Depression and risk of cognitive decline and Alzheimer's disease. Results of two prospective community-based studies in The Netherlands

Design, synthesis and evaluation of vilazodone-tacrine hybrids as multitarget-directed ligands against depression with cognitive impairment

Depression, a severe mental disease, is greatly difficult to treat and easy to induce other neuropsychiatric symptoms, the most frequent one is cognitive impairment. In this study, a series of novel vilazodone-tacrine hybrids were designed, synthesized and evaluated as multitarget agents against depression with cognitive impairment. Most compounds exhibited good multitarget activities and appropriate blood-brain barrier permeability. Specifically, compounds 1d and 2a exhibited excellent 5-HT_1A agonist activities (1d, EC₅₀ = 0.36 ± 0.08 nM; 2a, EC₅₀ = 0.58 ± 0.14 nM) and 5-HT reuptake inhibitory activities (1d, IC₅₀ = 20.42 ± 6.60 nM; 2a, IC₅₀ = 22.10 ± 5.80 nM). In addition, they showed moderate ChE inhibitory activities (1d, AChE IC₅₀ = 1.72 ± 0.217 μM, BuChE IC₅₀ = 0.34 ± 0.03 μM; 2a, AChE IC₅₀ = 2.36 ± 0.34 μM, BuChE IC₅₀ = 0.10 ± 0.01 μM). Good multitarget activities with goodt blood-brain barrier permeability of 1d and 2a make them good lead compounds for the further study of depression with cognitive impairment.

Reducing Depressive Symptoms in Nursing Home Residents: Evaluation of the Pennsylvania Depression Collaborative Quality Improvement Program

Depression reduces quality of life for nursing home (NH) residents and places them at greater risk for disability, medical morbidity, and mortality. However, accumulating evidence suggests that interventions for early detection and treatment can mitigate symptoms of clinical and subclinical levels of depression. The Promoting Positive Well-Being (PPW) program is a quality improvement (QI) intervention that features tools and strategies to assist NHs in early identification, assessment, treatment, and monitoring of residents with depressive symptoms. The PPW was evaluated in 40 NHs through an 8-month QI collaborative that provided participants with tools, webinar training, and technical support. Results showed a significant group by time interaction effect with facility quality rating as a covariate; the active group (n = 18 NHs) outperformed the waitlist control group (n = 19 NHs). In all, there was a 58% relative reduction in the percentage of residents with self-reported moderate-to-severe depressive symptoms. Most NHs reported that they were satisfied with the collaborative (97%) and would recommend it to others (86%); only 15% reported significant challenges. The rate of webinar attendance and data submission compliance was 92%. Results suggest that PPW is a promising approach that should be further evaluated in larger NH initiatives and other settings.

Trajectories of depressive and anxiety symptoms in older adults: a 6-year prospective cohort study

OBJECTIVE

Depressive and anxiety symptoms are common in older adults, significantly affect quality of life, and are risk factors for Alzheimer's disease. We sought to identify the determinants of predominant trajectories of depressive and anxiety symptoms in cognitively normal older adults.

METHOD

Four hundred twenty-three older adults recruited from the general community underwent Aβ positron emission tomography imaging, apolipoprotein and brain-derived neurotrophic factor genotyping, and cognitive testing at baseline and had follow-up assessments. All participants were cognitively normal and free of clinical depression at baseline. Latent growth mixture modeling was used to identify predominant trajectories of subthreshold depressive and anxiety symptoms over 6 years. Binary logistic regression analysis was used to identify baseline predictors of symptomatic depressive and anxiety trajectories.

RESULTS

Latent growth mixture modeling revealed two predominant trajectories of depressive and anxiety symptoms: a chronically elevated trajectory and a low, stable symptom trajectory, with almost one in five participants falling into the elevated trajectory groups. Male sex (relative risk ratio (RRR) = 3.23), lower attentional function (RRR = 1.90), and carriage of the brain-derived neurotrophic factor Val66Met allele in women (RRR = 2.70) were associated with increased risk for chronically elevated depressive symptom trajectory. Carriage of the apolipoprotein epsilon 4 allele (RRR = 1.92) and lower executive function in women (RRR = 1.74) were associated with chronically elevated anxiety symptom trajectory.

CONCLUSION

Our results indicate distinct and sex-specific risk factors linked to depressive and anxiety trajectories, which may help inform risk stratification and management of these symptoms in older adults at risk for Alzheimer's disease. Copyright © 2017 John Wiley & Sons, Ltd.

Late-Life Depressive Symptoms and Lifetime History of Major Depression: Cognitive Deficits are Largely Due to Incipient Dementia rather than Depression

BACKGROUND

Late-life depression is frequently accompanied by cognitive impairments.

OBJECTIVE

Whether these impairments indicate a prodromal state of dementia, or are a symptomatic expression of depression per se is not well-studied.

METHODS

In a cohort of very old initially non-demented primary care patients (n = 2,709, mean age = 81.1 y), cognitive performance was compared between groups of participants with or without elevated depressive symptoms and with or without subsequent dementia using ANCOVA (adjusted for age, sex, and education). Logistic regression analyses were computed to predict subsequent dementia over up to six years of follow-up. The same analytical approach was performed for lifetime major depression.

RESULTS

Participants with elevated depressive symptoms without subsequent dementia showed only small to medium cognitive deficits. In contrast, participants with depressive symptoms with subsequent dementia showed medium to very large cognitive deficits. In adjusted logistic regression models, learning and memory deficits predicted the risk for subsequent dementia in participants with depressive symptoms. Participants with a lifetime history of major depression without subsequent dementia showed no cognitive deficits. However, in adjusted logistic regression models, learning and orientation deficits predicted the risk for subsequent dementia also in participants with lifetime major depression.

CONCLUSION

Marked cognitive impairments in old age depression should not be dismissed as "depressive pseudodementia", but require clinical attention as a possible sign of incipient dementia. Non-depressed elderly with a lifetime history of major depression, who remained free of dementia during follow-up, had largely normal cognitive performance.

Cognitive reserve as a moderator of the negative association between mood and cognition: evidence from a population-representative cohort

BACKGROUND

Cognitive reserve (CR) has been associated with better cognitive function and lower risk of depression in older people, yet it remains unclear whether CR moderates the association between mood and cognition. This study aimed to investigate whether a comprehensive indicator of CR, including education, occupation and engagement in cognitive and social activities, acts as a moderator of this association.

METHODS

This was a cross-sectional study utilising baseline data from the Cognitive Function and Ageing Study II (CFAS II), a large population-based cohort of people aged 65+ in England. Complete data on the measures of CR, mood and cognition were available for 6565 dementia-free individuals. Linear regression models were used to investigate the potential modifying effect of CR on the association between cognition and mood with adjustment for age, sex and missing data.

RESULTS

Levels of CR did moderate the negative association between mood and cognition; the difference in cognition between those with and without a clinical level mood disorder was significantly smaller in the middle (-2.28; 95% confidence interval (CI) -3.65 to -0.90) and higher (-1.30; 95% CI -2.46 to -0.15) CR groups compared with the lower CR group (-4.01; 95% CI -5.53 to -2.49). The individual components of CR did not significantly moderate the negative association between mood and cognition.

CONCLUSION

These results demonstrate that CR, indexed by a composite score based on multiple indicators, can moderate the negative association between lowered mood and cognition, emphasising the importance of continuing to build CR across the lifespan in order to maintain cognitive health.

Positive affect and cognitive decline: a 12-year follow-up of the Maastricht Aging Study

OBJECTIVE

In cross-sectional studies, positive affect (PA) has been associated with higher levels of cognitive functioning. This study examined whether positive affect (PA) is associated with change in cognitive function over 12 years in an adult population sample.

METHODS

Participants (n = 258), aged 40 to 82 years, were drawn from a subsample of the Maastricht Aging Study (MAAS) and assessed at baseline, 6 years and 12 years. PA was measured at baseline with a Dutch translation of the Positive and Negative Affect Schedule (PANAS). PA scores and associations with cognitive decline were tested in random-effects models.

