Antidepressant use is related to larger white matter lesion volume in patients with symptomatic atherosclerotic disease: the SMART-MR study

Association Between Cerebral Small Vessel Disease With Antidepressant Use and Depression: 3C Dijon Magnetic Resonance Imaging Study

Background and Purpose- Evidence links antidepressant use with cerebral small vessel disease; however, it remains unclear whether people with depression face comparable risk. This study aims to determine the association between antidepressant drug use and depression with markers of cerebral small vessel disease. Methods- One thousand nine hundred five participants (mean age, 72.5 years; 60% women) without stroke or dementia history underwent brain magnetic resonance imaging at baseline, and 1402 individuals underwent a second magnetic resonance imaging at 4 years. Outcomes were lacunes 3 to 15 mm and white matter hyperintensity volume (cm³) at baseline and follow-up. Exposure to antidepressants was grouped as (1) selective serotonin reuptake inhibitors (n=68), (2) tricyclics (n=40), (3) atypicals (n=24), (4) depressed nonusers (n=303), and (5) nondepressed/nonuser group (reference group, n=1470). Statistical analyses adjusted for propensity scores due to the nonrandomized exposure to antidepressant drugs. Results- There was an association between use of atypical antidepressants with lacunes at baseline (adjusted rate ratio, 2.59 [95% CI, 1.14-5.88]; P=0.023) and follow-up (adjusted rate ratio, 3.05 [95% CI, 1.25-7.43]; P=0.014). Lacunes at baseline were also associated with depressed nonusers (adjusted rate ratio, 1.53 [95% CI, 1.06-2.21]; P=0.023). Selective serotonin reuptake inhibitor users and depressed nonusers displayed higher total, periventricular, and deep white matter hyperintensity volumes at baseline. Selective serotonin reuptake inhibitor users had higher deep white matter hyperintensity volumes at follow-up. Conclusions- Users of atypical antidepressants, selective serotonin reuptake inhibitors, and depressed people without any antidepressant exposure all displayed markers of cerebral small vessel disease higher than the nondepressed/nonuser group. The findings suggest that cerebral small vessel disease is associated with depression and exposure to antidepressants.

Oxygenation differs among white matter hyperintensities, intersected fiber tracts and unaffected white matter

White matter hyperintensities of presumed vascular origin are frequently observed on magnetic resonance imaging in normal aging. They are typically found in cerebral small vessel disease and suspected culprits in the etiology of complex age- and small vessel disease-related conditions, such as late-onset depression. White matter hyperintensities may interfere with surrounding white matter metabolic demands by disrupting fiber tract integrity. Meanwhile, risk factors for small vessel disease are thought to reduce tissue oxygenation, not only by reducing regional blood supply, but also by impairing capillary function. To address white matter oxygen supply–demand balance, we estimated voxel-wise capillary density as an index of resting white matter metabolism, and combined estimates of blood supply and capillary function to calculate white matter oxygen availability. We conducted a cross-sectional study with structural, perfusion- and diffusion-weighted magnetic resonance imaging in 21 patients with late-onset depression and 21 controls. We outlined white matter hyperintensities and used tractography to identify the tracts they intersect. Perfusion data comprised cerebral blood flow, blood volume, mean transit time and relative transit time heterogeneity—the latter a marker of capillary dysfunction. Based on these, white matter oxygenation was calculated as the steady state cerebral metabolic rate of oxygen under the assumption of normal tissue oxygen tension and vice versa. The number, volume and perfusion characteristics of white matter hyperintensities did not differ significantly between groups. Hemodynamic data showed white matter hyperintensities to have lower blood flow and blood volume, but higher relative transit time heterogeneity, than normal-appearing white matter, resulting in either reduced capillary metabolic rate of oxygen or oxygen tension. Intersected tracts showed significantly lower blood flow, blood volume and capillary metabolic rate of oxygen than normal-appearing white matter. Across groups, lower lesion oxygen tension was associated with higher lesion number and volume. Compared with normal-appearing white matter, tissue oxygenation is significantly reduced in white matter hyperintensities as well as the fiber tracts they intersect, independent of parallel late-onset depression. In white matter hyperintensities, reduced microvascular blood volume and concomitant capillary dysfunction indicate a severe oxygen supply–demand imbalance with hypoxic tissue injury. In intersected fiber tracts, parallel reductions in oxygenation and microvascular blood volume are consistent with adaptations to reduced metabolic demands. We speculate, that aging and vascular risk factors impair white matter hyperintensity perfusion and capillary function to create hypoxic tissue injury, which in turn affect the function and metabolic demands of the white matter tracts they disrupt.

Characterization of White Matter Hyperintensities in Large-Scale MRI-Studies

Background: White matter hyperintensities of presumed vascular origin (WMH) are a common finding in elderly people and a growing social malady in the aging western societies. As a manifestation of cerebral small vessel disease, WMH are considered to be a vascular contributor to various sequelae such as cognitive decline, dementia, depression, stroke as well as gait and balance problems. While pathophysiology and therapeutical options remain unclear, large-scale studies have improved the understanding of WMH, particularly by quantitative assessment of WMH. In this review, we aimed to provide an overview of the characteristics, research subjects and segmentation techniques of these studies.

