Stress-Induced Inflammation and Reward Processing


Anhedonia, or loss of interest or pleasure, is a key feature of depression and transdiagnostic construct in psychopathology. Both theory and compelling evidence from preclinical models implicates stress-induced inflammation as a key psychobiological pathway to anhedonic behavior; however, this pathway has not been demonstrated in human models. Further, although anhedonia may reflect dysregulation in multiple dimensions of reward, the extent to which stress-induced inflammation alters these dimensions is unclear. The current placebo controlled study used a standardized laboratory stressor task to elicit an inflammatory response in a sample of a healthy young women and evaluate effects of stress-induced inflammation on multiple behavioral indices of reward processing.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Basic Science
    • Masking: Single (Participant)
  • Study Primary Completion Date: December 8, 2017

Detailed Description

In this study we propose to examine the association between psychosocial stress, the stress-induced inflammatory response, and reward processing in a female undergraduate sample. Specifically, we will 1) examine effects of an acute psychosocial stressor on reward processing; 2) evaluate the association between stress-related changes in inflammation and reward processing; and 3) test key vulnerability factors that may moderate the association between stress and reward. To achieve these goals, this study will recruit 60 female undergraduate students to test effects of stress on reward processing in a 3.5 hour laboratory session. Participants will be randomly assigned to either experience a laboratory stressor or a placebo control, and will complete reward tasks 90 minutes post stress/placebo onset, at which point the peripheral inflammatory response to stress reaches its peak. The reward tasks are computerized behavioral tasks that assess three domains of reward processing: reward-learning, reward motivation, and reward sensitivity. Throughout the session, all participants will complete self-report measures of affect and provide blood and saliva samples for evaluation of the psychological and physiological stress response. Within one week prior to the session, participants will attend a 1 hour visit in which they complete baseline reward tasks and self-report questionnaires assessing mood, personality, early life stress, and health behaviors. In total, participants will complete two visits, with a duration of 4.5 hours. This study builds upon prior studies demonstrating immediate effects of acute stress on reward processing, and further tests for delayed effects of acute stress on reward processing. Furthermore, this will be the first study to examine inflammation as a mechanism linking stress to deficits in reward processing. Findings may inform theory of depression etiology and contribute to more specialized treatment that is targeted at specific symptoms of depression.


  • Behavioral: Stress; Trier Social Stress Task
    • Standardized acute psychosocial stressor
  • Behavioral: Placebo Trier Social Stress Task
    • Active control version of the TSST

Arms, Groups and Cohorts

  • Experimental: Stress; Trier Social Stress Task
    • 5 min challenging speech task, 5 min challenging math task; performed in front of evaluators
  • Active Comparator: Placebo Trier Social Stress Task
    • 5 min speech task, 5 min math task; performed alone

Clinical Trial Outcome Measures

Primary Measures

  • Probabilistic Reward Task – Reward Responsiveness
    • Time Frame: Pre-TSST/P-TSST and 90 min post-TSST/P-TSST
    • Change in the magnitude of response bias from pre to post Trier Social Stress Task (TSST) or Placebo-TSST (P-TSST).
  • Effort Expenditure for Rewards Task – Reward Motivation
    • Time Frame: Pre-TSST/P-TSST and 120 min post-TSST/P-TSST
    • Change in amount of hard trials chosen from pre to post-TSST/P-TSST (overall, and at 3 levels of probability of potential rewards; low, medium, and high)
  • Attentional Bias Task
    • Time Frame: Pre-TSST/P-TSST and 110 min post-TSST/P-TSST
    • Change in attentional bias from pre to post-TSST/P-TSST

Secondary Measures

  • Effort Expenditure for Rewards Task – Reward Sensitivity
    • Time Frame: 120 min post-TSST
    • Strength of the relationship between changes in reward magnitude and high effort trial choice as a function of degree of change in IL-6 following acute stress
  • Face Morphing Task
    • Time Frame: Pre-TSST/P-TSST and 115 min post-TSST/P-TSST
    • Change in latency to detect emotional expressions

Participating in This Clinical Trial

Inclusion Criteria

  • English fluency
  • Age 18-28
  • Biologically female

Exclusion Criteria

  • Current illness
  • Presence or history of major medical conditions
  • Current or past diagnosis of alcohol use disorder
  • Use of tobacco
  • Use of immune-altering medications
  • Current pregnancy

Gender Eligibility: Female

Minimum Age: 18 Years

Maximum Age: 28 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • University of California, Los Angeles
  • Collaborator
    • UCLA Norman Cousins Center for Psychoneuroimmunology
  • Provider of Information About this Clinical Study
    • Principal Investigator: Chloe Boyle, PhD, Principal Investigator – University of California, Los Angeles
  • Overall Official(s)
    • Chloe C Boyle, PhD, Principal Investigator, University of California, Los Angeles
    • Julienne E Bower, PhD, Principal Investigator, University of California, Los Angeles

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