RESULTS

Controlling for demographics and depressive symptoms, there was no significant association with PA scores and decline in memory (χ²  = 1.52; df = 2; P = 0.47), executive functions (χ²  = 0.99; df = 2; P = 0.61), and information processing speed (χ²  = 0.52; df = 2; P = 0.77) at 6- and 12-year follow-up.

CONCLUSIONS

PA did not predict cognitive change over time. These findings question the extent of protective effects of PA on cognitive aging in adulthood, and are discussed in terms of age range and types of measures used for PA and cognition.

The Association Between the Use of Zolpidem and the Risk of Alzheimer's Disease Among Older People

OBJECTIVES

To evaluate the association between zolpidem use and the risk of Alzheimer's disease among older people.

DESIGN

A retrospective cohort study using data from 2001 to 2011 from the National Health Insurance Research Database.

SETTING

Taiwan.

PARTICIPANTS

A total of 6,922 patients aged 65 years or older enrolled from January 2002 to December 2004 (the enrollment period).

INTERVENTION (EXPOSURE)

Zolpidem users were identified as patients who used zolpidem during the enrollment period. The index date was the date of the first zolpidem prescription. Dosage of zolpidem use was defined using cumulative defined daily dose (cDDD) based on the cumulative dosage that patients took within one year after the index date (grouped as: less than 28, 28-90, 91-180, and more than 180 cDDD).

MEASUREMENTS

The occurrence of Alzheimer's disease was defined as the time period from the end of one year after the index date to the date of the Alzheimer's disease diagnosis. The propensity score was used to adjust the measured confounders of Alzheimer's disease. Cox proportional hazards models were used to evaluate the association between zolpidem use and the incidence of Alzheimer's disease.

RESULTS

Zolpidem users with a high cumulative dose (>180 cDDD) in the first year after initiation had a significantly greater risk of Alzheimer's disease than non-zolpidem users (HR = 2.97, 95% CI = 1.61-5.49) and low cumulative dose (<28 cDDD) users (HR = 4.18, 95% CI = 1.77-9.86).

CONCLUSION

We found the use of a high cumulative dose of zolpidem was associated with an increased risk of Alzheimer's disease among older people living in Taiwan. It is advised to use caution when considering long-term use of zolpidem in older patients.

Signs and symptoms preceding the diagnosis of Alzheimer's disease: a systematic scoping review of literature from 1937 to 2016

OBJECTIVE

Late diagnosis of Alzheimer's disease (AD) may be due to diagnostic uncertainties. We aimed to determine the sequence and timing of the appearance of established early signs and symptoms in people who are subsequently diagnosed with AD.

METHODS

We used systematic review methodology to investigate the existing literature. Articles were reviewed in May 2016, using the following databases: MEDLINE, PsycINFO, CINAHL, British Nursing Index, PubMed central and the Cochrane library, with no language restriction. Data from the included articles were extracted independently by two authors and quality assessment was undertaken with the quality assessment and diagnostic accuracy tool-2 (QUADAS tool-2 quality assessment tool).

RESULTS

We found that depression and cognitive impairment were the first symptoms to appear in 98.5% and 99.1% of individuals in a study with late-onset AD (LOAD) and 9% and 80%, respectively, in early-onset AD (EOAD). Memory loss presented early and was experienced 12 years before the clinically defined AD dementia in the LOAD. However, the rapidly progressive late-onset AD presented predominantly with 35 non-established focal symptoms and signs including myoclonus (75%), disturbed gait (66%) and rigidity. These were misdiagnosed as symptoms of Creutzfeldt-Jacob disease (CJD) in all the cases. The participant with the lowest mini-mental state examination score of 25 remained stable for 2 years, which is consistent with the score of the healthy family members.

CONCLUSIONS

The findings of this review suggest that neurological and depressive behaviours are an early occurrence in EOAD with depressive and cognitive symptoms in the measure of semantic memory and conceptual formation in LOAD. Misdiagnosis of rapidly progressive AD as CJD and the familial memory score can be confounding factors while establishing a diagnosis. However, the study was limited by the fact that each one of the findings was based on a single study.

Trajectories of Depressive Symptoms Before Diagnosis of Dementia: A 28-Year Follow-up Study

IMPORTANCE

Neuropsychiatric symptoms, depressive symptoms in particular, are common in patients with dementia but whether depressive symptoms in adulthood increases the risk for dementia remains the subject of debate.

OBJECTIVE

To characterize the trajectory of depressive symptoms over 28 years prior to dementia diagnosis to determine whether depressive symptoms carry risk for dementia.

DESIGN, SETTING, AND PARTICIPANTS

Up to 10 308 persons, aged 35 to 55 years, were recruited to the Whitehall II cohort study in 1985, with the end of follow-up in 2015. Data analysis for this study in a UK general community was conducted from October to December 2016.

EXPOSURES

Depressive symptoms assessed on 9 occasions between 1985 and 2012 using the General Health Questionnaire.

MAIN OUTCOMES AND MEASURES

Incidence of dementia (n = 322) between 1985 and 2015.

RESULTS

Of the 10 189 persons included in the study, 6838 were men (67%) and 3351 were women (33%). Those reporting depressive symptoms in 1985 (mean follow-up, 27 years) did not have significantly increased risk for dementia (hazard ratio [HR], 1.21; 95% CI, 0.95-1.54) in Cox regression adjusted for sociodemographic covariates, health behaviors, and chronic conditions. However, those with depressive symptoms in 2003 (mean follow-up, 11 years) had an increased risk (HR, 1.72; 95% CI, 1.21-2.44). Those with chronic/recurring depressive symptoms (≥2 of 3 occasions) in the early study phase (mean follow-up, 22 years) did not have excess risk (HR, 1.02; 95% CI, 0.72-1.44) but those with chronic/recurring symptoms in the late phase (mean follow-up, 11 years) did have higher risk for dementia (HR, 1.67; 95% CI, 1.11-2.49). Analysis of retrospective depressive trajectories over 28 years, using mixed models and a backward time scale, shows that in those with dementia, differences in depressive symptoms compared with those without dementia became apparent 11 years (difference, 0.61; 95% CI, 0.09-1.13; P = .02) before dementia diagnosis and became more than 9 times larger at the year of diagnosis (difference, 5.81; 95% CI, 4.81-6.81; P < .001).

CONCLUSIONS AND RELEVANCE

Depressive symptoms in the early phase of the study corresponding to midlife, even when chronic/recurring, do not increase the risk for dementia. Along with our analysis of depressive trajectories over 28 years, these results suggest that depressive symptoms are a prodromal feature of dementia or that the 2 share common causes. The findings do not support the hypothesis that depressive symptoms increase the risk for dementia.

The relationship between cognition and depressive symptoms, and factors modifying this association, in Alzheimer's disease: A multivariate multilevel model

OBJECTIVES

To examine whether there was a bidirectional association between cognition and depressive symptoms in Alzheimer's disease (AD), and to explore the role of socio-demographic factors and daily performance in this association.

METHODS

We conducted a longitudinal study of 104 community-dwelling patients with confirmed AD from Taiyuan, China. We assessed cognition and depressive symptoms (dependent variables) with the Montreal Cognitive Assessment (MoCA) and the Geriatric Depression Scale-30 (GDS-30), respectively. Socio-demographic information and daily performance were treated as explanatory variables. A multivariate multilevel model was built to investigate the interrelationship between patients' cognition and depression, as well as the effect of related factors on both outcomes.

RESULTS

MoCA scores were negatively correlated with GDS-30 both at the subject level (correlation coefficient r₃=-0.68, χ²=19.26, P<0.001) and time point level (r₂=-0.35, χ²=35.68, P<0.001) in patients with AD. Multivariate analysis showed several significant factors for cognitive function, including educational level, personality, hobbies, exercise, reading, aluminum utensil use, dietary restriction and hypertension (regression coefficients: 0.60, 0.52, 0.51, 0.48, 0.45, -0.48, 0.67, and -0.74, respectively). Significant factors for depressive symptoms included family status, employment before retirement, homemaking, reading, aluminum utensil use, dietary restriction, and hypertension (regression coefficients: 3.09, -1.33, -1.62, -1.31, 0.96, -1.15, and 1.14, respectively).

