The occurrence of depressive symptoms in the preclinical phase of AD: a population-based study

Modern Methods of Diagnostics and Treatment of Neurodegenerative Diseases and Depression

This paper discusses the promising areas of research into machine learning applications for the prevention and correction of neurodegenerative and depressive disorders. These two groups of disorders are among the leading causes of decline in the quality of life in the world when estimated using disability-adjusted years. Despite decades of research, the development of new approaches for the assessment (especially pre-clinical) and correction of neurodegenerative diseases and depressive disorders remains among the priority areas of research in neurophysiology, psychology, genetics, and interdisciplinary medicine. Contemporary machine learning technologies and medical data infrastructure create new research opportunities. However, reaching a consensus on the application of new machine learning methods and their integration with the existing standards of care and assessment is still a challenge to overcome before the innovations could be widely introduced to clinics. The research on the development of clinical predictions and classification algorithms contributes towards creating a unified approach to the use of growing clinical data. This unified approach should integrate the requirements of medical professionals, researchers, and governmental regulators. In the current paper, the current state of research into neurodegenerative and depressive disorders is presented.

Linking Social Cognition, Parvalbumin Interneurons, and Oxytocin in Alzheimer's Disease: An Update

Finding a cure for Alzheimer's disease (AD) has been notoriously challenging for many decades. Therefore, the current focus is mainly on prevention, timely intervention, and slowing the progression in the earliest stages. A better understanding of underlying mechanisms at the beginning of the disease could aid in early diagnosis and intervention, including alleviating symptoms or slowing down the disease progression. Changes in social cognition and progressive parvalbumin (PV) interneuron dysfunction are among the earliest observable effects of AD. Various AD rodent models mimic these early alterations, but only a narrow field of study has considered their mutual relationship. In this review, we discuss current knowledge about PV interneuron dysfunction in AD and emphasize their importance in social cognition and memory. Next, we propose oxytocin (OT) as a potent modulator of PV interneurons and as a promising treatment for managing some of the early symptoms. We further discuss the supporting evidence on its beneficial effects on AD-related pathology. Clinical trials have employed the use of OT in various neuropsychiatric diseases with promising results, but little is known about its prospective impacts on AD. On the other hand, the modulatory effects of OT in specific structures and local circuits need to be clarified in future studies. This review highlights the connection between PV interneurons and social cognition impairment in the early stages of AD and considers OT as a promising therapeutic agent for addressing these early deficits.

Inter-relationship between cognitive performance and depressive symptoms and their association with quality of life in older adults: A network analysis based on the 2017-2018 wave of Chinese Longitudinal Healthy Longevity Survey (CLHLS)

BACKGROUND

Depressive symptoms and cognitive impairment are common psychiatric conditions and often co-occur in older adults. Network analysis has been widely used in exploring the inter-connections between psychiatric symptoms. The aim of this study was to explore the network model of depressive symptoms and cognitive performance, and their association with quality of life in people aged 65 years or above based on the 2017-2018 wave of Chinese Longitudinal Healthy Longevity Survey (CLHLS).

METHOD

Global cognitive performance, depressive symptoms, and global quality of life (QoL) were measured using the validated Chinese version of the Mini Mental State Examination (MMSE), the 10-item Center for Epidemiologic Studies Short Depression Scale (CES-D), and the World Health Organization Quality of Life-brief version (WHOQOL-BREF), respectively. Central symptoms and bridge symptoms were identified via strength and bridge strength, respectively. The flow network was used to identify symptoms directly related to QoL. Network stability was examined using the case dropping bootstrap method.

RESULTS

A total of 9023 participants were included in the network analysis. CESD3 "Feeling blue/depressed", CESD4 "Everything was an effort", and At_C "Attention and Calculation" were the central (influential) symptoms that had the highest strength value. Three bridge symptoms (i.e., Nam "Naming", CESD2 "Difficulty with concentrating", and Lan "Language") were also identified. CESD10 "Sleep disturbances" had the strongest direct connection to QoL.

CONCLUSIONS

This exploratory study highlights the inter-relationships between cognitive performance and depressive symptoms in older adults in the general population. Interventions targeting bridge symptoms have the potential to alleviate depressive and cognitive symptoms in this population. Furthermore, improving sleep quality in older adults may reduce the negative impact of depression and cognition decline on QoL.

Reduced Hippocampal and Anterior Cingulate Expression of Antioxidant Enzymes and Membrane Progesterone Receptors in Alzheimer's Disease with Depression

BACKGROUND

Major depressive disorder (MDD) is a risk factor for dementia including that caused by Alzheimer's disease (AD). Both MDD and AD have a higher prevalence in women than men, and estrogen-related processes have been implicated in this sex difference.

OBJECTIVE

To identify if enhanced oxidative stress and decreased expression of the memory enhancer insulin-like growth factor 2 (IGF2), each implicated separately in MDD and AD, are exaggerated in individuals with both AD and MDD compared to those with AD.

METHODS

Expression of target genes are determined by qPCR in postmortem hippocampus (Hip) and anterior cingulate cortex (ACC) of individuals with dementia and autopsy confirmed AD and those of AD+MDD.

RESULTS

Transcript levels of the antioxidant enzymes catalase (CAT) and superoxide dismutase 1 (SOD1), as well as IGF2 and its receptor (IGF2R) were significantly lower in the Hip and ACC of individuals with both AD and MDD compared to those with AD and no MDD. Expressions of Progestin and AdipoQ Receptor Family Member 7 (PAQR7, alias progesterone receptor alpha, mPRa) and PAQR8 (mPRβ), receptors that bind neurosteroids, were also lower in the Hip and ACC of AD+MDD samples compared to those of AD without MDD. Correlations among these transcripts revealed that estrogen receptor 2 (ESR2) and mPR β are direct or indirect regulators of the expression of the antioxidant enzymes and IGF2R.

CONCLUSION

Reduced levels of antioxidant enzymes, decreased IGF2 expression, and diminished estrogen or membrane progesterone receptor-dependent processes might be more pronounced in the subpopulation of individuals with AD and MDD than without MDD.

Negative and Positive Psychosocial Factors in Relation to Cognitive Health in Older African Americans

Background and Objectives

Identifying potential intervention strategies to reduce cognitive decline, particularly among older African Americans at high risk for Alzheimer’s dementia, is critical. This study aimed to investigate whether depressive symptoms, purpose in life, and their interrelations are associated with cognitive decline in older African Americans.

Research Design and Methods

We included older African Americans from the Minority Aging Research Study (n = 748) and Rush Memory and Aging Project (n = 109), without dementia at baseline. We assessed associations of depressive symptoms, purpose in life, and their interrelations, with baseline levels and change in global cognition using linear mixed-effects models.

Results

At baseline, each unit increment in depressive symptoms was related to worse initial global cognition (mean difference = −0.03 standard unit; p = .003), while higher purpose in life was related to better cognition (mean difference = 0.12; p = .002). Further, participants with ≥1 depressive symptom who had a purpose in life score above the median appeared to have better global cognition (mean difference = 0.10; p = .01), compared to those with depressive symptoms but lower levels of purpose in life. However, we did not find relations of depressive symptoms or purpose in life with rates of cognitive decline over time, likely due to the modest follow-up.

Discussion and Implications

In older African Americans, we found that lower depressive symptoms and greater purpose in life were independently related to higher initial levels of global cognition, but not cognitive decline. Preliminary findings of higher global cognition in individuals with depressive symptoms but greater purpose in life merit further investigation if purpose may eventually be considered as an intervention.

Mid to late-life scores of depression in the cognitively healthy are associated with cognitive status and Alzheimer's disease pathology at death

OBJECTIVES

Early diagnosis of Alzheimer's disease (AD) is essential for early interventions. Symptoms of depression could represent a prodromal stage of AD. Very early mood alterations may help to stratify those at highest risk of late-life AD. We aim to investigate associations between baseline/longitudinal scores for depression, presence of cognitive impairment and/or AD pathology at death.

