The course of depressive symptoms with decline in cognitive function - a longitudinal study of older adults receiving in-home care at baseline

Association between home and community-based services utilization and self-rated health among Chinese older adults with chronic diseases: evidence from the 2018 China Health and Retirement Longitudinal Study

BACKGROUND

As global aging intensifies, older adults with chronic diseases are of increasing concern. Home and community-based services (HCBSs) have been proven to promote self-rated health (SRH) in older adults, but no research explored the associations between the use of overall HCBSs, three different types of HCBSs (health care, daily care, and social support services) and SRH among older adults with chronic diseases. Consequently, this study applies a national publicly available database to examine these associations among older adults with chronic diseases.

METHODS

8,623 older adults with chronic diseases (≥ 60 years old) were included in this study. SRH was evaluated applying a concise question with a 1 - 5 scale. HCBSs utilization was assessed through the question, "What kind of HCBSs were used in the community?". Univariate general linear regression models aimed to compare the mean values of SRH in terms of HCBSs utilization in each group. This study is a cross-sectional study design and the relationship between HCBSs utilization and SRH was assessed by multilevel linear regression.

RESULTS

The mean score for SRH among the respondents was 3.19, of whom 20.55% used one or more HCBSs, 19.47% utilized health care services, 2.44% utilized social support services, and only 0.55% utilized daily care services. The use of HCBSs was found to be linked to SRH among older adults with chronic diseases (β = 0.085, SE = 0.025, p < 0.001). SRH among older adults with chronic diseases was strongly linked to the use of health care and social support services (β = 0.068, SE = 0.025, p < 0.001; β = 0.239, SE = 0.063, p < 0.001, respectively). However, there was no significant association between the use of daily care services and SRH among older adults with chronic diseases.

CONCLUSION

This study revealed that HCBSs utilization was positively and significantly linked to SRH in Chinese older adults with chronic diseases. Furthermore, this study supposes the low utilization of social support and daily care services may be due to a mismatch between supply and demand. The government should offer the targeted HCBSs for older adults with chronic diseases according to their unique features to enhance their health status.

Development and validation of risk of CPS decline (RCD): a new prediction tool for worsening cognitive performance among home care clients in Canada

BACKGROUND

To develop and validate a prediction tool, or nomogram, for the risk of a decline in cognitive performance based on the interRAI Cognitive Performance Scale (CPS).

METHODS

Retrospective, population-based, cohort study using Canadian Resident Assessment Instrument for Home Care (RAI-HC) data, collected between 2010 and 2018. Eligible home care clients, aged 18+, with at least two assessments were selected randomly for model derivation (75%) and validation (25%). All clients had a CPS score of zero (intact) or one (borderline intact) on intake into the home care program, out of a possible score of six. All individuals had to remain as home care recipients for the six months observation window in order to be included in the analysis. The primary outcome was any degree of worsening (i.e., increase) on the CPS score within six months. Using the derivation cohort, we developed a multivariable logistic regression model to predict the risk of a deterioration in the CPS score. Model performance was assessed on the validation cohort using discrimination and calibration plots.

RESULTS

We identified 39,292 eligible home care clients, with a median age of 79.0 years, 62.3% were female, 38.8% were married and 38.6% lived alone. On average, 30.3% experienced a worsening on the CPS score within the six-month window (i.e., a change from 0 or 1 to 2, 3, 4, 5, or 6). The final model had good discrimination (c-statistic of 0.65), with excellent calibration.

CONCLUSIONS

The model accurately predicted the risk of deterioration on the CPS score over six months among home care clients. This type of predictive model may provide useful information to support decisions for home care clinicians who use interRAI data internationally.

Understanding factors associated with the trajectory of subjective cognitive complaints in groups with similar objective cognitive trajectories

BACKGROUND

Cognitive complaints are often regarded as an early sign of Alzheimer's disease (AD) but may also occur in several other conditions and contexts. This study examines the correlates of cognitive complaint trajectories over a 5-year period in individuals who shared similar objective cognitive trajectories.

METHODS

We analyzed a subsample (n = 1748) of the MEMENTO cohort, consisting of individuals with subjective cognitive decline or mild cognitive impairment at baseline. Participants were stratified based on their latent MMSE trajectory over a 5-year period: "high and increasing," "subtle decline," and "steep decline." Within each of the three strata, we used a latent-class longitudinal approach to identify distinct trajectories of cognitive complaints. We then used multiple logistic regressions to examine the association between these complaint trajectories and several factors, including AD biomarkers (blood pTau/Aβ42 ratio, cortical thickness, APOE genotype), anxiety, depression, social relationships, a comorbidity-polypharmacy score, and demographic characteristics.