CONCLUSION

These findings indicated that cognition was negatively associated with depression in patients with AD, and both were influenced by reading, aluminum utensil use, dietary restriction, and hypertension. Considering patient factors may help to slow the progression of dementia.

Assessing the presence of shared genetic architecture between Alzheimer's disease and major depressive disorder using genome-wide association data

Major depressive disorder (MDD) and Alzheimer's disease (AD) are both common in older age and frequently co-occur. Numerous phenotypic studies based on clinical diagnoses suggest that a history of depression increases risk of subsequent AD, although the basis of this relationship is uncertain. Both illnesses are polygenic, and shared genetic risk factors could explain some of the observed association. We used genotype data to test whether MDD and AD have an overlapping polygenic architecture in two large population-based cohorts, Generation Scotland's Scottish Family Health Study (GS:SFHS; N=19 889) and UK Biobank (N=25 118), and whether age of depression onset influences any relationship. Using two complementary techniques, we found no evidence that the disorders are influenced by common genetic variants. Using linkage disequilibrium score regression with genome-wide association study (GWAS) summary statistics from the International Genomics of Alzheimer's Project, we report no significant genetic correlation between AD and MDD (r_G=-0.103, P=0.59). Polygenic risk scores (PRS) generated using summary data from International Genomics of Alzheimer's Project (IGAP) and the Psychiatric Genomics Consortium were used to assess potential pleiotropy between the disorders. PRS for MDD were nominally associated with participant-recalled AD family history in GS:SFHS, although this association did not survive multiple comparison testing. AD PRS were not associated with depression status or late-onset depression, and a survival analysis showed no association between age of depression onset and genetic risk for AD. This study found no evidence to support a common polygenic structure for AD and MDD, suggesting that the comorbidity of these disorders is not explained by common genetic variants.

Sensitivity and specificity of executive function tests for Alzheimer's disease

Decline in executive function (EF) occurs early in Alzheimer's disease (AD) and can interfere with daily functioning. Unfortunately, little is known about the relative ability of traditional EF tests to detect these cognitive changes. Given that timely diagnosis and intervention are essential to improving functional outcome in this population, our aim was to identify the specific EF measures that best differentiated mild dementia from normal aging. Thirty-one patients with mild AD and 31 controls were administered 7 EF tests. Findings indicated significant between-group differences on all measures except Wisconsin Card Sorting Test. The remaining 6 tests displayed fair to good accuracy discriminating between AD cases and controls. Only category fluency and Tower of London test remained in the final regression model that yielded the highest AUC of 0.90, which was not statistically different from that of either test alone. Overall, most of the tests employed were valid for assessing mild EF disturbances. Specifically, the two measures can be used in isolation for quick screening or in combination to facilitate a more in-depth evaluation of EF performance. This study contributes to clinical field by testifying to the validity of various EF tests to identify AD-related compromises in this cognitive domain.

Nationwide Inpatient Prevalence, Predictors, and Outcomes of Alzheimer's Disease among Older Adults in the United States, 2002-2012

In the inpatient setting, prevalence, predictors, and outcomes [mortality risk (MR), length of stay (LOS), and total charges (TC)] of Alzheimer's disease (AD) are largely unknown. We used data on older adults (60+ y) from the Nationwide Inpatient Sample (NIS) 2002-2012. AD prevalence was ∼3.12% in 2012 (total weighted discharges with AD ± standard error: 474, 410 ± 6,276). Co-morbidities prevailing more in AD inpatient admissions included depression (OR = 1.67, 95% CI: 1.63-1.71, p <  0.001), fluid/electrolyte disorders (OR = 1.25, 95% CI: 1.22-1.27, p <  0.001), weight loss (OR = 1.26, 95% CI: 1.22-1.30, p <  0.001), and psychosis (OR = 2.59, 95% CI: 2.47-2.71, p <  0.001), with mean total co-morbidities increasing over time. AD was linked to higher MR and longer LOS, but lower TC. TC rose in AD, while MR and LOS dropped markedly over time. In AD, co-morbidities predicting simultaneously higher MR, TC, and LOS (2012) included congestive heart failure, chronic pulmonary disease, coagulopathy, fluid/electrolyte disorders, metastatic cancer, paralysis, pulmonary circulatory disorders, and weight loss. In sum, co-morbidities and TC increased over time in AD, while MR and LOS dropped. Few co-morbidities predicted occurrence of AD or adverse outcomes in AD.

Comorbidity between neurological illness and psychiatric disorders

Psychiatric disorders are common in many neurological disorders, including epilepsy, migraine, Alzheimer's disease, Parkinson's disease, essential tremor, and stroke. These comorbidities increase disease burden and may complicate the treatment of the combined disorders. Initial studies of the comorbidity of psychiatric and neurological disorders were cross-sectional, and time order of the associations was impossible to elucidate. More recent work has clarified time associations between psychiatric disorders and neurological disorders, particularly in epilepsy and stroke where epidemiological evidence suggests that there is a bidirectional relationship. This article takes an epidemiological approach to understanding these relationships and focuses mostly on epilepsy. Although, these relationships are understood in many neurological disorders, routine screening for psychiatric disorders in neurological disorders is infrequent, mostly due to the lack of partnerships between psychiatrists and neurologists and the paucity of neuropsychiatrists. Much more needs to be done to improve the detection and treatment of patients affected by neurological and psychiatric disorders. Understanding the scope of this overlap may inspire collaborations to improve the lives of people affected by both disorders.

Depression as a risk factor for Alzheimer's disease: Genes, steroids, cytokines and neurogenesis - What do we need to know?

Depression (MDD) is prodromal to, and a component of, Alzheimer's disease (AD): it may also be a trigger for incipient AD. MDD is not a unitary disorder, so there may be particular subtypes of early life MDD that pose independent high risks for later AD, though the identification of these subtypes is problematical. There may either be a common pathological event underlying both MDD and AD, or MDD may sensitize the brain to a second event ('hit') that precipitates AD. MDD may also accelerate brain ageing, including altered DNA methylation, increased cortisol but decreasing DHEA and thus the risk for AD. So far, genes predicting AD (e.g. APOEε4) are not risk factors for MDD, and those implicated in MDD (e.g. SLC6A4) are not risks for AD, so a common genetic predisposition looks unlikely. There is as yet no strong indication that an epigenetic event occurs during some forms of MDD that predisposes to later AD, though the evidence is limited. Glucocorticoids (GCs) are disturbed in some cases of MDD and in AD. GCs have marked degenerative actions on the hippocampus, a site of early β-amyloid deposition, and rare genetic variants of GC-regulating enzymes (e.g. 11β-HSD) predispose to AD. GCs also inhibit hippocampal neurogenesis and plasticity, and thus episodic memory, a core symptom of AD. Disordered GCs in MDD may inhibit neurogenesis, but the contribution of diminished neurogenesis to the onset or progression of AD is still debated. GCs and cytokines also reduce BDNF, implicated in both MDD and AD and hippocampal neurogenesis, reinforcing the notion that those cases of MDD with disordered GCs may be a risk for AD. Cytokines, including IL1β, IL6 and TNFα, are increased in the blood in some cases of MDD. They also reduce hippocampal neurogenesis, and increased cytokines are a known risk for later AD. Inflammatory changes occur in both MDD and AD (e.g. raised CRP, TNFα). Both cytokines and GCs can have pro-inflammatory actions in the brain. Inflammation (e.g. microglial activation) may be a common link, but this has not been systematically investigated. We lack substantial, rigorous and comprehensive follow-up studies to better identify possible subtypes of MDD that may represent a major predictor for later AD. This would enable specific interventions during critical episodes of these subtypes of MDD that should reduce this substantial risk.

Amyloid-associated depression and ApoE4 allele: longitudinal follow-up for the development of Alzheimer's disease

BACKGROUND

Amyloid-associated depression is associated with cognitive impairment cross sectionally. This follow-up study was to determine the relationship between amyloid-associated depression and the development of Alzheimer's disease (AD).

