Stress and the Sympathetic Nervous System in Adults With Depression

University of Delaware94 enrolled

Overview

To test our hypotheses, we will enroll healthy adults having no history of mood disorders and adults with major depressive disorder (MDD) having a broad range of depressive symptom severity. After screening, subjects will meet with the research coordinator or an investigator for a discussion, with opportunity for questions, before applicable consent forms are obtained. Daily stress processes will be assessed using an ecological momentary assessment approach for 8 consecutive days. On the last day of the daily stress assessment, we will directly measure muscle sympathetic nerve activity, blood pressure, and heart rate during acute laboratory-based cognitive, emotional, and physiological interventions to induce a stress response. A venous blood sample will be taken for measurements of metabolic and renal health and systemic inflammation. Aim 1: To examine the effect of daily psychosocial stressor exposure on acute sympathetic stress reactivity in MDD. Two stressor exposure indicators will be calculated: stressor frequency (i.e., percentage of interview days during which at least one stressor occurred) and total stress (i.e., total number of stressors reported across all interview days) and will be related to the magnitude of responsiveness to the acute stress interventions. We hypothesize that the slope of this relation will be steeper in adults with MDD compared to healthy non-depressed adults. Aim 2: To determine the relation between negative affective reactivity to daily psychosocial stressor exposure and acute sympathetic stress reactivity in MDD. Negative affective reactivity will be calculated as the change in affect on days when stressors occurred compared to one's typical affect on non-stressor days and will be related to the magnitude of responsiveness to the acute stress interventions. We hypothesize that the slope of this relation will be steeper in adults with MDD compared to healthy non-depressed adults.

Study Type

INTERVENTIONAL

Allocation

Purpose

BASIC_SCIENCE

Masking

NONE

Eligibility

Sex: ALLMin age: 18 YearsMax age: 30 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * All participants will be 18-30 yrs. * Healthy non-depressed men and women will have no history or evidence of psychiatric illness and will not have a family history of MDD or major psychiatric illness. * Men and women with MDD will have symptomatic depression that meets diagnostic criteria and will be non-medicated. * The capacity and willingness to provide written informed consent, to attend all study related visits, and to comply with the study protocol. Exclusion Criteria: Subjects will be excluded at the discretion of the PI/collaborating clinician or for any of the following reasons: * psychiatric illness aside from MDD (including current or past psychotic disorders, bipolar disorder, schizophrenia or schizoaffective disorder, panic disorder, post-traumatic stress disorder, obsessive compulsive disorder) * subthreshold depression * current use of psychotropic medications (including major classes of antidepressants, anxiolytics, antipsychotics, mood stabilizers) * active suicidal or homicidal ideation * active substance dependence or eating disorders * current use of any medications that could alter sympathetic reactivity * diagnosed or suspected cardiovascular, renal, or metabolic disease (hypertension, heart disease, diabetes, hyperlipidemia) * autonomic disorders * tobacco use (including electronic cigarettes) * obesity (body mass index \> 30 kg/m2) * breastfeeding or pregnancy * \<18 or \>30 yrs

Outcomes

Primary Outcomes

Percent of Days Participants Report Stressors

the percentage of days that participants reported stressors over the course of 8 days before the intervention, measured each day via self-report using ecological momentary assessment

Time frame: 8 days before intervention

Negative Affective Reactivity to Daily Stressors

Negative affect was measured each day via self-report using ecological momentary assessment using Positive and Negative Affect Schedule (possible range 1-5 arbitrary units, AU), and negative affective reactivity score was defined as the magnitude of the change in negative affect on days when stressors occurred compared to negative affect on non-stressor days over the 8-day timeframe. A singe negative affective reactivity score was calculated for each participant using two-level multi-level modeling (within person slopes). This outcome was operationalized as described in the funded grant and does not have a scale/construct name. There is no defined/set range: more negative slopes indicate a paradoxical increase in negative affect on stressor days, whereas more positive slopes indicate a greater decline in negative affect on stressor days.

Time frame: 8 days before intervention

Change in Muscle Sympathetic Nerve Activity in Response to Acute Stress (Compared to Resting Baseline Activity)

muscle sympathetic nerve activity was measured using microneurography and the change was calculated as the difference between the mean value during baseline and during the mean value during each of three laboratory-based interventions (cold pressor test, Stroop color word test, International Affective Picture System); a larger value indicates a greater increase in sympathetic activity

Time frame: 3 minutes after each laboratory-based intervention

Stress and the Sympathetic Nervous System in Adults With Depression

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes