Major depression, cognitive dysfunction and Alzheimer's disease: Is there a link?

Association between depression and incident dementia: Longitudinal findings from the share study

BACKGROUND

The association between depression and dementia is still unclear, particularly regarding depression as a potential risk factor preceding dementia. Therefore, we aimed to verify if the presence of depression at baseline may increase the risk of dementia and cognitive impairment during 15 years of follow-up in the SHARE (Survey of Health, Aging and Retirement in Europe) study.

METHODS

Depressive symptoms were defined using the EURO-D, with a score ≥4 indicative of depression. Incident dementia was ascertained using self-reported data and caregivers' information, cognitive impairment using objective cognitive tests. Cox regression analysis, adjusted for 10 baseline confounders, was run and hazard ratios (HRs), with their 95% confidence intervals, were estimated.

RESULTS

In total 22,789 participants were included in the present analysis (mean age 64.2 years) and were predominantly female. The prevalence of depression at baseline was 24.9%. Over 15 years of follow-up, the onset of dementia occurred a median 2 years earlier in people with depression compared to those without. Depression at the baseline significantly increased the risk of dementia in the overall sample (HR = 1.74; 95% CI: 1.54-1.95) and the risk of cognitive impairment (HR = 1.15; 95% CI: 1.06-1.25). For dementia, the association was stronger in people less than 60 years (HR = 2.07; 95% CI: 1.42-3.02) than in participants aged ≥80 years (HR = 1.47; 95% CI: 1.14-1.91). A similar trend was observed for cognitive impairment. Among the single items of the EURO-D, loss of concentration was the strongest individual variable predicting the onset of dementia.

CONCLUSIONS

Depression increased the risk of dementia and cognitive impairment, particularly in younger adults, whereas loss of concentration was the strongest individual predicting variable of dementia. These findings demonstrate the need for early detection of depression for preventing future cognitive worsening.

Association between depression and young-onset dementia in middle-aged women

BACKGROUND

Dementia is associated with older adults; however, it can also affect younger individuals, known as young-onset dementia (YOD), when diagnosed before the age of 65 years. We aimed to conduct a retrospective cohort study involving middle-aged women to investigate the association between premorbid depression and YOD development.

METHODS

We included 1.6 million women aged 40-60 years who underwent health checkups under the Korean National Health Insurance Service and investigated the association between depression and YOD.

RESULTS

Women with depression had a significantly higher risk of developing YOD than women without depression. Among premenopausal women, those with depression had a 2.67-fold increased risk, whereas postmenopausal women with depression had a 2.50-fold increased risk. Late age at menarche (> 16 years) and young age at menopause (< 40 years) was associated with an increased risk of YOD.

CONCLUSIONS

Depression in middle-aged women is a significant risk factor for the development of YOD. Understanding the role of reproductive factors can aid in the development of targeted therapeutic interventions to prevent or delay YOD.

Cingulate white matter mediates the effects of fecal Ruminococcus on neuropsychiatric symptoms in patients with amyloid-positive amnestic mild cognitive impairment

BACKGROUND

Microbiota-gut-brain axis interacts with one another to regulate brain functions. However, whether the impacts of gut dysbiosis on limbic white matter (WM) tracts contribute to the neuropsychiatric symptoms (NPS) in patients with amyloid-positive amnestic mild cognitive impairment (aMCI+), have not been explored yet. This study aimed to investigate the mediation effects of limbic WM integrity on the association between gut microbiota and NPS in patients with aMCI+.

METHODS

Twenty patients with aMCI + and 20 healthy controls (HCs) were enrolled. All subjects underwent neuropsychological assessments and their microbial compositions were characterized using 16S rRNA Miseq sequencing technique. Amyloid deposition inspected by positron emission tomography imaging and limbic WM tracts (i.e., fornix, cingulum, and uncinate fasciculus) detected by diffusion tensor imaging were additionally measured in patients with aMCI+. We employed a regression-based mediation analysis using Hayes's PROCESS macro in this study.

RESULTS

The relative abundance of genera Ruminococcus and Lactococcus was significantly decreased in patients with aMCI + versus HCs. The relative abundance of Ruminococcus was negatively correlated with affective symptom cluster in the aMCI + group. Notably, this association was mediated by WM integrity of the left cingulate gyrus.

CONCLUSIONS

Our findings suggest Ruminococcus as a potential target for the management of affective impairments in patients with aMCI+.

Association of Early-, Middle-, and Late-Life Depression With Incident Dementia in a Danish Cohort

Importance

Late-life depressive symptoms are associated with subsequent dementia diagnosis and may be an early symptom or response to preclinical disease. Evaluating associations with early- and middle-life depression will help clarify whether depression influences dementia risk.

Objective

To examine associations of early-, middle-, and late-life depression with incident dementia.

Design, Setting, and Participants

This was a nationwide, population-based, cohort study conducted from April 2020 to March 2023. Participants included Danish citizens from the general population with depression diagnoses who were matched by sex and birth year to individuals with no depression diagnosis. Participants were followed up from 1977 to 2018. Excluded from analyses were individuals followed for less than 1 year, those younger than 18 years, or those with baseline dementia.

Exposure

Depression was defined using diagnostic codes from the International Classification of Diseases (ICD) within the Danish National Patient Registry (DNPR) and Danish Psychiatric Central Research Register (DPCRR).

Main Outcomes and Measure

Incident dementia was defined using ICD diagnostic codes within the DPCRR and DNPR. Cox proportional hazards regression was used to examine associations between depression and dementia adjusting for education, income, cardiovascular disease, chronic obstructive pulmonary disease, diabetes, anxiety disorders, stress disorders, substance use disorders, and bipolar disorder. Analyses were stratified by age at depression diagnosis, years since index date, and sex.

Results

There were 246 499 individuals (median [IQR] age, 50.8 [34.7-70.7] years; 159 421 women [64.7%]) with diagnosed depression and 1 190 302 individuals (median [IQR] age, 50.4 [34.6-70.0] years; 768 876 women [64.6%]) without depression. Approximately two-thirds of those diagnosed with depression were diagnosed before the age of 60 years (684 974 [67.7%]). The hazard of dementia among those diagnosed with depression was 2.41 times that of the comparison cohort (95% CI, 2.35-2.47). This association persisted when the time elapsed from the index date was longer than 20 to 39 years (hazard ratio [HR], 1.79; 95% CI, 1.58-2.04) and among those diagnosed with depression in early, middle, or late life (18-44 years: HR, 3.08; 95% CI, 2.64-3.58; 45-59 years: HR, 2.95; 95% CI, 2.75-3.17; ≥60 years: HR, 2.31; 95% CI, 2.25-2.38). The overall HR was greater for men (HR, 2.98; 95% CI, 2.84-3.12) than for women (HR, 2.21; 95% CI, 2.15-2.27).

Conclusions and Relevance

Results suggest that the risk of dementia was more than doubled for both men and women with diagnosed depression. The persistent association between dementia and depression diagnosed in early and middle life suggests that depression may increase dementia risk.

