Association between a history of clinical depression and dementia, and the role of sociodemographic factors: population-based cohort study

Depression in Alzheimer's Disease: Epidemiology, Mechanisms, and Treatment

Depression and Alzheimer's disease (AD) are substantial public health concerns. In the past decades, a link between the 2 disease entities has received extensive acknowledgment, yet the complex nature of this relationship demands further clarification. Some evidence indicates that midlife depression may be an AD risk factor, while a chronic course of depression in late life may be a precursor to or symptom of dementia. Recently, multiple pathophysiological mechanisms have been proposed to underlie the bidirectional relationship between depression and AD, including genetic predisposition, immune dysregulation, accumulation of AD-related biomarkers (e.g., amyloid-β and tau), and alterations in brain structure. Accordingly, numerous therapeutic approaches, such as pharmacology treatments, psychotherapy, and lifestyle interventions, have been suggested as potential means of interfering with these pathways. However, the current literature on this topic remains fragmented and lacks a comprehensive review characterizing the association between depression and AD. In this review, we aim to address these gaps by providing an overview of the co-occurrence and temporal relationship between depression and AD, as well as exploring their underlying mechanisms. We also examine the current therapeutic regimens for depression and their implications for AD management and outline key challenges facing the field.

Which factors preceding dementia identification impact future healthcare use trajectories: multilevel analyses in administrative data

BACKGROUND

Healthcare use patterns preceding a diagnosis of Alzheimer's Disease and Related Diseases (ADRD) may be associated with the quality of healthcare use trajectories (HUTs) after diagnosis. We aimed to identify determinants of future favorable HUTs, notably healthcare use preceding ADRD identification.

METHODS

This nationwide retrospective observational study was conducted on subjects with incident ADRD identified in 2012 in the French health insurance database. We studied the 12-month healthcare use ranging between 18 and 6 months preceding ADRD identification. The five-year HUTs after ADRD identification were qualified by experts as favorable or not. In order to take into account geographical differences in healthcare supply, we performed mixed random effects multilevel multivariable logistic regression model to identify determinants of future favorable HUTs. Analyses were stratified by age group (65-74, 75-84, ≥ 85).

RESULTS

Being a woman, and preventive and specialist care preceding ADRD identification increased the probability of future favorable HUT, whereas institutionalization, comorbidities, medical transportation and no reimbursed drug during [-18;-6] months decreased it. Besides, some specificities appeared according to age groups. Among the 65-74 years subjects, anxiolytic dispensing preceding ADRD identification decreased the probability of future favorable HUT. In the 75-84 years group, unplanned hospitalization and emergency room visit preceding ADRD identification decreased this probability. Among subjects aged 85 and older, short hospitalization preceding ADRD identification increased the probability of future favorable HUTs.

CONCLUSION

Regular healthcare use with preventive and specialist care preceding ADRD identification increased the probability of future favorable HUTs whereas dependency decreased it.

Income inequality and depressive symptoms among Chinese adults: a quasi-experimental study

OBJECTIVE

There is a lack of causal evidence on the impact of income inequality on depressive symptoms. The impact of China's Targeted Poverty Alleviation (TPA) policy on depressive symptoms is also unclear. Using a quasi-experimental design, this study aims to investigate the causal effects of TPA and income inequality on depressive symptoms among Chinese adults.

STUDY DESIGN

This is a population-based study.

METHODS

Three waves (2012, 2016, and 2018) of the China Family Panel Studies (CFPS), a nationally representative sample of China, were included in this study. We performed difference-in-difference (DID) models to assess the effect of TPA and income inequality on depressive symptoms. We further conducted the mixed effect models to examine the impact of income inequality on depressive symptoms. The study considered a range of spatial factors and spatial splines to address spatial autocorrelations.

RESULTS

This study included valid measures of depressive symptoms (Center for Epidemiologic Studies Depression Scale [CES-D-8] score) from 14,442 adults of CFPS. The DID results indicated that at the provincial level, the CES-D-8 score of the TPA treatment group was on average 0.570 (95% confidence interval [CI]: 0.358-0.783) less than the control group. Furthermore, a 0.1 increase in Gini index would lead to a 0.256 (95% CI: 0.064-0.448) increase in CES-D-8 score. The mixed effect model showed that income inequality was a risk factor for depressive symptoms at the provincial level (excess risk = 5.602% [95% CI: 3.047%-8.219%]).

CONCLUSIONS

Our findings suggest that income inequality adversely affects mental health, but China's Targeted Poverty Alleviation improves the mental health of the Chinese population.

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

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

The relationship between optimism, MCI, and dementia among postmenopausal women

OBJECTIVES

The relationship between optimism and cognitive functioning is not fully understood. We examined the association of optimism with risk of mild cognitive impairment (MCI) and dementia in the Women's Health Initiative Memory Study (WHIMS).

METHODS

Optimism was measured by the Life Orientation Test-Revised (LOT-R) total score, and optimism and pessimism subscales. A panel of experts adjudicated cognitive endpoints based on annual cognitive assessments. We used cox proportional hazard regression models to examine the association of LOT-R total score and optimism and pessimism sub-scores with MCI/dementia. We also examined the relationship between vascular disease, LOT-R total score, optimism and pessimism, and cognition.

RESULTS

Mean age was 70.5 (SD = 3.9) years. The sample (N = 7249) was 87% white, and 29.8% of participants had < 12 years of education. Total LOT-R score (HR = 0.96, 95% CI: 0.94, 0.98, p < 0.001) was associated with lower risk of combined MCI or dementia. More pessimism (HR = 1.08, 95% CI: 1.05, 1.11, p < 0.0001) was associated with higher risk of MCI or dementia after adjustment for ethnicity, education, vascular disease, and depression. No significant relationships emerged from the optimism subscale.

CONCLUSION

These data suggest that less pessimism, but not more optimism, was associated with a lower risk of MCI and dementia.

Association between mental health symptoms and behavioral performance in younger vs. older online workers

Background

The COVID-19 pandemic has been associated with increased rates of mental health problems, particularly in younger people.

Objective

We quantified mental health of online workers before and during the COVID-19 pandemic, and cognition during the early stages of the pandemic in 2020. A pre-registered data analysis plan was completed, testing the following three hypotheses: reward-related behaviors will remain intact as age increases; cognitive performance will decline with age; mood symptoms will worsen during the pandemic compared to before. We also conducted exploratory analyses including Bayesian computational modeling of latent cognitive parameters.

Methods

Self-report depression (Patient Health Questionnaire 8) and anxiety (General Anxiety Disorder 7) prevalence were compared from two samples of Amazon Mechanical Turk (MTurk) workers ages 18-76: pre-COVID 2018 (N = 799) and peri-COVID 2020 (N = 233). The peri-COVID sample also completed a browser-based neurocognitive test battery.

Results

We found support for two out of three pre-registered hypotheses. Notably our hypothesis that mental health symptoms would increase in the peri-COVID sample compared to pre-COVID sample was not supported: both groups reported high mental health burden, especially younger online workers. Higher mental health symptoms were associated with negative impacts on cognitive performance (speed/accuracy tradeoffs) in the peri-COVID sample. We found support for two hypotheses: reaction time slows down with age in two of three attention tasks tested, whereas reward function and accuracy appear to be preserved with age.

Conclusion

This study identified high mental health burden, particularly in younger online workers, and associated negative impacts on cognitive function.