White matter hyperintensities, cortisol levels, brain atrophy and continuing cognitive deficits in late-life depression

Cognitive Function in Heart Failure Is Associated With Nonsomatic Symptoms of Depression But Not Somatic Symptoms

BACKGROUND

Patients with heart failure (HF) have high rates of cognitive impairment and depressive symptoms. Depressive symptoms have been associated with greater cognitive impairments in HF; however, it is not known whether particular clusters of depressive symptoms are more detrimental to cognition than others.

OBJECTIVE

The aim of this study was to identify whether somatic and/or nonsomatic depressive symptom clusters were associated with cognitive function in persons with HF.

METHODS

Participants were 326 HF patients (40.5% women, 26.7% non-white race-ethnicity, aged 68.6 ± 9.7 years). Depressive symptoms were measured using a depression questionnaire commonly used in medical populations: the Patient Health Questionnaire-9. Somatic and nonsomatic subscale scores were created using previous factor analytic results. A neuropsychological battery tested attention, executive function, and memory. Composites were created using averages of age-adjusted scaled scores. Regressions adjusting for demographic and clinical factors were conducted.

RESULTS

Regressions revealed that Patient Health Questionnaire-9 total was associated with attention (β = -.14, P = .008) and executive function (β = -.17, P = .001). When analyzed separately, the nonsomatic subscale, but not the somatic symptoms subscale (P values ≥ .092), was associated with attention scores (β = -.15, P = .004) and memory (β = -.11, P = .044). Both nonsomatic (β = -.18, P < .001) and somatic (β = -.11, P = .048) symptoms were related to executive function. When included together, only the nonsomatic symptom cluster was associated with attention (β = -.15, P = .020) and executive function (β = -.19, P = .003).

CONCLUSIONS

Greater overall depressive symptom severity was associated with poorer performance on multiple cognitive domains, an effect driven primarily by the nonsomatic symptoms of depression.

CLINICAL IMPLICATIONS

These findings suggest that screening explicitly for nonsomatic depressive symptoms may be warranted and that the mechanisms underlying the depression-cognitive function relationship in HF are not solely related to sleep or appetite disturbance. Thus, interventions that target patients' somatic symptoms only (eg, poor appetite or fatigue) may not yield maximum cognitive benefit compared with a comprehensive treatment that targets depressed mood, anhedonia, and other nonsomatic symptoms.

Depression as a risk factor for cognitive impairment in later life: the Health In Men cohort study

BACKGROUND

Depression is an established risk factor for dementia in later life, but it is unclear if this relationship is causal. This study aimed to determine if clinically significant depressive symptoms are likely to be causally related to cognitive impairment in later life.

METHODS

Observational cohort study of 4568 men aged 70-89 years living in Perth, Western Australia, who were free of cognitive impairment at the beginning of follow-up. Current clinically significant depressive symptoms were defined by a score of 7 or more on the Geriatric Depression Scale 15 items. Past depression was ascertained via electronic medical records, by self-report or use of antidepressants. A score of 27 or less on the Telephone Interview for Cognitive Status modified or a recorded diagnosis of dementia in electronic medical records established the presence of cognitive impairment.

RESULTS

During the 5-year follow-up, 534 men developed cognitive impairment, 811 died and 1455 were lost. The presence of clinically significant depressive symptoms at study entry was associated with increased risk rate (RR) of cognitive impairment (RR = 2.59, 95% confidence interval: 95%CI = 1.57-4.27), death (RR = 5.07, 95%CI = 3.32-7.75) and loss to follow-up (RR = 2.03, 95%CI = 1.32-3.13). These associations remained statistically significant after adjustment for age, country of birth, education, smoking history, and prevalence hypertension, diabetes, coronary heart disease and stroke. History of past clinically significant depressive symptoms was not associated with incident cognitive impairment (RR = 1.09, 95%CI = 0.78-1.52).

CONCLUSIONS

The lack of association between past depression and cognitive impairment suggests that the link between depression and cognitive impairment is not causal and that the presence of clinically significant depressive symptoms in later life may herald the onset of cognitive impairment in at least some people.

Cognitive Dysfunction in Major Depressive Disorder: Assessment, Impact, and Management

Cognitive dysfunction is increasingly being recognized as an important clinical dimension in major depressive disorder. This review summarizes the existing data on the epidemiology, assessment, and treatment of cognitive dysfunction among nonelderly adults with the disorder. Overall, cognitive dysfunction is prevalent, persists through periods of symptom remission, and may be independently associated with functional outcomes. However, although the evidence increasingly suggests that clinicians should be heedful of their patients' cognitive functioning, there is as yet no consensus on how best to monitor cognition clinically. In addition, although most studies have reported improved cognition with antidepressant medications, psychotherapy, and neuromodulation, the clinical significance of these improvements is unclear, and high-level evidence to guide decision making is limited. Nonetheless, given the important functional implications, clinicians should assess and monitor cognition and optimize both medication and psychological treatments to mitigate cognitive dysfunction among patients with major depressive disorder.

The impact of periventricular white matter lesions in patients with bipolar disorder type I

INTRODUCTION

White matter hyperintensities (WMHs) are one the most common neuroimaging findings in patients with bipolar disorder (BD). It has been suggested that WMHs are associated with impaired insight in schizophrenia and schizoaffective patients; however, the relationship between insight and WMHs in BD type I has not been directly investigated.

METHODS

Patients with BD-I (148) were recruited and underwent brain magnetic resonance imaging (MRI). Affective symptoms were assessed using Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale (HDRS17); the presence of impaired insight was based on the corresponding items of YMRS and HDRS17.

RESULTS

Multiple punctate periventricular WMHs (PWMHs) and deep WMHs (DWMHs) were observed in 49.3% and 39.9% of the cases, respectively. Subjects with lower insight for mania had significantly more PWMHs (54.6% vs 22.2%; p < 0.05) when compared to BD-I patients with higher insight for mania. The presence of PWMHs was independently associated with lower insight for mania: patients who denied illness according to the YMRS were 4 times more likely to have PWMHs (95% CI: 1.21/13.42) than other patients.

CONCLUSIONS

Impaired insight in BD-I is associated with periventricular WMHs. The early identification of BD-I subjects with PWMHs and impaired insight may be crucial for clinicians.

Duration of diabetes and its association with depression in later life: The Health In Men Study (HIMS)

OBJECTIVE

To examine if diabetes and duration of diabetes are direct or indirect causes of depression in later life.

RESEARCH DESIGN AND METHODS

Cross-sectional study of a community-derived sample of 5462 men aged 70-89 years. Men with 'current depression' scored 7 or more on the abbreviated Geriatric Depression Scale (GDS-15), whereas men with 'ever depression' were either currently depressed or reported history or treatment for past depression. The presence of diabetes was established by self-reported history, fasting glucose ≥7 mmol/L (126 mg/dL), or use of insulin or hypoglycemic drugs. Duration of diabetes relied on self-report. Other measured factors included age, place of birth, education, smoking history, and the FRAIL scale.

RESULTS

Diabetes was associated with increased odds ratio (OR) of ever (OR=1.49, 95%CI=1.25, 1.76) and current depression (OR=1.94, 95%CI=1.15, 2.48). The association between duration of diabetes and risk of current depression was 'J-shaped' with odds ratios of 1.92 (95%CI=1.44, 2.54), 1.56 (95%CI=0.89, 2.75), 2.49 (95%CI=1.16, 5.32) and 3.13 (95%CI=1.28, 7.63) for <10, 10-19.9, 20-29.9 and ≥30 years of diabetes history compared with older men without diabetes. The strength of these associations was attenuated after the analyses were adjusted for other measured factors, but the shape of the curve did not change. Structural equation modeling showed that frailty mediated some of the association between diabetes duration and depression (about 15%) and was a strong predictor of depression in the sample.

CONCLUSIONS

In older men, the association between time lived with the diagnosis of diabetes and the risk of depression is 'J-shaped'. Frailty mediates some of the association between diabetes and depression, although other unmeasured factors are also likely to play a role. The introduction of strategies that are effective at decreasing diabetes-related complications may also contribute to decrease the risk of depression among older men.

Lessons from a pilot and feasibility randomised trial in depression (Blood pressure Rapid Intensive Lowering And Normal Treatment for Mood and cognition in persistent depression (BRILiANT mood study))

BACKGROUND

The blood pressure rapid intensive lowering and normal treatment for mood and cognition in persistent depression (BRILiANT mood study) was devised as a pilot study to investigate the feasibility and safety of intensive blood pressure lowering as treatment for persistent mood and cognitive symptoms in older adults with major depressive disorder and to assess the availability of this population for recruitment. In addition, the relationship between reduced blood pressure and the change in cerebral blood flow and mood was to be investigated.

METHODS

A single centre pilot randomised controlled trial (RCT), with two parallel groups of intensive or normal treatment for hypertension, recruiting from primary and secondary care and newspaper advert, with an aim of recruiting 66 participants, was observed in this study. At the end of the recruitment period, in order to explore the reasons for failure to recruit to target, surveys were developed and issued to those involved in recruitment.

RESULTS

Recruitment rates were lower than expected which led to the study being expanded to further areas and opened to self-referral via advertisement. However, because of better management of hypertension due to changes in the UK Quality and Outcomes Framework guidelines for blood pressure treatment, few eligible patients were identified and the study closed at the end of the recruitment period, with 13 participants consenting, but 12 failing screening resulting in one recruited participant.

CONCLUSIONS

Overall, the BRILiANT mood study was found not to be feasible, and results suggest that the expected patient population no longer exists. To overcome such recruitment difficulties, a prompt commencement of a study after funding so no relevant care changes occur might help prevent similar problems in future studies. In addition, self-referral, in this case via advertisement in papers, may be a useful tool to increase response rate. When recruiting in primary care, direct access to primary care databases, in a secure and anonymised way, may enable more effective screening. Ultimately, the BRILiANT mood study was shown not to be feasible; this was a useful conclusion from this pilot study.

TRIAL REGISTRATION

ISRCTN 64524251; UKCRN Portfolio No: 13284.

Altered functional interaction hub between affective network and cognitive control network in patients with major depressive disorder

Emotional and cognitive dysregulation in major depressive disorder (MDD) have been consistently considered to be attributed to structural and functional abnormalities in affective network (AN) and cognitive control network (CCN). This study was to investigate the functional connectivity (FC) patterns and altered functional interactions between both networks in MDD. We investigated resting-state functional connectivity magnetic resonance imaging in the AN and the CCN in 25 MDD and 35 healthy controls (HC). The seeds were from voxel-based morphometry (VBM) analysis results. Then FC within the AN was assessed from a seed placed in the left amygdala (AMG) and FC within CCN was determined by placing seeds in the right dorsolateral prefrontal cortex (DLPFC). Compared with HC, MDD showed reduced FC between left AMG and bilateral precuneus and right anterior cingulated cortex (ACC) within AN and reduced FC between right DLPFC and left cuneus, left lingual gyrus, and right ACC within CCN. An interaction hub of altered FC in MDD between AN and CCN located in the right ACC. Interestingly, the altered FC between right ACC and left AMG was negatively correlated with depressive symptom score while the altered FC between right ACC and DLPFC was positively correlated the executive function in MDD. The right ACC not only supports the cognitive and emotional processes, but also is an altered functional interaction hub between AN and CCN in MDD. It further suggest multiple sources of dysregulation in AN and CCN implicate both top-down cognitive control and bottom-up emotional expression dysfunction in MDD.

Cognitive function in older adults with major depression: Effects of mineralocorticoid receptor stimulation

Memory and executive function are often impaired in older adults with major depression. Mineralocorticoid receptors (MR) are abundantly expressed in the hippocampus and in the prefrontal cortex, brain areas critical for memory and executive function. In both aging and depression, MR expression in the brain is reduced. Therefore, diminished MR function could contribute to impaired cognition in older adults with depression and might be a promising target for pharmacological intervention. Twenty-three older adults with major depression (mean age 61.6 yrs ± 8.1, n = 13 women) without medication and 24 age-, sex- and education-matched healthy participants received the MR-agonist fludrocortisone (0.4 mg) or placebo in a randomized, double-blind, within-subject cross-over design. We measured psychomotor speed, executive function, verbal learning and memory, and visuospatial memory. Compared to controls, depressed patients performed worse in psychomotor speed (group effect p = 0.01), executive function (group effect p < 0.01), verbal learning (group effect p = 0.02), and verbal memory (group effect p < 0.01) but not in visuospatial memory. There were no significant treatment effects. However, we found a group × treatment interaction in verbal learning (p = 0.04) and visuospatial memory (p = 0.02) indicating that depressed patients performed worse after fludrocortisone whereas controls performed better after fludrocortisone. Our data suggest that -in contrast to younger depressed patients-older adults with depression do not benefit from MR stimulation but deteriorate in cognitive function.

Machine learning approaches for integrating clinical and imaging features in late-life depression classification and response prediction

OBJECTIVE

Currently, depression diagnosis relies primarily on behavioral symptoms and signs, and treatment is guided by trial and error instead of evaluating associated underlying brain characteristics. Unlike past studies, we attempted to estimate accurate prediction models for late-life depression diagnosis and treatment response using multiple machine learning methods with inputs of multi-modal imaging and non-imaging whole brain and network-based features.

METHODS

Late-life depression patients (medicated post-recruitment) (n = 33) and older non-depressed individuals (n = 35) were recruited. Their demographics and cognitive ability scores were recorded, and brain characteristics were acquired using multi-modal magnetic resonance imaging pretreatment. Linear and nonlinear learning methods were tested for estimating accurate prediction models.

RESULTS

A learning method called alternating decision trees estimated the most accurate prediction models for late-life depression diagnosis (87.27% accuracy) and treatment response (89.47% accuracy). The diagnosis model included measures of age, Mini-mental state examination score, and structural imaging (e.g. whole brain atrophy and global white mater hyperintensity burden). The treatment response model included measures of structural and functional connectivity.