Multimorbid Patterns and Cognitive Performance in the Presence of Informative Dropout Among Community-Dwelling Taiwanese Older Adults

Background and Objectives

Longitudinal studies among older adults often feature elevated dropout rates and multiple chronic conditions. How Taiwanese multimorbid patterns relate to different cognitive domains remains unclear. This study aims to identify sex-specific multimorbid patterns and associate them with cognitive performance while modeling the risk for dropout.

Research Design and Methods

A prospective cohort study (2011-19) in Taiwan recruited 449 Taiwanese older adults without dementia. Global and domain-specific cognition were assessed biennially. We used exploratory factor analysis to identify baseline sex-specific multimorbid patterns of 19 self-reported chronic conditions. We utilized a joint model incorporating longitudinal and time-to-dropout data to examine the association between multimorbid patterns and cognitive performance accounting for the informative dropout via the shared random effect.

Results

At the end of the study, 324 participants (72.1%) remained in the cohort, with an average annual attrition rate of 5.5%. We found that advanced age, low levels of physical activities, and poor cognition at baseline were associated with increased dropout risks. Besides, 6 multimorbid patterns were identified, labeled Mental, Renal-vascular, and Cancer-urinary patterns in men, and Mental, Cardiometabolic, and Cancer-endocrine patterns in women. For men, as the follow-up time increased, the Mental pattern was associated with poor global cognition and attention; the Renal-vascular pattern was associated with poor executive function. For women, the Mental pattern was associated with poor memory; as follow-up time increased, and Cardiometabolic patterns were related to poor memory.

Discussion and Implications

Sex-specific multimorbid patterns identified in the Taiwanese older population showed differences (notably Renal-vascular pattern in men) from patterns found in Western countries and were differentially associated with cognitive impairment over time. When informative dropout is suspected, appropriate statistical methods should be applied.

Crosstalk between Depression and Breast Cancer via Hepatic Epoxide Metabolism: A Central Comorbidity Mechanism

Breast cancer (BC) is a serious global challenge, and depression is one of the risk factors and comorbidities of BC. Recently, the research on the comorbidity of BC and depression has focused on the dysfunction of the hypothalamic–pituitary–adrenal axis and the persistent stimulation of the inflammatory response. However, the further mechanisms for comorbidity remain unclear. Epoxide metabolism has been shown to have a regulatory function in the comorbid mechanism with scattered reports. Hence, this article reviews the role of epoxide metabolism in depression and BC. The comprehensive review discloses the imbalance in epoxide metabolism and its downstream effect shared by BC and depression, including overexpression of inflammation, upregulation of toxic diols, and disturbed lipid metabolism. These downstream effects are mainly involved in the construction of the breast malignancy microenvironment through liver regulation. This finding provides new clues on the mechanism of BC and depression comorbidity, suggesting in particular a potential relationship between the liver and BC, and provides potential evidence of comorbidity for subsequent studies on the pathological mechanism.

A Single-Case Design Investigation for Measuring the Efficacy of Gestalt Therapy to Treat Depression in Older Adults with Dementia in Italy and in Mexico: A Research Protocol

Psychotherapy is one of the evidence-based clinical interventions for the treatment of depression in older adults with dementia. Randomised controlled trials are often the first methodological choice to gain evidence, yet they are not applicable to a wide range of humanistic psychotherapies. Amongst all, the efficacy of the Gestalt therapy (GT) is under-investigated. The purpose of this paper is to present a research protocol, aiming to assess the effects of a GT-based intervention on people with dementia (PWD) and indirect influence on their family carers. The study implements the single-case experimental design with time series analysis that will be carried out in Italy and Mexico. Six people in each country, who received a diagnosis of dementia and present depressive symptoms, will be recruited. Eight or more GT sessions will be provided, whose fidelity will be assessed by the GT fidelity scale. Quantitative outcome measures are foreseen for monitoring participants' depression, anxiety, quality of life, loneliness, carers' burden, and the caregiving dyad mutuality at baseline and follow-up. The advantages and limitations of the research design are considered. If GT will effectively result in the treatment of depression in PWD, it could enrich the range of evidence-based interventions provided by healthcare services.

A Systematic Analysis on the Genes and Their Interaction Underlying the Comorbidity of Alzheimer's Disease and Major Depressive Disorder

Background

During the past years, clinical and epidemiological studies have indicated a close relationship between Alzheimer's disease (AD) and other mental disorders like major depressive disorder (MDD). At the same time, a number of genes genetically associated with AD or MDD have been detected. However, our knowledge on the mechanisms that link the two disorders is still incomplete, and controversies exist. In such a situation, a systematic analysis on these genes could provide clues to understand the molecular features of two disorders and their comorbidity.

Methods

In this study, we compiled the genes reported to be associated with AD or MDD by a comprehensive search of human genetic studies and genes curated in disease-related database. Then, we investigated the features of the shared genes between AD and MDD using the functional enrichment analysis. Furthermore, the major biochemical pathways enriched in the AD- or MDD-associated genes were identified, and the cross talks between the pathways were analyzed. In addition, novel candidate genes related to AD and MDD were predicted in the context of human protein-protein interactome.

Results

We obtained 650 AD-associated genes, 447 MDD-associated genes, and 77 shared genes between AD and MDD. The functional analysis revealed that biological processes involved in cognition, neural development, synaptic transmission, and immune-related processes were enriched in the common genes, indicating a complex mechanism underlying the comorbidity of the two diseases. In addition, we conducted the pathway enrichment analysis and found 102 shared pathways between AD and MDD, which involved in neuronal development, endocrine, cell growth, and immune response. By using the pathway cross-talk analysis, we found that these pathways could be roughly clustered into four modules, i.e., the immune response-related module, the neurodevelopmental module, the cancer or cell growth module, and the endocrine module. Furthermore, we obtained 37 novel candidate genes potentially related to AD and MDD with node degrees > 5.0 by mapping the shared genes to human protein-protein interaction network (PPIN). Finally, we found that 37 novel candidate genes are significantly expressed in the brain.

Conclusion

These results indicated shared biological processes and pathways between AD and MDD and provided hints for the comorbidity of AD and MDD.

Association of Depressive Symptoms and Cognition in Older Adults Without Dementia Across Different Biomarker Profiles

BACKGROUND

Depression is a late-life risk factor for cognitive decline. Evidence suggests an association between Alzheimer's disease (AD) associated pathologic changes and depressive symptoms.

OBJECTIVE

To investigate the influence of AT(N) biomarker profile (amyloid-β [A], p-tau [T], and neurodegeneration [N]) and gender on cross-sectional associations between subclinical depressive symptoms and cognitive function among older adults without dementia.