RESULTS

Among participants with high and increasing MMSE scores, greater baseline comorbidity-polypharmacy scores (odds ratio (OR) = 1.30, adjusted p = 0.03) were associated with higher odds of moderate and increasing cognitive complaints (as opposed to mild and decreasing complaints). Baseline depression and social relationships also showed significant associations with the complaint pattern but did not survive correction for multiple comparisons. Among participants with subtle decline in MMSE scores, greater baseline depression (OR = 1.76, adjusted p = 0.02) was associated with higher odds of moderate and increasing cognitive complaints (versus mild and decreasing). Similarly, baseline comorbidity-polypharmacy scores and pTau/Aβ42 ratio exhibited significant associations, but they did not survive correction. Among participants with a steep decline in MMSE scores, greater baseline comorbidity-polypharmacy scores increased the odds of moderate complaints (versus mild, OR = 1.38, unadjusted p = 0.03, adjusted p = 0.32), but this effect did not survive correction for multiple comparisons.

CONCLUSIONS

Despite similar objective cognitive trajectory, there is heterogeneity in the subjective perception of these cognitive changes. This perception was explained by both AD-related and, more robustly, non-AD-related factors. These findings deepen our understanding of the multifaceted nature of subjective cognitive complaints in individuals at risk for dementia and underscore the importance of considering a range of factors when interpreting cognitive complaints.

The course of depressive symptoms in Lewy body dementia and Alzheimer's disease

BACKGROUND

Depressive symptoms frequently affect patients with neurocognitive disorders. In cross-sectional studies, patients with Lewy body dementia (DLB) showed higher levels of depressive symptoms than those with Alzheimer's disease (AD). We here describe the 5 year course of depressive symptoms in patients with DLB and AD.

METHODS

Secondary analysis of a dementia study in Western Norway (DemVest) longitudinal cohort study.

SETTING

This multicenter study was conducted in memory clinics in Western Norway. 187 patients newly diagnosed with AD (n = 111) and DLB (n = 76) were followed up annually for 5 years. Depressive symptoms were assessed using the Montgomery Åsberg Depression Rating Scale (MADRS). MADRS subclusters dysphoria, retardation, vegetative, anhedonia were analyzed. The impact of proximity of death and the role of risk factors for depression and dementia on the course of depressive symptoms were evaluated.

RESULTS

We observed continuously increasing mean levels of depressive symptoms in DLB, while patients with AD showed a delayed increase at later follow-up visits. Increase in MADRS total score was mainly driven by increases in the anhedonia and retardation subclusters. Proximity to death was associated with an increase in depressive symptoms in DLB, while it tended to decrease in AD. Previous smoking and hearing loss were associated with higher MADRS scores during follow-up in the total sample.

LIMITATIONS

Yearly assessment of depressive symptoms might be too infrequent.

CONCLUSION

Depressive symptom load was consistently higher in DLB compared to AD during five years after diagnosis, but tended to become more similar at later stages.

Depression in Major Neurodegenerative Diseases and Strokes: A Critical Review of Similarities and Differences among Neurological Disorders

Depression and anxiety are highly prevalent in most neurological disorders and can have a major impact on the patient's disability and quality of life. However, mostly due to the heterogeneity of symptoms and the complexity of the underlying comorbidities, depression can be difficult to diagnose, resulting in limited recognition and in undertreatment. The early detection and treatment of depression simultaneously with the neurological disorder is key to avoiding deterioration and further disability. Although the neurologist should be able to identify and treat depression initially, a neuropsychiatry team should be available for severe cases and those who are unresponsive to treatment. Neurologists should be also aware that in neurodegenerative diseases, such as Alzheimer's or Parkinson's, different depression symptoms could develop at different stages of the disease. The treatment options for depression in neurological diseases include drugs, cognitive-behavioral therapy, and somatic interventions, among others, but often, the evidence-based efficacy is limited and the results are highly variable. Here, we review recent research on the diagnosis and treatment of depression in the context of Alzheimer's disease, Parkinson's disease, and strokes, with the aim of identifying common approaches and solutions for its initial management by the neurologist.