CONCLUSIONS

Combinations of multi-modal imaging and/or non-imaging measures may help better predict late-life depression diagnosis and treatment response. As a preliminary observation, we speculate that the results may also suggest that different underlying brain characteristics defined by multi-modal imaging measures-rather than region-based differences-are associated with depression versus depression recovery because to our knowledge this is the first depression study to accurately predict both using the same approach. These findings may help better understand late-life depression and identify preliminary steps toward personalized late-life depression treatment.

Depression, vascular factors, and risk of dementia in primary care: a retrospective cohort study

OBJECTIVES

To study the interaction between and timing effects of depression and vascular disorders on dementia risk.

DESIGN

Retrospective cohort study.

SETTING

Primary care practices in the south of the Netherlands.

PARTICIPANTS

Individuals in primary care aged 50 to 100 followed for 13 years (N = 35,791).

MEASUREMENTS

Medical diagnoses of incident depression, hypertension, obesity, type 2 diabetes mellitus, stroke, and dementia were extracted from a research database. Cox proportional hazards regression was used to test whether incident depression predicted dementia and its putative interactions with vascular factors.

RESULTS

In total, 1,680 participants developed dementia. Individuals with depression (n = 978) had a higher risk of dementia (adjusted hazard ratio (HR) = 2.03, 95% confidence interval (CI) = 1.56-2.64). Depression exerted most effect in participants with incident stroke (HR = 5.29, 95% CI = 2.52-11.14) or newly diagnosed hypertension (HR = 3.09, 95% CI = 1.54-6.20).

CONCLUSION

Depression in later life increases the risk of dementia. The effect is particularly high in individuals with depression and vascular disorders. Targeting late-onset depression in individuals with vascular disorders might lower dementia risk by preventing cerebrovascular changes.

Plasma biosignature and brain pathology related to persistent cognitive impairment in late-life depression

Cognitive impairment is highly prevalent among individuals with late-life depression (LLD) and tends to persist even after successful treatment. The biological mechanisms underlying cognitive impairment in LLD are complex and likely involve abnormalities in multiple pathways, or 'cascades,' reflected in specific biomarkers. Our aim was to evaluate peripheral (blood-based) evidence for biological pathways associated with cognitive impairment in older adults with LLD. To this end, we used a data-driven comprehensive proteomic analysis (multiplex immunoassay including 242 proteins), along with measures of structural brain abnormalities (gray matter atrophy and white matter hyperintensity volume via magnetic resonance imaging), and brain amyloid-β (Aβ) deposition (PiB-positron emission tomography). We analyzed data from 80 older adults with remitted major depression (36 with mild cognitive impairment (LLD+MCI) and 44 with normal cognitive (LLD+NC)) function. LLD+MCI was associated with differential expression of 24 proteins (P<0.05 and q-value <0.30) related mainly to the regulation of immune-inflammatory activity, intracellular signaling, cell survival and protein and lipid homeostasis. Individuals with LLD+MCI also showed greater white matter hyperintensity burden compared with LLD+NC (P=0.015). We observed no differences in gray matter volume or brain Aβ deposition between groups. Machine learning analysis showed that a group of three proteins (Apo AI, IL-12 and stem cell factor) yielded accuracy of 81.3%, sensitivity of 75% and specificity of 86.4% in discriminating participants with MCI from those with NC function (with an averaged cross-validation accuracy of 76.3%, sensitivity of 69.4% and specificity of 81.8% with nested cross-validation considering the model selection bias). Cognitive impairment in LLD seems to be related to greater cerebrovascular disease along with abnormalities in immune-inflammatory control, cell survival, intracellular signaling, protein and lipid homeostasis, and clotting processes. These results suggest that individuals with LLD and cognitive impairment may be more vulnerable to accelerated brain aging and shed light on possible mediators of their elevated risk for progression to dementia.

Medial temporal lobe atrophy and depressive symptoms in elderly patients with and without Alzheimer disease

OBJECTIVE

To determine whether depressive symptoms are associated with medial temporal lobe atrophy in older people with and without Alzheimer disease (AD).

METHOD

A total of 368 memory clinic patients with AD, mild cognitive impairment, and subjective cognitive impairment (SCI) were included. Depressive symptoms were defined as a score of 8 or higher on Cornell Scale for Depression in Dementia or use of antidepressant medications. Magnetic resonance imaging and computer tomography scans were rated for medial temporal lobe atrophy (MTA), using the Scheltens scale. For a subsample (n = 57 patients), hippocampal volume was manually traced.

RESULTS

Based on visual assessment, AD patients with depressive symptoms had less atrophy of the right medial temporal lobe (odds ratio [OR] for having MTA: 0.39; 95% confidence interval [CI] 0.16-0.99) and decreased scores on Scheltens scale for the left medial temporal lobe (OR: 0.43, 95% CI 0.19-0.96) in comparison to AD patients without depressive symptoms. In the subgroup where manual tracing was used to measure hippocampal volume, people with SCI experiencing depressive symptoms had smaller right (mean difference: 0.28 cm(3); P = .005) and left (mean difference 0.32 cm(3); P = .002) hippocampal volumes compared to people with SCI who did not have depressive symptoms.

CONCLUSION

Hippocampal atrophy was more pronounced among patients having SCI with depressive symptoms, while the medial temporal lobe was less atrophic in patients having AD with depressive symptoms than those without depressive symptoms. These findings suggest that different mechanisms underlie depression in older people with and without AD and may explain some of the inconsistent observations in previous studies.

Hypothalamic-pituitary-adrenal axis activity in older persons with and without a depressive disorder

BACKGROUND

Altered functioning of the hypothalamic-pituitary-adrenal axis (HPA-axis) has been associated with depression, but findings have been inconsistent. Among older depressed persons, both hyperactivity and hypo-activity of the HPA-axis were demonstrated. However, most studies were population-based studies, with single cortisol measurements, lacking insight into diurnal patterns of HPA-axis functioning. We aim to provide insight into functioning of the HPA-axis, assessed by various salivary cortisol samples, in depressed older adults and non-depressed controls.

METHODS

Data were derived from the Netherlands Study of Depression in Older Persons. Cortisol levels of older persons without a lifetime diagnosis of depression and/or anxiety (n=109) were compared with older persons with a 6-month major depression diagnosis (n=311). ANCOVA analyses and random coefficient analysis on the four morning cortisol samples were performed. A possible U-shaped association between cortisol and depression status was examined.

RESULTS

Depressed older persons showed higher morning cortisol levels at awakening (T1) and a less dynamic awakening response compared to non-depressed older persons. Dexamethasone suppression did not differ across groups. No U-shaped association between HPA-axis activity and depression was observed.

CONCLUSION

We demonstrated a hypercortisolemic state and a diminished ability to respond to the stress of awakening among depressed older persons. Previously it was shown, that hypercortisolemic states may indicate a lifelong biological vulnerability for depression. Our findings expand on previous literature by demonstrating that in older persons the HPA-axis may become less responsive to stress, culminating in a further dysregulation of the diurnal cortisol-rhythm, superimposed on - possibly lifelong - hypercortisolemic states.

Association of age at depression onset with cognitive functioning in individuals with late-life depression and executive dysfunction

OBJECTIVE

To compare patterns of cognitive performance in older adults with late-onset depression (LOD; ≥65 years of age) with that of older adults with early-onset depression (EOD; <65 years).