METHODS

Participants included 868 individuals without dementia from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Depressive symptoms were measured using the Geriatric Depression Scale (GDS). ADNI neuropsychological composite scores assessed memory and executive function (EF). PET, cerebrospinal fluid, and MRI modalities classified the study sample into biomarker profiles: normal biomarkers (A-T-N-), AD continuum (A+T±N±), and suspect non-AD pathology (SNAP; A-T±N-or A-T-N±). Multivariate regression models were used to investigate associations between GDS and cognitive domains.

RESULTS

GDS was negatively associated with memory (β= -0.156, p < 0.001) and EF (β= -0.147, p < 0.001) in the whole sample. When classified by biomarker profile, GDS was negatively associated with memory and EF in AD continuum (memory: β= -0.174, p < 0.001; EF: β= -0.129 p = 0.003) and SNAP (memory: β= -0.172, p = 0.005; EF: β= -0.197, p = 0.001) subgroups. When stratified by sex, GDS was negatively associated with memory (β= -0.227, p < 0.001) and EF (β= -0.205, p < 0.001) in men only.

CONCLUSION

The association between subclinical depressive symptoms and cognitive function is highly influenced by the AT(N) biomarker profile.

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

RATIONALE

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Alterations of dynamic redundancy of functional brain subnetworks in Alzheimer's disease and major depression disorders

The human brain is not only efficiently but also "redundantly" connected. The redundancy design could help the brain maintain resilience to disease attacks. This paper explores subnetwork-level redundancy dynamics and the potential of such metrics in disease studies. As such, we looked into specific functional subnetworks, including those associated with high-level functions. We investigated how the subnetwork redundancy dynamics change along with Alzheimer's disease (AD) progression and with major depressive disorder (MDD), two major disorders that could share similar subnetwork alterations. We found an increased dynamic redundancy of the subcortical-cerebellum subnetwork and its connections to other high-order subnetworks in the mild cognitive impairment (MCI) and AD compared to the normal control (NC). With gained spatial specificity, we found such a redundancy index was sensitive to disease symptoms and could act as a protective mechanism to prevent the collapse of the brain network and functions. The dynamic redundancy of the medial frontal subnetwork and its connections to the frontoparietal subnetwork was also found decreased in MDD compared to NC. The spatial specificity of the redundancy dynamics changes may provide essential knowledge for a better understanding of shared neural substrates in AD and MDD.

Prevalence, risk and protective factors for mild cognitive impairment in a population-based study of Singaporean elderly

The prevalence of dementia has been widely reported, and its potential risk and protective factors are well-characterized. However, there is a scarcity of related information regarding mild cognitive impairment (MCI). Thus this population-based study aimed to determine the prevalences of MCI and its subtypes, as well as to identify the risk and protective factors for MCI in the Chinese elderly population of Singapore. Results showed that the overall prevalence of MCI was 12.5%, while the gender-adjusted prevalence of MCI was 12.3%. Gender was found to be significantly associated with the subtypes of MCI, with males more likely to have amnestic MCI and females more likely to have non-amnestic MCI. Older age, lower educational levels, lower social activity levels, depression, hypertension, hyperlipidemia, diabetes and stroke were found to be risk factors for MCI in univariate analysis. However, multivariable analysis showed that only hypertension and stroke were the significant risk factors for MCI. Higher educational levels and active social engagements were significant protective factors for MCI in multivariable analysis. Age and depression had boundary significant associations with the prevalence of MCI. After adjusting for gender, the influence of hypertension, stroke, social engagement, age and depression on MCI remained unchanged, except that education became a boundary significant lower risk factor of MCI development. In conclusion, this study presented the prevalence, risk and protective factors for MCI among Singaporean Chinese older adults, which facilitates the screening of vulnerable groups for MCI.

Antidepressants in Alzheimer's Disease: A Focus on the Role of Mirtazapine

Mirtazapine belongs to the category of antidepressants clinically used mainly in major depressive disorder but also used in obsessive-compulsive disorders, generalized anxiety, and sleep disturbances. This drug acts mainly by antagonizing the adrenergic α2, and the serotonergic 5-HT2 and 5-HT3 receptors. Neuropsychiatric symptoms, such as depression and agitation, are strongly associated with Alzheimer’s disease, reducing the life quality of these patients. Thus, it is crucial to control depression in Alzheimer’s patients. For this purpose, drugs such as mirtazapine are important in the control of anxiety, agitation, and other depressive symptoms in these patients. Indeed, despite some contradictory studies, evidence supports the role of mirtazapine in this regard. In this review, we will focus on depression in Alzheimer’s disease, highlighting the role of mirtazapine in this context.

Benincasa hispida alleviates amyloid pathology by inhibition of Keap1/Nrf2-axis: Emphasis on oxidative and inflammatory stress involved in Alzheimer's disease model

OBJECTIVES

Alzheimer's disease is a progressive neurodegenerative disorder with cognitive and memory impairment. Benincasa hispida is being used in the treatment of various neurological diseases in Ayurveda system of medicine. The objective of the study was to investigate the effect of Benincasa hispida fruit extract in the Alzheimer's disease rats.

METHODS

Benincasa hispida fruits extract was administered orally for 16 weeks at doses of 250 and 500-mg/kg/day. The cognitive deficits were examined by behavioural tests like Morris water maze test, Y-maze and rota-rod test. Biochemical and neurochemical analysis of Acetylcholine, dopamine, serotonin levels and anti-oxidant, anti-inflammatory markers were evaluated and the mRNA expression of Keap/Nrf2 axis was analysed by RT-PCR.

RESULTS

Aluminum chloride (AlCl₃) induction altered the behavioural profile and produced significant alterations in the cortical and hippocampal regions of the brain and the treatment with Benincasa hispida extract at doses of 250-mg/kg/day (p<0.05) and 500mg/kg/day (p<0.05) alleviated the acetylcholine, dopamine and serotonin neurotransmitter levels. The antioxidant enzyme markers such as superoxide dismutase (SOD), Catalase (CAT), glutathione (GSH) were increased and the oxidative stress marker malondialdehyde(MDA) was decreased. The inflammatory cytokine levels of TNF-α, IL-1β were decreased in Alzheimer's disease induced rats. We further estimated Keap/Nrf2/HO-1 genes these anti-oxidant genes were upregulated(p < 0.001) in treatment groups. Further, the neuroprotective activity of Benincasa was further confirmed by histopathological studies of hippocampal CA3 fields.

CONCLUSIONS

The findings of the current study indicates Benincasa hispida as a possible neuroprotective alternative for Alzheimer's disease.

Does the application of acetylcholinesterase inhibitors in the treatment of Alzheimer's disease lead to depression?

