MRI signal hyperintensities in geriatric depression

Life's Essential 8 and Poor Brain Health Outcomes in Middle-Aged Adults

BACKGROUND AND OBJECTIVES

Mounting evidence points to a strong connection between cardiovascular risk during middle age and brain health later in life. The American Heart Association's Life's Essential 8 (LE8) constitutes a research and public health construct capturing key determinants of cardiovascular health. However, the overall effect of the LE8 on global, clinically relevant metrics of brain health is still unknown. We tested the hypothesis that worse LE8 profiles are associated with higher composite risk of the most important clinical endpoints related to poor brain health.

METHODS

We conducted a two-stage (discovery and replication) prospective study using data from the UK Biobank (UKB) and All of Us (AoU), 2 large population studies in the United Kingdom and the United States, respectively. The primary exposure was the LE8 score, a validated tool that captures 8 modifiable cardiovascular risk factors (blood pressure, glucose, cholesterol, body mass index, smoking, physical activity, diet, and sleep duration), organized in 3 categories (optimal, intermediate, and poor). The primary outcome was a composite of stroke, dementia, or late-life depression. We evaluated associations using multivariable Cox proportional hazard models.

RESULTS

The discovery stage included 316,127 UKB participants (mean age 56, 52% female). Over a mean (SD) follow-up time of 4.9 (0.4) years, the unadjusted risk of the composite outcome was 0.7% (95% CI 0.61-0.74), 1.2% (95% CI 1.11-1.22), and 1.8% (95% CI 1.70-1.91) in participants with optimal, intermediate, and poor cardiovascular health, respectively (p < 0.001). This association remained significant in multivariable Cox models (intermediate vs optimal cardiovascular health hazard ratio [HR], 1.37; 95% CI 1.24-1.52, and poor vs optimal cardiovascular health HR, 2.11; 95% CI 1.88-2.36, p trend <0.001). The replication stage included 68,407 AoU participants (mean age 56, 60% female). Over a mean (SD) follow-up time of 2.9 (1.41) years, the unadjusted risk of the composite outcome was 2.8% (95% CI 2.49-3.05), 6% (95% CI 5.76-6.22), and 9.7% (95% CI 9.24-10.24) in participants with optimal, intermediate, and poor cardiovascular health, respectively (p < 0.001). This association remained significant in multivariable Cox models (intermediate vs optimal cardiovascular health, HR 1.35; 95% CI 1.21-1.51, and poor vs optimal cardiovascular health, HR 1.94; 95% CI 1.72-2.18; p trend <0.001).

DISCUSSION

Among middle-aged adults enrolled in 2 large population studies, poor cardiovascular health profiles were associated with two-fold higher risk of developing a composite outcome that captures the most important diseases related to poor brain health. Because the evaluated risk factors are all modifiable, our findings highlight the potential brain health benefits of using the Life's Essential 8 to guide cardiovascular health optimization.

Subclinical Cognitive and Neuropsychiatric Correlates and Hippocampal Volume Features of Brain White Matter Hyperintensity in Healthy People

White matter hyperintensities (WMH) are associated with brain aging and behavioral symptoms as a possible consequence of disrupted white matter pathways. In this study, we investigated, in a cohort of asymptomatic subjects aged 50 to 80, the relationship between WMH, hippocampal atrophy, and subtle, preclinical cognitive and neuropsychiatric phenomenology. Thirty healthy subjects with WMH (WMH+) and thirty individuals without (WMH−) underwent comprehensive neuropsychological and neuropsychiatric evaluations and 3 Tesla Magnetic Resonance Imaging scan. The presence, degree of severity, and distribution of WMH were evaluated with a semi-automated algorithm. Volumetric analysis of hippocampal structure was performed through voxel-based morphometry. A multivariable logistic regression analysis indicated that phenomenology of subclinical apathy and anxiety was associated with the presence of WMH. ROI-based analyses showed a volume reduction in the right hippocampus of WMH+. In healthy individuals, WMH are associated with significant preclinical neuropsychiatric phenomenology, as well as hippocampal atrophy, which are considered as risk factors to develop cognitive impairment and dementia.

Familial aggregation of depression, but no familial aggregation of individual depressive symptoms

Background

Familial aggregation of major depression might indicate a genetic liability for the disorder. The complete disorder or, alternatively, only some individual symptoms might be inherited. Under the latter condition, an increased frequency of inherited symptoms might consecutively increase the likelihood to reach the threshold for depression in relatives and, thus, might cause the familial aggregation of depression. Up to now, no study investigated the possibility of a relationship between individual depressive symptoms and the familial aggregation of depression.

Methods

The familial aggregation of early-onset depression (age-at-onset < 60 years, EOD) but less so of late-onset depression (LOD) has been shown in this sample. To assess the hypothesis of an inheritance of individual depressive symptoms as a possible cause of the familial aggregation of depression, frequencies of symptoms were compared in relatives of depressed patients and of controls using forward logistic regression analyses.

Results

Some individual depressive symptoms showed clustering in relatives of patients with depression, but the pattern of inheritance was inconsistent, i.e. the clustering of symptoms was different between non-depressed and depressed relatives of patients with EOD and LOD, respectively. No intra-familial clustering of specific depressive symptoms within families of depressed subjects could be observed.

Conclusions

Due to the inconsistencies in the clustering of individual symptoms in non-depressed and depressed relatives and the lack of intra-familial clustering, the familial aggregation of depression is unlikely to be caused by the aggregation of individual depressive symptoms. An inheritance of the vulnerability for complete depressive disorders influenced by environmental factors is more likely.

Confining the Concept of Vascular Depression to Late-Onset Depression: A Meta-Analysis of MRI-Defined Hyperintensity Burden in Major Depressive Disorder and Bipolar Disorder

Background: The vascular depression hypothesis emphasizes the significance of vascular lesions in late-life depression. At present, no meta-analytic model has investigated whether a difference in hyperintensity burden compared to controls between late-life and late-onset depression is evident. By including a substantial number of studies, focusing on a meaningful outcome measure, and considering several moderating and control variables, the present meta-analysis investigates the severity of hyperintensity burden in major depressive disorder (MDD) and bipolar disorder (BD). A major focus of the present meta-analysis refers to the role of age at illness onset. It is analyzed whether late-onset rather than late-life depression characterizes vascular depression. Method: In total, 68 studies were included in the meta-analysis and a multilevel random effects model was calculated using Hedges' g as the effect size measure. Results: The severity of hyperintensity burden was significantly greater in the patient group compared to the control group. This effect was evident regarding the whole patient group (g = 0.229) as well as both depression subgroups, with a significantly greater effect in BD (g = 0.374) compared to MDD (g = 0.189). Hyperintensity burden was more pronounced in late-onset depression than in early-onset depression or late-life depression. A considerable heterogeneity between the included studies was observed, which is reflected by the large variability in effects sizes. Conclusion: In conclusion, the present meta-analysis underscores the association of hyperintensities with MDD and BD. Especially late-onset depression is associated with an increased hyperintensity burden, which is in line with the vascular depression hypothesis. The results suggest that it might be more feasible to confine the concept of vascular depression specifically to late-onset depression as opposed to late-life depression. Further research is needed to understand the causal mechanisms that might underlie the relation between hyperintensity burden and depression.

Vascular Effects on Depressive Symptoms in Cognitive Impairment

Late life depression is related to pathologic burdens, such as cerebral small vascular disease (CSVD) and amyloid, which are associated with brain network changes and cortical thinning. To examine the associations of various CSVD imaging markers, amyloid, and network changes with depression in cognitively impaired patients, we prospectively recruited 228 cognitively impaired patients having various degrees of amyloid and CSVD who underwent diffuse tensor image and PiB PET. Greater CSVD burden was associated with greater Geriatric Depression Scale (GDS) (white matter hyperintensities, WMH: p = 0.025, lacunes: p < 0.001) but not with amyloid (p = 0.095), and cortical thinning (p = 0.630) was not associated with greater GDS. The changes in white matter networks were related to GDS with decreasing integration (global efficiency: p < 0.001) and increasing segregation (clustering coefficient: p = 0.009). The network changes mediated the relationships of WMH and lacunes with GDS. Our findings provide insight to better understand how CSVD burdens contribute to depression in cognitively impaired patients having varying degrees of amyloid and vascular burdens.

Late-onset major depression is associated with age-related white matter lesions in the brainstem

OBJECTIVE

Age-related white matter lesions (ARWMLs) have been identified in various clinical conditions such as reduced gait speed, cognitive impairment, urogenital dysfunction, and mood disturbances. Previous studies indicated an association between ARWML and late-onset major depression. However, most of these focused on the extent of supratentorial ARWML and neglected presence and degree of infratentorial lesions.

METHODS

In 45 patients (mean age 73.7 ± 6.3 years, 17 (37.8%) men, 28 (62.2%) women) with late-onset major depression, MRI findings (3.0-T MR system, Magnetom Trio, Siemens Medical Systems, Erlangen, Germany) were analyzed with emphasis on the extent of supratentorial and infratentorial, as well as brainstem ARWMLs, and compared with control subjects. ARWMLs were determined by semiquantitative rating scales (modified Fazekas rating scale, Scheltens' rating scale), as well as a semiautomatic volumetric assessment, using a specific software (MRIcron). Supratentorial and infratentorial, as well as brainstem ARWMLs, were assessed both on fluid attenuated inversion recovery and T2-weighted images.

RESULTS

Patients with late-onset major depression had significantly higher infratentorial ARWML rating scores (5 (5-7) vs 4.5 (3-6), p = 0.003) on T2-weighted images and volumes (1.58 ± 1.35 mL vs 1.05 ± 0.81 mL, p = 0.03) on T2-weighted images, as well as fluid attenuated inversion recovery images (2.07 ± 1.35 mL vs 1.52 ± 1.10 mL, p = 0.04), than normal controls. In more detail, in particular, the pontine ARWML rating subscore was significantly higher in patients with late-onset major depression (1 (1-2) vs 1 (1-1), p = 0.004).

CONCLUSIONS

The extent and localization of brainstem ARWML might be of importance for the pathophysiology of late-onset major depression. In particular, this may hold true for pontine ARWML. Copyright © 2016 John Wiley & Sons, Ltd.

Disrupted orbitomedial prefrontal limbic network in individuals with later-life depression

BACKGROUND

Depression in old age is an increasing contributor to poor health and accompanying health care costs. Although there is an abundance of literature on later-life depression (LLD), the neural correlates have not been clarified. The aim of this study was to determine whether patients with LLD show abnormal gray matter volume (GMV) and white matter integrity by using multiple image analysis methods.

METHODS

The study included 45 patients with LLD and 61 healthy participants who were matched for age, sex, years of education, and vascular risk factors. GMV was examined using voxel-based morphometry, while the white matter integrity was determined by tract-based spatial statistics and tract-specific analysis, which were obtained from high-resolution magnetic resonance images.

RESULTS

Patients with LLD showed significantly less GMV in the orbitofrontal cortex, anterior cingulate, insula, amygdala, and temporal regions, as well as higher fractional anisotropy in the uncinate fasciculus, compared with healthy participants. Patients with LLD who had reduced orbitofrontal and insular GMV had more severe clinical variables. The reduced orbitofrontal GMV was associated with higher fractional anisotropy in the uncinate fasciculus.

LIMITATION

The effects of medication should also be considered when interpreting the results of this study.

CONCLUSION

Our results suggest that regional GMV is linked to white matter integrity of the uncinate fasciculus in the orbitomedial prefrontal limbic network, and the disruption of this network may be involved in the pathophysiology of LLD.

Applications of magnetic resonance imaging for treatment-resistant late-life depression

Late-life depression (LLD) is a growing public and global health concern with diverse clinical manifestations and etiology. This literature review summarizes neuroimaging findings associated with depression in older adults and treatment-response variability. LLD has been associated with cerebral atrophy, diminished myelin integrity, and cerebral lesions in frontostriatal-limbic regions. These associations help explain the depression-executive dysfunction syndrome observed in LLD, and support cerebrovascular burden as a pathogenic mechanism. Furthermore, this review suggests that neuroimaging determinants of treatment resistance also reflect cerebrovascular burden. Of the theoretical etiologies of LLD, cerebrovascular burden may mediate treatment resistance. This review proposes that neuroimaging has the potential for clinical translation. Controlled trials may identify neuroimaging biomarkers that may inform treatment by identifying depressed adults likely to remit with pharmacotherapy, identifying individualized therapeutic dose, and facilitating earlier treatment response measures. Neuroimaging also has the potential to similarly inform treatment response variability from treatment with aripiprazole (dopamine modulator) and buprenorphine (opiate modulator).

[Depression: A predictor of dementia]

Many studies suggest that in 10-25% of cases of Alzheimer's, the most common dementia in our society, can be prevented with the elimination of some risk factors. Barnes and Yaffe found that one-third of Alzheimer's cases are attributable to depression, but in the scientific literature it is not clear if it has a real causal effect on the development of dementia. The purpose of this study is to analyse the scientific evidence on the hypothesis that depression increases the risk of developing dementia. A systematic review and a meta-analysis were performed on the scientific literature published up until the present day, searching articles that were published between 1990 and 2014. Ten of the studies found met the selection criteria -similar to a) size and characteristics of the sample (origin, age…), b) process of gathering data c) method of studying the relationship (within and/or between group comparison), and d) statistical analysis of the results- and the previously established quality. The value of odds ratio varied from 1.72 to 3.59, and the hazard ratio from 1,72 to 5.44. This indicates that the subjects with a history of depression have a higher risk of developing dementia than others who did not suffer depression.

Brain Structural Effects of Antidepressant Treatment in Major Depression

Depressive disorder is a very frequent and heterogeneous syndrome. Structural imaging techniques offer a useful tool in the comprehension of neurobiological alterations that concern depressive disorder. Altered brain structures in depressive disorder have been particularly located in the prefrontal cortex (medial prefrontal cortex and orbitofrontal cortex, OFC) and medial temporal cortex areas (hippocampus). These brain areas belong to a structural and functional network related to cognitive and emotional processes putatively implicated in depressive symptoms. These volumetric alterations may also represent biological predictors of response to pharmacological treatment. In this context, major findings of magnetic resonance (MR) imaging, in relation to treatment response in depressive disorder, will here be presented and discussed.

White matter lesions and depression: a systematic review and meta-analysis

We sought to determine if an association exists between overall, deep, and periventricular white matter hyperintensities and depression. We searched PubMed (Medline) and Scopus (Embase) from April-October 2012 using the MeSH terms: "White matter lesions" OR "white matter disease" OR "Cerebrovascular Disease" OR "Leukoencephalopathies" AND "Depressive Disorder" AND "magnetic resonance imaging," and "Depression" AND "leukoaraiosis." No language limits were implemented. Hand searching was performed of all included studies and relevant review articles. 913 PubMed and 188 Scopus citations were identified. Relevant, human, non-overlapping magnetic resonance imaging studies were eligible for inclusion if they reported generic data. We extracted the most adjusted odds ratios reported generated from comparing depression across severe (determined either volumetrically or visually) and mild/no white matter lesion groups. 19 reports were included. Cross-sectional subgroup analyses showed that deep white matter hyperintensities significantly associated with depression (N = 2261, odds ratio 1.02, 95% confidence interval 1.00-1.04, p = 0.02), whereas periventricular (N = 3813, odds ratio 1.08, 95% confidence interval 0.99-1.17, p = 0.07) and overall did not (N = 5876, odds ratio 1.12, 95% confidence interval 0.96-1.30, p = 0.14). Overall longitudinal analysis revealed a pooled odds ratio of 1.12 (N = 2015; 95% confidence interval 0.97-1.29; p = 0.13; Q = 7.19, p = 0.07; I2 = 58.3%). Longitudinal subgroup analyses revealed that overall white matter hyperintensities (N = 1882, odds ratio 1.22, 95% confidence interval, 1.06-1.4, p < 0.01) significantly associated with depression but deep did not (N = 660, odds ratio 2.02, 95% confidence interval, 0.56-7.22, p = 0.281). No significant heterogeneity was present in subgroup analyses. In conclusion, we found a significant, but weak association between white matter hyperintensities and depression.

What are the causes of late-life depression?

Although depression in old age is less common than depression in younger populations, it still affects more than 1 million community-living older adults. Depression in late life has been associated with reduced quality of life and increased mortality from both suicide and illness. Its causes are multifactorial but are prominently related to both biologic and social factors. Psychological factors, although less studied in elders, are also important in understanding its cause. In this article, multiple facets of late-life depression are reviewed, including its clinical presentation, epidemiology, and biopsychosocial causes.

Cognition as a therapeutic target in late-life depression: potential for nicotinic therapeutics

Depression is associated with impairments to cognition and brain function at any age, but such impairments in the elderly are particularly problematic because of the additional burden of normal cognitive aging and in some cases, structural brain pathology. Individuals with late-life depression exhibit impairments in cognition and brain structural integrity, alongside mood dysfunction. Antidepressant treatment improves symptoms in some but not all patients, and those who benefit may not return to the cognitive and functional level of nondepressed elderly. Thus, for comprehensive treatment of late-life depression, it may be necessary to address both the affective and cognitive deficits. In this review, we propose a model for the treatment of late-life depression in which nicotinic stimulation is used to improve cognitive performance and improve the efficacy of an antidepressant treatment of the syndrome of late-life depression. The cholinergic system is well-established as important to cognition. Although muscarinic stimulation may exacerbate depressive symptoms, nicotinic stimulation may improve cognition and neural functioning without a detriment to mood. While some studies of nicotinic subtype specific receptor agonists have shown promise in improving cognitive performance, less is known regarding how nicotinic receptor stimulation affects cognition in depressed elderly patients. Late-life depression thus represents a new therapeutic target for the development of nicotinic agonist drugs. Parallel treatment of cognitive dysfunction along with medical and psychological approaches to treating mood dysfunction may be necessary to ensure full resolution of depressive illness in aging.

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.

Heterogeneity of elderly depression: increased risk of Alzheimer's disease and Aβ protein metabolism

Epidemiological studies have proposed that depression may increase the risk for Alzheimer's disease (AD), even in patients with early-onset depression. Although metabolism of amyloid β protein (Aβ) in elderly depression received attention in terms of their correlation, there is a serious heterogeneity in elderly depression in terms of age at onset of depression. Moreover, it is unknown whether early-onset major depressive disorder (MDD) has a long-term effect on the involvement of Aβ metabolism and later development of AD. Thus, we evaluated serum Aβ40 and Aβ42 levels, the Aβ40/Aβ42 ratio in 89 elderly (≥60 years of age) inpatients with MDD and 81 age-matched healthy controls, and compared them among patients with early-onset (<60 years) and late-onset (≥60years) MDD and controls. The results showed that the serum Aβ40/Aβ42 ratio was significantly higher in patients with both early- and late-onset MDD than in controls (early-onset, p=0.010; late-onset, p=0.043), and it is of great interest that the serum Aβ40/Aβ42 ratio was negatively correlated with the age at MDD onset (R=-0.201, p=0.032). These results suggest that an earlier onset of MDD may have a more serious abnormality in Aβ metabolism, possibly explaining a biological mechanism underlying the link between depression and AD.

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.

Greater striatal dopamine transporter density may be associated with major depressive episode

BACKGROUND

We examined striatal dopamine transporter (DAT) distribution volume ratio (DVR) values in subjects with unipolar or bipolar major depressive episode (versus non-depressed healthy volunteers) using the selective DAT radioligand [(99m)Tc]TRODAT-1 and single photon emission computed tomography (SPECT). We hypothesized that striatal DVR values would be greater in depressed versus non-depressed subjects, and that greater DVR values may represent a possible clinical biomarker of depression.

METHODS

[(99m)Tc]TRODAT-1 spect images were acquired from 39 depressed and 103 non-depressed drug-free subjects. The primary outcome measure was the DVR value of [(99m)Tc]TRODAT-1 binding for the putamen region and the combined putamen plus caudate region.

RESULTS

DVR values were significantly correlated across all striatal regions within both subject groups (p<0.005). Depressed subjects had significantly greater DVR values (versus non-depressed subjects) in the putamen (p<0.0005) and the combined putamen plus caudate (p<0.0005) regions. There was no difference in DVR values between unipolar (n=24) and bipolar (n=15) depressed subjects, and no difference in DVR values for depressed subjects with or without prior antidepressant exposure. The predictive probability of the putamen or combined putamen plus caudate DVR value to distinguish depressed from non-depressed subjects was significant (p<0.0005).

LIMITATIONS

DAT values could potentially be influenced by age, gender, diagnosis, prior psychotropic dug exposure, illness length, or symptom severity.

CONCLUSION

Results confirm prior observations of greater striatal DAT density in depressed versus non-depressed subjects, and suggest that greater DVR values may possibly represent a potential diagnostic biomarker for distinguish depressed from non-depressed individuals.

Neuropathological substrates and structural changes in late-life depression: the impact of vascular burden

A first episode of depression after 65 years of age has long been associated with both severe macrovascular and small microvascular pathology. Among the three more frequent forms of depression in old age, post-stroke depression has been associated with an abrupt damage of cortical circuits involved in monoamine production and mood regulation. Late-onset depression (LOD) in the absence of stroke has been related to lacunes and white matter lesions that invade both the neocortex and subcortical nuclei. Recurrent late-life depression is thought to induce neuronal loss in the hippocampal formation and white matter lesions that affect limbic pathways. Despite an impressive number of magnetic resonance imaging (MRI) studies in this field, the presence of a causal relationship between structural changes in the human brain and LOD is still controversial. The present article provides a critical overview of the contribution of neuropathology in post-stroke, late-onset, and late-life recurrent depression. Recent autopsy findings challenge the role of stroke location in the occurrence of post-stroke depression by pointing to the deleterious effect of subcortical lacunes. Despite the lines of evidences supporting the association between MRI-assessed white matter changes and mood dysregulation, lacunes, periventricular and deep white matter demyelination are all unrelated to the occurrence of LOD. In the same line, neuropathological data show that early-onset depression is not associated with an acceleration of aging-related neurodegenerative changes in the human brain. However, they also provide data in favor of the neurotoxic theory of depression by showing that neuronal loss occurs in the hippocampus of chronically depressed patients. These three paradigms are discussed in the light of the complex relationships between psychosocial determinants and biological vulnerability in affective disorders.

Biological basis of late life depression

Late life depression (LLD) is an important area of research given the growing elderly population. The purpose of this review is to examine the available evidence for the biological basis of LLD. Structural neuroimaging shows specific gray matter structural changes in LLD as well as ischemic lesion burden via white matter hyperintensities. Similarly, specific neuropsychological deficits have been found in LLD. An inflammatory response is another possible underlying contributor to the pathophysiology of LLD. We review the available literature examining these multiple facets of LLD and how each may affect clinical outcome in the depressed elderly.

Diminished performance on neuropsychological testing in late life depression is correlated with microstructural white matter abnormalities

BACKGROUND

Traditional T2 weighted MR imaging results are non-specific for the extent of underlying white matter structural abnormalities present in late life depression (LLD). Diffusion tensor imaging provides a unique opportunity to investigate the extent and nature of structural injury, but has been limited by examining only a subset of regions of interest (ROI) and by confounds common to the study of an elderly population, including comorbid vascular pathology. Furthermore, comprehensive correlation of diffusion tensor imaging (DTI) measurements, including axial and radial diffusivity measurements, has not been demonstrated in the late life depression population.

METHODS

51 depressed and 16 non-depressed, age- and cerebrovascular risk factor-matched elderly subjects underwent traditional anatomic T1 and T2 weight imaging, as well as DTI. The DTI data were skeletonized using tract based spatial statistics (TBSS), and both regional and global analyses were performed.

RESULTS

Widespread structural abnormalities within white matter were detected in the LLD group, accounting for age, gender and education and matched for cerebrovascular risk factors and global T2 white matter hyperintensities (T2WMH). Regional differences were most prominent in uncinate and cingulate white matter and were generally characterized by an increase in radial diffusivity. Age-related changes particularly in the cingulate bundle were more advanced in individuals with LLD relative to controls. Regression analysis demonstrated significant correlations of regional fractional anisotropy and radial diffusivity with five different neuropsychological factor scores. TBSS analysis demonstrated a greater extent of white matter abnormalities in LLD not responsive to treatment, as compared to controls.

CONCLUSIONS

White matter integrity is compromised in late life depression, largely manifested by increased radial diffusivity in specific regions, suggesting underlying myelin injury. A possible mechanism for underlying myelin injury is chronic white matter ischemia related to intrinsic cerebrovascular disease. In some regions such as the cingulate bundle, the white matter injury related to late life depression appears to be independent of and compounded by age-related changes. The correlations with neuropsychological testing indicate the essential effects of white matter injury on functional status. Lastly, response to treatment may depend on the extent of white matter injury, suggesting a need for intact functional networks.

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.

Structural neuroimaging of geriatric depression

There is a large literature on the neuroanatomy of late-life depression that continues to grow with the discovery of novel structural imaging techniques along with innovative methods to analyze the images. Such advances have helped identify specific areas, characteristic lesions, and changes in the chemical composition in these regions that might be important in the pathophysiology of this complex disease. This article reviews relevant findings by each structural neuroimaging technique. When validated across many studies, such findings can serve as neuroanatomic markers that can help generate rational hypotheses for future studies to further understanding of geriatric depression.

The relationship between pulse pressure and leukoaraiosis in the elderly

Leukaraiosis and a higher level of pulse pressure are well-recognized as associated with cardiovascular disease, vascular angiopathy, and geriatric syndrome. A cross-sectional study was conducted to examine the relation between pulse pressure and leukoaraiosis based on brain magnetic resonance imaging (MRI) scans in the apparently healthy elderly (147 men aged 60-84 years and 89 women aged 60-82 years). The odds ratios (OR) and 95% confidence interval (CI) for leukoaraiosis were calculated using multivariate logistic regression analyses according to each quartile of pulse pressure. The percentage of leukoaraiosis gradually increased in accordance with pulse pressure quartiles: 5.1%, 8.6%, 16.1%, and 26.2% for men, and 4.5%, 8.7%, 13.0%, and 23.8% for women. In comparison with subjects in the lowest quartile, the OR (95%CI) for leukoaraiosis in the highest quartile was 6.80 (1.20-38.45) in men after adjusting for age, body mass index, fasting plasma glucose, HDL-cholesterol, triglyceride (TG), smoking status, and current drinking. However, the relationship was not evident in women after adjusting for the same co-variables. In conclusion, pulse pressure was found to be independently associated with leukoaraiosis regardless of classical cardiovascular risk factors in elderly men.