METHODS

Two hundred and twenty three subjects who did not have dementia at baseline were given a repeat cognitive evaluation for incident AD. Depression was defined by having a Center for Epidemiological Studies Depression (CES-D) score ≥ 16, and non-amyloid vs. amyloid-associated depression by having a low vs. high plasma amyloid-β peptide 40 (Aβ40)/Aβ42 ratio. Apolipoprotein E (ApoE) genotype was determined, and antidepressant usage was documented.

RESULTS

Fifteen subjects developed AD (7%) after an average follow-up time of 6.2 years. While none of those with non-amyloid depression developed AD, 9% of those with amyloid-associated depression developed AD. Further, among those with amyloid-associated depression, ApoE4 carriers tended to have a higher risk of AD than ApoE4 non-carriers (40% vs. 4%, p = 0.06). In contrast, 8% of those who did not have depression at baseline developed AD, but ApoE4 carriers and non-carriers did not show a difference in the AD risk. After adjusting for age, the interaction between ApoE4 and amyloid-associated depression (β = +0.113, SE = 0.047, P = 0.02) and the interaction between ApoE4 and antidepressant use (β = +0.174, SE = 0.064, P = 0.007) were associated with the AD risk.

CONCLUSIONS

Amyloid-associated depression may be prodromal depression of AD especially in the presence of ApoE4. Future studies with a larger cohort and a longer follow-up are warranted to further confirm this conclusion.

How does cognitive reserve impact on the relationships between mood, rumination, and cognitive function in later life?

OBJECTIVES

Higher levels of cognitive reserve (CR) are associated with better cognitive function in later life. In contrast, depressive symptoms, anxiety, and rumination are associated with diminished cognitive function. There has been limited research to date examining the influence of CR on the relationship between mood and cognitive function, and results are inconsistent. The aim of this study was to investigate the role CR plays in the relationships between mood, rumination, and cognitive function in later life.

METHOD

Two hundred and thirty-six healthy people aged 60+ completed measures of CR, depression, anxiety, rumination, recall, and verbal fluency. Participants were dichotomised at the median into those with lower and higher levels of CR.

RESULTS

CR, mood, and rumination together accounted for between 13% and 15.6% of the variance in scores on the cognitive tasks in the sample as a whole. Mood and rumination explained a significant amount of variance in cognitive test scores in those with lower levels of CR, but not in those with higher levels of CR.

CONCLUSION

The way in which mood and rumination are related to cognitive function differs depending on the individual's level of CR. These results support the view that it is important to continue to build on CR as people move into later life in order to maintain cognitive health.

Performance of low-educated elders with depression on Addenbrooke's Cognitive Examination-Revised (ace-r) test

Along with cognitive disorders, depression has been a concern for mental health services due to its highly debilitating effect on the functioning and quality of life of the elderly. However, there is still little understanding of the cognitive alterations resulting from depression or of the difficult differential diagnosis with mild cognitive impairment (MCI). It is known that performance on cognitive tests is strongly influenced by education but few studies have been conducted involving low-educated populations.

Objective

To evaluate the performance of elders with low education and no dementia on Addenbrooke's Cognitive Examination-Revised (ACE-R) test and its cognitive domains, and compare patients with Current Major Depressive Episode (CMDE) against those without depressive symptoms.

Methods

A retrospective, cross-sectional analytical study was conducted based on medical files of patients treated at the Cerebral Aging Clinic of the Hospital São Lucas of the PUCRS. The study included 116 individuals with low education (< 8 years of education) aged between 60 and 84 (69.6 ± 6.4) years, with MCDE (N = 41) and controls (N = 75).

Results

No significant difference was observed between control and MCDE groups in median scores on the ACE-R, Mini-Mental State Examination, and the five cognitive domains. There was also no difference between the groups on separate analyses of results on the clock drawing test, the categorical verbal and phonological fluency test, and the naming test.

Conclusion

The results of this study showed that depressive symptoms did not influence scores on the ACE-R tests conducted in elders with low education.

Vitamin D and Memory Decline: Two Population-Based Prospective Studies

BACKGROUND

Vitamin D deficiency has been linked with dementia risk, cognitive decline, and executive dysfunction. However, the association with memory remains largely unknown.

OBJECTIVE

To investigate whether low serum 25-hydroxyvitamin D (25(OH)D) concentrations are associated with memory decline.

METHODS

We used data on 1,291 participants from the US Cardiovascular Health Study (CHS) and 915 participants from the Dutch Longitudinal Aging Study Amsterdam (LASA) who were dementia-free at baseline, had valid vitamin D measurements, and follow-up memory assessments. The Benton Visual Retention Test (in the CHS) and Rey's Auditory Verbal Learning Test (in the LASA) were used to assess visual and verbal memory, respectively.

RESULTS

In the CHS, those moderately and severely deficient in serum 25(OH)D changed -0.03 SD (95% CI: -0.06 to 0.01) and -0.10 SD (95% CI: -0.19 to -0.02) per year respectively in visual memory compared to those sufficient (p = 0.02). In the LASA, moderate and severe deficiency in serum 25(OH)D was associated with a mean change of 0.01 SD (95% CI: -0.01 to 0.02) and -0.01 SD (95% CI: -0.04 to 0.02) per year respectively in verbal memory compared to sufficiency (p = 0.34).

CONCLUSIONS

Our findings suggest an association between severe vitamin D deficiency and visual memory decline but no association with verbal memory decline. They warrant further investigation in prospective studies assessing different memory subtypes.

Does cognitive reserve moderate the association between mood and cognition? A systematic review

The evidence regarding the association between mood and cognitive function is conflicting, suggesting the involvement of moderating factors. This systematic review aimed to assess whether cognitive reserve moderates the association between mood and cognition in older people. Cognitive reserve was considered in terms of the three key proxy measures – educational level, occupation, and engagement in cognitively stimulating leisure activities – individually and in combination. Sixteen studies representing 37,101 participants were included in the review. Of these, 13 used a measure of education, one used a measure of occupation, two used a measure of participation in cognitively stimulating activities, and one used a combination of these. In general, cognitive reserve moderated the association between mood and cognition, with a larger negative association between mood and cognition in those with low cognitive reserve than in those with high cognitive reserve. Further research utilizing multiple proxy measures of cognitive reserve is required to elucidate the associations.

Incidence of and risk factors for Alzheimer's disease and mild cognitive impairment in Korean elderly

BACKGROUND/AIMS

Knowledge of incidence rates and risk factors is essential for the development of strategies to treat patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI).

METHODS

A subpopulation of the Nationwide Survey on Dementia Epidemiology (460 Korean subjects aged ≥65 years from 2 rural and 2 urban districts) was followed up for 3.5 years. The age-specific incidence was estimated and risk factors were identified.

RESULTS

The age-standardized incidence of AD and MCI was 7.9 and 28.1 cases per 1,000 person-years, respectively. MCI was associated with a 6-fold increased risk of AD. Depression was a risk factor for AD with MCI. Age, lack of formal education, illiteracy, rural residence, and marital status were associated with the risk of AD.

CONCLUSION

Strategies to control modifiable risk factors should be implemented to decrease the incidence of AD.

Examining the association between late-life depressive symptoms, cognitive function, and brain volumes in the context of cognitive reserve

OBJECTIVE

The present study aimed to investigate whether cognitive reserve moderated the association between depressive symptoms and cognition, as well as brain volumes in a sample of older adults.

METHODS

Non-demented participants (n = 3484) were selected from the Washington Heights/Hamilton Heights Inwood Columbia Aging Project (Northern Manhattan). A subsample of these participants without dementia (n = 703), who had brain imaging data, was also selected for a separate analysis. Depressive symptomatology was assessed with the 10-item Center for Epidemiologic Studies Depression Scale. Reading level and years of education were used as measures of cognitive reserve. Four distinct cognitive composite scores were calculated: executive function, memory, visual-spatial, and language.

RESULTS

Multiple regression analysis revealed interaction effects between both measures of cognitive reserve and depressive symptoms on all the cognitive outcome measures except for visual-spatial ability. Those with greater reserve showed greater cognitive decrements than those with lower levels of reserve as depressive symptoms increased. A borderline interaction effect was revealed between reading level and depressive symptoms on total brain volumes. Those with lower reading scores showed greater volume loss as depressive symptoms increased than those with higher reading scores.