Methods: We performed a systematic review according to the PRISMA statement. One thousand one hundred and ninety-six potentially relevant articles were identified via PubMed search. Six further articles classified as relevant were added manually. After applying a catalog of exclusion criteria, remaining articles were read full-text and the following information was extracted into a standardized form: year of publication, sample size, mean age of subjects in the study, the cohort included, and segmentation details like the definition of WMH, the segmentation method, reference to methods papers as well as validation measurements.

Results: Our search resulted in the inclusion and full-text review of 137 articles. One hundred and thirty-four of them belonged to 37 prospective cohort studies. Median sample size was 1,030 with no increase over the covered years. Eighty studies investigated in the association of WMH and risk factors. Most of them focussed on arterial hypertension, diabetes mellitus type II and Apo E genotype and inflammatory markers. Sixty-three studies analyzed the association of WMH and secondary conditions like cognitive decline, mood disorder and brain atrophy. Studies applied various methods based on manual (3), semi-automated (57), and automated segmentation techniques (75). Only 18% of the articles referred to an explicit definition of WMH.

Discussion: The review yielded a large number of studies engaged in WMH research. A remarkable variety of segmentation techniques was applied, and only a minority referred to a clear definition of WMH. Most addressed topics were risk factors and secondary clinical conditions. In conclusion, WMH research is a vivid field with a need for further standardization regarding definitions and used methods.

Direct and indirect effects of psychopharmacological treatment on the cardiovascular system

Background Severe mental disorders, i.e. psychotic disorders, unipolar and bipolar disorders are associated with increased morbidity and mortality from cardiovascular and metabolic disorders. The underlying cause of this association is complex and comprises disorder specific alterations such as dysfunctions of immunological and hormonal systems, body-composition changes and health associated behaviors (smoking, sedentary lifestyle, alcohol intake and treatment compliance). Furthermore, some psychopharmacological drugs may exert unwanted side effects that impact the cardiovascular system. Methods This paper reviews studies concerning commonly used antidepressant and antipsychotics drugs with a particular focus on direct and indirect cardiovascular side effects. Results Newer antidepressant drugs have a favorable cardiovascular safety profile compared to tricyclic antidepressants. However, QTc prolongation, increased blood pressure and potentially higher risks of bleeding have been observed in some newer antidepressants. Some second generation (atypical) antipsychotics have raised concern because of indirect cardiovascular, metabolic side effects such as weight gain and disturbances in lipid and glucose metabolism. Conclusions Psychiatrists need to be aware of potential direct and indirect cardiovascular side effects and to include them in the risk/benefit assessment when choosing a specific individualized treatment.

White Matter Hyperintensity Accumulation During Treatment of Late-Life Depression

White matter hyperintensities (WMHs) have been shown to be associated with the development of late-life depression (LLD) and eventual treatment outcomes. This study sought to investigate longitudinal WMH changes in patients with LLD during a 12-week antidepressant treatment course. Forty-seven depressed elderly patients were included in this analysis. All depressed subjects started pharmacological treatment for depression shortly after a baseline magnetic resonance imaging (MRI) scan. At 12 weeks, patients underwent a follow-up MRI scan, and were categorized as either treatment remitters (n=23) or non-remitters (n=24). Among all patients, there was as a significant increase in WMHs over 12 weeks (t(46)=2.36, P=0.02). When patients were stratified by remission status, non-remitters demonstrated a significant increase in WMHs (t(23)=2.17, P=0.04), but this was not observed in remitters (t(22)=1.09, P=0.29). Other markers of brain integrity were also investigated including whole brain gray matter volume, hippocampal volume, and fractional anisotropy. No significant differences were observed in any of these markers during treatment, including when patients were stratified based on remission status. These results add to existing literature showing the association between WMH accumulation and LLD treatment outcomes. Moreover, this is the first study to demonstrate similar findings over a short interval (ie 12 weeks), which corresponds to the typical length of an antidepressant trial. These findings serve to highlight the acute interplay of cerebrovascular ischemic disease and LLD.

Depression in small-vessel disease relates to white matter ultrastructural damage, not disability

Objective:

To determine whether cerebral small-vessel disease (SVD) is a specific risk factor for depression, whether any association is mediated via white matter damage, and to study the role of depressive symptoms and disability on quality of life (QoL) in this patient group.

Methods:

Using path analyses in cross-sectional data, we modeled the relationships among depression, disability, and QoL in patients with SVD presenting with radiologically confirmed lacunar stroke (n = 100), and replicated results in a second SVD cohort (n = 100). We then compared the same model in a non-SVD stroke cohort (n = 50) and healthy older adults (n = 203). In a further study, to determine the role of white matter damage in mediating the association with depression, a subgroup of patients with SVD (n = 101) underwent diffusion tensor imaging (DTI).

Results:

Reduced QoL was associated with depression in patients with SVD, but this association was not mediated by disability or cognition; very similar results were found in the replication SVD cohort. In contrast, the non-SVD stroke group and the healthy older adult group showed a direct relationship between disability and depression. The DTI study showed that fractional anisotropy, a marker of white matter damage, was related to depressive symptoms in patients with SVD.

Conclusion:

These results suggest that in stroke patients without SVD, disability is an important causal factor for depression, whereas in SVD stroke, other factors specific to this stroke subtype have a causal role. White matter damage detected on DTI is one factor that mediates the association between SVD and depression.