The Impact of Engagement with the PARO Therapeutic Robot on the Psychological Benefits of Older Adults with Dementia

OBJECTIVES

This study aimed to examine the effect of 8-weeks of a 60-minute PARO intervention to reduce depressive symptoms and loneliness in older adults with dementia and investigated changes in their emotional or behavioral expressions and level of engagement with the PARO robot.

METHODS

This was a quasi-experimental study with a repeated measures design. The outcome measures were evaluated at four time-points: before the intervention, week 4, immediately after the intervention, and one month after the PARO intervention.

RESULTS

Fifty-two participants were recruited. The age of the participants ranged from 65 to 96 years, with a mean age of 81.81 years (SD = 8.54) in the PARO group and 79.08 years (SD = 7.71) in the control group. Using a mixed between-within subjects' analysis of variance, the results showed that there were significant interaction effects between the groups and time-periods for depression (p < .000), loneliness (p < .000), and engagement (p < .000).

CONCLUSIONS

The PARO intervention alleviated depression and loneliness for older adults. Furthermore, the process of engagement with PARO may play an important role in the PARO effects.

CLINICAL IMPLICATIONS

A tailored PARO intervention of at least 4 weeks could engender positive psychological benefits for older adults.

The association between street connectivity and depression among older Japanese adults: the JAGES longitudinal study

Mental health is important in older age; neighborhood environment is considered a protective factor of depression. Research has established that a critical indicator of neighborhood environment, street connectivity, is related to older people's health. However, little is known about the relationship between street connectivity and depression. We examined the relationship between street connectivity and depression among older people. Using Japan Gerontological Evaluation Study 2013-2016, the target population comprised 24,141 independent older people without depression (Geriatric Depression Scale scores below 5) in 2013. The outcome variable was depression in 2016; the explanatory variable was street connectivity calculated by intersection density and space syntax within 800 m around the subject's neighborhood in 2013. We used logistic regression analysis to calculate the odds ratio and 95% confidence interval for the new occurrence of depression among participants in 2016. This analysis demonstrated incidence of new depression after 3 years that is 17% and 14% lower among participations living in high-intersection density and high-street-connectivity areas, respectively, than those living in low-intersection density and low-street-connectivity areas. The association held after adjusting for physical activities and social interaction. Given the established connection between street connectivity and mental health, the findings can contribute to healthy urban planning.

Defining and assessing intrinsic capacity in older people: A systematic review and a proposed scoring system

INTRODUCTION

The World Health Organization has introduced the term 'intrinsic capacity' (IC) as a marker of healthy ageing. However, controversy exists on the definition and assessment of IC. We aimed to review the definitions and methods used for the assessment of IC in older adults. In addition, we proposed a new IC scoring method.

METHODS

A systematic search was performed in PubMed, Web of Science, Cochrane Library, Scopus and SPORTDiscus (up to February 10th, 2022) for studies assesing IC in older adults (>60 years).

RESULTS

Thirty-three studies were included. There is overall consensus on the definition of IC as well as on its different dimensions, that is: locomotion, vitality, sensory, cognition and psychological. However, the methods for assessing each of these five dimensions differ substantially across studies and there is no consensus on the best method to compute an eventual global compound score to evaluate IC taking into account all its different dimensions.

CONCLUSIONS

The IC represents a highly relevant clinical concept that has been unfortunately underutilized. We propose a standardization for the assessment of each dimension of IC, with a global 0 (worst) to 10 (highest) score.

Longitudinal association between depressive symptoms and cognitive decline among middle-aged and elderly population

BACKGROUND

Depression is considered a risk factor for cognitive decline. The long-term impact of depressive symptoms on cognitive performance has not been established thus far.

OBJECTIVES

This study aimed to determine the longitudinal associations between depressive symptoms and cognitive performance among middle-aged and elderly population.

METHODS

We included 10,387 adults aged ≥45 years from the Health and Retirement Study (2004 to 2014) in this study. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CESD) scale. Participant's cognitive function was assessed via the telephone interview for cognitive status (TICS); the total cognitive score ranged from 0 to 35. We classified the participants into four clusters according to the quartile of the total cognitive score (TCS). We examined the change of depressive symptoms and cognitive performance by using the unconditional latent growth curve modeling (LGCM) method, and a parallel LGCM method was used to examine the longitudinal associations between depressive symptoms and cognitive performance among middle-aged and elderly adults in each cluster.