The prefrontal-limbic network in depression: Modulation by hypothalamus, basal ganglia and midbrain

The anterior cingulate cortex, amygdala and hippocampus form part of an interconnected prefrontal neocortical and limbic archicortical network that is dysregulated in major depressive disorders (MDD). Modulation of this prefrontal-limbic network (PLN) is principally through the hypothalamus, basal ganglia and midbrain. Here the likely mechanisms by which these modulations are affected are described and the implications of their failure for depression associated with suicidal diathesis, late-life and psychoses discussed.

MRI signal hyperintensities and treatment remission of geriatric depression

BACKGROUND

White matter abnormalities may interfere with limbic-cortical balance and contribute to chronic depressive syndromes in the elderly. This study sought to clarify the relationship of SH to treatment response. We hypothesized that patients who failed to remit during a 12-week controlled treatment trial of escitalopram would exhibit greater SH burden than patients who remitted.

METHODS

The participants were 42 non-demented individuals with non-psychotic major depression and 25 elderly comparison subjects. After a 2-week single blind placebo period, subjects who still had a Hamilton Depression Rating Scale (HDRS) of 18 or greater received escitalopram 10mg daily for 12 weeks. Remission was defined as a HDRS score of 7 or below for 2 consecutive weeks. FLAIR sequences were acquired on a 1.5 T scanner and total SH were quantified using a semi-automated thresholding method.

RESULTS

The patient sample consisted of 22 depressed patients who achieved remission during the study and 20 depressed patients who remained symptomatic. ANCOVA, with age and gender as covariates, revealed that depressed subjects had greater total SH burden relative to non-depressed controls. Furthermore, patients who failed to remit following escitalopram treatment had significantly greater SH burden than both patients who remitted and elderly comparison subjects, whereas SH burden did not differ between depressed patients who remitted and elderly comparison subjects.

LIMITATIONS

Patients were treated with a fixed dose of antidepressants and the index of SH is an overall measure that does not permit examination of the relationship of regional SH to treatment remission.

DISCUSSION

SH may contribute to a "disconnection state" both conferring vulnerability to and perpetuating late-life depression.

Cortical and subcortical abnormalities in late-onset depression with history of suicide attempts investigated with MRI and voxel-based morphometry

Late-onset major depression is thought to have a biological (vascular) basis, which could be a result of brain structure change. Vascular lesions can affect both the gray matter (GM) and white matter (WM), while most previous studies addressed WM abnormality. This study explored the disease- and symptom (history of suicide attempt) -related GM morphometry in elderly male patients with late-onset depression. A total of 70 patients with depression admitted to our geriatric psychiatric ward were investigated, and 26 age-matched males were recruited as controls. We used T1-weighted magnetic resonance imaging (MRI) to obtain cerebral structural information and adopted voxel-based morphometry (VBM) to investigate brain volume change related to disease (depression vs control) and symptom (depression with history of suicide attempt vs depression without history of suicide attempt). Late-onset depression was associated with smaller volumes in several regions of GM (insula and the posterior cingulate region) and WM (subcallosal cingulate cortex, floor of lateral ventricles, parahippocampal region, insula, and the cerebellum). Compared with nonsuicidal counterpart, suicidal depression was associated with decreased GM and WM volume in the frontal, parietal, and temporal regions, and the insula, lentiform nucleus, midbrain, and the cerebellum. Marked regional volume reduction was noticed at dorsal medial prefrontal cortex. Our results demonstrate that the development of suicidal behaviors in major depression is related to widespread but discrete volume reduction in several cortical and subcortical structures, fitting with the hypothesis that decreased cerebral volume in certain regions renders biological susceptibility to attempt suicide during depressive states.

The emerging modern face of mood disorders: a didactic editorial with a detailed presentation of data and definitions

The present work represents a detailed description of our current understanding and knowledge of the epidemiology, etiopathogenesis and clinical manifestations of mood disorders, their comorbidity and overlap, and the effect of variables such as gender and age. This review article is largely based on the 'Mood disorders' chapter of the Wikibooks Textbook of Psychiatry http://en.wikibooks.org/wiki/Textbook_of_Psychiatry/Mood_Disorders.

How late-life depression affects cognition: neural mechanisms

Late-life depression is a major health problem and a significant cause of dysfunction that warrants closer evaluation and study. In contrast to younger depressed patients, most depressed older adults suffer more severe variants of the disorder, including significant cognitive impairments. These cognitive changes add to the severity of symptoms and disability that older depressed patients face and likely reflect compromise of certain neural circuits, linking cognitive impairment to late-life depression. Studies examining clinical correlates, neuropsychological testing, and functional and anatomic imaging have yielded a clearer understanding of the neural mechanisms underlying cognitive deficits in late-life depression. This article discusses cognitive impairment in geriatric depression and how developing a better understanding of its neural correlates may lead to improved understanding and outcome of this specific disorder.

Imaging phenotypes of major depressive disorder: genetic correlates

Imaging techniques are a potentially powerful method of identifying phenotypes that are associated with, or are indicative of, a vulnerability to developing major depressive disorder (MDD). Here we identify seven promising MDD-associated traits identified by magnetic resonance imaging (MRI) or positron emission tomography (PET). We evaluate whether these traits are state-independent, heritable endophenotypes, or state-dependent phenotypes that may be useful markers of treatment efficacy. In MDD, increased activity of the amygdala in response to negative stimuli appears to be a mood-congruent phenomenon, and is likely moderated by the 5-HT transporter gene (SLC6A4) promoter polymorphism (5-HTTLPR). Hippocampal volume loss is characteristic of elderly or chronically-ill samples and may be impacted by the val66met brain-derived neurotrophic factor (BDNF) gene variant and the 5-HTTLPR SLC6A4 polymorphism. White matter pathology is salient in elderly MDD cohorts but is associated with cerebrovascular disease, and is unlikely to be a useful marker of a latent MDD diathesis. Increased blood flow or metabolism of the subgenual anterior cingulate cortex (sgACC), together with gray matter volume loss in this region, is a well-replicated finding in MDD. An attenuation of the usual pattern of fronto-limbic connectivity, particularly a decreased temporal correlation in amygdala-anterior cingulate cortex (ACC) activity, is another MDD-associated trait. Concerning neuroreceptor PET imaging, decreased 5-HT(1A) binding potential in the raphe, medial temporal lobe, and medial prefrontal cortex (mPFC) has been strongly associated with MDD, and may be impacted by a functional single nucleotide polymorphism in the promoter region of the 5-HT(1A) gene (HTR1A: -1019 C/G; rs6295). Potentially indicative of inter-study variation in MDD etiology or mood state, both increased and decreased binding potential of the 5-HT transporter has been reported. Challenges facing the field include the problem of phenotypic and etiological heterogeneity, technological limitations, the confounding effects of medication, and non-disease related inter-individual variation in brain morphology and function. Further advances are likely as epigenetic, copy-number variant, gene-gene interaction, and genome-wide association (GWA) approaches are brought to bear on imaging data.

