Is the clinical expression of late-life depression influenced by brain changes? MRI subcortical neuroanatomical correlates of depressive symptoms

Translational application of neuroimaging in major depressive disorder: a review of psychoradiological studies

Major depressive disorder (MDD) causes great decrements in health and quality of life with increments in healthcare costs, but the causes and pathogenesis of depression remain largely unknown, which greatly prevent its early detection and effective treatment. With the advancement of neuroimaging approaches, numerous functional and structural alterations in the brain have been detected in MDD and more recently attempts have been made to apply these findings to clinical practice. In this review, we provide an updated summary of the progress in translational application of psychoradiological findings in MDD with a specified focus on potential clinical usage. The foreseeable clinical applications for different MRI modalities were introduced according to their role in disorder classification, subtyping, and prediction. While evidence of cerebral structural and functional changes associated with MDD classification and subtyping was heterogeneous and/or sparse, the ACC and hippocampus have been consistently suggested to be important biomarkers in predicting treatment selection and treatment response. These findings underlined the potential utility of brain biomarkers for clinical practice.

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.

Treatment of late-life depression: a role of non-invasive brain stimulation techniques

Late-life depression (LLD) is a frequent complication of the ageing process, occurring in up to 5% of community-dwelling elderly and in a higher proportion of subjects with coexistent medical illnesses. Its presence has been consistently associated with cognitive impairment, greater disability and increased mortality. Approximately half of patients with LLD have evidence of subcortical ischaemic damage in prefrontal circuits revealed by MRI. This might constitute the biological substrate of the cardinal symptoms of depression and of executive dysfunction. An important proportion of patients with LLD do not achieve remission of their depressive symptoms in spite of adequate pharmacological and psychotherapeutic treatment. In addition, a group of LLD patients progress to further impairment and disability in the form of a dementing disorder. There is an imperative need to develop new treatment strategies for LLD. Non-invasive brain stimulation techniques such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are safe and efficacious interventions that might be used in combination with other therapeutic options to improve treatment outcomes. However, there are still questions regarding the optimal way in which rTMS and dTCS should be delivered as well as to the way in which we may identify the subjects who will benefit the most from these interventions.

Clinical correlates of age of onset in psychotic depression

The issue whether the clinical characteristics of unipolar psychotic major depression (PMD) vary according to the age of onset remains still unclear. Thus, the aim of this study was to assess comparatively a broad set of clinical characteristics of three groups of PMD patients, namely young early-onset (n=30), elderly early-onset (n=34) and elderly late-onset (n=35). Ninety-nine inpatients suffering from DSM-IV unipolar PMD were assessed on the basis of Structured Clinical Interview for DSM-IV (SCID-IV), Hamilton Rating Scale for Depression (HRSD) and a physical impairment rating scale. The elderly late-onset patients suffered from overall more severe depression compared to both early-onset ones, more psychic anxiety compared to elderly early-onset patients and more gastrointestinal symptoms compared to young early-onset patients. Additionally, they expressed significantly more frequently delusions of somatic content and higher scores on the HRSD item of hypochondriasis than their young early-onset counterparts. The group of elderly early-onset PMD patients was found to hold an intermediate position between the young early-onset and elderly late-onset PMD patients with regard to hypochondriacal ideation, gastrointestinal symptoms and delusions of somatic, guilt, and paranoid content. Their stability of delusional content across successive episodes was found to extend into old age. Nevertheless, they expressed additional somatic delusions. Overall, the findings of the present study suggest considerable differences between young early-onset, elderly early-onset and elderly late-onset PMD patients with respect to their clinical features.