RESULTS

Participants with lower levels of cognitive performance were associated with a greater risk of high depressive symptoms. Results from unconditional LGCM showed a sustained decline in cognitive performance and an increasing trend in depressive symptoms per 2 years for each cluster of participants. The parallel LGCM indicated that baseline levels of depression showed a significant negative correlation with the cognitive performance at baseline (β [95% CI] of intercept_(Dep) predicting intercept_(TCS) were -0.33 [-0.41, -0.26], -0.03[-0.06, -0.00], -0.05 [-0.07, -0.02] and -0.64 [-0.70,-0.58], for clusters of Q1 to Q3 and the entire population, respectively). Further, a significant positive prospective association was observed between baseline levels of depression and changes in cognitive performance (intercept_(Dep) predicting slope_(TCS) were -0.05 [-0.08, -0.02], -0.09[-0.13, -0.05], -0.12 [-0.15, -0.08], -0.11 [-0.15, -0.06] and -0.04 [-0.06,-0.02] for clusters of Q1 to Q4 and the entire population, respectively). Moreover, for participants with the highest quartile of TCS, the rising trend of depressive symptoms accelerated the decline of cognitive performance during the follow-up period (Slope_(Dep) predicting Slope_(TCS): -0.44 [-0.86, -0.01]).

CONCLUSION

Our results suggest that depressive symptoms were associated with lower cognitive performance and larger subsequent decline during follow-up period. Adults with depression may require more medical attention, and early intervention is required to delay the development of cognitive impairment and dementia.

Relationship between Depressive Symptoms and Cognitive, Psychological, and Physical Performance in Community-Dwelling Older People with Cognitive Impairment

INTRODUCTION

Dementia and depression often coexist. Understanding how concomitant comorbidities affect function can improve assessment and management strategies. We examined the relationship between cognitive, psychological, and physical function and depressive symptoms in people with cognitive impairment.

METHODS

Cross-sectional study using baseline data from the iFOCIS randomized controlled trial involving 309 participants with mild-moderate cognitive impairment. The association between cognitive (Addenbrooke's Cognitive Examination-III [ACE-III], Frontal Assessment Battery), psychological (Goldberg Anxiety Scale; Iconographical Falls Efficacy Scale), and physical (Physiological Profile Assessment; Short Physical Performance Battery [SPPB]) function, and quality of life (QoL), physical activity levels and activities of daily living, and depressive symptoms (15-item Geriatric Depression Scale [GDS]) were assessed (adjusted for age, sex, education, and ACE-III as appropriate).

RESULTS

Participants with depressive symptoms (GDS ≥4) had significantly more falls in the previous year and a higher number of comorbidities than people without depressive symptoms (GDS <4). Each point increase in the GDS was associated with better memory, higher levels of anxiety and concern about falling, poorer balance, slower gait speed, and reduced QoL. The relationship between the GDS and poor balance and QoL withstood additional adjustment for comorbidity tertiles. The relationship between GDS and concern about falls withstood additional adjustment for previous falls (12 months) and SPPB scores.

CONCLUSIONS

Depressive symptomatology is associated with poorer physical and psychological function and reduced QoL in people with cognitive impairment. These factors should be considered when assessing and intervening in this group. Future research could examine these relationships longitudinally to establish causality and examine intervention efficacy in this group.

The role of positive behaviors, attitudes and virtues in the mental health of community-dwelling older adults: A 1-year follow-up study

OBJECTIVES

Few studies have investigated the influence of positive behaviors, attitudes and virtues on mental health outcomes of older adults, particularly in developing countries. The aim of this longitudinal study was to investigate the influence of positive behaviors, attitudes and values on the mental health (depression, anxiety and stress) of Brazilian older adults treated in primary care.

METHODS

A longitudinal study, with a 1-year follow-up, of older adults seen by Family Medicine teams was conducted. Instruments were applied assessing traditional factors (cognition, physical activity, sleep, quality of life, social support), behavioral factors (religiousness, spirituality, satisfaction with life, resilience, altruism, volunteerism, loneliness, meaning in life) and mental health (depression, anxiety and stress). Analyses using linear and logistic regression models were performed.

RESULTS

A total of 490 older adults (91.8% of individuals assessed at baseline) were included. Traditional factors such as gender, sleep problems, ethnicity and alcohol use, as well as positive behavioral factors including loneliness, resilience and well-being at baseline, were found to be associated with mental health at 1-year follow-up. Similarly, changes in scores for quality of life, loneliness, religiousness, feeling at peace, sleep problems and altruism were associated with changes in mental health scores.