METHODS

Participants were 171 adults aged 60 years or older with major depression and executive dysfunction who were participating in a randomized psychotherapy trial. Participants included 72 LOD and 99 EOD individuals. Cognitive performance on measures of verbal learning, memory, and executive functioning were evaluated. Demographic and clinical characteristics, severity of cerebrovascular risk factors, and disability ratings were also compared between groups.

RESULTS

The LOD group was older and had fewer previous episodes of depression and lower severity of depression compared with EOD participants. The LOD group demonstrated poorer performance on measures of verbal learning (F(1,161) = 4.28, p = 0.04) and memory (F(1,160) = 4.65, p = 0.03) than the EOD group. Linear regression analysis demonstrated that LOD and fewer years of education were significant predictors of poorer verbal learning (F(7,114) = 6.25, p <0.001) and memory (F(7,113)=7.24, p <0.001). Performance on measures of executive functioning, severity of vascular risk factors, and disability ratings did not differ between the two groups.

CONCLUSION

In older adults with depression and executive dysfunction, LOD was associated with poorer performance on measures of verbal learning and memory. Aging-related brain changes associated with LOD may play a more important role, leading to dysfunction in these cognitive domains than a history of recurrent depressive episodes in older adults with a dysexecutive syndrome.

Depression in context of low neuroticism is a risk factor for stroke: a 9-year cohort study

OBJECTIVE

Depression predicts stroke; however, meta-analyses show significant heterogeneity. We hypothesize that the risk of depression on incident stroke is conditional upon the relative contribution of vascular disease and of neuroticism in the underlying pathways to depression in a specific patient. We examined whether depression increases stroke in persons with low neuroticism and without preexisting cardiac disease.

METHODS

This was a population-based cohort study with 9-year follow-up (n = 2,050; ≥55 years, 52% female). The incidence of stroke was determined by self-report data as well as data from general practitioners and death certificates. Neuroticism was measured using the Dutch Personality Questionnaire and depression using the Center for Epidemiologic Studies-Depression scale. All data were analysed by Cox proportional hazards regression.

RESULTS

A total of 117 incident cases of stroke occurred during follow-up. Among persons with a history of cardiac disease (n = 401), depression predicted incident stroke independent of neuroticism level with a hazard ratio (HR) of 1.05 (95% confidence interval [CI] 1.01-1.10) (p = 0.02). In persons without cardiac disease (n = 1,649), depression and neuroticism interacted significantly in predicting incident stroke (p = 0.028). Stratified analyses showed that depression predicted incident stroke in those with low neuroticism, HR 1.05 (95% CI 1.00-1.09) (p = 0.033), but not in those with high neuroticism, HR 1.01 (95% CI 0.96-1.05) (p = 0.82).

CONCLUSIONS

In persons without preexistent cardiac disease, depression is only predictive for future stroke in absence of high neuroticism. This might be explained by the hypothesis that late-life depression in context of low neuroticism is a marker of subclinical vascular disease.

Shortened telomere length in white matter oligodendrocytes in major depression: potential role of oxidative stress

Telomere shortening is observed in peripheral mononuclear cells from patients with major depressive disorder (MDD). Whether this finding and its biological causes impact the health of the brain in MDD is unknown. Brain cells have differing vulnerabilities to biological mechanisms known to play a role in accelerating telomere shortening. Here, two glia cell populations (oligodendrocytes and astrocytes) known to have different vulnerabilities to a key mediator of telomere shortening, oxidative stress, were studied. The two cell populations were separately collected by laser capture micro-dissection of two white matter regions shown previously to demonstrate pathology in MDD patients. Cells were collected from brain donors with MDD at the time of death and age-matched psychiatrically normal control donors (N = 12 donor pairs). Relative telomere lengths in white matter oligodendrocytes, but not astrocytes, from both brain regions were significantly shorter for MDD donors as compared to matched control donors. Gene expression levels of telomerase reverse transcriptase were significantly lower in white matter oligodendrocytes from MDD as compared to control donors. Likewise, the gene expression of oxidative defence enzymes superoxide dismutases (SOD1 and SOD2), catalase (CAT) and glutathione peroxidase (GPX1) were significantly lower in oligodendrocytes from MDD as compared to control donors. No such gene expression changes were observed in astrocytes from MDD donors. These findings suggest that attenuated oxidative stress defence and deficient telomerase contribute to telomere shortening in oligodendrocytes in MDD, and suggest an aetiological link between telomere shortening and white matter abnormalities previously described in MDD.

Social adaptive functioning, apathy, and nondysphoric depression among nursing home-dwelling very old adults

BACKGROUND

Apathetic and subsyndromal depressive conditions are common in the oldest old. This study examined whether nondysphoric depression (NDD), a clinical condition characterized by ideational and vegetative but no emotional symptoms of depression, belongs to the apathetic presentations of late-life depression. Rates of NDD, dysphoric depression (DD), apathy, and social functional impairment were examined in a sample of nondemented very old (mean age 87.5 years, SD = 7.7) nursing home residents. It was hypothesized that individuals with NDD show greater apathy and greater social functional impairment relative to DD and nondepressed individuals.

METHODS

Social functioning was measured using the Social-Adaptive Functioning Evaluation (SAFE) and apathy was measured using the global apathy rating on the Scale for the Assessment of Negative Symptoms (SANS).

RESULTS

The rates of DD (50.0%) and NDD (27.4%) were quite high. Participants with DD reported greater apathy than those with NDD (and nondepressed individuals). NDD and DD subjects showed greater social functional impairment relative to the comparison group. There was no difference in social functioning between DD and NDD individuals.

CONCLUSIONS

The present data are inconsistent with the view that NDD among the oldest old is an apathetic form of depression. NDD involves social functional impairment. Limitations include rather selected population of nursing home residents that may have included individuals with early dementia, lack of data on prior depressive episodes, and apathy assessment not validated on the specific population.

Atherosclerosis decreases the impact of neuroticism in late-life depression: hypothesis of vascular apathy

OBJECTIVE

To examine the interplay between subclinical atherosclerotic disease and neuroticism in explaining variance in late-life depressive symptoms.

METHODS

This study was part of the Nijmegen Biomedical Study, a population-based survey; 1,517 participants aged 50-70 years were included. Depressive symptoms were measured by the Beck Depression Inventory (BDI). Principal components analysis of the BDI items yielded two factors, representing a cognitive-affective symptom cluster and a somatic-affective symptom cluster. Atherosclerotic disease was measured by the intima media thickness (IMT) of the carotid arteries and neuroticism by the revised Eysenck Personality Questionnaire.

RESULTS

Multiple linear regression analyses using different measures of depressive symptoms as the dependent variable showed that neuroticism was strongly and significantly associated with the sum score of the BDI and with the two depressive symptom clusters. IMT, however, was only significantly associated with the somatic-affective symptom cluster but not with the cognitive-affective symptom cluster. Interestingly, we found a significant negative interaction between neuroticism and IMT in explaining the severity of the cognitive-affective symptom cluster but not with respect to the somatic-affective symptom cluster.