Bipolar and major depressive disorder: neuroimaging the developmental-degenerative divide

Both major depressive disorder and bipolar disorder are the subject of a voluminous imaging and genetics literature. Here, we attempt a comprehensive review of MRI and metabolic PET studies conducted to date on these two disorders, and interpret our findings from the perspective of developmental and degenerative models of illness. Elevated activity and volume loss of the hippocampus, orbital and ventral prefrontal cortex are recurrent themes in the literature. In contrast, dorsal aspects of the PFC tend to display hypometabolism. Ventriculomegaly and white matter hyperintensities are intimately associated with depression in elderly populations and likely have a vascular origin. Important confounding influences are medication, phenotypic and genetic heterogeneity, and technological limitations. We suggest that environmental stress and genetic risk variants interact with each other in a complex manner to alter neural circuitry and precipitate illness. Imaging genetic approaches hold out promise for advancing our understanding of affective illness.

Three-dimensional surface mapping of the caudate nucleus in late-life depression

OBJECTIVE

To compare the volumes of the caudate nucleus, using traditional volumetry and a three-dimensional brain mapping technique, in a group of individuals with late-life depression and a group of age- and education-equated nondepressed comparison subjects.

DESIGN

Cross-sectional.

SETTING

University Medical Center.

PARTICIPANTS

Twenty-three nondemented subjects with late-life depression and 15 age- and education-equated elderly comparison subjects (depressed mean years of age: 70.5 +/- 5.7 SD, comparison subjects = 69.9 years +/- 6.4) with no history of psychiatric or neurologic disease.

MEASUREMENTS

Structural magnetic resonance imaging. Three-dimensional (3-D) surface models were created from manually traced outlines of the caudate nucleus from spoiled gradient echo images. Models were geometrically averaged across subjects and statistical maps created to localize any regional volume differences between groups.

RESULTS

Relative to comparison subjects, depressed subjects had significantly lower mean volumes for both the left (p = 0.029) and right (p = 0.052) caudate nucleus as well as total caudate volume (p = 0.032). Total volumes were 13.1% less in the depressed group (13.5% on the left and 12.6% on the right). 3-D maps further localized these reductions to the caudate head. Volume reductions were correlated with depression severity, as measured by the 17-item Hamilton Depression Rating Scale.

CONCLUSION

Late-life depression is associated with left and right caudate nucleus reduction especially in anterior portions. Among depressed subjects, greater caudate reduction was associated with more severe depression. These results are consistent with growing evidence that the anterior caudate nucleus, especially the head, may be structurally and functionally abnormal in affective disorders.

Executive dysfunction in medicated, remitted state of major depression

BACKGROUND

Past neuropsychological studies on depression have documented executive dysfunction and it has been reported that some dysfunction persists even after depressive symptoms disappear. Studies have shown a correlation between cerebrovascular lesions and executive dysfunction in depression among the elderly. The aim of the present study was to focus on executive functions in remitted major depressive disorder (MDD) patients, and to investigate whether remitted young and elderly patients show different patterns of executive dysfunction, and to ascertain the relationships with vascular lesions.

METHODS

Subjects were 79 inpatients with MDD and 85 healthy controls. Each subject received Wisconsin Card Sorting Test (WCST), Stroop test, and Verbal Fluency Test (VFT) in a remitted state. Both the MDD and control groups were divided into young and elderly groups, and the performances between 4 groups were compared.

RESULTS

For Stroop test, the scores of the MDD group were significantly lower than controls. In addition, as for VFT, the scores for the elderly MDD group were significantly lower than the other groups. Multiple regression analysis showed that VFT scores were affected by the presence of vascular lesions.

CONCLUSIONS

The results of the present study demonstrated that executive dysfunction remained even in a remitted state in MDD patients, but the patterns of impairment were different between young and elderly patients. The results also suggested that vascular lesions affect executive dysfunction, particularly in elderly depressive patients.

Changes in regional cerebral blood flow following antidepressant treatment in late-life depression

OBJECTIVE

Reversible/irreversible abnormalities of regional cerebral blood flow (rCBF) are seen in patients with depression. However, in late-life depression there is little evidence of a longitudinal change in rCBF through remission. We examined whether the decreased rCBF in individuals with late-life depression resolves following treatment.

METHODS

Twenty-five depressed patients older than 55 years completed the Hamilton Rating Scale for Depression and single photon emission computed tomography before and after a mean of 13.7 weeks of pharmacotherapy. Quantitative analyses were performed using the Statistical Parametric Mapping procedure.

RESULTS

Patients with depression demonstrated decreased rCBF in the anterior ventral and dorsal medial prefrontal cortex (PFC), including anterior cingulate cortices, bilateral ventrolateral PFC to temporal cortices, and bilateral medial to lateral parieto-occipital lobes relative to healthy controls. No particular areas showed increased rCBF. Following pharmacotherapy, rCBF significantly increased in the left dorsolateral PFC to precentral areas and the right parieto-occipital regions. However, decreased rCBF at baseline in the anterior ventral/dorsal medial PFC, bilateral ventrolateral PFC, bilateral temporal lobes, and bilateral parietal lobes did not show significant improvement after treatment.

CONCLUSIONS

Remarkable improvements in rCBF in the left dorsolateral PFC to precentral regions are consistent with the hypothesis that neuronetworks including the left frontal cortex may be functionally and reversibly involved in late-life unipolar major depression (state-dependent). In contrast, neural circuits including bilateral medial, dorsolateral, and parietal areas may reflect underlying and continuous pathognomonic brain dysfunction of depression (trait-dependent).

Naturalistic outcomes of minor and subsyndromal depression in older primary care patients

OBJECTIVE

To review the literature regarding the naturalistic outcomes of minor and subsyndromal depression ('Min/SSD') in older primary care patients, synthesizing and critiquing findings and discussing avenues for future research.