Introduction: Alzheimer's disease and depression are health conditions affecting millions of people around the world. Both are strongly related to the level of the neurotransmitter acetylcholine. Since cholinergic deficit is characteristic of Alzheimer's disease, acetylcholinesterase inhibitors are applied as relevant drugs for the treatment of this disease, elevating the level of acetylcholine. On the other hand, a high level of acetylcholine is found to be associated with the symptoms of clinical depression.Areas covered: This article aims to discuss if acetylcholinesterase inhibitors used as anti-Alzheimer's drugs could be the cause of the symptoms of clinical depression often linked to this neurological disorder. Emphasis will be put on drugs currently in use and on newly investigated natural products, which can inhibit AChE activity.Expert opinion: Currently, it is not proven that the patient treated for Alzheimer's disease is prone to increased risk for depression due to the acetylcholinesterase inhibition, but there are strong indications. The level of acetylcholine is not the only factor in highly complicated diseases like AD and depression. Still, it needs to be considered isolated, keeping in mind the nature of presently available therapy, especially during a rational drug design process.

Cognition-oriented treatments for older adults: A systematic review of the influence of depression and self-efficacy individual differences factors

The increasing prevalence of cognitive decline, mild cognitive impairment (MCI), and dementia with the aging population has led to scrutiny of the efficacy of cognition-oriented treatments (COTs) aiming to maintain functioning, and delay or prevent further cognitive decline. However, little is known regarding the role of individual differences patient-variables (such as depression, self-efficacy, and motivation) in moderating the efficacy of COTs. This systematic review aimed to identify and analyze COT trials which investigated the relationship between differences in these patient-variables and intervention outcomes for older adults across healthy, MCI, and dementia populations. Of the 4854 studies extracted from the systematic search, 14 were included for analysis. While results were mixed across interventions and populations, on balance, greater depression severity predicted poorer cognitive functioning, and improvement in depressive symptom severity may account for at least part of the cognitive benefits seen at post-intervention. These findings were strongest for studies of MCI populations, with there being limited evidence of a relationship for healthy older adults or those with dementia. Overall, this review demonstrates the need for further investigation into the role of individual differences and clinical variables - particularly depression symptom severity - in attenuating COT outcomes through larger sample, high-quality randomized controlled trials.

Beyond Haemostasis and Thrombosis: Platelets in Depression and Its Co-Morbidities

Alongside their function in primary haemostasis and thrombo-inflammation, platelets are increasingly considered a bridge between mental, immunological and coagulation-related disorders. This review focuses on the link between platelets and the pathophysiology of major depressive disorder (MDD) and its most frequent comorbidities. Platelet- and neuron-shared proteins involved in MDD are functionally described. Platelet-related studies performed in the context of MDD, cardiovascular disease, and major neurodegenerative, neuropsychiatric and neurodevelopmental disorders are transversally presented from an epidemiological, genetic and functional point of view. To provide a complete scenario, we report the analysis of original data on the epidemiological link between platelets and depression symptoms suggesting moderating and interactive effects of sex on this association. Epidemiological and genetic studies discussed suggest that blood platelets might also be relevant biomarkers of MDD prediction and occurrence in the context of MDD comorbidities. Finally, this review has the ambition to formulate some directives and perspectives for future research on this topic.

Associations of Subsyndromal Symptomatic Depression with Cognitive Decline and Brain Atrophy in Elderly Individuals without Dementia: A Longitudinal Study

BACKGROUND

Subsyndromal symptomatic depression (SSD) is prevalent in older adults. However, it remains unclear whether there are effects of SSD on brain aging outcomes (cognition and brain structures), especially in the presence of Alzheimer's Disease (AD) pathology.

METHODS

A total of 1,188 adults without dementia were recruited from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Participants with SSD were measured using the 15-item Geriatric Depression Scale (GDS-15). In multivariable models, the cross-sectional and longitudinal associations of SSD with brain aging outcomes were explored. We further evaluated whether baseline amyloid-β (Aβ) load modifies the relations between SSD and brain aging outcomes.

RESULTS

SSD at baseline was associated with significantly longitudinal decline in cognition and displayed significantly accelerated atrophy in hippocampus (β = -29.53, p = 0.001) and middle temporal gyrus (β = - 77.82, p = 0.006) among all participants and Aβ-Positive individuals. SSD interacted with baseline Aβ load in predicting longitudinal decline in Mini Mental State Examination (MMSE) (β = - 0.327, p = 0.023), episodic memory (β = -0.065, p = 0.004) and increase in Alzheimer's Disease Assessment Scale Cognition 13-item scale (ADAS-cog13) (β = 0.754, p = 0.026).

LIMITATIONS

Our study didn't look at AD diagnosis but Aβ status.

CONCLUSIONS

Our findings suggested that older people without dementia with both SSD and a high level of Aβ load may have higher risk of cognitive deterioration and brain atrophy. Therapeutic mitigation of depressive symptoms, especially in those with abnormal Aβ levels, may help delay progressive decline in cognition.

Cognitive impairment in remitted late-life depression is not associated with Alzheimer's disease-related CSF biomarkers

BACKGROUND

Cognitive impairment is a common feature of late-life depression (LLD). Early studies using Alzheimer's disease (AD) biomarkers inferred a biological link between AD pathology and LLD, but recent findings have challenged this association. The aim of this investigation was to determine a panel of AD-related cerebrospinal fluid (CSF) biomarkers in a cross-section of elders with mild cognitive impairment (MCI) with and without LLD.

METHODS

Subjects comprised 102 older adults: 27 with 'pure' amnestic MCI (aMCI), 53 with major depression and cognitive impairment - encompassing 22 late-onset (LOD) and 31 early-onset depression (EOD), and 22 euthymic elders without cognitive impairment (controls). Participants underwent lumbar puncture for determination of CSF concentrations of Aβ_1-42, T-tau, and P-tau. Cut-off scores for suspected AD were: Aβ_1-42 < 416p g/mL, P-tau > 36.1 pg/mL and Aβ/P-tau ratio < 9.53 (O. V. Forlenza et al. 2015). Statistical analyses consisted of analyses of variance (ANOVA), analyses of covariance (ANCOVA), Bonferroni post-hoc tests, and Pearson's chi-squared tests.

RESULTS

ANCOVA (age and schooling as covariates) displayed statistically significant results with respect to CSF biomarkers' profiles regardless of the socio-demographic divergencies previously identified by one-way ANOVA. Mean Aβ_1-42 values (pg/mL) were: aMCI, 360.3 (p < 0.001); LOD, 486.6 (p < 0.001); EOD, 494.2 (p < 0.001); controls, 528.3 (p < 0.001); p< 0.05. Mean Aβ_1-42/P-tau ratio: aMCI, 7.9 (p < 0.001); LOD 14.2 (p < 0.001); EOD, 15.3 (p < 0.001); controls, 17.1 (p < 0.001); p < 0.05. Post-hoc tests indicated that patients with aMCI showed significant differences in biomarker profile compatible with AD signature.

LIMITATION

The main limitation is the relatively small sample.

CONCLUSION

Our findings suggest that, distinctively from aMCI, cognitive impairment in LLD is not associated with AD's CSF pathological signature.