METHODS/DESIGN

Between 1991 and 2015, participants from The University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age underwent 10 waves of assessment using the Geriatric Depression Scale (GDS). AD pathology at death was evaluated in 106 eligible cases. Analyses aimed to examine associations between GDS scores, cognitive status and AD pathology (as measured by Braak stage, Thal phase and CERAD).

RESULTS

Baseline GDS scores were significantly higher for those cognitively impaired at death than those cognitively normal. Significantly higher baseline GDS scores were found for those with greater Consortium to Establish a Registry for Alzheimer's Disease (CERAD) scores than those with lower CERAD scores. Similarly, significantly higher baseline GDS scores were found for those with a greater Braak stage than those with lower tau burden. These correlations remained after controlling for age at death, education and APOE ε4, but were less robust. Mean longitudinal GDS scores associated with cognition but not pathology.

CONCLUSIONS

GDS scores collected approximately 20 years before death were associated with cognitive status and AD pathology at death. We postulate that early AD-related pathological change produces raised GDS scores due to an overlapping neural basis with depression, and that this may be considered as an early diagnostic marker for AD.

The effect of electroconvulsive therapy on neuroinflammation, behavior and amyloid plaques in the 5xFAD mouse model of Alzheimer's disease

Microglial cells are affected in Alzheimer’s disease (AD) and interact with amyloid-beta (Aβ) plaques. Apart from memory loss, depression is common in patients with AD. Electroconvulsive therapy (ECT) is an anti-depressive treatment that may stimulate microglia, induce neuroinflammation and alter the levels of soluble Aβ, but the effects of ECT on microglia and Aβ aggregation in AD are not known. We investigated the short- and long-term effects of ECT on neuroinflammation and Aβ accumulation. 5xFAD mice received either electroconvulsive stimulation (ECS n = 26) or sham treatment (n = 25) for 3 weeks. Microglia and Aβ were analyzed in samples collected 24 h, 5 weeks, or 9 weeks after the last treatment. Aβ plaques and microglia were quantified using immunohistochemistry. The concentration of soluble Aβ and cytokines was quantified using ELISA and levels of Aβ aggregates were measured with Western Blot. Microglial phagocytosis of Aβ in the hippocampus was evaluated by flow cytometry in Methoxy-X04 injected mice 24 h following the last ECS treatment. Y-maze and Elevated plus maze were performed to study behavior after 5 weeks. We could not detect any significant short- or long-term effects of ECS on Aβ pathology or neuroinflammation, but ECS reduced abnormal behavior in the Elevated Plus maze.

Risk factors of major depression in the elderly

Background

Several risk factors of depression have been identified in retrospective as well as some prospective studies in the elderly. Confirmation in independent samples is needed. The present follow-up study prospectively investigated risk factors of depression in an elderly German sample.

Methods

One thousand four hundred and thirty-one subjects from a family study were re-investigated after 4.7 ± 2.5 years. Bivariate and multivariate forward logistic regression analyses were used to identify risk factors of the development of new depression in the elderly.

Results

Risk factors of a new depressive episode in 1408 elderly without current depression were age, female gender, a previous depression, subjective memory impairment, previous anxiety and somatoform disorders. The presence of dementia or mild cognitive impairment were significant risk factors in bivariate, but not multivariate analysis controlling for possible confounding. Risk factors of a first geriatric depressive episode were age, gender and subjective memory impairment; age remained the only significant risk factor in multivariate analysis.

Conclusions

This investigation confirms previous studies from other countries concerning the relevance of risk factors for depression in the elderly. The knowledge of risk factors might help identify subjects at increased risk of depression for early intervention approaches. Elderly with a history of previous depression carry the highest risk.

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

Objectives

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

Design

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

Setting

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

Partcipants

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

Materials and methods

Extensive neuropsychological test battery to assess cognitive profile.

Results

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

Conclusion

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

Shared genetic etiology underlying Alzheimer's disease and major depressive disorder

Patients with late-onset Alzheimer's disease (LOAD) frequently manifest comorbid neuropsychiatric symptoms with depression and anxiety being most frequent, and individuals with major depressive disorder (MDD) have an increased prevalence of LOAD. This suggests shared etiologies and intersecting pathways between LOAD and MDD. We performed pleiotropy analyses using LOAD and MDD GWAS data sets from the International Genomics of Alzheimer's Project (IGAP) and the Psychiatric Genomics Consortium (PGC), respectively. We found a moderate enrichment for SNPs associated with LOAD across increasingly stringent levels of significance with the MDD GWAS association (LOAD|MDD), of maximum four and eightfolds, including and excluding the APOE-region, respectively. Association analysis excluding the APOE-region identified numerous SNPs corresponding to 40 genes, 9 of which are known LOAD-risk loci primarily in chromosome 11 regions that contain the SPI1 gene and MS4A genes cluster, and others were novel pleiotropic risk-loci for LOAD conditional with MDD. The most significant associated SNPs on chromosome 11 overlapped with eQTLs found in whole-blood and monocytes, suggesting functional roles in gene regulation. The reverse conditional association analysis (MDD|LOAD) showed a moderate level, ~sevenfold, of polygenic overlap, however, no SNP showed significant association. Pathway analyses replicated previously reported LOAD biological pathways related to immune response and regulation of endocytosis. In conclusion, we provide insights into the overlapping genetic signatures underpinning the common phenotypic manifestations and inter-relationship between LOAD and MDD. This knowledge is crucial to the development of actionable targets for novel therapies to treat depression preceding dementia, in an effort to delay or ultimately prevent the onset of LOAD.

Anhedonia and Dysphoria Are Differentially Associated with the Risk of Dementia in the Cognitively Normal Elderly Individuals: A Prospective Cohort Study

OBJECTIVE

We investigated the impact of depressed mood (dysphoria) and loss of interest or pleasure (anhedonia)on the risk of dementia in cognitively-normal elderly individuals.

METHODS

This study included 2,685 cognitively-normal elderly individuals who completed the baseline and 4-year follow-up assessments of the Korean Longitudinal Study on Cognitive Aging and Dementia. We ascertained the presence of dysphoria and anhedonia using the Mini International Neuropsychiatric Inventory. We defined subjective cognitive decline as the presence of subjective cognitive complaints without objective cognitive impairments. We analyzed the association of dysphoria and anhedonia with the risk of cognitive disorders using multinomial logistic regression analysis adjusted for age, sex, education, Cumulative Illness Rating Scale score, Apolipoprotein E genotype, and neuropsychological test performance.

RESULTS

During the 4-year follow-up period, anhedonia was associated with an approximately twofold higher risk of mild cognitive impairment (OR=2.09, 95% CI=1.20-3.64, p=0.008) and fivefold higher risk of dementia (OR=5.07, 95% CI=1.44-17.92, p=0.012) but was not associated with the risk of subjective cognitive decline. In contrast, dysphoria was associated with an approximately twofold higher risk of subjective cognitive decline (OR=2.06, 95% CI=1.33-3.19, p=0.001) and 1.7-fold higher risk of mild cognitive impairment (OR=1.75, 95% CI=1.00-3.05, p=0.048) but was not associated with the risk of dementia.

CONCLUSION

Anhedonia, but not dysphoria, is a risk factor of dementia in cognitively-normal elderly individuals.

Associations between subclinical depressive symptoms and reduced brain volume in middle-aged to older adults

OBJECTIVES

The associations between subclinical depressive symptoms, as well specific symptom subscales, on brain structure in aging are not completely elucidated. This study investigated the extent to which depressive symptoms were related to brain volumes in fronto-limbic structures in a sample of middle-aged to older adults.