CONCLUSIONS

Our findings indicate that the association between late-life depressive symptoms and core aspects of cognition varies depending on one's level of cognitive reserve. Those that had greater levels of education and/or reading ability showed a greater decrease in memory, executive, and language performances as depressive symptoms increased than those with lower years of education and reading ability.

Increased brain amyloid deposition in patients with a lifetime history of major depression: evidenced on 18F-florbetapir (AV-45/Amyvid) positron emission tomography

PURPOSE

The literature suggests that a history of depression is associated with an increased risk of developing Alzheimer's disease (AD). The aim of this study was to examine brain amyloid accumulation in patients with lifetime major depression using (18)F-florbetapir (AV-45/Amyvid) PET imaging in comparison with that in nondepressed subjects.

METHODS

The study groups comprised 25 depressed patients and 11 comparison subjects who did not meet the diagnostic criteria for AD or amnestic mild cognitive impairment. Vascular risk factors, homocysteine and apolipoprotein E (ApoE) genotype were also examined. The standard uptake value ratio (SUVR) of each volume of interest was analysed using whole the cerebellum as the reference region.

RESULTS

Patients with a lifetime history of major depression had higher (18)F-florbetapir SUVRs in the precuneus (1.06 ± 0.08 vs. 1.00 ± 0.06, p = 0.045) and parietal region (1.05 ± 0.08 vs. 0.98 ± 0.07, p = 0.038) than the comparison subjects. Voxel-wise analysis revealed a significantly increased SUVR in depressed patients in the frontal, parietal, temporal and occipital areas (p < 0.01). There were no significant associations between global (18)F-florbetapir SUVRs and prior depression episodes, age at onset of depression, or time since onset of first depression.

CONCLUSION

Increased (18)F-florbetapir binding values were found in patients with late-life major depression relative to comparison subjects in specific brain regions, despite no differences in age, sex, education, Mini Mental Status Examination score, vascular risk factor score, homocysteine and ApoE ε4 genotype between the two groups. A longitudinal follow-up study with a large sample size would be worthwhile.

Depressive symptoms and cognitive performance in older adults

Many longitudinal studies have found that older adults with depressive symptoms or depression have increased risk of cognitive impairment. We investigated the relationships between depressive symptoms or depression, cognitive function, serum brain-derived neurotrophic factor (BDNF), and volumetric MRI measurements in older adults. A total of 4352 individuals aged 65 years or older (mean age 72 years) participated in the study. We investigated medical history and geriatric depression scale-15 (GDS-15) items to determine depression and depressive symptoms. Cognitive tests included the mini-mental state examination (MMSE), story memory, word list memory, trail-making tests, and the symbol digit substitution task. Of the 4352 participants, 570 (13%) fulfilled the criteria for depressive symptoms (GDS-15: 6 + points) and 87 (2%) were diagnosed with depression. All cognitive tests showed significant differences between the 'no depressive symptoms', 'depressive symptoms', and 'depression' groups. The 'depressive symptoms' and 'depression' groups showed lower serum BDNF (p < 0.001) concentrations than the 'no depressive symptoms' group. The 'depressive symptoms' group exhibited greater atrophy of the right medial temporal lobe than did the 'no depressive symptoms' group (p = 0.023). These results suggest that memory, executive function, and processing speed examinations are useful to identify cognitive decline in older adults who have depressive symptoms and depression. Serum BDNF concentration and atrophy of the right medial temporal lobe may in part mediate the relationships between depressive symptoms and cognitive decline.

Melancholia in later life: late and early onset differences in presentation, course, and dementia risk

OBJECTIVES

Depression is a risk factor for cognitive decline and dementia. This risk may vary with age of onset and depression subtype. Late onset depression (LOD, 60 years and older) is associated with more cognitive decline, whereas early onset depression (EOD, before 60 years) is associated with more residual depressive symptoms. Potential differences may reflect divergent etiologies. These onset differences, however, have not been examined in the melancholic subtype of depression in older adults.

METHODS

Data were obtained from the Neurocognitive Outcomes of Depression in the Elderly study. Participants (N = 284, 73% EOD-melancholic (EOD-M) and 27% LOD-melancholic (LOD-M)) were followed up over 3 years. Factor analyses examined differences in baseline depressive symptoms. Hierarchical linear growth curve models examined changes in depressive symptoms (Montgomery-Asberg Depression Rating Scale) and cognition (mini mental state examination). An annual clinical review panel assigned diagnoses of dementia.

RESULTS

The LOD-M participants had more vegetative symptoms at baseline. LOD-M exhibited greater cognitive decline but fewer residual depressive symptoms than EOD-M. Among participants who remained in the study for at least 1 year, in uncontrolled analyses, a greater percentage of LOD-M compared with EOD-M developed dementia (23.0% vs. 7.8%). Whereas in logistic analyses, controlling for baseline demographics, age at onset remained a predictor of dementia, the odds ratio suggested that the effect was relatively small.

CONCLUSIONS

The EOD-M and LOD-M participants have a different presentation and course. LOD-M may represent a syndrome of neuropsychiatric deterioration with expression of both depressive symptoms and cognitive decline.

Relationship between depressive symptoms and cognition in older, non-demented African Americans

Knowledge of the relationship between depressive symptoms and cognition in older adults has primarily come from studies of clinically depressed, functionally impaired or cognitively impaired individuals, and in predominately White samples. Limited minority representation in depression research exposes the need to examine these associations in more ethnic/racially diverse populations. We sought to examine the relationship between depressive symptoms and cognition in a sample of non-demented older African Americans recruited from surrounding U.S. cities of New York, Greensboro, Miami, and Nashville (N=944). Depressive symptoms were evaluated with the Geriatric Depression Scale (GDS). Cognition was evaluated with a comprehensive neuropsychological battery. Test scores were summarized into attention, executive function, memory, language, and processing speed composites. Controlling for age, education, reading level, and sex, African American older adults who endorsed more symptoms obtained significantly lower scores on measures of memory, language, processing speed, and executive functioning. Further investigation of the causal pathway underlying this association, as well as potential mediators of the relationship between depressive symptoms and cognitive test performance among older African Americans, such as cardiovascular and cerebrovascular disease, may offer potential avenues for intervention.

Parallels between major depressive disorder and Alzheimer's disease: role of oxidative stress and genetic vulnerability

The thesis of this review is that oxidative stress is the central factor in major depressive disorder (MDD) and Alzheimer's disease (AD). The major elements involved are inflammatory cytokines, the hypothalamic-pituitary axis, the hypothalamic-pituitary gonadal, and arginine vasopressin systems, which induce glucocorticoid and "oxidopamatergic" cascades when triggered by psychosocial stress, severe life-threatening events, and mental-affective and somatic diseases. In individuals with a genomic vulnerability to depression, these cascades may result in chronic depression-anxiety-stress spectra, resulting in MDD and other known depressive syndromes. In contrast, in subjects with genomic vulnerability to AD, oxidative stress-induced brain damage triggers specific antioxidant defenses, i.e., increased levels of amyloid-β (Aβ) and aggregation of hyper-phosphorylated tau, resulting in paired helical filaments and impaired functions related to the ApoEε4 isoform, leading to complex pathological cascades culminating in AD. Surprisingly, all the AD-associated molecular pathways mentioned in this review have been shown to be similar or analogous to those found in depression, including structural damage, i.e., hippocampal and frontal cortex atrophy. Other interacting molecular signals, i.e., GSK-3β, convergent survival factors (brain-derived neurotrophic factor and heat shock proteins), and transition redox metals are also mentioned to emphasize the vast array of intermediates that could interact via comparable mechanisms in both MDD and AD.

Feelings of loneliness, but not social isolation, predict dementia onset: results from the Amsterdam Study of the Elderly (AMSTEL)

BACKGROUND

Known risk factors for Alzheimer's disease and other dementias include medical conditions, genetic vulnerability, depression, demographic factors and mild cognitive impairment. The role of feelings of loneliness and social isolation in dementia is less well understood, and prospective studies including these risk factors are scarce.