CONCLUSION

The negative interaction between neuroticism and atherosclerosis indicates that neuroticism is less strongly associated with cognitive-depressive symptoms in the presence of more severe atherosclerosis. This may be explained by apathy due to cerebrovascular disease and fits with a hypothesis of vascular apathy.

Depression in the elderly: brain correlates, neuropsychological findings, and role of vascular lesion load

PURPOSE OF REVIEW

Late-life depression (LLD) presents in older adults as a heterogeneous mood disorder. Because of the diverse outcomes and symptomatology of LLD, several theories, especially the vascular depression hypothesis, have been proposed to identify its cause. This review outlines the features of LLD and explores the recent advances in characterizing this disorder through studies of brain functioning and cognition, with an emphasis on how vascular changes may mediate this disorder.

RECENT FINDINGS

LLD is associated with brain changes, including atrophy of hippocampus, independent of other neurodegenerative states. White matter lesions (WMLs) are frequently found in patients with LLD. Functional imaging has revealed both distinct characteristics of LLD and overlap of some cognitive symptoms with other dementias. Executive dysfunction and impaired processing speeds are at the core of the cognitive deficits in LLD and are associated with the development of WMLs in specific fiber tracts in the brain.

SUMMARY

LLD is associated with brain changes in both gray matter and white matter, including cerebrovascular changes, atrophy, and loss of myelin integrity. These brain changes are associated with age of onset of depression, as well as cumulative life-time depression burden, and can explain the increased dementia risk associated with LLD.

The link between cardiovascular risk, Alzheimer's disease, and mild cognitive impairment: support from recent functional neuroimaging studies

OBJECTIVE

To review functional neuroimaging studies about the relationship between cardiovascular risk factors (CVRFs), Alzheimer's disease (AD), and mild cognitive impairment (MCI).

METHODS

We performed a comprehensive literature search to identify articles in the neuroimaging field addressing CVRF in AD and MCI. We included studies that used positron emission tomography (PET), single photon emission computerized tomography (SPECT), or functional magnetic resonance imaging (fMRI).

RESULTS

CVRFs have been considered risk factors for cognitive decline, MCI, and AD. Patterns of AD-like changes in brain function have been found in association with several CVRFs (both regarding individual risk factors and also composite CVRF measures). In vivo assessment of AD-related pathology with amyloid imaging techniques provided further evidence linking CVRFs and AD, but there is still limited information resulting from this new technology.

CONCLUSION

There is a large body of evidence from functional neuroimaging studies supporting the hypothesis that CVRFs may play a causal role in the pathophysiology of AD. A major limitation of most studies is their cross-sectional design; future longitudinal studies using multiple imaging modalities are expected to better document changes in CVRF-related brain function patterns and provide a clearer picture of the complex relationship between aging, CVRFs, and AD.

Hair cortisol and cognitive performance in healthy older people

Worse cognitive performance in older people has been associated with hypothalamic-pituitary-adrenal axis dysregulation (in particular, higher cortisol levels). Analysis of hair cortisol concentrations (HCC) is a novel method to measure long-term cortisol exposure, and its relationship with cognition in healthy older people has not yet been studied. We investigated whether HCC (measured in hair scalp) and diurnal salivary cortisol levels (awakening, 30min after awakening, and evening, across two days) were related to cognitive performance (assessed with the Trail-making Test A and B, Digit Span Forward and Backward, word list-RAVLT and Stories subtest of the Rivermead) in 57 healthy older people (mean age=64.75 years, SD=4.17). Results showed that lower HCC were consistently related to worse working memory, learning, short-term verbal memory (RAVLT first trial and immediate recall) and long-term verbal memory. In contrast, higher mean levels and higher diurnal area under the curve of diurnal salivary cortisol were related to worse attention and short-term verbal memory (immediate story recall), respectively. Interestingly, a higher ratio of mean levels of diurnal salivary cortisol over HCC were related to worse performance on working memory and short-term verbal memory, suggesting that those individuals with lower long-term cortisol exposure might be more vulnerable to the negative effect of HPA-axis dysregulation on these cognitive processes. Our findings suggest that both low long-term cortisol exposure and a possible dysregulation of the diurnal rhythm of the HPA-axis may account, at least in part, for the inter-individual variability in cognitive performance in healthy older people.

Depression and dementia: cause, consequence or coincidence?

The relationship between depression and dementia is complex and still not well understood. A number of different views exist regarding how the two conditions are linked as well as the underlying neurobiological mechanisms at work. This narrative review examined longitudinal and cross sectional studies in the existing literature and determined the evidence supporting depression being a risk factor, a prodrome, a consequence, or an independent comorbidity in dementia. Overall there is convincing evidence to support both the notion that early life depression can act as a risk factor for later life dementia, and that later life depression can be seen as a prodrome to dementia. There is also evidence to support both conditions showing similar neurobiological changes, particularly white matter disease, either indicating shared risk factors or a shared pattern of neuronal damage. These findings highlight the need to examine if effective treatment of depressive episodes has any effect in reducing the prevalence of dementia, as well as clinicians being vigilant for late life depression indicating the incipient development of dementia, and therefore carefully following up these individuals for future cognitive impairment.

HPA axis and aging in depression: systematic review and meta-analysis

One of the most consistent findings in the biology of depression is an altered activity of the hypothalamic-pituitary-adrenal (HPA) axis. However, data concerning this issue have never been examined with a focus on the older population. Here we present a systematic review and meta-analysis, based on studies investigating levels of cortisol, adrenocorticotropic hormone (ACTH) and corticotropin-releasing hormone (CRH) in depressed participants older than 60 and compared with healthy controls. We found 20 studies, for a total of 43 comparisons on different indices of HPA axis functioning. Depression had a significant effect (Hedges' g) on basal cortisol levels measured in the morning (0.89), afternoon (0.83) and night (1.39), but a smaller effect on cortisol measured continuously (0.51). The effect of depression was even higher on post-dexamethasone cortisol levels (3.22), whereas it was non-significant on morning ACTH and CRH levels. Subgroup analyses indicated that various methodological and clinical factors can influence the study results. Overall, older participants suffering from depression show a high degree of dysregulation of HPA axis activity, with differences compared with younger adults. This might depend on several mechanisms, including physical illnesses, alterations in the CNS and immune-endocrinological alterations. Further studies are needed to clarify the implications of altered HPA axis activity in older patients suffering from depression. Novel pharmacological approaches might be effective in targeting this pathophysiological feature, thus improving the clinical outcomes.

The impact of stress and glucocorticoids on memory

Responses to stress are mediated by a complex network of the nervous and endocrine systems. Glucocorticoids, which are among the most important “players” in stress resilience, may have important implications in the cognitive functions, particularly in the modulation of memory. Declarative memory, the memory for facts, events and word meaning is the most studied type of memory on which glucocorticoids exert an influence, both positively through consolidation and negatively through impairment. These effects depend on the receptor type, dose, time of exposure, memory component and the salience of stimuli, retrieval being generally affected and storage being facilitated, especially for emotionally relevant events. Glucocorticoids also induce hippocampal atrophy, which is a hallmark seen in various diseases accompanied by a chronic high level of cortisol, such as the Cushing syndrome, major depression, post-traumatic stress disorder. Also, chronic stress might be a risk factor for the development of Alzheimer’s disease, especially when a genetic background and other environmental influences are present.

