Clinical Research Directory

Dopaminergic Dysfunction in Late-Life Depression

Late-Life Depression (LLD), or depression in older adults, often presents with motivational deficits, deficits in performance in cognitive domains including processing speed and executive dysfunction, and mobility impairments. This triad of findings implicate dopaminergic dysfunction as a core pathophysiologic feature in depression, and may contribute to cognitive decline and motor disability. Normal aging results in brain-wide dopamine declines, decreased D1/D2 receptor density, and loss of dopamine transporters. Although brain changes associated with depression and aging converge on dopamine circuits, the specific disturbances in LLD and how responsive the system is to modulation remain unclear. In this study, investigators are testing integrative model that aging, in concert with pro-inflammatory shifts, decreases dopamine signaling. These signally changes affects behaviors supported by these circuits, in the context of age-associated cortical atrophy and ischemic microvascular changes, resulting in variable LLD phenotypes. Investigators propose a primary pathway where dopaminergic dysfunction in depressed elders contributes to slowed processing speed and mobility impairments that increase the effort cost associated with voluntary behavior. The central hypothesis of this study is that late-life depression is characterized by dysfunction in the dopamine system and, by enhancing dopamine functioning in the brain. By improving cognitive and motor slowing, administration of carbidopa/levodopa (L-DOPA) will improve depressive symptoms.

Chronic Anergic Depression IDentification - Magnetic Resonance Imaging Exploration in the Elderly of Traits Related to Onset

Depression in the elderly, or "late life depression" (LLD), is often considered to be homogeneous, legitimizing standardized treatment. Yet the literature suggests that there are different forms of LLD, with different pathophysiology, course and treatment. Our experience has led us to identify an "anergic" form, marked by adynamia and anhedonia (anergic depression, AnD). Highly represented among LLDs, it readily resists the usual antidepressants, so that its course is often chronic. Thanks to the "Chronic Anergic Depression Open Trial", the investigators were able to show that AnD responds to dopaminergic (DA) molecules. Therefore the invastigators hypothesized a pathophysiology linked to dysfunction of the mesolimbic DA system. However, not all patients would present the same form: two subgroups could be isolated, each contributing equally. The first corresponds to patients for whom the episode is a recurrence, the so-called "early onset depression" (EOD). The first episode occurs at 34 ±16 years of age and is frequently associated with a personality disorder (73%). The index episode usually lasts 6 ±3 years and is typically associated with anxiety (96%). The second group corresponds to the onset of primary depression after the age of 60, known as "late onset depression" (LOD). The index episode occurs at around 71 ±6 years of age, in people with no premorbid personality disorders. The episode is shorter (3 ±1 years) and anxiety is frequent (75%) but less marked. These patients showed a high propensity for a course compatible with synucleinopathies, but often less rapid than that of the classic forms of these diseases. The investigators hypothesize that within AnD, EOD and LOD present different pathophysiologies, and that this difference is observable on functional magnetic resonance imaging (MRI): LOD patients should present a greater reduction in functional connectivity in the mesolimbic system. The investigators make the subsidiary hypothesis that LODs also show a structural alteration observable with other types of MRI measurements, i.e. multiparametric imaging.

One-Year Trajectory of Cognitive Changes in Patients With Late-life Depression in the Short Term

The purpose of this study was to investigate the one-year trajectory of cognitive change in elderly patients with depression, to explore the transfer characteristics and transfer rules of various states of cognitive impairment in patients, to predict the relevant risk factors of cognitive decline, and to find possible influencing factors affecting state change, so as to provide a theoretical basis and reference for subsequent targeted intervention research on geriatric depression.