A systematic review of diffusion tensor imaging studies in affective disorders

White matter abnormalities constitute one element of the network dysfunction that underlies affective disorders: differences between the white matter of subjects with affective disorders and control subjects have been identified using a range of neuroimaging and histological techniques. Diffusion tensor imaging (DTI) can uniquely study the orientation and integrity of white matter tracts and is thus an ideal tool to shed light on white matter abnormalities in subjects with affective disorders. Here, we systematically review DTI studies of affective disorders. We identified DTI studies of affective disorders from EMBASE and MEDLINE and searched the reference lists of relevant papers. Twenty-seven articles comparing subjects with affective disorders with control subjects were included in the review, with eight studies included in a meta-analysis of superior frontal regions. Twenty-one of 27 studies found significantly lower anisotropy in subjects with affective disorders compared with control subjects, more specifically within the frontal and temporal lobes or tracts. A large effect size was detected within the superior frontal gyrus, although heterogeneity and one index of publication bias were significant. Although there is significant heterogeneity of acquisition and analysis methods and subject properties, DTI studies of affective disorders consistently identify reduced anisotropy in the frontal and temporal lobes and tracts of subjects with affective disorders relative to control subjects.

Potential surrogate markers of cerebral microvascular angiopathy in asymptomatic subjects at risk of stroke

Cerebral microvascular angiopathy (MVA) is associated with clinical vascular risk factors and is characterised by histological changes, including thickening of the walls of arterial vessels and dilatation of the Virchow-Robin spaces (VRS). We have previously described two novel biomarkers of MVA based on magnetic resonance imaging (MRI), VRS dilatation and abnormalities in the transfer of systolic arterial pulsation to the ventricular CSF, which occur as a result of decreased cerebral arterial compliance. These are associated with vascular dementia and treatment-resistant late onset depression. We studied a group of normal subjects at risk of cerebrovascular disease to determine if these biomarkers are present in patients who have no evidence of symptomatic vascular disease. We studied 31 subjects, 16 with three or more vascular risk factors and 15 with one or less significant risk factors. We measured arterial blood flow and CSF flow in the cerebral aqueduct, white matter lesion load, and the distribution and number of VRS. There were significant differences in CSF pulsatility and in VRS in the basal ganglia between the two groups, but no differences in white matter lesion load. We conclude that asymptomatic subjects at risk of stroke have MRI evidence of MVA before white matter lesions become apparent.

Biomarkers of cerebrovascular disease in dementia

There is increasing recognition that cerebrovascular disease contributes significantly to the development and progression of patients with dementia. The concepts of pure vascular and pure degenerative dementia have been replaced with a recognition that, in many patients, there is a spectrum of neurodegenerative and vascular processes. This is supported by preliminary studies showing response to vascular therapeutics and ventriculo-peritoneal shunting in patients with Alzheimer's disease. This article examines the imaging biomarkers that are available for the characterization of microvascular abnormality in the ageing brain, with particular reference to microvascular angiopathy, cerebral embolic disease, orthostatic hypotension and abnormalities of Monro-Kellie homeostasis.

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.

Late-life depression, religiosity, cerebrovascular disease, cognitive impairment and attitudes towards death in the elderly: Interpreting the data

Geriatric depression is considered to be a major health problem in the elderly. Passing the age, the speed of mental process is decreasing and personality obtains more mature functioning (better coping) while most of its traits remain stable. Empirical studies have shown that fear of death is most prominent during midlife and not late-life. Neuroimaging studies led to the "vascular depression" hypothesis. Depression was found to be a strong predictive factor leading to stroke, while religiosity seemed to be a 'protective' factor. A possible interpretation of these reports could consider late-life depression to be an early symptomatology of an undergoing vascular disease. Religiosity could be interpreted as absence of depression, and therefore, mainly as absence of vascular lesions. The above have profound implications in the understanding of late-life depression and to the therapeutic design, especially in the primary care setting.

[Validity of vascular depression as a specific diagnostic: a review]

INTRODUCTION

A number of authors have suggested that cerebrovascular disease may predispose, precipitate, or perpetuate some geriatric depressive syndromes. These "vascular depressions" may result from damage of striato-pallido-thalamo-cortical pathways which frequently occurs in cerebrovascular disease.

METHOD

We have searched the English and French literature published between 1996 (when the "vascular depression" hypothesis was first stated) and December 2004 through the Medline computer database and examined the validity of the concept of "vascular depression" thanks to four levels of validity: face validity, descriptive validity, construct validity and predictive validity. The face validity is the extent to which experts agree about the existence of a nosological entity.

RESULTS

The reviews published in this field broadly support the concept of "vascular depression" as a specific disorder. However many authors highlighted the fact that depression has been shown to precede vascular diseases and that depression and vascular diseases may both share some pathogenic or genetic determinants. These interactive and co-morbid relationships between depression and cerebrovascular diseases are difficult to disentangle. The descriptive validity refers to the degree of the clinical specificity of a disorder. It appears only moderate regarding the clinical studies carried out on this issue. However, a late-onset, the absence of a family history of mental illness, the lack of insight, lassitude, psychomotor retardation, a greater disability and particular neuropsychological dysfunctions may be associated with vascular depression. The construct validity, which refers to the degree to which the physiopathological processes involved in an illness are understood, appears difficult to establish because of the complex interactive relationships between cerebrovascular disease and depression. However, cerebrovascular diseases may contribute to the occurrence of depressive symptoms independently of its psychosocial burden. The predictive validity refers to the degree to which a syndrome is characterized by a specific response to treatment or a specific natural history. As regards response to treatment, vascular depression appears rather specific in the sense of a worse response to antidepressants and electroconvulsive therapy. The studies on the natural history of vascular depression lead to inconsistent results. According to some authors, this relative resistance to treatment may be explained by structural rather than functional, and thus potentially irreversible disruption in neural networks.

CONCLUSION

In conclusion, the systematic review of the validity of vascular depression broadly supports this concept. However, further studies are needed to decipher the relationships between depression and cerebrovascular disease. Finally, we suggest that it could be more relevant for future researches in this field if the diagnostic criteria for vascular depression were narrowed and required the presence of both neuro-imaging changes and cerebrovascular disease.

Neuroimaging in late-life depression

Late-life depression may be associated with vasculopathy. Neuroimaging has been a critical tool in exploring the relationship between this form of depression and vascular factors. Magnetic resonance imaging has been the most widely used tool, but there is potential to use other structural imaging techniques as well as functional neuroimaging methodologies. Neuroimaging may potentially be utilized at some point as a biomarker for late-life depression, thus helping with diagnosis and guiding treatment.

Depressive symptoms and white matter changes in patients with dementia

OBJECTIVE

The aim of the present study was to investigate if depressive symptoms in demented patients are associated with white matter changes (WMCs) in the brain.

BACKGROUND

WMCs are frequently found in patients with dementia, as well as among elderly nondemented patients with depressive symptoms. However, it is less established whether or not WMCs are related to depressive symptoms in demented patients.

METHODS

67 (26 men, 41 women) patients with primary degenerative dementia (Alzheimer's disease, frontotemporal dementia), vascular dementia (VaD), or mixed Alzheimer/VaD dementia were included in the study. The patients were young-old (mean 68.1, SD 7.3). All patients underwent a standardized examination procedure and MRI of the brain. The degree of WMCs was visually rated, blindly. Depressive symptoms were rated according to the Gottfries-Bråne-Steen scale (anxiety, fear-panic, depressed mood).

RESULTS

No significant relationship was found between WMCs and depressive symptoms in the demented patients.

CONCLUSION

The possible involvement of WMCs in the pathogenesis of depressive symptoms in dementia is unclear. A link between disruptions of frontal-subcortical pathways, due to WMCs, and depressive symptomatology in dementia has been hypothesised from earlier findings, which would imply common elements of pathogenesis for depressive symptomatology and cognitive impairment in dementia. However, the results of the present study do not add further support to this hypothesis.

Cerebrovascular disease and late-life depression

Depression may occur as a result of vascular disease in a significant subpopulation of elderly persons. Indirect support for vascular disease as an underlying etiology of late-life depression includes the high rate of depression in patients with vascular disease, the frequency of "silent stroke" and white-matter hyperintensities in late-life depression, and the lower frequency of positive family histories of depression in such patients. The authors evaluate the associations of late-life depression with cerebrovascular disease by reviewing the existing pathophysiological, prognosis, and treatment-outcomes studies. Findings are based on review of the current literature systematically searched in electronic databases. Review of such studies indicates a high frequency of depression in older patients with cardiovascular and cerebrovascular diseases, and the possibility of a bidirectional relationship between depression and vascular disease. Studies examining patients with vascular depression have found that such patients have different symptom profiles, greater disability, and higher risk for poorer outcomes than those with nonvascular depression. Since the vascular depression hypothesis was proposed as a conceptual framework, evidence has accumulated that patients with vascular depression may have poorer outcomes that may be related in part to executive dysfunction and consequent disability. However, the association of vascular risk factors with geriatric depression has not been consistent in the studies to-date. Although an association between a subset of late-life depression and vascular disease is clear, significant gaps remain in our understanding. Further research is needed to establish the precise linkages and interactions between vascular disease and geriatric depression.