METHOD

Eighty participants underwent structural neuroimaging and completed the Beck Depression Inventory, 2nd Edition (BDI-II), which comprises separate affective, cognitive, and somatic subscales. Gray matter volumes were extracted from the caudal and rostral anterior cingulate, posterior cingulate, hippocampus, and amygdala. Hierarchical regression models examined the relationship between brain volumes and (i) total depressive symptoms and (ii) BDI-II subscales were conducted.

RESULTS

After adjusting for total intracranial volume, race, and age, higher total depressive symptoms were associated with smaller hippocampal volume (p = 0.005). For the symptom subscales, after controlling for the abovementioned covariates and the influence of the other symptom subscales, more somatic symptoms were related to smaller posterior cingulate (p = 0.025) and hippocampal (p < 0.001) volumes. In contrast, the affective and cognitive subscales were not associated with brain volumes in any regions of interest.

CONCLUSION

Our data showed that greater symptomatology was associated with smaller volume in limbic brain regions. These findings provide evidence for preclinical biological markers of major depression and specifically advance knowledge of the relationship between subclinical depressive symptoms and brain volume. Importantly, we observed variations by specific depressive symptom subscales, suggesting a symptom-differential relationship between subclinical depression and brain volume alterations in middle-aged and older individuals.

A bi-factor model of the Montgomery Åsberg depression rating scale and future cognitive impairments in older adults: A 6-year follow-up study

Depression has been found to be associated with cognitive decline. This study evaluated the association of general depressive symptoms and motivational-related symptoms with cognitive impairment 6 years later and to explore the role of potential underlying mechanisms. In 2690 cognitively healthy persons aged ≥60 from the Swedish National study on Aging and Care in Kungsholmen (SNAC-K) depressive symptoms were derived from the Montgomery Åsberg Depression Rating Scale (MADRS). Cognitive performance was assessed at baseline and 6 years later in 1810 persons with the Mini Mental State Examination (global cognition), Digit Span Forward (short-term memory), Digit Span Backward (working memory), Clock-test (visuospatial construction), and the 5-item test (immediate and delayed recall). Bi-factor analysis on the MADRS yielded a General Depression factor and an unrelated Motivational factor. After adjusting for demographics, the General Depression factor was only associated with 6-year impairment in delayed recall (OR (95% CI): 1.18 (1.04-1.34)). This association was no longer significant after adjusting for demographics, cardiovascular risk, lifestyle factors and medication use. The Motivational factor was not significantly associated with future cognitive impairments after adjusting for demographics. Concluding, almost all associations of general depressive symptoms and motivational-related symptoms with future cognitive impairments appeared to be confounded by demographics. Only the association of general depressive symptoms with future memory impairments appeared to be explained by a combination of demographics, cardiovascular risk, lifestyle and medication use.

Atypical presentation of progressive young onset dementia

We present the case of a 34-year-old Jordanian woman who was referred to mainstream mental health services because of irritability, agitation, loss of appetite, withdrawal from family activities and sleeping difficulties. She was initially diagnosed with major depressive disorder but subsequently showed very poor response to antidepressant therapy. Her presentation gradually and dramatically progressed into full blown dementia within couple of years. Brain MRI showed atrophic cortical changes and subcortical white matter alterations consistent with Alzheimer's dementia. Brain PET scan revealed reduction in cerebral glucose metabolism in temporoparietal areas bilaterally most consistent with Alzheimer's dementia. There was a strong family history of early-onset dementia. A final diagnosis of young onset dementia was made, and unfortunately, she passed away at the age of 44 years.

Hypertension and obesity moderate the relationship between β-amyloid and cognitive decline in midlife

BACKGROUND

This study tested if central obesity, hypertension, or depressive symptoms moderated the relationship between β-amyloid (Aβ) and longitudinal cognitive performance in late middle-aged adults enriched for Alzheimer's disease (AD) risk.

METHODS

Participants (n = 207; ages = 40-70 years; 73% parental AD) in the Wisconsin Registry for Alzheimer's Prevention study completed 3+ neuropsychological evaluations and a [¹¹C]PiB positron emission tomography scan or lumbar puncture. Linear mixed-effects regression models tested interactions of risk factor × Aβ × visit age on longitudinal Verbal Learning & Memory and Speed & Flexibility factor scores.

RESULTS

The relationship between Aβ and Verbal Learning & Memory decline was moderated by hypertension (χ²₍₁₎ = 3.85, P = .04) and obesity (χ²₍₁₎ = 6.12, P = .01); those with both elevated Aβ and the risk factor declined at faster rates than those with only elevated Aβ or elevated risk factors.

CONCLUSION

In this cohort, hypertension and obesity moderated the relationship between Aβ and cognitive decline.

Lower Late-Life Body-Mass Index is Associated with Higher Cortical Amyloid Burden in Clinically Normal Elderly

BACKGROUND

Lower body-mass index (BMI) in late life has been associated with an increased risk of dementia, and weight loss has been associated with more rapid decline in Alzheimer's disease (AD) dementia.

OBJECTIVE

To explore the association between BMI and cortical amyloid burden in clinically normal (CN) elderly at risk for AD dementia.

METHODS

Cross-sectional analyses were completed using baseline data from the Harvard Aging Brain Study, consisting of 280 community-dwelling CN older adults aged 62-90. Assessments included medical histories and physical exam, Pittsburgh compound B (PiB) positron emission tomography (PET) amyloid imaging, and apolipoprotein E ɛ4 (APOE4) genotyping. For the primary analysis, a general linear regression model was used to evaluate the association of BMI with PiB retention. Covariates included age, sex, years of education, and APOE4 carrier status. Secondary analyses were performed for BMI subdivisions (normal, overweight, obese), APOE4 carriers, and BMI×APOE4 interaction.

RESULTS

In the primary analysis, greater PiB retention was associated with lower BMI (β  =  -0.14, p = 0.02). In the secondary analyses, APOE4 carrier status (β= -0.27, p = 0.02) and normal BMI (β= -0.25, p = 0.01), as opposed to overweight or obese BMI, were associated with greater PiB retention. The BMI×APOE4 interaction was also significant (β= -0.14, p = 0.04).

CONCLUSIONS

This finding offers new insight into the role of BMI at the preclinical stage of AD, wherein lower BMI late in life is associated with greater cortical amyloid burden. Future studies are needed to elucidate the mechanism behind this association, especially in those with lower BMI who are APOE4 carriers.

Depression in dementia with Lewy bodies: A comparison with Alzheimer's disease

BACKGROUND

Depression is highly associated with dementia, and this study will compare the frequencies, severity, and symptoms of depression between dementia with Lewy bodies (DLB) and Alzheimer's disease (AD).

METHODS

Frequency of depression was determined according to the DSM-IV criteria for major depression or the National Institute of Mental Health criteria for depression in AD (NIMH-dAD). Severity of depression were assessed using the Hamilton Depression Rating Scale, the Cornell Scale for Depression in Dementia, and the depression subscale in Neuropsychiatric Inventory. The rates of depressive symptoms were compared between AD and DLB.

RESULTS

A total of 312 patients were investigated (AD/DLB = 241/71). The frequency of major depression was significantly higher (p = 0.017) in DLB (19.7%) than in AD (8.7%). The higher frequency of depression in DLB was not reproduced by using the NIMH-dAD criteria (DLB: AD = 43.7%: 33.2%; p = 0.105). The severity of depression was higher in DLB than in AD according to the Hamilton Depression Rating Scale (p < 0.001) and the Cornell Scale for Depression in Dementia (p < 0.001). Among depressive symptoms, pervasive anhedonia had the highest odds ratio in DLB compared with AD.