CONCLUSIONS

The results revealed that positive behavioral factors influenced the mental health of older adults as much as traditional factors and should therefore be addressed by health professionals and medical managers.

Worldwide Occurrence of HIV-Associated Neurocognitive Disorders and Its Associated Factors: A Systematic Review and Meta-Analysis

BACKGROUND

HIV-associated neurocognitive disorders are common in people living with HIV/AIDS and affect the adherence of patients to prescriptions, activities of daily living, and quality of life of patients. However, there is a lack of summative evidence in the area. The present meta-analysis was therefore addressing this gap.

METHODS

We did our electronic search in Psych-Info, EMBASE, Scopus, and PubMed. The retrieved articles were stored with the endnote reference manager and data was extracted using Meta-XL version 5.3. The quality of studies was evaluated with the modified Newcastle-Ottawa Scale (NOS). A random-effect model and STATA-16 were used to compute the average estimate of HAND. Heterogeneity was weighed with I² statistics. A sensitivity analysis and subgroup analysis were employed. The existence/nonexistence of a publication bias was checked with the Eggers test of publication bias.

RESULTS

The average prevalence of HAND was 50.41% (95% CI: 45.56, 55.26). The average estimate of HAND in Europe was found to be 50.015% whereas in Africa, Asia, and the United States of America (USA) it was 49.566, 52.032, and 50.407% respectively. The prevalence of HAND in studies that used the HIV Dementia Scale (IHDS) was 36.883% and 59.956% at cutoff points of IHDS <9.5 and IHDS <10 respectively. Besides, the estimated average of HAND with the global dementia scale (GDS) was 40.766%. The prevalence of HAND in cross-sectional, cohort, and case-control studies was 49.52, 54.087, and 44.45% in that order. Socio-demographic variables; low level of education and older age, clinical and HIV related variables; the advanced stage of the illness and CD4 count of 500 cells/dl or less and psychological variables such as comorbidity of depression increases the risk of HAND.

CONCLUSION

The prevalence of HIV-associated neurocognitive disorders was about 50.41%. Low level of education and older age, clinical and HIV related variables such as the advanced stage of the illness and CD4 count of 500 cells/dl or less, and comorbidity of depression were associated with HIV associated neurocognitive disorders. Public health interventions for HIV patients should target these essential problems.

Association between Sleep Duration and Depression among the Elderly Population in China

OBJECTIVES

The objective of this study was to understand how sleep duration could affect depression among elderly in China.

METHOD

A total of 7103 individuals aged 60 and older were selected from China Health and Retirement Longitudinal Study. A generalized linear mixed-effects model was used to estimate the relationship between sleep duration and depression, and we performed stratified analyses by age: young-old elderly, old-old elderly and oldest-old elderly.

RESULTS

Short sleep duration significantly incresased CES-D10 depression scores. In addition, the participants with middle sleep duration had higher CES-D10 scores compared to the participants with long sleep duration among young-old elderly, and we found that middle sleep duration was not significantly different from CES-D10 scores after adjustment for demographics, frequencies of activities and Chronic diseases.

CONCLUSIONS

These findings suggested that there was a complex association between depression and sleep duration among elderly in China. Different from previous research results on the middle or normal sleep time of the elderly, the middle sleep duration maybe not optimal sleep duration in this study. Investigation of sleep extension to prevent depression may be warranted among the elderly.

Screening for depression in older adults with cognitive impairment in the homecare setting: a systematic review

OBJECTIVE

Previous systematic reviews have examined depression screening in older adults with cognitive impairment (CI) in outpatient and inpatient clinics, nursing homes, and residential care. Despite an increasing number of older adults with CI receiving care in their homes, less is known about best depression screening practices in homecare. The objective of this review is to identify evidence-based practices for depression screening for individuals with CI receiving homecare by assessing tool performance and establishing the current evidence for screening practices in this setting.

METHODS

This review is registered under PROSPERO (ID: CRD42018110243). A systematic search was conducted using MEDLINE, EMBASE, Health and Psychosocial Abstracts, PsycINFO and CINAHL. The following criteria were used: assessment of depression at home in older adults (>55 years) with CI, where performance outcomes of the depression screening tool were reported.