METHODS

We tested the association between social isolation (living alone, unmarried, without social support), feelings of loneliness and incident dementia in a cohort study among 2173 non-demented community-living older persons. Participants were followed for 3 years when a diagnosis of dementia was assessed (Geriatric Mental State (GMS) Automated Geriatric Examination for Computer Assisted Taxonomy (AGECAT)). Logistic regression analysis was used to examine the association between social isolation and feelings of loneliness and the risk of dementia, controlling for sociodemographic factors, medical conditions, depression, cognitive functioning and functional status.

RESULTS

After adjustment for other risk factors, older persons with feelings of loneliness were more likely to develop dementia (OR 1.64, 95% CI 1.05 to 2.56) than people without such feelings. Social isolation was not associated with a higher dementia risk in multivariate analysis.

CONCLUSIONS

Feeling lonely rather than being alone is associated with an increased risk of clinical dementia in later life and can be considered a major risk factor that, independently of vascular disease, depression and other confounding factors, deserves clinical attention. Feelings of loneliness may signal a prodromal stage of dementia. A better understanding of the background of feeling lonely may help us to identify vulnerable persons and develop interventions to improve outcome in older persons at risk of dementia.

Impact of inflammation on neurotransmitter changes in major depression: an insight into the action of antidepressants

This review summarises the evidence that chronic low grade inflammation plays an important role in the pathology of depression. Evidence is provided that pro-inflammatory cytokines, together with dysfunctional endocrine and neurotransmitter systems, provide a network of changes that underlie depression and may ultimately contribute to the neurodegenerative changes that characterise depression in the elderly. Antidepressants attenuate the inflammatory changes and hypercortisolaemia by reducing the release of the pro-inflammatory cytokines from activated microglia, and by sensitizing the glucocorticoids receptors in the HPA axis. These effects correlate with an improvement in monoamine neurotransmitter function. The possible mechanisms whereby this cascade of changes occurs are outlined. In conclusion, the mechanisms whereby antidepressants act should now consider the involvement of the immune and endocrine systems in addition to the central neurotransmitters. This may open up possibilities for a new generation of antidepressants in the future.

Long-term cumulative depressive symptom burden and risk of cognitive decline and dementia among very old women

BACKGROUND

Depressive symptoms and cognitive outcomes are strongly interrelated. Despite that rates of depressive symptoms fluctuate during late life, little is known about the impact of long-term cumulative depressive symptom burden on cognitive decline and dementia in older adults. This study examines the association of nearly 20 years of cumulative depressive symptoms with cognitive outcomes in a cohort of older women.

METHODS

We assessed depressive symptoms in 7,240 women using the Geriatric Depression scale (GDS) at serial visits. We used a Poisson model with random slopes to estimate GDS trajectories for each participant from baseline to death or end of follow-up, and then characterized depressive symptom burden by quartile of the area under the curve. We assessed cognitive outcomes using repeated measures of the Mini-Mental State Examination (MMSE) and Trails B score over 20 years, Year-20 neuropsychological test battery, and adjudicated dementia and mild cognitive impairment (MCI).

RESULTS

Adjusting for potential confounders, compared with women in the lowest quartile of cumulative depressive symptoms burden, women in the highest quartile had 21% more MMSE errors over time (95% CI = 17%, 26%), 20% worse Trails B score over time (95% CI = 17%, 23%), worse scores on most of the Year-20 cognitive tests, and a twofold greater likelihood of developing dementia or MCI (95% CI = 1.48, 3.11).

CONCLUSIONS

Long-term cumulative depressive symptom burden was associated with cognitive decline and risk of dementia or MCI. Older adults with a history of depression should be closely monitored for recurrent episodes or unresolved depressive symptoms as well as any cognitive deficits.

Heterogeneity of elderly depression: increased risk of Alzheimer's disease and Aβ protein metabolism

Epidemiological studies have proposed that depression may increase the risk for Alzheimer's disease (AD), even in patients with early-onset depression. Although metabolism of amyloid β protein (Aβ) in elderly depression received attention in terms of their correlation, there is a serious heterogeneity in elderly depression in terms of age at onset of depression. Moreover, it is unknown whether early-onset major depressive disorder (MDD) has a long-term effect on the involvement of Aβ metabolism and later development of AD. Thus, we evaluated serum Aβ40 and Aβ42 levels, the Aβ40/Aβ42 ratio in 89 elderly (≥60 years of age) inpatients with MDD and 81 age-matched healthy controls, and compared them among patients with early-onset (<60 years) and late-onset (≥60years) MDD and controls. The results showed that the serum Aβ40/Aβ42 ratio was significantly higher in patients with both early- and late-onset MDD than in controls (early-onset, p=0.010; late-onset, p=0.043), and it is of great interest that the serum Aβ40/Aβ42 ratio was negatively correlated with the age at MDD onset (R=-0.201, p=0.032). These results suggest that an earlier onset of MDD may have a more serious abnormality in Aβ metabolism, possibly explaining a biological mechanism underlying the link between depression and AD.

Late-life depression and risk of vascular dementia and Alzheimer's disease: systematic review and meta-analysis of community-based cohort studies

BACKGROUND

Late-life depression may increase the risk of incident dementia, in particular of Alzheimer's disease and vascular dementia.

AIMS

To conduct a systematic review and meta-analysis to evaluate the risk of incident all-cause dementia, Alzheimer's disease and vascular dementia in individuals with late-life depression in population-based prospective studies.

METHOD

A total of 23 studies were included in the meta-analysis. We used the generic inverse variance method with a random-effects model to calculate the pooled risk of dementia, Alzheimer's disease and vascular dementia in older adults with late-life depression.

RESULTS

Late-life depression was associated with a significant risk of all-cause dementia (1.85, 95% CI 1.67-2.04, P<0.001), Alzheimer's disease (1.65, 95% CI 1.42-1.92, P<0.001) and vascular dementia (2.52, 95% CI 1.77-3.59, P<0.001). Subgroup analysis, based on five studies, showed that the risk of vascular dementia was significantly higher than for Alzheimer's disease (P = 0.03).

CONCLUSIONS

Late-life depression is associated with an increased risk for all-cause dementia, vascular dementia and Alzheimer's disease. The present results suggest that it will be valuable to design clinical trials to investigate the effect of late-life depression prevention on risk of dementia, in particular vascular dementia and Alzheimer's disease.

Coordinated analysis of age, sex, and education effects on change in MMSE scores

OBJECTIVES

We describe and compare the expected performance trajectories of older adults on the Mini-Mental Status Examination (MMSE) across six independent studies from four countries in the context of a collaborative network of longitudinal studies of aging. A coordinated analysis approach is used to compare patterns of change conditional on sample composition differences related to age, sex, and education. Such coordination accelerates evaluation of particular hypotheses. In particular, we focus on the effect of educational attainment on cognitive decline.

METHOD

Regular and Tobit mixed models were fit to MMSE scores from each study separately. The effects of age, sex, and education were examined based on more than one centering point.

RESULTS

Findings were relatively consistent across studies. On average, MMSE scores were lower for older individuals and declined over time. Education predicted MMSE score, but, with two exceptions, was not associated with decline in MMSE over time.

CONCLUSION

A straightforward association between educational attainment and rate of cognitive decline was not supported. Thoughtful consideration is needed when synthesizing evidence across studies, as methodologies adopted and sample characteristics, such as educational attainment, invariably differ.

Depression and cognition: how do they interrelate in old age?

OBJECTIVES

To disentangle the reciprocal effects between depressive symptoms and cognitive functioning over time and to study the association between changes in their trajectories using 13 years of follow-up.

DESIGN AND PARTICIPANTS

Data were used from five waves of the population-based Longitudinal Aging Study Amsterdam. Subjects were included if data was present on depressive symptoms and cognitive performance on at least two occasions, which resulted in a study sample of N = 2,299.

MEASUREMENTS

Depressive symptoms were assessed with the Center for Epidemiologic Studies Depression Scale. Cognitive functioning was assessed using the Mini-Mental State Examination (general cognitive functioning) and timed coding task (speed of information processing).