CONCLUSION

This is the first study using the NIMH-dAD criteria to investigate the frequency of depression in DLB. Our study shows that co-morbid major depression is more frequent in DLB than in AD. Pervasive anhedonia had the greatest value for the differential diagnosis of depression between DLB and AD.

Role of Pro-Inflammatory Cytokines and Vitamin D in Probable Alzheimer's Disease with Depression

Symptoms of depression are present in a significant proportion of Alzheimer's disease (AD) patients. While epidemiological studies have shown a strong association between depression and AD, it has not been established whether depression is a risk factor or merely a co-morbidity of AD. It is also uncertain if depression affects the pathogenesis of AD. In this paper, we address these questions by measuring the serum levels of two common metabolic risk factors of AD and depression, inflammatory cytokines (IL 6 and TNF alpha) and serum 25-hydroxyvitamin D, in a case-control study. We measured the serum levels of IL 6, TNF α and 25-hydroxyvitamin D in age-matched healthy controls (n= 60) and in AD patients without depression (n=26) or AD patients with depression (n=34), and statistically analyzed the changes in these parameters among different groups under this study. Our results show that in AD there is a significant increase in IL 6 and TNF α and a marked decrease in 25-hydroxyvitamin D in the peripheral circulation compared to age-matched healthy controls. Furthermore, AD patients with depression have even significantly higher levels of IL 6 or TNF α and a lower level of 25-hydroxyvitamin D in circulation than in AD patients without depression. We also found a strong statistical correlation between the disease severity and the serum levels of IL 6, TNF α and 25-hydroxyvitamin D in AD patients with depression. These results suggest that altered circulating levels of common metabolic risk factors lead to the co-existence of depression with AD in many patients, and when they co-exist, the depression presumably affects the severity of AD presentations through more aggravated changes in these risk factors.

Incidence and Course of Depression in Patients with Alzheimer's Disease

OBJECTIVE

Depressive symptoms are common in Alzheimer's disease (AD) and they might influence the course and prognosis of AD. Depression could appear anytime in the course of the disease, and could either last considerably long or disappear easily. This study is intended to investigate the occurrence of depression in the course of AD and the risk factors of incidence.

METHODS

This study targeted 1,272 AD patients without depressive symptoms at the start of this study in Korea. A total of 775 subjects completed the study, and the occurrence of depression was assessed after 12 months. Demographic information of subjects was collected and cognitive functions, overall functions, and depression severity were assessed at the start of this study and after 12 months.

RESULTS

Among the 775 subjects, 103 subjects (13.29%) developed depression 12 months later. The MMSE-KC scores showed significant changes in both groups that developed depression and did not. In the univariate analysis, significant differences in the incidence of depression were found in terms of gender, the administration of the antidepressant at the baseline, the SGDS-K score, and the GDS score. The multiple logistic regression analysis showed that the increase in the incidence of depression was associated with a female, in the increase in SGDS-K score and the GDS score.

CONCLUSION

The incidence of depression in the subjects who completed the 12-month follow-up observation was 13.29%. Moreover, in the multivariate analysis, a female gender and the severity of dementia, including the overall functions, seemed associated with the occurrence of depression.

Risk analysis of use of different classes of antidepressants on subsequent dementia: A nationwide cohort study in Taiwan

Depression and dementia are common mental health problems and are associated in several ways. Early-life depression is associated with increased risk of later life dementia, and depression can present as a preclinical symptom or consequence of dementia. Despite the plausible relationship between these two clinical entities, the potential association between antidepressant medication and dementia has rarely been investigated. We conducted a 9-year retrospective analysis of Taiwan’s National Health Insurance Research Database (NHIRD), enrolling 5819 cases who had received prescriptions of antidepressants between 2003 and 2006, and 23,276 (with ratio of 1:4) age, sex, and index date-matched controls. The hazard ratio (HR) of dementia among antidepressant users with depression was 2.42 (95% confidence interval (CI): 1.15–5.10), for those without depression was 4.05 (95% CI: 3.19–5.15), compared to antidepressant non-users respectively. Among the 6 classes of common antidepressants used in Taiwan, the adjusted HRs were 3.66 (95% CI: 2.62–5.09) for SSRIs, 4.73 (95% CI: 2.54–8.80) for SNRI, 3.26 (95% CI: 2.30–4.63) for TCAs, 6.62 (95% CI: 3.34–13.13) for TeCA, 4.94 (95% CI: 2.17–11.24) for MAOI, and 4.48 (95% CI: 3.13–6.40) for SARI. Furthermore, the multivariate analysis result showed that the adjusted HRs of cumulative defined daily doses (cDDDs) were 3.74 (95% CI: 2.91–4.82), 3.73 (95% CI: 2.39–5.80) and 5.22 (95% CI: 3.35–8.14) for those who had cDDDs of <90, 90–180 and >180 compared to those who had taken no antidepressant medication. This is a retrospective study based on secondary data, hence, we could not claim causality between antidepressant medication and dementia. However, a potential association between antidepressant and occurrence of dementia after controlling for the status of depression was observed. Lack of patients’ data about smoking status and body mass index in NHIRD, which are considered related to dementia, was also a limitation in this study. In this study, we concluded that antidepressant medication is a potential risk factor for dementia, independent from any effect of depression itself.

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.

Longitudinal associations between late-life depression dimensions and cognitive functioning: a cross-domain latent growth curve analysis

BACKGROUND

Cognitive impairment and depression often co-occur in older adults, but it is not clear whether depression is a risk factor for cognitive decline, a psychological reaction to cognitive decline, or whether changes in depressive symptoms correlate with changes in cognitive performance over time. The co-morbid manifestation of depression and cognitive impairment may reflect either a causal effect or a common cause, depending on the specific symptoms experienced and the cognitive functions affected.

METHOD

The study sample comprised 1506 community-dwelling older adults aged ⩾65 years from the Longitudinal Aging Study Amsterdam (LASA). We conducted cross-domain latent growth curve analyses to examine longitudinal associations between late-life depression dimensions (i.e. depressed affect, positive affect, and somatic symptoms) and specific domains of cognitive functioning (i.e. processing speed, inductive reasoning, immediate recall, and delayed recall).

RESULTS

Poorer delayed recall performance at baseline predicted a steeper increase in depressed affect over time. Steeper decline in processing speed correlated with a steeper increase in somatic symptoms of depression over time.

CONCLUSIONS

Our findings suggest a prospective association between memory function and depressed affect, whereby older adults may experience an increase in depressed affect in reaction to poor memory function. Somatic symptoms of depression increased concurrently with declining processing speed, which may reflect common neurodegenerative processes. Our findings do not support the hypothesis that depression symptoms may be a risk factor for cognitive decline in the general population. These findings have potential implications for the treatment of late-life depression and for the prognosis of cognitive outcomes.

Associations of fat and muscle tissue with cognitive status in older adults: the AGES-Reykjavik Study

Background/Objective

studies on the association of dementia with specific body composition (BC) components are scarce. Our aim was to investigate associations of BC measures with different levels of cognitive function in late-life.

Methods

we studied 5,169 participants (mean age 76 years, 42.9% men) in the AGES-Reykjavik Study of whom 485 (9.4%) were diagnosed with mild cognitive impairment (MCI) and 307 (5.9%) with dementia. Visceral fat, abdominal and thigh subcutaneous fat, and thigh muscle were assessed by computed tomography. MCI and dementia were based on clinical assessment and a consensus meeting; those without MCI or dementia were categorised as normal. Multinomial regression models assessed the associations stratified by sex and in additional analyses by midlife body mass index (BMI).