DESIGN

The author obtained relevant articles from repeated computer-assisted literature searches over the past 15 years, and by reviewing the reference citations of the articles so obtained.

RESULTS

A variety of relevant outcome domains were identified, as were important putative predictors, moderators, and mediators of outcome. In general, minor and subsyndromal depression each have comparable outcomes, outcomes that are clearly worse than non-depressed subjects, with substantially elevated risk of worsening into major depression, albeit not as poor as those with major depression.

CONCLUSIONS

Min/SSD is common and of real clinical importance in primary care seniors. Several definitions of SSD may be used, each with overlapping but distinguishable utility in identifying patients. While the evidence base has expanded greatly in the past decade, considerable work remains to be done. Naturalistic studies of several outcome domains are needed, focusing on the predictive, moderating, and mediating roles of a wide range of psychopathological, medical, functional, and psychosocial factors. Such work will complement interventions and biomarker research approaches.

Relationship between age at onset and magnetic resonance image-defined hyperintensities in mood disorders

OBJECTIVES

To examine in patients with mood disorders the relationship of age at onset with the location and degree of MRI-defined brain hyperintensities.

METHOD

Fifty-two patients diagnosed as having mood disorders and 14 controls participated in the study. Brain MR images were analyzed according to semiquantitative ratings for the anatomical distribution and severity of T2-weighted hyperintensities. We compared these hyperintensities among the three age- and sex-matched groups of late-onset mood disorder patients (LOM), early-onset mood disorder patients (EOM), and controls. The time since the onset of disorder was significantly longer in the EOM than in the LOM group. We also conducted linear multiple regression analysis using the severity of hyperintensities as dependent variable to determine whether the clinical features correlate with vascular pathology.

RESULTS

As for deep white matter hyperintensity (DWMH), LOM exhibited higher ratings than EOM; as for brain areas, significant between-group differences were detected in the bilateral frontal areas and in the left parieto-occipital area. No significant difference was observed between EOM and controls. As for periventricular hyperintensity, there was no difference among the three groups. We obtained a significant regression model to predict DWMH ratings; age, number of ECTs, and LOM were selected as significant variables.

CONCLUSION

The present study suggests that the time since the onset of disorder does not affect the development of white matter lesions, but that white matter lesions are associated with late-onset mood disorders. The frontal areas and the left parieto-occipital area would be important for the development of late-onset mood disorders.

Prospective study of major depressive disorder with white matter hyperintensity: comparison of patients with and without lacunar infarction

OBJECTIVE

To investigate clinical characteristics, outcome, and risk factor for cerebrovascular disease in patients who had major depressive disorder and white matter hyperintensity (WMHI).

METHOD

A total of 123 new patients diagnosed with major depressive disorder by semi-structured interview underwent magnetic resonance imaging (MRI) and were placed into one of three groups based on results. Patients with no abnormal findings (NF), patients with WMHI and no lacunar infarction (WMHI), and patients with lacunar infarction (LI).

RESULTS

In the WMHI group, age at initial onset of depression and age at time of interview were both higher than in the NF group, as was severity of depression. Hamilton Rating Scale for Depression (HRSD) scores were significantly higher in the WMHI group than in the NF group. Total WMHI was significantly correlated only with age at initial onset of depression and age at time of interview. In the WMHI group, age at interview was lower than in the LI group and systolic and diastolic blood pressures were lower. Survival analysis regarding the clinical outcome of remission was conducted, but no significant differences were discovered among the three groups, WMHI, LI, and NF. However, the suicide rate was significantly higher in the LI group than in the other two groups.

CONCLUSIONS

The origin and clinical characteristics of depression accompanied by WMHI may be specific; additional stringent study in comparison with individuals with LI is needed.

Regional white matter hyperintensity burden in automated segmentation distinguishes late-life depressed subjects from comparison subjects matched for vascular risk factors

OBJECTIVE

Segmented brain white matter hyperintensities were compared between subjects with late-life depression and age-matched subjects with similar vascular risk factor scores. Correlations between neuropsychological performance and whole brain-segmented white matter hyperintensities and white and gray matter volumes were also examined.

METHOD

Eighty-three subjects with late-life depression and 32 comparison subjects underwent physical examination, psychiatric evaluation, neuropsychological testing, vascular risk factor assessment, and brain magnetic resonance imaging (MRI). Automated segmentation methods were used to compare the total brain and regional white matter hyperintensity burden between depressed patients and comparison subjects.

RESULTS

Depressed patients and comparison subjects did not differ in demographic variables, including vascular risk factor, or whole brain-segmented volumes. However, depressed subjects had seven regions of greater white matter hyperintensities located in the following white matter tracts: the superior longitudinal fasciculus, fronto-occipital fasciculus, uncinate fasciculus, extreme capsule, and inferior longitudinal fasciculus. These white matter tracts underlie brain regions associated with cognitive and emotional function. In depressed patients but not comparison subjects, volumes of three of these regions correlated with executive function; whole brain white matter hyperintensities correlated with executive function; whole brain white matter correlated with episodic memory, processing speed, and executive function; and whole brain gray matter correlated with processing speed.

CONCLUSIONS

These findings support the hypothesis that the strategic location of white matter hyperintensities may be critical in late-life depression. Further, the correlation of neuropsychological deficits with the volumes of whole brain white matter hyperintensities and gray and white matter in depressed subjects but not comparison subjects supports the hypothesis of an interaction between these structural brain components and depressed status.

White matter hyperintensities and their associations with suicidality in patients with major affective disorders

INTRODUCTION

A large body of evidence suggests that predisposition to suicide, an important public health problem, is mediated to a certain extent by neurobiological factors. The objective of this cross-sectional study was to compare the prevalence of white matter hyperintensities (WMH) in patients with major affective disorders with and without histories of suicide attempts.

METHODS

T2-weighted magnetic resonance images (MRI) of 65 psychiatric inpatients with major depressive disorder or bipolar disorder were rated for the presence of WMH. Diagnoses, presence or absence of suicide risk and substance abuse were determined by the Mini International Neuropsychiatric Interview (MINI). Medical charts were reviewed to ascertain history of suicide attempt and basic clinical variables. Fisher's Exact Tests and logistic regression modeling were used to test the association between WMH and suicidality. Suicidal patients and controls were not matched for demographic variables and exposure to some risk factors.

RESULTS

Bivariate analysis showed that the prevalence of WMH was significantly higher in subjects with past suicide attempts (Fisher's Exact Test, p = 0.01) and other clinical indicators of elevated suicide risk. Logistic regression analyses controlling for age, sex, and several clinical risk factors supported this finding (odds ratio = 4.7; 95% confidence interval: 1.4, 16.1).