Depression-an underrecognized target for prevention of dementia in Alzheimer's disease

It is broadly acknowledged that the onset of dementia in Alzheimer's disease (AD) may be modifiable by the management of risk factors. While several recent guidelines and multidomain intervention trials on prevention of cognitive decline address lifestyle factors and risk diseases, such as hypertension and diabetes, a special reference to the established risk factor of depression or depressive symptoms is systematically lacking. In this article we review epidemiological studies and biological mechanisms linking depression with AD and cognitive decline. We also emphasize the effects of antidepressive treatment on AD pathology including the molecular effects of antidepressants on neurogenesis, amyloid burden, tau pathology, and inflammation. We advocate moving depression and depressive symptoms into the focus of prevention of cognitive decline and dementia. We constitute that early treatment of depressive symptoms may impact on the disease course of AD and affect the risk of developing dementia and we propose the need for clinical trials.

The Challenge of Antidepressant Therapeutics in Alzheimer's Disease

The link between depression and Alzheimer's disease (AD) is controversial, because it is not clear if depression is an independent risk factor for the disease or a prodromal symptom in the older population. Cerebral amyloid-β (Aβ) peptide deposition is associated with both cognitive symptoms and neuropsychiatric symptoms (NPS), which may be a biological mechanism of compensation. Despite the widespread use of antidepressant therapeutics (30-50% of patients with AD/dementia are on antidepressants), there is mixed evidence regarding the benefits from their use in AD depression. Monoaminergic antidepressant drugs have shown only modest or no clinical benefits. Therefore, it is important to understand the reason of this drug-resistance and the relationship between antidepressant drugs and the Aβ peptide. The goal of the present review is to highlight the etiology of depression in patients affected by AD in comparison to depressive disorders without AD, and to speculate on more appropriate and alternative therapeutics.

Exploring prior diseases associated with incident late-onset Alzheimer's disease dementia

Studies have identified prior conditions associated with late-onset Alzheimer's disease dementia (LOAD), but all prior diseases have rarely been screened simultaneously in the literature. Our objective in the present study was to identify prior conditions associated with LOAD and construct pathways for them. We conducted a population-based matched case-control study based on data collected in the National Health Insurance Research database of Taiwan and the Catastrophic Illness Certificate database for the years 1997-2013. Prior diseases definitions were based on the first three digits of the codes listed in the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Inclusion criteria required that each ICD-code existed for at least 1 year and incurred at least 2 outpatient visits or inpatient diagnosis. The case group comprised 4,600 patients newly diagnosed with LOAD in 2007-2013. The LOAD patients were matched by sex and age to obtain 4,600 controls. Using stepwise multivariate logistic regression analysis, diseases were screened for 1, 2 …, 9 years prior to the first diagnosis of LOAD. Path analysis was used to construct pathways between prior diseases and LOAD. Our results revealed that the following conditions were positively associated with the incidence of LOAD: anxiety (ICD-code 300), functional digestive disorder (ICD code 564), psychopathology-specific symptoms (ICD-code 307), disorders of the vestibular system (ICD-code 386), concussion (ICD-code 850), disorders of the urethra and urinary tract (ICD-code 599), disorders of refraction and accommodation (ICD-code 367), and hearing loss (ICD-code 389). A number of the prior diseases have previously been described in the literature in a manner identical to that in the present study. Our study supports the assertion that mental, hearing, vestibular system, and functional digestive disorders may play an important role in the pathogenesis of LOAD.

Low Mood and Risk of Dementia: The Role of Marital Status and Living Situation

OBJECTIVE

This study aims to explore whether low mood is related to an increased dementia risk in two cohorts of older adults of different generations, and whether marital status and living situation modify this association.

METHODS

Participants (≥70 years), free from dementia and living at home, were identified from two population-based studies: the Kungsholmen Project (KP; n = 1,197) and the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K; n = 1,402). Low mood was obtained by self-report (KP and SNAC-K) at baseline in 1987-89 (KP) and 2001-04 (SNAC-K). Incident dementia cases were ascertained over 9 years, using the same diagnostic procedures and comparable criteria for the two cohorts (DSM-III-R in KP and DSM-IV-TR in SNAC-K). Hazard ratios (HR) were derived from Cox proportional hazards models.

RESULTS

Those having low mood at baseline were at higher risk of dementia in both cohorts combined (HR: 1.2, 95% confidence interval (CI): 1.0-1.4) than those without low mood. However, an increased risk was detected only in those who did not have a partner (HR: 1.5, 95% CI: 1.2-1.9), or lived alone (HR: 1.5, 95% CI: 1.2-1.9), but not among those who had a partner or lived with someone (HR: 0.8, 95% CI: 0.5-1.2).

CONCLUSION

Marital status and living situation have the potential to buffer the detrimental effects of low mood on dementia onset. Thus, specific attention from health care should target individuals having low mood and who do not have a partner or live alone.

Physical activity modifies the association between depression and cognitive function in older adults

OBJECTIVE

To examine the effects of gender and physical activity on the interplay between depression and cognitive function in late adulthood.

METHOD

Data on physical activity, depressive symptoms, two measures of cognitive function (the Animal Fluency Test (AFT) and the Digital Symbol Substitution Test (DSST)), and other demographic characteristics were extracted from 2604 adults aged ≥ 60 years participating in the National Health and Nutrition Examination Survey (2011-2014). Gender-specific multiple linear regressions examined the relationship between depressive symptoms and cognitive function in the overall sample and stratified by level of leisure-time physical activity.

RESULTS

Sample included 1327 women and 1277 men (mean age 69.0 years), Women with moderate to severe depressive symptoms had a 1.7 (95% CI: 0.5-2.9) point lower score on the AFT than those with none or minimal depressive symptoms. No such association was observed in men. In the stratified analyses, lower AFT test scores only persisted among women who were inactive. With respective to the DSST, lower test scores were observed in both men (-7.2, 95% CI: -13.1 to -1.3) and women (-6.4, 95% CI: -11.8 to -1.1) with moderate to severe depressive symptoms. In the stratified analyses, this association persisted in those who were insufficiently active, but attenuated to null among those engaged in sufficient physical activity.

CONCLUSIONS

Moderate-to-vigorous physical activity modifies the depression-cognition relationship and preserves cognition function. Engaging in sufficient (150 min/week) leisure-time physical activity at moderate-to-vigorous intensity may protect those with depressive symptoms from cognitive decline in older age.

The relationship of anxious and depressive symptoms in Parkinson's disease with voxel-based neuroanatomical and functional connectivity measures

BACKGROUND

Anxiety and depression are two frequent comorbidities of Parkinson's disease (PD). However, the underlying neural mechanism is still unclear and the studies on their neural correlates were insufficient.

METHODS

Using voxel-based neuroanatomical and functional connectivity (FC) measures, i.e. grey matter volume, fractional anisotropy, and weighted degree centrality (WD), we examined their correlations with the severity levels of anxious and depressive symptoms in 36 PD patients.

RESULTS

Positive correlations were shown between anxiety and the WDs in the left amygdala, and between depression and short-ranged WDs in the left parahippocampal gyrus. Using these two regions as the seeds, we found that the severity levels of anxiety and depression were positively correlated with the FCs between the two seeds and the areas in the default mode network (DMN), while negatively correlated with the FCs between the two seeds and the prefrontal and superior temporal cortices. Anxiety was also positively correlated with the FC between the amygdala and the superior parietal lobule.