RESULTS

Cross-domain latent change analyses showed that depression at baseline predicted both decline of general cognitive functioning and information processing speed, independent of relevant covariates. Conversely, information processing speed at baseline, but not general cognitive functioning was related to the course of depressive symptoms. The course of cognitive functioning was not significantly associated with the course of depressive symptoms.

CONCLUSION

Depressive symptoms in older patients flag an increased likelihood of cognitive decline. This effect is considerable and may be due to several underlying mechanisms. The likelihood of the relationship reflecting either a causal effect of depression on cognitive decline, or a common cause, or both, should be estimated. Likewise, older persons with more limitations in information processing speed specifically are more vulnerable to increases in depression.

Depression subtypes and 5-year risk of dementia and Alzheimer disease in patients aged 70 years

OBJECTIVE

The objective of this study was to estimate several subtypes of depressive disorders as risk factors for dementia and Alzheimer disease (AD) specifically.

METHODS

This is a population-based cohort study using a sample of 451 non-demented older people. Adjusted Cox proportional hazard models were calculated to determine the association of depression with dementia or AD development after 5 years. Baseline evaluation included the Cambridge Mental Disorders of the Elderly Examination (CAMDEX). Depressive disorders (major episode [MD] and minor depressive disorders [MDDIS]) were assessed following DSM-IV criteria and further classified according to the age at onset (early versus late onset). In turn, all late-onset depressions were grouped as with or without depression-executive dysfunction syndrome (DEDS). Dementia (and dementia subtypes) diagnoses were made using the CAMDEX. When the patients were deceased, the Retrospective Collateral Dementia Interview was used.

RESULTS

Late-onset depressions (both MD and MDDIS) were associated with increased dementia (hazard ratio [HR] = 2.635; 95% CI = 1.153-6.023; and HR = 2.517; 95% CI = 1.200-5.280, respectively), and AD (HR = 6.262; 95% CI = 2.017-19.446; and HR = 4.208; 95% CI = 1.828-9.685, respectively) after adjustment by age, gender, marital status, education, cognitive impairment, executive function and stroke history. A second model revealed that only late-onset depressions with DEDS increased the risk for both dementia (late-onset MD with DEDS: HR = 6.262; 95% CI = 2.017-19.446; late-onset MDDIS with DEDS: HR = 4.208; 95% CI = 1.828-9.685) and AD (late-onset MD with DEDS: HR = 7.807; 95% CI = 1.567-38.894; late-onset MDDIS with DEDS: HR = 6.099; 95% CI = 2.123-17.524).

CONCLUSIONS

Late-onset depressive episodes with DEDS are risk factors for dementia and AD development, regardless of the severity of the depression.

Depression and incident dementia. An 8-year population-based prospective study

Aims

The aim of the study was to investigate the impact of depression (categorical diagnosis; major depression, MD) and depressive symptoms (dimensional diagnosis and symptom patterns) on incident dementia in the German general population.

Methods

Within the Leipzig Longitudinal Study of the Aged (LEILA 75+), a representative sample of 1,265 individuals aged 75 years and older were interviewed every 1.5 years over 8 years (mean observation time 4.3 years; mean number of visits 4.2). Cox proportional hazards and binary logistic regressions were used to estimate the effect of baseline depression and depressive symptoms on incident dementia.

Results

The incidence of dementia was 48 per 1,000 person-years (95% confidence interval (CI) 45–51). Depressive symptoms (Hazard ratio HR 1.03, 95% CI 1.01–1.05), and in particular mood-related symptoms (HR 1.08, 95% CI 1.03–1.14), showed a significant impact on the incidence of dementia only in univariate analysis, but not after adjustment for cognitive and functional impairment. MD showed only a significant impact on incidence of dementia in Cox proportional hazards regression, but not in binary logistic regression models.

Discussion

The present study using different diagnostic measures of depression on future dementia found no clear significant associations of depression and incident dementia. Further in-depth investigation would help to understand the nature of depression in the context of incident dementia.

Affective disorders and risk of developing dementia: systematic review

BACKGROUND

Affective disorders are associated with cognitive disturbances but their role as risk factors for dementia is still not fully investigated.

AIMS

To evaluate the risk of developing dementia in individuals with a history of affective disorder.

METHOD

We conducted a systematic review of case-control and cohort studies addressing the risk of developing dementia in people with affective disorders. To the best of our knowledge, this is the first systematic review that has included studies evaluating this risk specifically in people with bipolar disorder.

RESULTS

Fifty-one studies were included. Most of the studies found an increased risk for developing dementia in individuals with depression. Greater frequency and severity of depressive episodes seem to increase this risk. The evidence is contradictory regarding whether there is a difference in risk in people with early- or late-onset depression. The few available risk estimates for dementia in people with bipolar disorder suggest an even higher risk than for those with depression.

CONCLUSIONS

Affective disorders appear to be associated with an increased risk of developing dementia, and one that is dependent on clinical and demographic variables. Depression may be both a prodrome and a risk factor for dementia. Future research should aim to elucidate the mechanisms that mediate these links.

Risk of dementia in patients with insomnia and long-term use of hypnotics: a population-based retrospective cohort study

BACKGROUND

Hypnotics have been reported to be associated with dementia. However, the relationship between insomnia, hypnotics and dementia is still controversial. We sought to examine the risk of dementia in patients with long-term insomnia and the contribution of hypnotics.

METHODS

Data was collected from Taiwan's Longitudinal Health Insurance Database. The study cohort comprised all patients aged 50 years or older with a first diagnosis of insomnia from 2002 to 2007. The comparison cohort consisted of randomly selected patients matched by age and gender. Each patient was individually tracked for 3 years from their insomnia index date to identify whether the patient had a first diagnosis of dementia. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

We identified 5693 subjects with long-term insomnia and 28,465 individuals without. After adjusting for hypertension, diabetes mellitus, hyperlipidemia, and stroke, those with long-term insomnia had significantly higher risks of dementia (HR, 2.34; 95% CI, 1.92-2.85). Patients with long-term insomnia and aged 50 to 65 years had a higher increased risk of dementia (HR, 5.22; 95% CI, 2.62-10.41) than those older than 65 years (HR, 2.33; 95% CI, 1.90-2.88). The use of hypnotics with a longer half-life and at a higher prescribed dose predicted a greater increased risk of dementia.

CONCLUSIONS

Patients with long-term use of hypnotics have more than a 2-fold increased risk of dementia, especially those aged 50 to 65 years. In addition, the dosage and half-lives of the hypnotics used should be considered, because greater exposure to these medications leads to a higher risk of developing dementia.

History of depression prior to Alzheimer's disease and vascular dementia verified post-mortem

The aim of this study was to analyze the medical history, with regards to previous remote depression, in patients with neuropathologically verified Alzheimer's disease (AD), vascular dementia (VaD) and mixed AD/VaD. The 201 patients included (115 AD, 44 VaD and 42 mixed AD/VaD) had been referred to the Psychogeriatric/Psychiatric Department, Lund University Hospital, for psychogeriatric investigation and were followed-up with clinical records and detailed information on psychiatric history prior to the onset of dementia. Depression was considered to exist when the patient had consulted a psychiatrist or physician and had been diagnosed with a "depressive episode" or "depression" and when anti-depressants and/or other specific treatments had been prescribed. Twenty patients (10%) had suffered from depression earlier in life well before the onset of dementia. Eight of the 9 AD patients with a previous diagnosis of depression had suffered from only one depressive episode and all had responded well to treatment, with complete recovery. In the VaD group, 8 out of 9 patients suffered two or more depressive episodes and only two recovered completely. Events with a possible significant relationship to depression were seen in 8 of the 9 AD patients but in only 1 of the 9 VaD patients. Psychotic symptoms were more common in VaD than in the AD group. The treatment modality of depression was similar in the groups. In conclusion, a history of depression prior to dementia is more common and more therapy-resistant in VaD than in AD.