Results

among women, there was a decreased likelihood of dementia per SD increase in abdominal subcutaneous fat (OR 0.72; 95% CI: 0.59-0.88), thigh subcutaneous fat (0.81; 0.67-0.98) and thigh muscle (0.63; 0.52-0.76), but not visceral fat, adjusting for demographics, vascular risk factors, stroke and depression. Inverse associations of fat with dementia were attenuated by weight change from midlife and were strongest in women with midlife BMI <25. In men, one SD increase in thigh muscle was associated with a decreased likelihood of dementia (0.75; 0.61-0.92). BC was not associated with MCI in men or women.

Conclusion

a higher amount of abdominal and thigh subcutaneous fat were associated with a lower likelihood of dementia in women only, while more thigh muscle was associated with a lower likelihood of dementia in men and women.

Effects of white matter integrity and brain volumes on late life depression in the Framingham Heart Study

BACKGROUND

It is unclear whether brain white matter hyperintensities (WMHI) causes or is a result of late life depression. We used the Framingham Heart Study offspring to examine whether indices of brain aging are related to incident depression in the elderly.

METHODS

The Center for Epidemiologic Studies Depression Scale (CES-D) was administered along with a brain MRI scan at baseline and was re-administered (n = 1212) at an average 6.6 + 0.6 year follow-up. The outcomes (i) change in CES-D scores from baseline; (ii) depression defined as CES-D ≥16; (iii) severe depression defined as CES-D ≥21; and (iv) CES-D cutoff scores and/or on antidepressant were used.

RESULTS

Among those who did not have depression at baseline, 9.1% (n = 110) developed depression, 4.0% (n = 48) developed severe depressive symptoms, and 11.1% (n = 135) were put on antidepressants. When depressive symptoms only was the outcome, we found that baseline WMHI was positively associated with change in CES-D scores and that those with an extensive WMHI at baseline had a high risk of developing severe depressive symptoms; the relationship was strengthened in the absence of cardiovascular diseases. In contrast, when depressive symptoms or taking antidepressant was the outcome, larger total cerebral brain volume and temporal lobe brain volume, but not WMHI, were negatively associated with the development of depression.

CONCLUSIONS

Brain WMHI is a probable risk factor for vascular depression in the elderly. The depression outcomes with and without antidepressant were related to different brain pathologies. Copyright © 2016 John Wiley & Sons, Ltd.

Cerebral vascular burden on hippocampal subfields in first-onset drug-naïve subjects with late-onset depression

BACKGROUND

Although there is substantial evidence of associations between frontal-striatal circuits and cerebral vascular burden in late-onset depression (LOD), relationships between vascular burden and hippocampal subfields are not clear. The purpose of this study was to investigate relationships between cerebral vascular burden and hippocampal subfield volume in LOD patients.

METHODS

Fifty subjects with LOD and 50 group-matched healthy control subjects underwent magnetic resonance imaging scanning. Hippocampal subfields volumes were measured and compared between the groups. In addition, association patterns between white matter hyperintensity (WMH) volumes, clinical measures and hippocampal subfield volumes were investigated in the LOD group.

RESULTS

Subjects with LOD exhibited significant hippocampal volume reductions in the total hippocampus, cornu ammonis (CA) 1 and 3 and dentate gyrus (DG) areas compared with healthy subjects. Total WMH volume was negatively correlated with left total hippocampal volume and CA1 in the LOD group. In addition, depression severity was negatively associated with left and right CA3 volumes in the LOD group.

LIMITATION

Our findings of distinctive relationships between WMH and hippocampal subfields demonstrate a simple correlation, but do not prove causation CONCLUSION: This study is the first to elaborate distinctive association patterns between hippocampal subfield volumes and cerebral vascular burden in LOD. These structural changes in the hippocampal CA1, CA3 and DG areas might be at the core of the underlying neurobiological mechanisms of hippocampal dysfunction in LOD. However, longitudinal studies will be needed to identify the mechanisms of these structural changes.

Mood Changes in Cognitively Normal Older Adults are Linked to Alzheimer Disease Biomarker Levels

OBJECTIVES

To evaluate whether cerebrospinal fluid (CSF) and PET Pittsburgh Compound B (PiB) biomarkers of underlying Alzheimer disease (AD) pathology (β-amyloid₄₂ [Aβ₄₂], tau, phosphorylated tau₁₈₁ [ptau₁₈₁], tau/Aβ₄₂, ptau₁₈₁/Aβ₄₂ and mean cortical binding potential [MCBP] for PET-PiB) predict changes in mood in cognitively normal older adults.

SETTING

Knight Alzheimer's Disease Research Center (ADRC) at Washington University (WU).

PARTICIPANTS

Participants, 65 years of age or older, were enrolled from longitudinal studies at the WU Knight ADRC.

MEASUREMENTS

CSF, PET-PiB biomarkers, Clinical Dementia Rating (CDR), Mini-Mental State Examination (MMSE), Profile of Mood States-Short Form (POMS-SF), the Geriatric Depression Scale (GDS), and Neuropsychiatric Inventory Questionnaire (NPI-Q).

RESULTS

Data from 118 participants at baseline and 66 participants at one-year follow-up were analyzed. CSF and PET biomarkers were not associated cross-sectionally with any mood disturbances at baseline (p > 0.05). Changes in mood as indicated by the total mood disturbance score on the POMS-SF, selected POMS-SF subscales, GDS, and NPI-Q scores from baseline to one-year follow-up were associated with (p < 0.05) CSF and PET-PiB biomarkers. There was no statistically significant decline in cognitive functioning.

CONCLUSIONS

Generally, higher values of CSF and PET-PiB biomarkers are associated with more changes in mood in cognitively normal older adults. Further work is needed to understand the temporal development of mood changes over several years during the phase of preclinical AD. Evaluating mood as a noncognitive outcome may provide further insight into the development of preclinical AD in cognitively normal older adults.

Association of Cerebral Amyloidosis, Blood Pressure, and Neuronal Injury with Late-Life Onset Depression

Previous literature suggests that Alzheimer's disease (AD) process may contribute to late-life onset depression (LLOD). Therefore, we investigated the association of LLOD with cerebral amyloidosis and neuronal injury, the two key brain changes in AD, along with vascular risks. Twenty nine non-demented individuals who first experienced major depressive disorder (MDD) after age of 60 years were included as LLOD subjects, and 27 non-demented elderly individuals without lifetime experience of MDD were included as normal controls (NC). Comorbid mild cognitive impairment (MCI) was diagnosed in 48% of LLOD subjects and in 0% of NC. LLOD, irrespective of comorbid MCI diagnosis, was associated with prominent prefrontal cortical atrophy. Compared to NC, LLOD subjects with comorbid MCI (LLOD_MCI) showed increased cerebral ¹¹C-Pittsburg compound B (PiB) retention and plasma beta-amyloid 1–40 and 1–42 peptides, as measures of cerebral amyloidosis; and, such relationship was not observed in overall LLOD or LLOD without MCI (LLOD_woMCI). LLOD subjects, particularly the LLOD_woMCI, had higher systolic blood pressure (SBP) than NC. When analyzed in the same multiple logistic regression model that included prefrontal gray matter (GM) density, cerebral amyloidosis, and SBP as independent variables, only prefrontal GM density showed a significant independent association with LLOD regardless of MCI comorbidity status. Our findings suggest AD process might be related to LLOD via prefrontal neuronal injury in the MCI stage, whereas vascular processes—SBP elevation, in particular—are associated with LLOD via prefrontal neuronal injury even in cognitively intact or less impaired individuals.