Pretreatment cortisol levels predict posttreatment outcomes among older adults with depression in cognitive behavioral therapy

Previous studies suggest that individuals with elevated levels of cortisol (the "stress hormone") could be particularly resistant to treatment for depression. However, most of these studies have been conducted in the context of antidepressant medications, and no study has examined pretreatment cortisol levels as a predictor of treatment outcomes among older adults with depression in cognitive-behavioral therapy (CBT), despite the relevance of this population for such a research question. The current study includes 54 older adults with depression who provided salivary cortisol samples at baseline and completed measures of depression at pretreatment and posttreatment, following a 12-week course of CBT. Structural equation modeling results suggest that those with higher daily outputs of cortisol and flatter diurnal slopes were less likely to benefit from CBT-a finding which if replicated could have important implications for clinical practice and future research.

A systematic review comparing clinical features in early age at onset and late age at onset late-life depression

BACKGROUND

Although evidence suggests that there are neurobiological differences between unipolar depression in younger versus older adults, conflicting evidence exists about whether these manifest as clinically identifiable differences.

METHOD

We conducted a systematic review of aetiological, phenomenological and outcome studies to examine the evidence for a distinction between early onset (EOD) and late onset (LOD) depression. A literature search was completed using the computer databases MEDLINE, EMBASE, PSYCHINFO and PUBMED for papers published between January 1982 and December 2012 which compared groups with EOD and LOD. Studies were included if they were of older people and compared symptoms, aetiological factors or outcomes. We conducted a quality assessment of included articles.

RESULTS

We identified 23 articles which met entry criteria. The only clinical feature which was different between the groups was a higher frequency of a family history of mood disorders in EOD.

LIMITATIONS

The number of studies identified was low and their quality was generally poor.

CONCLUSIONS

Although neurobiological studies have reported differences between EOD and LOD, generally these do not appear to translate into identifiable distinguishing clinical features.

The vascular depression hypothesis: mechanisms linking vascular disease with depression

The 'Vascular Depression' hypothesis posits that cerebrovascular disease may predispose, precipitate or perpetuate some geriatric depressive syndromes. This hypothesis stimulated much research that has improved our understanding of the complex relationships between late-life depression (LLD), vascular risk factors, and cognition. Succinctly, there are well-established relationships between LLD, vascular risk factors and cerebral hyperintensities, the radiological hallmark of vascular depression. Cognitive dysfunction is common in LLD, particularly executive dysfunction, a finding predictive of poor antidepressant response. Over time, progression of hyperintensities and cognitive deficits predicts a poor course of depression and may reflect underlying worsening of vascular disease. This work laid the foundation for examining the mechanisms by which vascular disease influences brain circuits and influences the development and course of depression. We review data testing the vascular depression hypothesis with a focus on identifying potential underlying vascular mechanisms. We propose a disconnection hypothesis, wherein focal vascular damage and white matter lesion location is a crucial factor, influencing neural connectivity that contributes to clinical symptomatology. We also propose inflammatory and hypoperfusion hypotheses, concepts that link underlying vascular processes with adverse effects on brain function that influence the development of depression. Testing such hypotheses will not only inform the relationship between vascular disease and depression, but also provide guidance on the potential repurposing of pharmacological agents that may improve LLD outcomes.

Plasma cortisol in Alzheimer's disease with or without depressive symptoms

Background

Cortisol is presumed to be a risk factor for stress- and age-related disorders, such as depressive disorder and Alzheimer’s disease (AD). The aim of this study was to investigate the association of plasma cortisol concentration with AD in presence or absence of comorbid depressive symptoms.

Material/Methods

Plasma cortisol concentration was measured in 80 AD patients (35 of them with depressive symptoms), 27 elderly depressive patients without AD, and 37 elderly controls.

Results

Compared to controls, a significant increase of mean plasma cortisol was found in AD patients but not in depressive patients. Plasma cortisol was positively correlated with cognitive impairment in AD patients. We confirmed a U-shaped association between plasma cortisol and major depression and a linear association between plasma cortisol and AD without depressive symptoms. Significantly increased relative risk of disease in people with high plasma cortisol was found for AD with depressive symptoms and for AD with mild dementia.

Conclusions

Plasma cortisol reflects the degree of cognitive impairment in AD rather than the severity of comorbid depression. We confirmed that both hypercortisolemia and hypocortisolemia are associated with depressive disorder. Significant association between high plasma cortisol and AD was found, supporting the use of high plasma cortisol as a component of a panel of biochemical markers for AD with depressive symptoms as well as AD in the early stage of dementia development.

Cortisol and depression: three questions for psychiatry

BACKGROUND

Cortisol plays a multifaceted role in major depression disorder (MDD). Diurnal rhythms are disturbed, there is increased resistance to the feedback action of glucocorticoids, excess cortisol may induce MDD, basal levels may be higher and the post-awakening cortisol surge accentuated in those at risk for MDD. Does this suggest new avenues for studying MDD or its clinical management?

METHOD

The relevant literature was reviewed.

RESULTS

Cortisol contributes to genetic variants for the risk for MDD and the way that environmental events amplify risk. The corticoids' influence begins prenatally, but continues into adulthood. The impact of cortisol at each phase depends not only on its interaction with other factors, such as psychological traits and genetic variants, but also on events that have, or have not, occurred previously.

CONCLUSIONS

This review suggests that the time is now right for serious consideration of the role of cortisol in a clinical context. Estimates of cortisol levels and the shape of the diurnal rhythm might well guide the understanding of subtypes of MDD and yield additional indicators for optimal treatment. Patients with disturbed cortisol rhythms might benefit from restitution of those rhythms; they may be distinct from those with more generally elevated levels, who might benefit from cortisol blockade. Higher levels of cortisol are a risk for subsequent depression. Should manipulation of cortisol or its receptors be considered as a preventive measure for some of those at very high risk of future MDD, or to reduce other cortisol-related consequences such as long-term cognitive decline?

Organic bases of late-life depression: a critical update

Late-life depression (LLD) is frequently associated with cognitive impairment and increases the risk of subsequent dementia. Cerebrovascular disease, deep white matter lesions, Alzheimer disease (AD) and dementia with Lewy bodies (DLB) have all been hypothesized to contribute to this increased risk, and a host of studies have looked at the interplay between cerebrovascular disease and LLD. This has resulted in new concepts of LLD, such as "vascular depression", but despite multiple magnetic resonance imaging (MRI) studies in this field, the relationship between structural changes in human brain and LLD is still controversial. While pathological findings of suicide in some elderly persons revealed multiple lacunes, small vessel cerebrovascular disease, AD-related lesions or multiple neurodegenerative pathologies, recent autopsy data challenged the role of subcortical lacunes and white matter lesions as major morphological substrates of depressive symptoms as well as poorer executive function and memory. Several neuropathological studies, including a personal clinico-pathological study in a small cohort of elderly persons with LLD and age-matched controls confirmed that lacunes, periventricular and deep white matter demyelination as well as AD-related lesions are usually unrelated to the occurrence of LLD. In the same line, neuropathological data show that early-onset depression is not associated with an acceleration of age-related neurodegenerative changes. Very recent data on the critical role of glia-modulating neuronal dysfunction and degeneration in depression are discussed.

