Purpose:
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.
Criteria:
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