RESULTS

Of 5,453 studies, only three met eligibility criteria. These studies evaluated the Patient Health Questionnaire (n = 236), the Geriatric Depression Scale (n = 79) and the Mental Health Index (n = 1,444) in older adults at home with and without CI. Psychometric evaluation demonstrated moderate performance in the subsamples of people with CI.

CONCLUSION

At present, there is insufficient evidence to support best practices in screening for depression in people with CI in homecare.

Predictors of Changes in Cognitive Function in Older Korean Adults: The 2006-2018 Korean Longitudinal Study of Aging

Cognitive decline with normal aging varies widely among individuals. This study aimed to investigate predictors of longitudinal changes in cognitive function in community-dwelling Korean adults aged 65 years and older. Data from 727 older adults who participated in the Korean Longitudinal Study of Aging (KLoSA) survey from 2006 (baseline) until 2018 (seventh wave) were used. Cognitive performance was assessed with the Korean Mini-Mental State Examination. The participants were retrospectively classified into normal cognition, mild cognitive impairment, and moderate/severe cognitive impairment. Education, income, religion, living area, alcohol intake, smoking, physical activity, handgrip strength, functional dependency, depression, comorbidity, medications, fall experience, and unintentional weight loss were included as covariates. A linear mixed regression analysis showed that a steeper decline in cognitive function over time was significantly associated with parameters of poor socio-economic status, health conditions, and unhealthy behaviors. Individuals with mild cognitive impairment or moderate/severe cognitive impairment were likely to have steeper cognitive declines compared with individuals with normal cognition. The current findings of the study showed that age-related cognitive decline was multifactorial in older Korean adults.

Depression as a Risk Factor for Dementia and Alzheimer's Disease

Preventing the onset of dementia and Alzheimer’s disease (AD), improving the diagnosis, and slowing the progression of these diseases remain a challenge. The aim of this study was to elucidate the association between depression and dementia/AD and to identify possible relationships between these diseases and different sociodemographic and clinical features. In this regard, a case-control study was conducted in Spain in 2018–2019. The definition of a case was: A person ≥ 65 years old with dementia and/or AD and a score of 5–7 on the Global Deterioration Scale (GDS). The sample consisted of 125 controls; among the cases, 96 had dementia and 74 had AD. The predictor variables were depression, dyslipidemia, type 2 diabetes mellitus, and hypertension. The results showed that depression, diabetes mellitus, and older age were associated with an increased likelihood of developing AD, with an Odds Ratio (OR) of 12.9 (95% confidence interval (CI): 4.3–39.9), 2.8 (95% CI: 1.1–7.1) and 1.15 (95% CI: 1.1–1.2), respectively. Those subjects with treated dyslipidemia were less likely to develop AD (OR 0.47, 95% CI: 0.22–1.1). Therefore, depression and diabetes mellitus increase the risk of dementia, whereas treated dyslipidemia has been shown to reduce this risk.

The role of perceived stress and cognitive function on the relationship between neuroticism and depression among the elderly: a structural equation model approach

BACKGROUND

Depression comprises common psychological problems, and has been strongly related to neuroticism and perceived stress. While neuroticism has been shown to have a direct effect on depression, it also has an indirect effect via perceived stress. Among the elderly, cognitive function produces influences that should not be overlooked when investigating depression. This study aimed to determine the role of mediating effects of perceived stress as well as cognitive function on neuroticism and depression among elderly patients.

METHODS

This research constituted a secondary analysis, with data collected during the pre-operative period of 429 elderly individuals undergoing elective, noncardiac surgery. The evaluation included the Perceived Stress Scale, the Neuroticism Inventory, the Montreal Cognitive Assessment, and the Geriatric Depression Scale. Structural equation modeling was used to investigate the hypothesized model.

RESULTS

Neuroticism exhibited a significant indirect effect on perceived stress via depression and cognition (β = 0.162, 95% CI 0.026, 0.322, p = .002). Neuroticism initially had a direct effect on depression (β = 0.766, 95% CI 0.675, 0.843 p = 0.003); thereafter, it was reduced after covariates were added (β = 0.557, 95% CI 0.432, 0.668 p = 0.002). Based on this model, the total variance explained by this model was 67%, and the model showed an acceptable fit with the data.

CONCLUSIONS

Both perceived stress and cognitive function partially mediated the effect of neuroticism on depression, with perceived stress exhibiting a greater effect.

TRIAL REGISTRATION

The study protocol has been registered at Clinicaltrials.gov under registered number: NCT02131181.