.: The National Health and Nutrition Examination Survey, 2011-2014

Discrepancies exist on the associations of late-life depression with cognition, and synergistic effect of depression and diabetes on cognition among older adults was suggested in literature. We aimed to examine the associations of late-life depression with cognitive function in a representative sample of older adults in the U.S., and to examine the associations among individuals with diabetes. A total of 3101 adults aged 60 and above of the 2011-2014 National Health and Nutrition Examination Survey who completed measurements of depressive symptoms and diabetes were included in cross-sectional analyses. The 9-item Patient Health Questionnaire (PHQ-9) was used to measure depressive symptoms (including overall, somatic and cognitive). Clinically relevant depression (CRD) and clinically significant depression (CSD) were defined by cutoffs of PHQ-9. Domain-specific cognitive function was examined using Delayed Word Recall Test, Digit Symbol Substitution Test, and Animal Fluency Test for memory, executive function/processing speed, and language, respectively. Z scores were created for overall cognition and specific domains. Multivariable linear regression models were applied to examine the association of depressive symptoms and scale-defined depression with cognition z scores. The overall, somatic and cognitive depressive symptoms were associated with lower cognitive function among older adults. Both CRD (β = -0.20, 95% CI: -0.28, -0.12) and CSD (β = -0.56, 95% CI: -0.75, -0.37) were associated with lower cognition. A synergistic relationship was found between depression and diabetes on lower cognition. These results suggested that cognition among older adults may be modified by late-life depression, and older adults with both depression and diabetes may be particularly impacted on cognition.

A Review on the General Stability of Mood Disorder Diagnoses Along the Lifetime

PURPOSE OF REVIEW

The purpose of this review is to review the most recent literature regarding diagnostic stability of mood disorders, focusing on epidemiological, clinical-psychopathological, and neurobiological data for unipolar and bipolar affective disorders.

RECENT FINDINGS

Unipolar depression follows a chronic course in at least half of all cases and presents a considerable diagnostic stability across all age ranges. Studies using latent class analysis are allowing improved profiling of depressive subtypes and assessment of their prevalence. Advances have been made in our understanding of the neurobiological underpinnings of depression, with data highlighting the roles of amyloid deposits, the ApoE4 allele, and atrophy of the anterior hippocampus or frontal cortex. The diagnostic instability of bipolar disorder is manifest in the early years, seen in both the extent of diagnostic delay and the high rate of diagnostic conversion from unipolar depression. Regarding disruptive mood dysregulation disorder, we have little data to date, but those which exist indicate a high rate of comorbidity and minimal diagnostic stability for this disorder. Diagnostic stability varies substantially among mood disorders, which would be related to the validity of current diagnostic categories and our diagnostic accuracy.

Plasma cytokine IL-6 levels and subjective cognitive decline: preliminary findings

OBJECTIVE

Detection of Alzheimer's disease (AD) prior to clinical inception will be paramount for introducing disease modifying treatments. We have begun collecting baseline characteristics of a community cohort for longitudinal assessment and testing of antecedent blood-based biomarkers. We describe the baseline visit from the first 131 subjects in relationship to a commonly described cytokine, interleukin 6 (IL-6).

METHODS

Subjects from the community presented for a free memory screening with varying degrees of memory concern. We quantified the baseline plasma levels of the cytokine IL-6 and assessed cognition (Montreal Cognitive Assessment, MoCA) and mood (Geriatric Depression Scale, GDS) in relationship to their memory concern.

RESULTS

Baseline MoCA scores were inversely related to age, and this association was influenced by an AD risk factor, Apolipoprotein E (APOE4) carrier status. The degree of subjective cognitive decline correlated with GDS and was inversely related to MoCA scores. Interleukin 6 levels were related to age, body mass index, and years of education.

CONCLUSIONS

It will be important to assess how these baseline IL-6 levels and forthcoming novel biomarkers relate to future cognitive decline. Copyright © 2017 John Wiley & Sons, Ltd.

Expression of Alzheimer's disease risk genes in ischemic brain degeneration

We review the Alzheimer-related expression of genes following brain ischemia as risk factors for late-onset of sporadic Alzheimer's disease and their role in Alzheimer's disease ischemia-reperfusion pathogenesis. More recent advances in understanding ischemic etiology of Alzheimer's disease have revealed dysregulation of Alzheimer-associated genes including amyloid protein precursor, β-secretase, presenilin 1 and 2, autophagy, mitophagy and apoptosis. We review the relationship between these genes dysregulated by brain ischemia and the cellular and neuropathological characteristics of Alzheimer's disease. Here we summarize the latest studies supporting the theory that Alzheimer-related genes play an important role in ischemic brain injury and that ischemia is a needful and leading supplier to the onset and progression of sporadic Alzheimer's disease. Although the exact molecular mechanisms of ischemic dependent neurodegenerative disease and neuronal susceptibility finally are unknown, a downregulated expression of neuronal defense genes like alfa-secretase in the ischemic brain makes the neurons less able to resist injury. The recent challenge is to find ways to raise the adaptive reserve of the brain to overcome such ischemic-associated deficits and support and/or promote neuronal survival. Understanding the mechanisms underlying the association of these genes with risk for Alzheimer's disease will provide the most meaningful targets for therapeutic development to date.