LIMITATIONS

The severity levels of anxious and depressive symptoms of our participants is relatively mild than some previous studies. The cross-sectional design of this study cannot clarify the etiological relationship between PD and two comorbidities.

CONCLUSIONS

Our results were in line with the key roles of the amygdala and parahippocampal gyrus in anxiety and depression, and reflected the distinct effects of the DMN, prefrontal and superior temporal cortices, and sensory-motor regions on emotional regulation. The identification of these neural substrates might assist clinical monitoring mood disturbances in PD.

Apolipoprotein E and affective symptoms in mild cognitive impairment and Alzheimer's disease dementia: A systematic review and meta-analysis

OBJECTIVE

APOE status has been associated to affective symptoms in cognitively impaired subjects, with conflicting results.

METHODS

Databases CINAHL, Embase, PsychINFO and PubMed were searched for studies evaluating APOE genotype with affective symptoms in MCI and AD dementia. Symptoms were meta-analyzed separately and possible sources of heterogeneity were examined.

RESULTS

Fifty-three abstracts fulfilled the eligibility criteria. No association was found between the individual symptoms and APOE ε4 carriership or zygosity. For depression and anxiety, only pooled unadjusted estimates showed positive associations with between-study heterogeneity, which could be explained by variation in study design, setting and way of symptom assessment.

CONCLUSIONS

There is no evidence that APOE ε4 carriership or zygosity is associated with the presence of depression, anxiety, apathy, agitation, irritability or sleep disturbances in cognitively impaired subjects. Future research should shift its focus from this single polymorphism to a more integrated view of other biological factors.

Established amyloid-β pathology is unaffected by chronic treatment with the selective serotonin reuptake inhibitor paroxetine

INTRODUCTION

Treatment with selective serotonin reuptake inhibitors has been suggested to mitigate amyloid-β (Aβ) pathology in Alzheimer's disease, in addition to an antidepressant mechanism of action.

METHODS

We investigated whether chronic treatment with paroxetine, a selective serotonin reuptake inhibitor, mitigates Aβ pathology in plaque-bearing double-transgenic amyloid precursor protein (APP)swe/presenilin 1 (PS1)ΔE9 mutants. In addition, we addressed whether serotonin depletion affects Aβ pathology. Treatments were assessed by measurement of serotonin transporter occupancy and high-performance liquid chromatography. The effect of paroxetine on Aβ pathology was evaluated by stereological plaque load estimation and Aβ42/Aβ40 ratio by enzyme-linked immunosorbent assay.

RESULTS

Contrary to our hypothesis, paroxetine therapy did not mitigate Aβ pathology, and depletion of brain serotonin did not exacerbate Aβ pathology. However, chronic paroxetine therapy increased mortality in APPswe/PS1ΔE9 transgenic mice.

DISCUSSION

Our results question the ability of selective serotonin reuptake inhibitor therapy to ameliorate established Aβ pathology. The severe adverse effect of paroxetine may discourage its use for disease-modifying purposes in Alzheimer's disease.

Effect of Antidepressant Medication Use and Social Engagement on the Level of Depressive Symptoms in Community-Dwelling, Older African Americans and Whites With Dementia

Objective: This study examines the effect of antidepressant medication use and social engagement on the level of depressive symptoms at the time of initially meeting criteria for dementia. Method: Measures of social engagement, medication use, and depressive symptoms from 402 participants with incident dementia were utilized for the study. Proportional odds models adjusted for demographics were constructed with depressive symptoms as the outcome and social network size, perceived social isolation, and antidepressant medication use as independent variables. Results: Each additional person in the social network was associated with a lower depressive symptom score, odds ratio (OR) = 0.93, 95% confidence interval (CI) = [0.90, 0.97], p ≤ .01, and each unit increase in perceived social isolation was associated with a higher depressive symptom score (OR = 4.14, 95% CI = [2.94, 5.85], p ≤ .01). No association was found between antidepressant medication use and depressive symptom score. Discussion: Depression management at the time of dementia diagnosis should probably be directed toward increasing social engagement in older adults.

Greater depressive symptoms, cognition, and markers of brain aging: Northern Manhattan Study

OBJECTIVE

We examined whether greater depressive symptoms were associated with domain-specific cognitive performance, change in cognition, and MRI markers of brain atrophy and subclinical cerebrovascular disease in a diverse sample of older adults from the Northern Manhattan Study.

METHODS

Data were analyzed from the Northern Manhattan Study, a prospective cohort study of mostly Caribbean Hispanic, stroke-free, older adults. A total of 1,111 participants had baseline measures of depressive symptoms, measured as the Center of Epidemiological Studies-Depression Scale, MRI markers, and cognitive function. A Center of Epidemiological Studies-Depression score ≥16 was considered indicative of greater depressive symptoms. Multivariable linear and logistic regression models were used to examine the associations of interest.

RESULTS

At baseline, 22% of participants had greater depressive symptoms. Greater depressive symptoms were significantly associated with worse baseline episodic memory in models adjusted for sociodemographic, vascular risk factor, behavioral, and antidepressive medication variables (β [95% confidence interval] = -0.21 [-0.33 to -0.10], p = 0.0003). Greater depressive symptoms were also associated with smaller cerebral parenchymal fraction (β [95% confidence interval] = -0.56 [-1.05 to -0.07], p = 0.02) and increased odds of subclinical brain infarcts (odds ratio [95% confidence interval] = 1.55 [1.00-2.42], p = 0.05), after adjustment for sociodemographic, behavioral, and vascular risk factor variables. Greater depressive symptoms were not significantly associated with white matter hyperintensity volume, hippocampal volume, or change in cognition over an average of 5 years. Results were unchanged when stabilized inverse probability weights were applied to address selective attrition during the study period.

CONCLUSIONS

In this sample of mostly Caribbean Hispanic, stroke-free, older adults, greater depressive symptoms were associated with worse episodic memory, smaller cerebral volume, and silent infarcts.

Pharmacotherapy for the treatment of depression in patients with alzheimer's disease: a treatment-resistant depressive disorder

INTRODUCTION

Pharmacotherapy for the treatment of depressive disorders in Alzheimer's Disease (AD) represents a clinical challenge. pharmacological options are often attempted after a period of watchful waiting (8-12 weeks). monoaminergic antidepressant drugs have shown only modest or null clinical benefits, maybe because the etiology of depressive symptoms in ad patients is fundamentally different from that of nondemented subjects.

AREAS COVERED

The following article looks at the selective serotonin reuptake inhibitor sertraline, which is one of the most frequently studied antidepressant medications in randomized controlled trials (RCTs). It also discusses many other pharmacological approaches that have proven to be inadequate (antipsychotics, acetylcholinesterase inhibitors, anticonvulsants, hormone replacement therapy) and new drug classes (mainly affecting glutamate transmission) that are being studied for treating depression in AD. It also gives discussion to the phase II RCT on the alternative drug S47445 and the potential effect on cognition of the multimodal antidepressant vortioxetine in older depressed patients. Finally, it discusses the N-methyl-D-aspartate antagonist ketamine.