[Loss of motivation and frontal dysfunction. Role of the white matter change]

Since the recognition of white matter changes on computed tomography, researches were done to investigate a possible relation with ageing and cognition. This study examined whether computed tomography evidence of cerebrovascular disease in the form of white matter changes was associated with decreased implicit performance of frontal tests and with a loss of motivation in a group of 10 elderly volunteers with a mild cognitive impairment and in a group of 29 demented patients; 39 old patients (28 females: 82.4 +/- 7.1; 10 males: 75.5 +/- 11.3) cared in a psycho-geriatric day care hospital were enrolled for this essay. Motivation was evaluated with a specific scale: EAD. Patients were tested during the same period with MMSE for cognition, Cornell's scale for depression, Marin's scale for apathy. There were also assessed with a battery of frontal tests: BREF test. A brain scan was used to determinate the presence of leukoaraïosis. Table 1 give a description of the population according to the pathology. Cognitive disorder, but also apathy and loss motivation, frontal evaluation significantly differ in the two studied groups. The presence of a leukoaraïosis is associated with older people, a weaker cognitive status, a more important apathy or loss of motivation, and weaker results with frontal evaluation (table 2). Similar results were obtained considering only the frontal lesions (table 3). Age related changes of the white matter observed on computed tomography were associated with a decreased cognitive status. Leukoaraïosis is associated with loss of motivation and related with a poor results on frontal assessment. Loss of motivation is associated with certain frontal dysfunctions and with brain abnormal scan anomalies.

Deep white matter hyperintensities in patients with bipolar depression, unipolar depression and age-matched control subjects

OBJECTIVE

Hyperintensities in the white matter of the brain (DWH) and in the periventricular area (PVH) seen on magnetic resonance imaging (MRI) have been reported to be more frequent in patients with bipolar disorder (BP) than in normal subjects. To examine this further we compared MRI of patients with BP with age-matched patients with major depressive disorder (unipolar depression, UP) and healthy control subjects.

METHODS

T2 weighted axial and coronal brain MRI scans were obtained from 13 patients in the depressive phase of BP, 11 with current UP and 19 age-matched control subjects. The degree of DWH and PVH present in each scan was determined using a standardized scoring method.

RESULTS

The PVH ratings were similar in the three groups of subjects. However, proportionately more BP patients had higher DWH scores than either UP patients or controls. Although this difference did attain statistical significant, a main effect of age was noted. Further, subjects over the age of 50 were under-represented in the UP group.

CONCLUSIONS

Notwithstanding the small total sample size and relative lack of older subjects in the UP group, the fact that almost twice as many BP patients showed more severe DWH suggests that patients with BP may be more vulnerable to develop these changes than UP patients and healthy controls.

The cerebrovascular model of depression in late life

Depression in older people, especially depression with an older age of onset, may be a manifestation of acquired brain disease. The cerebrovascular model of depression, often referred to as "vascular depression," hypothesizes that otherwise clinically occult small vessel brain disease contributes to the pathogeneses of some late-life depressive conditions. This paper reviews several lines of evidence supporting the cerebrovascular model and addresses the limitations of the existing literature. Several directions for future research are noted, including empirical testing of the notion that cerebrovascular disease might underlie the pathogeneses of depression with prominent executive dysfunction or other cognitive impairments. At this time, there are no specific therapeutic options for patients with suspected vascular depression beyond standard approaches to depression treatments, although education about the possibly greater risks of chronicity should be included in treatment planning. Therapy of cerebrovascular risk factors and stroke-risk reduction are important as consistent with general practice guidelines, although it is not known whether this will reduce the incidence or improve the outcome of late-life depression.