An examination of the mechanisms underlying the effects of physical activity on brain and cognition

Physical activity positively influences brain health and cognitive functioning in older adults. Several physiological and psychological mechanisms have been identified to underlie such a relationship. Cardiovascular fitness is accompanied with changes in mechanisms such as cerebral blood flow, neurotrophic factors, neurotransmitter systems and neural architecture that have themselves been associated with cognitive performance. Factors associated with exercise such as arousal, mood and self-perception of competence seem also to influence cognitive performance. Other explanation for the benefits of exercise in cognition, results from the fact that the performance of motor skills involve an important cognitive component (e.g., executive functions and information processing speed). Evidence of brain plasticity and behavior has been provided from studies where animals are exposed to enriched or complex environments. Exposure to such paradigms in which physical activity plays an important role has been found to influence various aspects of brain function and structure. Studies using neuroimaging techniques have established a link between the acquisition of different motor skills and the occurrence of neuroplasticity in human adults. This literature review indicates that the type of exercise and its specific perceptual and cognitive characteristics may influence cognitive performance. However, most of the research has been focused on self-paced movements or automatized skills and few intervention studies have examined the results of merging exercise and cognitive training in a single program. An important scientific challenge for the coming years is to design exercise programs capable of mobilizing several type of mechanisms underlying the effects of physical activity on brain and cognition.

Is there a bidirectional relationship between depressive symptoms and cognitive ability in older people? A prospective study using the English Longitudinal Study of Ageing

BACKGROUND

Cross-sectional surveys of older people commonly find associations between higher levels of depressive symptoms and poorer cognitive performance, but the direction of effect is unclear. We examined whether there was a bidirectional relationship between depressive symptoms and general cognitive ability in non-demented older people, and explored the role of physical health, smoking, exercise, social class and education as potential confounders of this association and as possible determinants of the rate of change of cognitive decline and depressive symptoms.

METHOD

The English Longitudinal Study of Ageing consists of people aged 50 years and over. Cognitive function and self-reported depressive symptoms were measured in 2002-2003, 2004-2005, 2006-2007 and 2008-2009. We fitted linear piecewise models with fixed knot positions to allow different slopes for different age groups. Analyses are based on 8611 people.

RESULTS

Mean cognitive function declined with age; there was no trend in the trajectory of depressive symptoms. Better cognitive function was associated with less depression up to the age of 80 years. Greater depression was associated with a slightly faster rate of cognitive decline but only in people aged 60-80 years. There were no consistent associations across age groups between sex, smoking, education, social class, exercise or number of chronic physical illnesses and the rate of change of cognitive decline or depressive symptoms.

CONCLUSIONS

In this longitudinal study of older people, there was no consistent evidence that being more depressed led to an acceleration in cognitive decline and no support for the hypothesis that there might be reciprocal dynamic influences between cognitive ability and depressive symptoms.

Depression and epilepsy: epidemiologic and neurobiologic perspectives that may explain their high comorbid occurrence

Depression is the most frequent psychiatric comorbidity in people with epilepsy (PWE) with lifetime prevalence rates ranging between 30 and 35%. Multifactorial variables play a pathogenic role in the high comorbid occurrence of these two disorders. These variables were critically examined during an international symposium held in Chicago in September 2010, the results of which are presented in two companion manuscripts. The first manuscript summarizes new epidemiologic data highlighting the bidirectional relation between depression and epilepsy and related methodological issues in studying this relationship. An examination of the neurobiologic aspects of primary mood disorders, mood disorders in PWE and pathogenic mechanisms of epilepsy derived from studies in animal models and humans is allowing a better understanding of the complex relation between the two conditions. In the first manuscript, we review data from animal models of epilepsy in which equivalent symptoms of depression and anxiety disorders develop and, conversely, animal models of depression in which the kindling process is facilitated. Data from structural and functional neuroimaging studies in humans provide a further understanding of potential common pathogenic mechanisms operant in depression and epilepsy that may explain their high comorbidity. The negative impact of depression on the control of seizure disorders has been documented in various studies. In this manuscript, these data are reviewed and potential mechanisms explaining this phenomenon are proposed.

Increased risk of mortality associated with social isolation in older men: only when feeling lonely? Results from the Amsterdam Study of the Elderly (AMSTEL)

BACKGROUND

Loneliness has a significant influence on both physical and mental health. Few studies have investigated the possible associations of loneliness with mortality risk, impact on men and women and whether this impact concerns the situation of being alone (social isolation), experiencing loneliness (feeling lonely) or both. The current study investigated whether social isolation and feelings of loneliness in older men and women were associated with increased mortality risk, controlling for depression and other potentially confounding factors.

METHOD

In our prospective cohort study of 4004 older persons aged 65-84 years with a 10-year follow-up of mortality data a Cox proportional hazard regression analysis was used to test whether social isolation factors and feelings of loneliness predicted an increased risk of mortality, controlling for psychiatric disorders and medical conditions, cognitive functioning, functional status and sociodemographic factors.

RESULTS

At 10 years follow-up, significantly more men than women with feelings of loneliness at baseline had died. After adjustment for explanatory variables including social isolation, the mortality hazard ratio for feelings of loneliness was 1.30 [95% confidence interval (CI) 1.04-1.63] in men and 1.04 (95% CI 0.90-1.24) in women. No higher risk of mortality was found for social isolation.

CONCLUSIONS

Feelings of loneliness rather than social isolation factors were found to be a major risk factor for increasing mortality in older men. Developing a better understanding of the nature of this association may help us to improve quality of life and longevity, especially in older men.

Depressive symptoms, cortisol, and cognition during human aging: the role of negative aging perceptions

Depressive symptoms and memory impairments are associated with heightened stress hormone levels during aging. A factor that is related to memory deficits during aging is internalized negative aging stereotypes; the idea people have about the process of aging. In this study, we assessed the associations between internalized negative aging stereotypes, depressive symptoms, subjective and objective memory assessments, and cortisol concentration among older adults. Forty older adults aged between 58 and 85 years (18 females and 22 males; mean age ± SD: 71.25 ± 8.80 years) were assessed in this study. Measures of internalized negative aging stereotypes, depressive symptoms, and both subjective and objective memory performance were assessed. Salivary samples were obtained for measurement of cortisol concentration. Stepwise linear regressions were executed in our main analyses. Internalized negative aging stereotypes were associated with increased depressive symptoms and subjective memory complaints. No significant differences were observed for objective memory performance, or cortisol concentration. Internalized negative aging stereotypes are associated with increased depressive symptomatology and subjective complaints of memory; however, they do not predict increased cortisol concentration nor objective memory performance during aging. These results indicate that the mechanism underlying the association between internalized negative aging stereotypes and cognitive impairments may not be related to dysregulations of cortisol secretion among older adults.

The association between mental health and cognitive screening scores in older veterans

OBJECTIVES

: To examine overall cognitive screening results and the relationship between cognitive screen score and sociodemographic characteristics, reason for referral, and clinical outcomes of older veterans referred by primary care for a behavioral health assessment.

DESIGN

: Cross-sectional, naturalistic study.

SETTING

: Primary care clinics affiliated with two VA Medical Centers.

PARTICIPANTS

: The sample included 4,325 older veterans referred to the Behavioral Health Laboratory who completed an initial mental health/substance abuse assessment. Veterans were categorized into the following three groups on the basis of cognitive status: within normal limits, possible cognitive impairment, and possible dementia.

MEASUREMENTS

: Sociodemographic and clinical data on reason for referral, cognitive functioning (i.e., Blessed Orientation-Memory-Concentration test), and behavioral health assessment outcomes were extracted from patients' medical records. Data were analyzed using multiple linear and logistic regressions.

RESULTS

: Results of cognitive screenings indicated that the majority of the sample was within normal limits (62.5%), with 25.8%, 8.1%, and 3.6% of patients evidencing possible cognitive impairment, possible dementia, and Blessed Orientation-Memory-Concentration scores of 17 or more, respectively. With regard to reason for referral, patients with greater cognitive impairment were more likely to be identified by the antidepressant case finder than patients with less impairment. Increased age, non-white ethnicity, self-perceived inadequate finances, major depressive disorder, and symptoms of psychosis were associated with greater cognitive impairment.

CONCLUSIONS

: Findings highlight the importance of evaluating cognitive status in older adults who are referred for a behavioral health assessment and/or receive a new mental health/substance abuse diagnosis. Doing so has the potential to improve recognition and treatment of cognitive impairment and dementia, thereby improving quality of care for many older adults.