EXPERT OPINION

The present RCT methodologies are too disparate to draw firm conclusions. Future studies are required to identify effective and multimodal pharmacological treatments that efficiently treat depression in AD. Genotyping may boost antidepressant treatment success.

The Study of White Matter Hyperintensity (WMH) and Factors Related to Geriatric Late-Onset Depression

BACKGROUND

Geriatric depression is one of the most common and harmful mental illnesses seen in the elderly. However, there are few studies focusing on the relationship between late-onset depression (LOD) and social and psychological factors, as well as brain structure.

AIMS

To explore factors related to late-onset depression (LOD) in elderly patients.

METHODS

24 first onset LOD patients over 60 years old (meeting ICD-10 diagnostic criteria for depression) and 23 non-depressed elders were selected for inclusion into this study. Scale assessments, including Fazelasscale for white matter hyperintensity (WMH) high signal level and the MTA-scale for medial temporal lobe atrophy levels, were combined with general demography and sociology data to find factors related to LOD.

RESULTS

There was no significant difference in age (t=0.419, p=0.678), gender (X2=1.705, p=0.244), or years of education (t=1.478, p=0.146) between the two groups. However, statistical differences were shown on scores on the WMH, (X2=7.817, p=0.008), periventricular white matter hyperintensity (PWMH)(Fisher exact test: p=0.031), having or not having religious beliefs (Fisher exact test: p=0.265) and family harmony (yes or no) (Fisher exact test: p=0.253) between the LOD group and control group. The results of linear regression analysis showed that the total score for WMH, religious beliefs (with or without) and family harmony (yes or no) were associated with depressive symptomology.

CONCLUSION

Scores on the WMH, religious beliefs and family harmony are all potentially related to LOD in elderly patients.

Glucocorticoid may influence amyloid β metabolism in patients with depression

Epidemiological studies have demonstrated that depression may be a risk factor for Alzheimer's disease (AD); however, the biological mechanisms of the transition from depression to AD are still not clear. Changes of amyloid β protein (Aβ) metabolism and increased glucocorticoid (GC) levels have been found in both depression and AD. Moreover, several studies in animal models have demonstrated that GC administration changes Aβ metabolism. To reveal whether GC affects amyloid metabolism in patients with depression, we evaluated serum levels of Aβ40, Aβ42 and cortisol at admission in 187 inpatients with major depressive disorder (MDD) and 224 healthy comparisons. Additionally, we re-evaluated the serum levels of Aβs in 27 patients with MDD 1 year later. The results of multiple regression analyses revealed that serum cortisol and Aβ levels are not correlated at the time of admission. However, serum cortisol levels at admission correlated with serum Aβ42 levels and Aβ40/Aβ42 ratio 1 year later. These findings suggest that increased cortisol in patients with MDD may influence the metabolism of Aβ over prolonged periods of time.

Citalopram Ameliorates Impairments in Spatial Memory and Synaptic Plasticity in Female 3xTgAD Mice

Alzheimer's disease (AD) is the primary cause of dementia. There is no effective treatment. Amyloid-β peptide (Aβ) plays an important role in the pathogenesis and thus strategies suppressing Aβ production and accumulation seem promising. Citalopram is an antidepressant drug and can decrease Aβ production and amyloid plaques in transgenic mice of AD and humans. Whether citalopram can ameliorate memory deficit was not known yet. We tested the effects of citalopram on behavioral performance and synaptic plasticity in female 3xTgAD mice, a well-characterized model of AD. Mice were treated with citalopram or water from 5 months of age for 3 months. Citalopram treatment at approximately 10 mg/kg/day significantly improved spatial memory in the Morris water maze (MWM) test, while not affecting anxiety-like and depression-like behavior in 3xTgAD mice. Further, hippocampal long-term potentiation (LTP) impairment in 3xTgAD mice was reversed by citalopram treatment. Citalopram treatment also significantly decreased the levels of insoluble Aβ₄₀ in hippocampal and cortical tissues in 3xTgAD mice, accompanied with a reduced amyloid precursor protein (APP). Together, citalopram treatment may be a promising strategy for AD and further clinical trials should be conducted to verify the effect of citalopram on cognition in patients with AD or mild cognitive impairment.

Medicinal species as MTDLs: Turnera diffusa Willd. Ex Schult inhibits CNS enzymes and delays glutamate excitotoxicity in SH-SY5Y cells via oxidative damage

One of the most promising approaches to confront the complexity of central nervous system disorders are new multi-target directed ligands (MTDLs). Five medicinal species (Cereus grandiflorus (L.) Mill., Hyssopus officinalis L., Acorus calamus L., Silybum marianum L. Gaertn. and Turnera diffusa Willd. Ex Schult), selected for their ethnopharmacological relevance, were object for in vitro screening. The aqueous extract of T. diffusa revealed the strongest neuroactive potential, inhibiting monoamine oxidase-A (IC₅₀ = 129.80 ± 11.97 μg/mL), and acetyl- and butyrylcholinesterase (IC₂₅ = 0.352 ± 0.011 and 0.370 ± 0.036 mg/mL, respectively). Its phenolic profile was established for the first time by HPLC-DAD-ESI/MSⁿ. Twenty-six out of thirty-seven compounds were newly identified in this species. The pre-treatment with this flavonoid-rich extract promoted a rightward shift of the glutamate concentration neuronal cell (SH-SY5Y) death response curve. Furthermore, it significantly reduced the early phase formation of intracellular reactive species after glutamate and t-BHP exposure, suggesting that neuroprotection in SH-SY5Y cells was, in part, mediated by antioxidant mechanisms.

How Studies of the Serotonin System in Macaque Models of Menopause Relate to Alzheimer's Disease1

Serotonin plays a key role in mood or affect, and dysfunction of the serotonin system has been linked to depression in humans and animal models. Depression appears prior to or coincident with overt symptoms of Alzheimer's disease (AD) in about 50% of patients, and some experts consider it a risk factor for the development of AD. In addition, AD is more prevalent in women, who also show increased incidence of depression. Indeed, it has been proposed that mechanisms underlying depression overlap the mechanisms thought to hasten AD. Women undergo ovarian failure and cessation of ovarian steroid production in middle age and the postmenopausal period correlates with an increase in the onset of depression and AD. This laboratory has examined the many actions of ovarian steroids in the serotonin system of non-human primates using a rhesus macaque model of surgical menopause with short or long-term estradiol (E) or estradiol plus progesterone (E+P) replacement therapy. In this mini-review, we present a brief synopsis of the relevant literature concerning AD, depression, and serotonin. We also present some of our data on serotonin neuron viability, the involvement of the caspase-independent pathway, and apoptosis-inducing factor in serotonin-neuron viability, as well as gene expression related to neurodegeneration and neuron viability in serotonin neurons from adult and aged surgical menopausal macaques. We show that ovarian steroids, particularly E, are crucial for serotonin neuron function and health. In the absence of E, serotonin neurons are endangered and deteriorating toward apoptosis. The possibility that this scenario may proceed or accompany AD in postmenopausal women seems likely.