Depression in Alzheimer's disease: is there a temporal relationship between the onset of depression and the onset of dementia?

Alzheimer's disease (AD) patients often present with concurrent major depression (MD). To investigate the reasons for this comorbidity, e.g. MD being a risk factor for AD, or both diagnoses having a common neurobiology, the temporal relationship between the first onset of AD and of MD during lifetime was investigated-57 out of 146 AD patients had a lifetime diagnosis of MD. The correlation between the ages at onset of MD and dementia was calculated. The incidence of MD in AD patients in several 5-year-intervals before and after the onset of AD was compared with the average incidence of MD in the present AD sample and with the expected incidence of MD in the general population. No significant correlation between the onset of AD and of MD could be found after controlling for age, gender and the Mini-Mental-State. However, the incidence of MD 5 years before and after the onset of AD significantly exceeded the expected incidences-MD is only partially related to AD. However, the increased incidence of MD within 5 years before and after the onset of dementia may indicate that a common neurobiological process causes cognitive decline and depression in a subsample of AD patients.

Relationship between depressive symptomatology and the subcortical brain syndrome in dementia

OBJECTIVES

the aim of the present study was to elucidate a possible relationship between depressive symptomatology and regional brain symptomatology in demented patients.

METHODS

170 consecutive inpatients were studied. They suffered from Alzheimer's disease (103 patients), vascular dementia (48 patients), or frontotemporal dementia (19 patients). The patients underwent a neuropsychiatric investigation, which included assessments of (1) depression, and (2) regional brain symptomatology. Depressive symptomatology was assessed as presence of (a) depressed mood, and (b) anxiety. In the further statistical analysis, the presence of depressed mood and/or anxiety was also evaluated. The principle of the regional symptom analysis was the successive aggregation of observable symptom variables, leading to the final determination of four possible regional brain syndromes (frontal, subcortical, parietal and global), by way of the Stepwise comparative status analysis (STEP). The possible correlations between regional brain symptomatology and depressive symptomatology were analysed by means of (a) chi(2) statistics, and (b) a logistic regression analysis in which confounding factors were included (age, degree of dementia, duration).

RESULTS

the subcortical syndrome correlated with depressed mood (chi(2), p = 0.002; logistic regression, p = 0.002). A negative correlation was noted between the parietal syndrome and depressed mood (p = 0.010 and p = 0.013, respectively). No other significant correlations between presence of regional brain syndrome and presence of depressive symptomatology could be seen.

CONCLUSIONS

demented patients with a clinically established subcortical dysfunction appear to be more susceptible to depressive symptomatology. The results of this study also suggest that posterior brain dysfunction in dementia is not correlated with depressive symptomatology.

Anatomic location and laterality of MRI signal hyperintensities in late-life depression

OBJECTIVES

Evidence is mounting linking cerebrovascular disease with the development of major depression in the elderly. Lesions in both white and gray matter have been associated with geriatric depression. In addition, the literature on poststroke depression suggests that left-sided lesions are associated with depression. We sought to examine the severity and location of white- and gray-matter lesions in a group of elderly depressives and nondepressed control subjects.

METHOD

115 depressed patients (69 with late onset, 46 with early onset) and 37 controls, all over age 45, received magnetic resonance imaging (MRI). Semiquantitative severity ratings and quantitative measurements of number and size of MRI hyperintensities were obtained, and groups were compared using Cochran-Mantel-Haenszel (CMH) analyses and repeated-measures analyses of covariance adjusting for age.

RESULTS

Late-onset depressed patients had more severe hyperintensity ratings in deep white matter than early-onset patients and controls. Late- and early-onset patients had more severe subcortical gray-matter hyperintensities (particularly in the putamen) compared with controls. Left-sided white-matter lesions were significantly associated with older age of depression onset, whereas right-anterior white matter and left-subcortical lesions (particularly in the putamen) were associated with melancholia in the depressed group.

CONCLUSION

These findings extend previous reports of an association between cerebrovascular disease and depression, as well as recent studies showing lateralized lesion involvement in geriatric depression. Such vascular pathology may disrupt neural pathways involved in affective processing and the maintenance of a normal mood and psychomotor state.