Relationship between cognition, magnetic resonance white matter hyperintensities, and cardiovascular autonomic changes in late-life depression

OBJECTIVES

To explore the relationship between specific aspects of cognition, white matter hyperintensities (WMHs), and cardiovascular autonomic parameters in late-life depression (LLD).

DESIGN

Cross-sectional analysis.

SETTING

Secondary care psychiatry.

PARTICIPANTS

Forty-one individuals older than 60 years, with current or previous history of major depression, and 32 age-matched comparison subjects.

MEASUREMENTS

Cognition was assessed by a standardized computer battery of tasks (Cognitive Drug Research) that measured processing speed, attention, episodic memory, and working memory. Cardiovascular autonomic parameters were estimated by a noninvasive device that calculated blood pressure, heart rate variability, and baroreflex sensitivity (Task Force Monitor). Magnetic resonance imaging was performed on a 3-T magnetic resonance imaging system, and WMH volume was estimated using an automated validated method.

RESULTS

As expected, cognitive deficits in all tested domains were present in LLD subjects compared with comparison subjects. In the LLD group, processing speed was correlated with scores on memory and working memory tasks. Attentional deficits were correlated with total and periventricular WMH volume, and episodic memory was associated with heart rate variability. There were no associations between cognitive variables and traditional vascular risk factors or between cognitive variables and any of these parameters in the comparison subjects.

CONCLUSIONS

This study suggests that processing speed may be an important factor underlying deficits in LLD, but it also indicates that other factors, including those related to vascular disease, are important and thus provide further support for the vascular depression hypothesis.

Correlations between Stroop task performance and white matter lesion measures in late-onset major depression

Cerebral white matter lesions (WMLs) are believed to play an important role in a subset of patients with late-onset depression by affecting the white matter connectivity in circuitries essential for mood and cognition. In this study we used diffusion tensor imaging-based (DTI-based) tractography to assess white matter fiber tracts affected by deep WMLs (DWMLs) in patients with late-onset major depression and age- and gender-matched controls. Tractography outcome, illustrated as pathways affected by DWMLs, was analyzed for associations with cognitive performance on the Stroop Test (ST). The patients (n=17) performed significantly worse on the ST than the controls (n=22). Poor performance on the ST correlated with higher lesion load. Regression analysis showed a significant correlation between poor performance on the ST and tracts affected by DWMLs in multiple brain areas in the control group, but very sparse correlation in the patient group. Our results suggest that DWMLs play an important role in the cognitive performance of controls,whereas their influence in depressed patients is overruled by additional, state-dependent factors. Future focus on the tract-specific localization of WMLs using DTI tractography may reveal important associations between neuroconnectivity and clinical measures.

A putative functional role for oligodendrocytes in mood regulation

Altered glial structure and function is implicated in several major mental illnesses and increasing evidence specifically links changes in oligodendrocytes with disrupted mood regulation. Low density and reduced expression of oligodendrocyte-specific gene transcripts in postmortem human subjects points toward decreased oligodendrocyte function in most of the major mental illnesses. Similar features are observed in rodent models of stress-induced depressive-like phenotypes, such as the unpredictable chronic mild stress and chronic corticosterone exposure, suggesting an effect downstream from stress. However, whether oligodendrocyte changes are a causal component of psychiatric phenotypes is not known. Traditional views that identify oligodendrocytes solely as nonfunctional support cells are being challenged, and recent studies suggest a more dynamic role for oligodendrocytes in neuronal functioning than previously considered, with the region adjacent to the node of Ranvier (i.e., paranode) considered a critical region of glial-neuronal interaction. Here, we briefly review the current knowledge regarding oligodendrocyte disruptions in psychiatric disorders and related animal models, with a focus on major depression. We then highlight several rodent studies, which suggest that alterations in oligodendrocyte structure and function can produce behavioral changes that are informative of mood regulatory mechanisms. Together, these studies suggest a model, whereby impaired oligodendrocyte and possibly paranode structure and function can impact neural circuitry, leading to downstream effects related to emotionality in rodents, and potentially to mood regulation in human psychiatric disorders.

The influence of subcortical ischemic lesions on cognitive function and quality of life in late life depression

OBJECTIVES

Subcortical ischemic lesions (SIL) are known to contribute to the pathogenesis of late life depression. The present study examined the influence of SIL on cognitive function and quality of life in elderly Koreans with major depressive disorder (MDD).

METHODS

MDD patients (n=86) underwent CT scans and were classified as having SIL if they had a score of 2 or above on age-related white matter changes (ARWMC) scale. Demographic data, psychiatric, medical history, neuropsychological test, quality of life, and depressive symptomatology were compared between MDD patients with and without SIL.

RESULTS

SIL with grade 2 or above were found in deep white matter of 22 (25.6%) depressed patients and in basal ganglia of 9 (10.5%) depressed patients. Depressed patients with deep white matter lesions showed poor performance on MMSE-KC and decreased quality of life, particularly in physical function and physical role limitation, as compared to depressed patients without deep white matter lesions.

CONCLUSION

These data support that SIL may cause general cognitive dysfunction and poor physical health. More attention should be paid to detection and management of SIL in late life depression in clinical setting.

Lack of association between prior depressive episodes and cerebral [11C]PiB binding

Depressive symptoms are frequent in Alzheimer's disease (AD), but it is controversial whether depression is a risk factor for AD. This study measured for the first time cortical amyloid-β (Aβ) levels using [(11)C] Pittsburgh Compound B (PiB) positron emission tomography (PET) in a group of nondemented patients with prior depressive episodes. Twenty-eight elderly patients (mean age 61 years, range 51-75, 18 women) with onset of first depressive episode more than 6 years ago but now remitted from depression and 18 healthy subjects (mean age 61 years, range 50-76, 12 women) were included. All subjects were investigated with cognitive testing, 3T magnetic resonance imaging (MRI) and [(11)C]PiB high resolution research tomography (HRRT) positron emission tomography scan. There was no between-groups difference in [(11)C]PiB binding (p = 0.5) and no associations to number of depressive episodes, cognitive performance, or antidepressant treatment. Patients with late onset of depression had increased severity of white matter lesions (p = 0.04). In this study depressive episodes were not associated with increased levels of [(11)C]PiB. Thus, our results do not support the notion that depressive episodes previously in life are a risk factor for developing AD.

Depressive symptoms and risk for dementia: a 9-year follow-up of the Maastricht Aging Study

OBJECTIVE

Depression relates to vascular disease and is a candidate risk factor for dementia. We assessed the risk associated with depressive symptoms for Alzheimer-type dementia and vascular dementia.

METHODS

Depressive symptoms (SCL-90 depression subscale) were assessed in 771 community-dwelling individuals age 55 years and older. Onset of dementia (N = 37) was recorded at serial assessments 3, 6, and 9 years after baseline.