CONCLUSIONS

The increased prevalence of WMH in adults with major affective disorders and a history of suicide attempt, compared to similar patients without such a history, is consistent with previous findings in depressed children, youth and young adults. However, the association between WMH and suicidality holds true for both, depressed and bipolar patients. Our results suggest that WMH in patients with major affective disorders might be useful biological markers of suicidality.

Distinguishing between depression and dementia in older persons: neuropsychological and neuropathological correlates

Dementia and depression are frequently comorbid among older adult patients. Depression is related to cognitive decrement and can even represent the first signs of a neurodegenerative process. It can be difficult to distinguish depressed patients exhibiting the first signs of dementia from those whose cognition will improve with treatment. In this article, studies from the neuropsychological literature are reviewed that aid in accurate diagnosis and prognosis. Furthermore, the relationship between depression and dementia is explored by examining potential neurobiological mechanisms that may potentiate both syndromes in the context of the ongoing debate on depression as a prodrome and/or a risk factor for dementia. This article is concluded with suggestions for clinicians when deciding who to refer for neuropsychological assessment and with ideas for further research that might promote a better understanding of the complex association between depression and dementia during old age.

Translational research in late-life mood disorders: implications for future intervention and prevention research

Clinical and epidemiological studies have consistently observed the heterogeneous symptomatology and course of geriatric depression. Given the importance of genetic and environmental risk factors, aging processes, neurodegenerative and cerebrovascular disease processes, and medical comorbidity, the integration of basic and clinical neuroscience research approaches is critical for the understanding of the variability in illness course, as well as the development of prevention and intervention strategies that are more effective. These considerations were the impetus for a workshop, sponsored by the Geriatrics Research Branch in the Division of Adult Translational Research and Treatment Development of the National Institute of Mental Health that was held on September 7-8, 2005. The primary goal of the workshop was to bring together investigators in geriatric psychiatry research with researchers in specific topic areas outside of geriatric mental health to identify priority areas to advance translational research in geriatric depression. As described in this report, the workshop focused on a discussion of the development and application of integrative approaches combining genetics and neuroimaging methods to understand such complex issues as treatment response variability, the role of medical comorbidity in depression, and the potential overlap between depression and dementia. Future directions for integrative research were identified. Understanding the nature of geriatric depression requires the application of translational research and interdisciplinary research approaches. Geriatric depression could serve as a model for translational research integrating basic and clinical neuroscience approaches that would have implications for the study of other neuropsychiatric disorders.

Cerebrovascular risk factors and subsequent depression in older general practice patients

BACKGROUND

This general practice-based case-control study tested the association between cerebrovascular risk factors (CVRFs) and the development of later-life depression by focusing on the impact of exposure duration to CVRFs and the modifying influence of age at depression onset.

METHODS

Cases were 286 patients aged > or = 50 years with a first diagnosis of depression at age > or = 50 years. Nondepressed controls (N=832) were individually matched for age, gender and practice. CVRF diagnoses (hypertension, diabetes mellitus, cardiovascular conditions) prior to depression were determined. Analyses controlled for education, somatic and nondepressive psychiatric disease.

RESULTS

No CVRF variable examined was significantly associated with subsequent depression in the total sample. An unexpected impact of age at onset of depression was observed: the odds ratio associated with having any CVRF was smaller for patients with age at onset > or = 70 years than for patients with onset between ages 50-59 years (p=.002) and 60-69 years (p=.067). Subsequent analyses excluding patients with onset at age > or = 70 years revealed that CVRF variables, including long-term exposure to CVRFs, significantly increased the odds of subsequent depression with onset between ages 50 and 69 years.

LIMITATIONS

Reliance on GPs' records of morbidity may have resulted in bias towards underestimation in patients with depression onset at age > or = 70 years.

CONCLUSIONS

Our findings suggest that CVRFs play a relevant role in the development of depression with onset between ages 50 and 69 years, but no evidence was found that they contribute to the occurrence of depression with onset at age > or = 70 years. Replication is warranted to exclude the possibility of bias.

Incidence and predictors of depression after stroke (DAS)

Objective. Depression after stroke (DAS) poses a treble burden to patients, families and health care system. The purpose of this paper is to estimate the incidence of depression among first-ever ischemic stroke patients and identify the predictors of DAS. Methods. A longitudinal study design was undertaken. Of 836 patients admitted to the stroke unit of two regional hospitals in Hong Kong during the period 1 June 2004 to 31 May 2005, 295 patients fulfilled the inclusion and exclusion criteria. A total of 260 patients had given their consents and were interviewed at 1 month after stroke onset. Results. Nearly one-quarter of the first ischemic stroke patients, who were known to be free of personal and family history of psychiatric illnesses, were found to satisfy the criteria of depression using Diagnostic and Statistical Manual IV (24%, 48 out of 200 participants; 95% CI: 18.6%, 30.4%). This result was close to that assessed by the Geriatric Depression Scale (GDS) - 15 items. The psycho-emotional factor and level of dependency were found to be most significant predictors for DAS onset. Conclusion. The high incidence of DAS and low rate of accessibility to treatment indicate timely action to be undertaken.

Psychiatric disease in the twenty-first century: The case for subcortical ischemic depression

The current approach to psychiatric diagnoses involves identifying symptom clusters that fit a specific syndrome. Although this approach has facilitated the field's development, advances in genetics and neuroimaging raise the question of how causality may fit into the diagnostic process. One approach would be a two-axial system, wherein clinical presentation is on one axis and putative risk factors are on the other. This approach applies to subcortical ischemic depression (SID), a diagnosis corresponding to the "vascular depression" hypothesis. Subcortical ischemic depression affects clinical presentation, long-term outcomes, and response to antidepressant therapy, arguing that it is a valid diagnostic entity worth further study.

Is depression different in older adults?

Psychiatric disorders such as depression are common conditions in older adults. Depression presents similarly to younger adults, but with more psychotic symptoms and apathy. Research has suggested that genetics play a less important role in the etiology of depression in the elderly, but that other biological factors may be more significant. Vascular pathology in particular is thought to be especially important. White-matter hyperintensities are found in the frontal lobes and basal ganglia in greater numbers in older adults with depression, with damage to the frontal–subcortical circuits thought to be particularly important. It is associated with treatment resistance. Prognosis is poor if depression is not detected and treated adequately and this may lead to a higher risk of dementia and death. However, treatment with selective serotonin reuptake inhibitors and other antidepressants, plus psychological therapies, are effective in the older depressed patient and reduce morbidity and mortality.