Progressively Disrupted Intrinsic Functional Connectivity of Basolateral Amygdala in Very Early Alzheimer's Disease

Very early Alzheimer’s disease (AD) – i.e., AD at stages of mild cognitive impairment (MCI) and mild dementia – is characterized by progressive structural and neuropathologic changes, such as atrophy or tangle deposition in medial temporal lobes, including hippocampus and entorhinal cortex and also adjacent amygdala. While progressively disrupted intrinsic connectivity of hippocampus with other brain areas has been demonstrated by many studies, amygdala connectivity was rarely investigated in AD, notwithstanding its known relevance for emotion processing and mood disturbances, which are both important in early AD. Intrinsic functional connectivity (iFC) patterns of hippocampus and amygdala overlap in healthy persons. Thus, we hypothesized that increased alteration of iFC patterns along AD is not limited to the hippocampus but also concerns the amygdala, independent from atrophy. To address this hypothesis, we applied structural and functional resting-state MRI in healthy controls (CON, n = 33) and patients with AD in the stages of MCI (AD-MCI, n = 38) and mild dementia (AD-D, n = 36). Outcome measures were voxel-based morphometry (VBM) values and region-of-interest-based iFC maps of basolateral amygdala, which has extended cortical connectivity. Amygdala VBM values were progressively reduced in patients (CON > AD-MCI and AD-D). Amygdala iFC was progressively reduced along impairment severity (CON > AD-MCI > AD-D), particularly for hippocampus, temporal lobes, and fronto-parietal areas. Notably, decreased iFC was independent of amygdala atrophy. Results demonstrate progressively impaired amygdala intrinsic connectivity in temporal and fronto-parietal lobes independent from increasing amygdala atrophy in very early AD. Data suggest that early AD disrupts intrinsic connectivity of medial temporal lobe key regions, including that of amygdala.

Late-life depression symptom dimensions and cognitive functioning in the Longitudinal Aging Study Amsterdam (LASA)

BACKGROUND

Depression often co-occurs in late-life in the context of declining cognitive functions, but it is not clear whether specific depression symptom dimensions are differentially associated with cognitive abilities.

METHODS

The study sample comprised 3107 community-dwelling older adults from the Longitudinal Aging Study Amsterdam (LASA). We applied a Multiple Indicators Multiple Causes (MIMIC) model to examine the association between cognitive abilities and latent dimensions of the Center for Epidemiologic Studies Depression Scale (CES-D), while accounting for differential item functioning (DIF) due to age, gender and cognitive function levels.

RESULTS

A factor structure consisting of somatic symptoms, positive affect, depressed affect, and interpersonal difficulties fitted the data well. Higher levels of inductive reasoning were significantly associated with lower levels of depressed affect and somatic symptoms, whereas faster processing speed was significantly associated with lower levels of somatic symptoms. DIF due to age and gender was found, but the magnitude of the effects was small and did not alter substantive conclusions.

LIMITATIONS

Due to the cross-sectional context of this investigation, the direction of influence between depression symptom levels and cognitive function levels cannot be established. Furthermore, findings are relevant to non-clinical populations, and they do not clarify whether certain DIF effects may be found only at high or low levels of depression.

CONCLUSIONS

Our findings suggest differential associations between late-life depression dimensions and cognitive abilities in old age, and point towards potential etiological mechanisms that may underline these associations. These findings carry implications for the prognosis of cognitive outcomes in depressed older adults.

Clinically significant psychiatric symptoms among male carriers of the fragile X premutation, with and without FXTAS, and the mediating influence of executive functioning

OBJECTIVES

To clarify the neuropsychiatric phenotype of fragile X-associated tremor/ataxia syndrome (FXTAS), and assess the extent to which it is mediated by the dysexecutive syndrome that is a major feature of the disorder.

METHODS

We examined the prevalence of clinically meaningful psychiatric symptoms among male carriers of the fragile X premutation, with and without FXTAS, in comparison with men with a normal allele. Measures included the Neuropsychiatric Inventory (NPI), Symptom Checklist-90-R (SCL-90-R), and the Behavioral Dyscontrol Scale, a measure of executive functioning. Between-group differences were evaluated using logistic regression, followed by a mediation analysis with ordinary least squares regression to assess the contribution of dysexecutive syndrome to the observed psychiatric domains.

RESULTS

Men with FXTAS showed higher rates of clinically significant symptoms overall and in specific domains: somatization, obsessive compulsive, depression, anxiety, psychoticism, agitation/aggression, apathy/indifference, irritability, and nighttime behavior problems. Post hoc analyses suggested that findings of psychoticism among men with FXTAS may be associated with participants' accurate acknowledgment of cognitive and physical dysfunction, rather than reflecting psychosis. Asymptomatic carriers showed no evidence of clinically significant psychiatric symptoms, but when all carriers were compared with men having a normal FMR1 allele, executive function deficits were found to mediate scores in several domains on both NPI and SCL-90-R.

CONCLUSIONS

Building on prior research, the results provide evidence that the psychiatric phenotype for men includes clinically meaningful depression, hostility, and irritability, in association with behavioral and attentional disinhibition. It is likely that these problems reflect the effects of impaired executive functioning.

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.

Symptom Dimensions of Depression and 3-Year Incidence of Dementia: Results From the Amsterdam Study of the Elderly

OBJECTIVE

To evaluate the association between depressive symptom dimensions and incident dementia in a community sample of older persons.

METHODS

Depressive symptoms at baseline and incident dementia at 3-year follow-up were assessed with the Geriatric Mental State (GMS)-Automated Geriatric Examination for Computer Assisted Taxonomy in nondemented persons aged 65 years or older. Exploratory and confirmatory bifactor analysis on the depression items yielded a general depression factor characterized by all GMS items and a cognitive/motivational factor characterized by cognitive and motivational "depressive" symptoms and the absence of depressed mood.

RESULTS

Ninety-three of 1911 persons had developed dementia at follow-up. The general depression factor increased the risk of dementia after adjustment for covariates (odds ratio [OR]: 1.48, 95% confidence interval [CI]: 1.14-1.92), but the cognitive/motivational factor did not (OR: 1.05, 95% CI: 0.75-1.47). However, in 1725 nondepressed older persons, the cognitive/motivational factor significantly predicted dementia after adjustment for covariates (OR: 1.53, 95% CI: 1.03-2.28) but not anymore after additional adjustment for subjective memory complaints (OR: 1.41, 95% CI: 0.94-2.13). The general depression factor did not significantly predict dementia in nondepressed older persons (OR: 1.15, 95% CI: 0.80-1.66).

CONCLUSION

Our findings suggest that the increased risk of dementia associated with depressive symptoms in many previous studies appears to be heterogeneous, that is, it is likely due to different underlying pathways, including a pathway involving depression itself and a pathway in which cognitive and motivational symptoms reflect subjective cognitive complaints, particularly in the absence of depressed mood. These different pathways might warrant a different treatment approach.

Motivational processes in mild cognitive impairment and Alzheimer's disease: results from the Motivational Reserve in Alzheimer's (MoReA) study

BACKGROUND

Brain reserve, i.e., the ability of the brain to tolerate age- and disease-related changes in a way that cognitive function is still maintained, is assumed to be based on the lifelong training of various abilities. The Motivational Reserve in Alzheimer's (MoReA) is a longitudinal study that aims to examine motivational processes as a protective factor in mild Alzheimer's dementia (AD) and mild cognitive impairment (MCI). This paper presents the results of motivational variables, frequency of diagnoses, and prediction of global cognition as well as depression in a one-year longitudinal study.

METHODS

The sample consists of 64 subjects with MCI and 47 subjects with mild AD at baseline. At baseline, the physical/neurological examinations, standard clinical assessment, neuropsychological testing, and assessment of motivational variables were performed. At follow-up (FU) one year later, neuropsychological testing including cognition, functional abilities, behavioral and affective symptoms, and global clinical assessments of severity have been repeated.