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.

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

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

[Late-onset depression : Pathophysiology, diagnostics and treatment]

Late-onset depression (LOD) is defined as depression manifesting for the first time in later life. Up to now, there has been no exact definition of the lower age limit for LOD. Psychopathological symptoms of LOD do not fundamentally differ from depression in other phases of life; however, cognitive deficits are typically more pronounced. The LOD is associated with an increased risk of developing dementia. Imaging studies show reduction in gray matter volume and white matter lesions caused by vascular diseases. The occurrence of depression with vascular lesions of the brain is also referred to as "vascular depression". The diagnostic procedure includes a detailed medical history and the observation of psychopathological changes, physical examination, laboratory tests, electroencephalograph (EEG), electrocardiograph (ECG) and magnetic resonance imaging (MRI) of the head and neuropsychological tests to measure cognitive deficits. Psychotherapy is an effective treatment option. Selective serotonin reuptake inhibitors are the first-line pharmacological therapy.

[Signaling molecules in the brain and epigenetic factors in neurodegenerative and mental disorders]

The literature on a role of signaling molecules in the organization of memory and cognitive functions is analyzed basing on mechanisms of memory physiology determined by a complex of biochemical processes initiated by the transmission of the signal to the synapse and completed by the synthesis of functionally significant molecules in the neuronal genetic apparatus. The center of these processes is a coordinated system of signal transduction, transcription, epigenetic and neurotrophic molecules. The dissonance of signal mechanisms is a prime cause of memory impairment and cognitive dysfunction as social maladaptation factors. The results of experimental and clinical studies of a role of the multilevel signaling system in age-related, neurodegenerative (Alzheimer’s disease) and mental (depression) disorders are discussed. At the same time, signaling molecules may be considered as particular targets for new therapeutic approaches.

Amyloid imaging with [(18)F]florbetapir in geriatric depression: early-onset versus late-onset

BACKGROUND

We examined patients with mild cognitive impairment (MCI) with a history of geriatric depression (GD) and healthy controls (HC) to evaluate the effect of beta-amyloid (Aβ) pathology on the pathology of GD by using [(18)F]florbetapir PET.

METHODS

Thirty-three elderly patients (76.7 ± 4.2 years) and 22 healthy controls (HC; 72.0 ± 4.5 years, average ± SD) were examined by [(18)F]florbetapir positron emission tomography (PET) to quantify the standard uptake value ratio (SUVR) as the degree of amyloid accumulation, by MRI to determine the degree of atrophy, by Mini-Mental State Examination for cognitive functions, and by Geriatric Depression Scale for the severity of depression, and by Clinical Dementia Rating for activity of daily living (ADL). The cut-off value of 1.08 for SUVR was defined as Aβ-positive.

RESULTS

Of the patients and HC, 39.4% and 27.3%, respectively, were beta-amyloid-positive. The onset age of GD was significantly correlated with SUVR (r = 0.44, p < 0.01). Compared to patients without Aβ (GD-Aβ), patients with Aβ (GD + Aβ) did not differ in terms of age, cognitive function, severity of depression and ADL, and brain atrophy. GD + Aβ had significantly older average ± SD age at onset of GD (73.6 ± 7.1 versus 58.7 ± 17.8, p < 0.01) and significantly shorter average ± SD time between onset of GD and PET scan day (3.1 ± 5.2 years versus 18.1 ± 18.6 years, p < 0.001) than GD-Aβ.

CONCLUSIONS

Our results showed that the rate of Aβ positivity was higher in late-onset GD and that onset-age was associated with SUVR, suggesting that the later the onset of GD, the more Aβ pathology affected its onset.

Learning from the past and looking to the future: Emerging perspectives for improving the treatment of psychiatric disorders

Modern neuropsychopharmacology commenced in the 1950s with the serendipitous discovery of first-generation antipsychotics and antidepressants which were therapeutically effective yet had marked adverse effects. Today, a broader palette of safer and better-tolerated agents is available for helping people that suffer from schizophrenia, depression and other psychiatric disorders, while complementary approaches like psychotherapy also have important roles to play in their treatment, both alone and in association with medication. Nonetheless, despite considerable efforts, current management is still only partially effective, and highly-prevalent psychiatric disorders of the brain continue to represent a huge personal and socio-economic burden. The lack of success in discovering more effective pharmacotherapy has contributed, together with many other factors, to a relative disengagement by pharmaceutical firms from neuropsychiatry. Nonetheless, interest remains high, and partnerships are proliferating with academic centres which are increasingly integrating drug discovery and translational research into their traditional activities. This is, then, a time of transition and an opportune moment to thoroughly survey the field. Accordingly, the present paper, first, chronicles the discovery and development of psychotropic agents, focusing in particular on their mechanisms of action and therapeutic utility, and how problems faced were eventually overcome. Second, it discusses the lessons learned from past successes and failures, and how they are being applied to promote future progress. Third, it comprehensively surveys emerging strategies that are (1), improving our understanding of the diagnosis and classification of psychiatric disorders; (2), deepening knowledge of their underlying risk factors and pathophysiological substrates; (3), refining cellular and animal models for discovery and validation of novel therapeutic agents; (4), improving the design and outcome of clinical trials; (5), moving towards reliable biomarkers of patient subpopulations and medication efficacy and (6), promoting collaborative approaches to innovation by uniting key partners from the regulators, industry and academia to patients. Notwithstanding the challenges ahead, the many changes and ideas articulated herein provide new hope and something of a framework for progress towards the improved prevention and relief of psychiatric and other CNS disorders, an urgent mission for our Century.

Depression and dementias among military veterans

Depression is very common throughout the course of veterans' lives, and dementia is common in late life. Previous studies suggest an association between depression and dementia in military veterans. The most likely biologic mechanisms that may link depression and dementia among military veterans include vascular disease, changes in glucocorticoid steroids and hippocampal atrophy, deposition of β-amyloid plaques, inflammatory changes, and alterations of nerve growth factors. In addition, military veterans often have depression comorbid with posttraumatic stress disorder or traumatic brain injury. Therefore, in military veterans, these hypothesized biologic pathways going from depression to dementia are more than likely influenced by trauma-related processes. Treatment strategies for depression, posttraumatic stress disorder, or traumatic brain injury could alter these pathways and as a result decrease the risk for dementia. Given the projected increase of dementia, as well as the projected increase in the older segment of the veteran population, in the future, it is critically important that we understand whether treatment for depression alone or combined with other regimens improves cognition. In this review, we summarize the principal mechanisms of this relationship and discuss treatment implications in military veterans.