RESULTS

Depressive symptom scores predicted all-type dementia (OR = 1.06, 95% CI = 1.01-1.10), and vascular dementia (OR = 1.11; 95% CI = 1.03-1.19), but not Alzheimer-type dementia (OR = 1.04; 95% CI = 0.98-1.09). People scoring in the upper quartile of the SCL-90 depression scale (N = 180) were at increased risk for dementia (OR = 2.06, 95% CI = 1.01-4.22). Results were unchanged after co-varying for baseline mini-mental state exam and presence of vascular disease.

CONCLUSION

Depressive symptoms increase the risk for later dementia in community-dwelling older adults.

Structural neuroimaging studies in major depressive disorder. Meta-analysis and comparison with bipolar disorder

CONTEXT

Although differences in clinical characteristics exist between major depressive disorder (MDD) and bipolar disorder (BD), consistent structural brain abnormalities that distinguish the disorders have not been identified.

OBJECTIVES

To investigate structural brain changes in MDD using meta-analysis of primary studies; assess the effects of medication, demographic, and clinical variables; and compare the findings with those of a meta-analysis of studies on BD.

DATA SOURCES

The MEDLINE, EMBASE, and PsycINFO databases were searched for studies from January 1, 1980, to February 2, 2010.

STUDY SELECTION

Two hundred twenty-five studies that used magnetic resonance imaging or x-ray computed tomography to compare brain structure in patients with MDD with that of controls were included in an online database, and 143 that measured common brain structures were selected for meta-analysis.

DATA EXTRACTION

Twenty-five variables, including demographic and clinical data, were extracted from each study, when available. For the meta-analysis, mean structure size and standard deviation were extracted for continuous variables, and the proportion of patients and controls with an abnormality in brain structure was extracted for categorical variables.

DATA SYNTHESIS

Compared with the structure of a healthy brain, MDD was associated with lateral ventricle enlargement; larger cerebrospinal fluid volume; and smaller volumes of the basal ganglia, thalamus, hippocampus, frontal lobe, orbitofrontal cortex, and gyrus rectus. Patients during depressive episodes had significantly smaller hippocampal volume than patients during remission. Compared with BD patients, those with MDD had reduced rates of deep white matter hyperintensities, increased corpus callosum cross-sectional area, and smaller hippocampus and basal ganglia. Both disorders were associated with increased lateral ventricle volume and increased rates of subcortical gray matter hyperintensities compared with healthy controls.

CONCLUSIONS

The meta-analyses revealed structural brain abnormalities in MDD that are distinct from those observed in BD. These findings may aid investigators attempting to discriminate mood disorders using structural magnetic resonance imaging data.

Chronic stress, cognitive functioning and mental health

This review aims to discuss the evidence supporting the link between chronic stress, cognitive function and mental health. Over the years, the associations between these concepts have been investigated in different populations. This review summarizes the findings that have emerged from older populations as well as from populations suffering from pathological aging, namely Mild Cognitive Impairment and Alzheimer's Disease. Although older adults are an interesting population to study in terms of chronic stress, other stress-related diseases can occur throughout the lifespan. The second section covers some of these stress-related diseases that have recently received a great deal of attention, namely burnout, depression, and post-traumatic stress disorder. Given that chronic stress contributes to the development of certain pathologies by accelerating and/or exacerbating pre-existing vulnerabilities that vary from one individual to the other, the final section summarizes data obtained on potential variables contributing to the association between chronic stress and cognition.

Electrophysiological changes in late life depression and their relation to structural brain changes

BACKGROUND

Late life depression is often accompanied by slowed information processing during neuropsychological testing, and this has been related to underlying cerebrovascular disease. We investigated whether changes in electrophysiological markers of information processing might share the same pathological correlates.

METHODS

Differences in power spectra frequency, contingent negative variation (CNV), post-imperative negative variation (PINV), and auditory P300a amplitude and latency in 19 patients with DSM-IV major depression aged ≥ 60 years were compared with 25 recordings in age-matched healthy controls. Associations with total brain volume and degree of white matter hyperintensities (WMH) were examined in those who had undergone additional magnetic resonance imaging (MRI).

RESULTS

Compared with healthy controls, patients had more slow-wave delta (group difference: p = 0.024) and theta activity (p = 0.015) as well as alpha activity (p = 0.005) but no decrease in beta band frequency (p = 0.077). None of these changes related differently to brain volume or WMH in patients or controls. Patients further showed prolonged P300a latencies (p = 0.027), which were associated with decreased total brain volume in patients but not controls (interaction by group: p = 0.004). While there were no overall differences in PINV between both groups, patients showed a decrease in PINV magnitude with increasing WMH, a relation that was not seen in controls (interaction by group: p = 0.024).

CONCLUSION

Patients with late life depression show changes in several electrophysiological markers of cerebral arousal and information processing, some of which relate to brain atrophy and WMH on MRI.

Anxiety and depression in the elderly: do we know any more?

PURPOSE OF REVIEW

The advent of global population ageing raises understandable concerns about the high-prevalence mental disorders in older people. Accordingly, this review covers recently published scientific articles concerning anxiety and depression.

RECENT FINDINGS

There is a paucity of findings on anxiety in older people, although the availability of several new scales suggests increased interest in this topic. The low prevalence of late-life depression in many population surveys does not appear to be due to misattribution of depressive symptoms to physical disorders. Although it is well established that dementia leads to depression, there is now increasing evidence for the proposition that depression leads to cognitive decline and dementia. There is now good evidence also for a bidirectional relationship between obesity and depression. The prognosis of treated late-life depression varies with baseline neuropsychological function and the severity of white matter hyperintensities.

SUMMARY

An excellent body of research on depression in older people is now available, although more work on both pharmacological and nonpharmacological treatments is needed. More research is urgently required into anxiety disorders in older people. These are highly prevalent and associated with considerable disease burden. As the literature on depression in older people reaches maturity, there should be greater research and clinical interest in anxiety.

Vascular diseases and old age mental disorders: an update of neuroimaging findings

PURPOSE OF REVIEW

To review neuroimaging findings that have been reported in samples of patients with cardiovascular disorders and their association with the onset of Alzheimer's disease, vascular dementia, depression and bipolar disorder in the elderly and to highlight the implications of these findings to the knowledge about the pathophysiology of psychiatric disorders in old age, as well as their potential clinical implications.

RECENT FINDINGS

Vascular risk factors, such as hypertension, diabetes, dyslipidemia, smoking habits and heart failure, have all been associated with signs of cerebrovascular dysfunction, including structural MRI findings of signal hyperintensities, lacunes and stroke and functional imaging findings of brain regional hypoperfusion and hypometabolism. Such brain abnormalities have been found to increase the risk of onset of psychiatric disorder (depression, bipolar and dementia) in old age.

SUMMARY

As vascular risk factors are potentially modifiable when detected in midlife, the early characterization of brain changes associated with the presence of cardiovascular diseases holds promise to afford clinical applications in psychiatry, providing new perspectives for the prevention of old age psychiatric disorders.