RESULTS

AD cases have lower motivational capacities as measured with a midlife motivation-related occupational score and informant-reported present motivational processes, but do not differ with regard to delay of gratification (DoG) and self-reported motivational processes. DoG and delay discounting (DD) were relatively stable during the measurement interval. However, 20 % of the MCI cases converted to mild AD at FU, and 17 % of the mild AD cases converted to moderate AD. The rate of depression of Alzheimer's disease was 9 at baseline and 21 % at FU, and the rate of apathy was 7 and 14 %, respectively. Global cognition at FU was mainly predicted by baseline global cognition but also by one of the motivational variables (scenario test). Depression at FU was predicted mainly by two motivational variables (self-reported and informant-reported motivational processes).

CONCLUSIONS

This research might inform motivation-related strategies for prevention and early intervention with older people or people at risk for AD.

Depressive symptoms, cognitive impairment, and metabolic syndrome in community-dwelling elderly in Southern Taiwan

OBJECTIVE

Metabolic syndrome and depression are both thought to be associated with cognitive impairment in the elderly. Metabolic syndrome is also correlated with depression. We examined their possible pathways in a population-based sample.

METHODS

We recruited 300 older community participants from Southern Taiwan. Demographics, medical history, severity of depressive symptoms, cognitive function, apolipoprotein genotyping, and lipid profile were collected. The presence of metabolic syndrome was confirmed with the Third Report of the National Cholesterol Education Program's Adult Treatment Panel. Possible relationships between metabolic syndrome, depressive symptoms, and cognitive dysfunction were explored using logistic regression and structured equation modelling.

RESULTS

When gender, age, education, marital status, and apolipoprotein genotype were adjusted for logistic regression, metabolic syndrome and depressive symptoms were independent and significant predictors of cognitive dysfunction for community-dwelling elderly. In structural equation modelling, metabolic syndrome and depressive symptoms were correlated to each other, and both contributed to the presence of cognitive dysfunction.

CONCLUSIONS

Depressive symptoms and metabolic syndrome are independently associated with cognitive impairment among community-dwelling elderly.

Severe psychiatric disorders in mid-life and risk of dementia in late- life (age 65-84 years): a population based case-control study

OBJECTIVE

To examine the association of mid-life exposure to several psychiatric disorders with the development of late-life dementia.

METHODS

A matched case-control study using Western Australian state-wide hospital inpatient, outpatient mental health and emergency records linked to death records. Incident dementia cases (2000-2009) aged 65 to 84 years were sex- and age-matched to an electoral roll control. Records as far back as 1970 were used to assess exposure to medical risk factors before age 65 years. Candidate psychiatric risk factors were required to be present at least 10 years before dementia onset to ensure direction of potential causality. Odds ratios were estimated using conditional logistic regression.

RESULTS

13, 568 dementia cases (median age 78.7 years, 43.4 % male) were matched to a control. Depression, bipolar disorder, schizophrenia, anxiety disorder and alcohol dependence were found to be significant and independent risk factors for late-life dementia after adjusting for diabetes, heart disease, cerebrovascular disease and smoking risk factors. The effect of a history of depression, schizophrenia and alcohol dependency on dementia risk varied with age, being strongest for earlier onset late-life dementia and waning at older ages.

CONCLUSION

Severe depression, anxiety disorder, bipolar disorder, schizophrenia and alcoholic dependency disorder treated by specialists in psychiatric facilities in mid-life are important risk factors for late-life dementia. These psychiatric conditions need to be considered in future studies of the risk and prevention of late-life dementia.

Depression versus dementia: is this construct still relevant?

Cognitive impairment has long been identified as a component of late-life depression (LLD), and depressive symptoms are common in neurodegeneration. Depression may confer a greater risk of cognitive decline in a cognitively intact population and further cognitive decline in a mild cognitive impairment population compared with those without depression. Exploration of the link between cognitive impairment in LLD and the depressive features of neurodegeneration is an essential part of a diagnostic algorithm. In this review, we will discuss these links; we will address depressive symptoms as a risk factor for dementia and as a prodrome to dementia. We will review clinical subtypes and imaging markers as predictors of development of dementia in depressed patients and explore vascular etiologies. We will also explore LLD and dementia as a spectrum, rather than mutually exclusive diagnostic entities.

Neuropsychological and neuropsychiatric prediction of global cognitive status among older Spanish-speaking Hispanics and English-speaking whites

BACKGROUND

Neuropsychological and depression measures have been found to predict cognitive functioning. We compared these associations among whites and Spanish-speaking Hispanics.

METHODS

Fifty-two pairs of whites and Hispanics were matched demographically and clinically in a cross-sectional study. Hierarchical regression analyses predicted Global Deterioration Scale (GDS) rating by baseline neuropsychological tests and depression symptoms.

RESULTS

Neuropsychological tests predicted GDS better in whites; depression symptoms--specifically retardation--predicted well in Hispanics but not whites. Immediate recall of the New York University (NYU)-Paragraph Test and the Retardation item of the Hamilton Depression Rating Scale were associated with GDS in Hispanics and delayed recall of the NYU-Paragraph Test and Wechsler Adult Intelligence Scale-Digit Symbol in whites. Neuropsychological tests and depression symptoms predicted GDS differently in Hispanics and whites.

DISCUSSION

These results suggest that other measures should be considered to increase the predictive accuracy of neuropsychological tests when assessing cognitive status in Spanish-speaking Hispanics. Additional studies of specific ethnic/racial and sociodemographic subgroups are warranted.

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.

Cognitive deficits in unipolar old-age depression: a population-based study

BACKGROUND

There is substantial variability in the degree of cognitive impairment among older depressed persons. Inconsistencies in previous findings may be due to differences in clinical and demographic characteristics across study samples. We assessed the influence of unipolar depression and severity of depression on cognitive performance in a population-based sample of elderly persons aged ⩾60 years.

METHOD

Eighty-nine persons fulfilled ICD-10 criteria for unipolar depression (mild, n = 48; moderate, n = 38; severe, n = 3) after thorough screening for dementia (DSM-IV criteria), psychiatric co-morbidities and antidepressant pharmacotherapy. Participants (n = 2486) were administered an extensive cognitive test battery.

RESULTS

Moderate/severe unipolar depression was associated with poorer performance on tasks assessing processing speed, attention, executive function, verbal fluency, episodic memory and vocabulary. Mild depression was associated with poorer performance in processing speed, and few differences between mild and moderate/severe depression were observed. No association between depression and short-term memory, general knowledge or spatial ability was observed. Increasing age did not exacerbate the depression-related cognitive deficits, and the deficits remained largely unchanged after excluding persons in a preclinical phase of dementia. Furthermore, depression-related cognitive deficits were not associated with other pharmacological treatments that may affect cognitive performance.

CONCLUSIONS

Cognitive deficits in unipolar old-age depression involve a range of domains and the cognitive deficits seem to follow the spectrum of depression severity. The finding that mild depression was also associated with poorer cognitive functioning underscores the importance of detecting mild depression in elderly persons.

Prevalence of minor depression in elderly persons with and without mild cognitive impairment: a systematic review

BACKGROUND

Minor depression (MinD) and mild cognitive impairment (MCI) are common disorders in late life that often coexist. The aim of the present review is to demonstrate prevalence rates of minor depression in older patients with and without MCI.

METHODS

Electronic database searches were performed through Medline, ISI Web of Knowledge, Psycinfo, and Cochrane library. Two independent reviewers extracted the original studies based on inclusion criteria: representative study population aged 55 and older, diagnostics of MinD according to DSM. Data on prevalence rates, risk factors, comorbidity and health care usage were analyzed.

RESULTS

Point prevalence for MinD is higher in medical settings (median 14.4%) than in the community-based settings (median 10.4%) and primary care patients (median 7.7%). Although minor depression is rarely investigated in elderly persons with MCI, nearly 20% of patients with MCI seem to suffer from MinD. No data was found on the prevalence of MCI in patients with MinD. Risk factors associated with MinD include female gender, history of cerebrovascular diseases, generalized anxiety disorder, loneliness, and long-term institutional care.

LIMITATIONS

Methodological differences of included studies resulted in a broad range of prevalence rates. No data is shown regarding the prevalence of MCI in MinD group due to insufficient evidence.

CONCLUSIONS

Our review indicates that MinD is frequent in elderly population. MCI among those subjects has not been sufficiently investigated. Future studies based on clinical structured interviews should be performed in longitudinal design in order to differentiate late-life depression from progressive MCI or early manifestation of Alzheimer's disease.

Correlates of cognitive impairment in older Vietnamese

OBJECTIVES

This study examined correlates of cognitive functioning and possible cognitive impairment among older adults living in Da Nang, Vietnam and surrounding rural areas.

METHODS

The analytic sample consisted of 489 adults, 55 and older stratified by gender, age, and residence in a rural or urban area. The sample was 46% rural, 44% women, with a mean age of 69.04. Interviews were conducted in individuals' homes by trained interviewers. The dependent variable was a Vietnamese version of the mini mental status examination (MMSE). A multiple linear regression was run with the MMSE continuous scores reflecting cognitive functioning, while a binary logistic regression was conducted with an education-adjusted cut-off score reflecting possible cognitive impairment. Age, gender, education, material hardship, depressive symptoms Center for Epidemiologic Studies - Depression Scale, war injury, head trauma, diabetes, cardiovascular and cerebrovascular disease conditions served as correlates, controlling for marital status and rural/urban residence.

RESULTS

About 33% of the sample scored below the standard cutoff of 23 on the MMSE. However, only 12.9% of the sample would be considered impaired using the education-adjusted cut-off score. Cognitive functioning and possible cognitive impairment as indicated by MMSE scores were significantly associated with being older, completing fewer years of education, and material hardship. Gender, depressive symptoms, and cerebrovascular disease were associated with cognitive functioning, but not cognitive impairment.

CONCLUSION

These results show that social characteristics, physical illness, and mental health are associated with cognitive functioning. The study also raises questions about the need for standardization of screening measures on Vietnamese populations.

Prevalence and characteristics of depression in mild cognitive impairment: the Sydney Memory and Ageing Study

OBJECTIVE

Depression might be a risk factor for dementia. However, little is known about the prevalence of depressive symptoms in mild cognitive impairment (MCI) and whether mood or motivation-related symptoms are predominant.

METHOD

A total of 767 non-demented community-dwelling adults aged 70-90 years completed a comprehensive assessment, including neuropsychological testing, and a past psychiatric/medical history interview. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS) and Kessler Psychological Distress Scale (K10). Exploratory factor analysis was performed on the GDS and K10 to derive 'mood' and 'motivation' subscales.

RESULTS

A total of 290 participants were classified as having MCI and 468 as cognitively normal (CN). Participants with MCI reported more depressive symptoms, and more MCI participants met the cut-off for clinically significant symptoms, relative to CN participants. Those with amnestic MCI (aMCI), but not non-amnestic MCI, had more depressive symptoms and were more likely to meet the cut-off for clinically significant depressive symptoms, relative to CN participants. Participants with MCI reported more mood-related symptoms than CN participants, while there were no differences between groups on motivation-related symptoms.

CONCLUSION

Individuals with MCI, especially aMCI, endorse more depressive symptoms when compared with cognitively intact individuals. These findings highlight the importance of assessing and treating depressive symptoms in MCI.

Subjective memory complaints in elders: depression, anxiety, or cognitive decline?

OBJECTIVES

To study the association of subjective memory complaints (SMC) with affective state and cognitive performance in elders.

MATERIALS AND METHODS

We studied community dwelling elderly persons with normal physical examination. Participants completed questionnaires regarding memory difficulties and lifestyle habits, the Geriatric Depression Scale (GDS) and the Spielberger State-Trait Anxiety Inventory (STAI). Depending on their answers to the question about their memory condition, participants were divided into complainers and non-complainers and to five groups according to their MMSE scores. These data have been compared to objective cognitive performance according to Mindstreams - a computerized neuropsychological battery. A logistic regression was performed to evaluate odds ratios (OR) and 95% confidence intervals (CI) for those factors, which were associated with SMС (dependent variable).

RESULTS

Of 636 consecutive subjects (61% females), 507 participants (79.7%) had SMС. Presence of SMC was inversely correlated with MMSE scores, (r = -0.108; P for trend = 0.007). GDS and STAI scores were higher among subjects with SMC (OR = 1.23: CI 95%: 1.1-1.36 and OR = 1.03: CI 95%: 1.01-1.07, respectively). SMC did not correlate with objective cognitive performance measured by Mindstreams.

CONCLUSIONS

Subjective memory complaints are associated with sub-syndromal depression and anxiety in healthy cognitively normal elders.

Influence of Social Support on Older Adults with Cognitive Impairment, Depressive Symptoms, or Both Coexisting

The influence of social support dimensions (the extent of contact with others, the satisfaction with contacts, and the availability of help if sick or disabled) in elderly people with cognitive impairment (COG), depressive symptoms (DEP), or the co-occurrence of these symptoms (COG-DEP) was assessed in a cross-sectional analysis of a representative sample of 579 individuals aged 65 years and older. A lower extent of contact was related to COG ( OR: 2.26). Fair satisfaction with contacts was related to DEP ( OR: 2.88) and COG-DEP (OR: 4.22). A low level of satisfaction with contacts was an important predictor for DEP ( OR: 7.99) and COG-DEP ( OR: 7.88). Therefore, different dimensions of social support were independently correlated with different aspects of mental health. Quantitative aspects of social support were significantly linked to the presence of cognitive impairment. Satisfaction with social support affected depressive symptoms both alone and when they co-occurred with cognitive impairment.

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.

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.

Depression in Taiwanese patients with Alzheimer's disease determined by the National Institutes of Mental Health Provisional Criteria

BACKGROUND

Depression is a common behavioral and psychological symptom of Alzheimer's disease (AD). The aims of the present study were to determine the rate of depression in Taiwanese patients with AD using the National Institutes of Mental Health Provisional Criteria for Depression in AD (NIMH-dAD criteria) and to investigate the association of depression with other behavioral and psychological symptoms.

METHODS

A consecutive series of 302 AD patients registered in a dementia clinic were investigated in this study. All patients met the criteria of the National Institute of Neurological Disorders and Stroke-Alzheimer's Disease and Related Disorders Association for probable AD. The rates of depression were determined according to the criteria of the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders for major depression (DSM-IV), the International Classification of Diseases-9-Clinical Modification (ICD-9-CM) for neurotic depression, the depression subscale of the Neuropsychiatric Inventory (NPI), and the NIMH-dAD criteria. Depression severity was assessed using the 17-item Hamilton Depression Rating Scale. The rates of depression determined by the NIMH-dAD criteria were compared with the rates derived from each of the other instruments. Other behavioral and psychological symptoms were assessed using NPI. A behavioral neurologist or a geriatric psychiatrist interviewed all the patients.

RESULTS

Using the NIMH-dAD criteria, it was found that 90 (29.8%) of the AD patients had depression, and all depressive symptoms in NIMH-dAD were significantly higher among depressed patients. Among other depression instruments, the frequency of depression was lowest using the DSM-IV major depression criteria (9.3%) and highest with the NPI depression subscale (54%). Behavioral and psychological symptoms determined with NPI were significantly higher among depressed patients in all domains except euphoria.

CONCLUSIONS

This is the first study of depression in Taiwanese patients with AD using the NIMH-dAD criteria. Our findings suggest that comorbid depression is high in Taiwanese patients with AD. It is clinically important to note the high frequency of most behavioral and psychological symptoms among depressed AD patients.