AnhedoniaPhase 1NCT03848715
Sleep and Healthy Aging Research on Depression for Younger Women
A Phase 1 study testing Endotoxin in people with Anhedonia and Depression, run by University of California, Los Angeles at 1 site in United States.
Trial summary
Compelling evidence indicates inflammation plays a role in depression, but potential mechanisms linking inflammation to depression, such as dysregulated reward processing, are poorly understood. Read more about this study
- Who is it for?
- Ages 25 to 44 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Anhedonia, Depression
- What is being tested?
- Endotoxin
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 40 participants
- Where
- 1 siteUnited States
- Study dates
- 2 Oct 2019to 22 Jul 2024
- Phase
- Phase 1
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 44 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Participants will be required to be in good general health (as evaluated during the phone and in-person baseline session)
- Participants will be biologically female and premenopausal (as evaluated by self report).
- Participants will 25-44 years of age.
Who cannot join
- Presence of chronic mental or physical illness
- History of allergies, autoimmune, liver, or other severe chronic diseases,
- Current and regular use of prescription medications such as steroids, non-steroid anti-inflammatory drugs, aspirin, immune modifying drugs, opioid analgesics, statins, antihypertensive drugs, anti-arrhythmic drugs, and antidepressant medications (none in the last 6 months).
- Nightshift work or time zone shifts (> 3hrs) within the previous 6 weeks
- Previous history of fainting during blood draws.
- Presence of co-morbid medical conditions not limited to but including cardiovascular (e.g., history of acute coronary event, stroke) and neurological diseases (e.g., Parkinson's disease), as well as pain disorders;
Show all 18Show fewer
- Presence of comorbid inflammatory disorders such as rheumatoid arthritis or other autoimmune disorders;
- Presence of an uncontrolled medical condition that is deemed by the investigators to interfere with the proposed study procedures, or to put the study participant at undue risk;
- Presence of chronic infection, which may elevate proinflammatory cytokines;
- Presence of an acute infectious illness in the two weeks prior to an experimental session.
- Current Axis I psychiatric disorders as determined by the Research Version of the Structured Clinical Interview including a current major depressive disorder and substance dependence
- Lifetime history of suicide attempt or inpatient psychiatric admission.
- Current history of sleep apnea or nocturnal myoclonus; Phase-shift disorder, which will be identified by the Structured Clinical Interview and the Duke Structured Interview for Sleep Disorders
- Current smoking or excessive caffeine use (>600 mg/day) because of the known effects on proinflammatory cytokine levels;
- Evidence of recreational drug use from urine test.
- Body mass index > 35 because of the effects of obesity on proinflammatory cytokine activity
- Any clinically significant abnormality on screening laboratory tests
- Clinically significant abnormalities in electrocardiogram
Trial locations and contacts
1 site in 1 country.
United States1 site
Norman Cousins Center for Psychoneuroimmunology, University of California, Los Angeles
Los Angeles, California, 90095
About this study
Compelling evidence indicates inflammation plays a role in depression, but potential mechanisms linking inflammation to depression, such as dysregulated reward processing, are poorly understood. This study comprehensively evaluates effects of inflammation on reward across dimensions (e.g., anticipating versus receiving a reward) and types (e.g., money vs. smiling faces) in younger and older women. Characterizing how inflammation shapes the dynamic and multidimensional reward system, and how this may differ by age, may give insight into risk factors for depression and help identify critical points for intervention.
Read the detailed description
This study will use an inflammatory challenge (i.e., endotoxin) to assess effects of inflammation on the behavioral response to social and non-social rewards, using tasks that assess reward motivation, sensitivity, and learning. Both elevated inflammation and reward dysregulation are associated with depression and have been shown to predict depression onset; understanding how inflammation alters the reward system in the laboratory setting may provide insight into risk factors and help identify potential areas for intervention. In this placebo-controlled, randomized, double-blind study of low dose endotoxin in 40 adult premenopausal women (25-44 y), the investigators will examine effects of endotoxin on reward responsiveness across dimensions (i.e., motivation, sensitivity, learning) and reward types (e.g., social and non-social). The investigators hypothesize that as compared to placebo, endotoxin will 1) decrease non-social reward responses across reward dimensions; 2) decrease "general" social reward responses across reward dimensions; 3) increase "close" social reward responses across reward dimensions; 4) decrease resting eye blink rate (EBR); EBR will be correlated with learning and motivation for non-social reward. The second component of the study is to examine whether effects of endotoxin on reward differ as a function of age; in particular it is hypothesized that effects will be more robust in younger compared to older women. In order to test for age differences, this study will use data from 40 older women (65+ y) participating in a parallel ongoing randomized controlled trial (ClinicalTrials.gov Identifier: NCT03256760). Thus, the investigation aims to: 1) Evaluate effects of inflammation on non-social reward as a function of age; 2) Evaluate effects of inflammation on general and close social reward as a function of age; 3) Examine changes in dopaminergic activity as a mechanism linking effects of inflammation on non-social reward processing as a function of age.
- Conditions
- Anhedonia, Depression
- Being tested
- Endotoxin, Placebo
- Medical subject headings
- Anhedonia, Depression
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
EndotoxinBiological
Endotoxin
PlaceboBiological
Placebo
| Study group | Role | What they receive |
|---|---|---|
| Endotoxin | Experimental | Endotoxin 0.8 ng/kg body weight; 1 infusion Receives: Biological: Endotoxin |
| Placebo | Placebo comparator | same volume of 0.9% saline Receives: Biological: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Non-social (Monetary) Reward Response (Reward Learning and Sensitivity)
Implicit reward learning and sensitivity to monetary reward is assessed with the probabilistic reward task (PRT) a behavioral computer task; change in the magnitude of response bias from baseline to post-injection is the outcome measure. More positive response bias indicates a bias towards the more frequently reward stimuli (a better outcome); more negative response bias indicates a bias towards the less frequently reward stimuli (a worse outcome). This is not a standardized scale with minimum and maximum values. Response bias is calculated using a formula from signal detection theory and is a logarithmic ratio derived from choice frequencies. The formula is log b=1/2log((Rich-correct+.5) *(Lean-incorrect+.5)/(rich-incorrect+.5) * (lean-incorrect+.5)), where rich refers to the more frequently rewarded option and lean refers to the less frequently rewarded option.
Measured: Baseline and post-injection (2.25 hrs)
Non-social (Monetary) Reward Response (Reward Motivation)
Motivation for monetary reward is assessed with a 10-minute version of the Effort Expenditure for Rewards Task (EEfRT), a behavioral computer task; change in the amount of hard trials chosen (relative to total trials) from baseline to post-injection is the outcome measure. The task is analyzed using generalized estimating equations (GEE) with a binary outcome; outcome values at each timepoint therefore range from 0 to 1, with higher numbers indicating higher motivation (a better outcome). The predictor for the GEE model is a time (coded as 0 and 1) by condition (coded as 0 and 1) interaction term. A negative result in the boxes below for each condition separately indicates a pre-to post-injection decrease in the proportion of hard trials chosen.
Measured: Baseline and post-injection (2.1 hrs)
Non-social (Monetary) Reward Response (Reward Sensitivity)
Sensitivity for monetary reward is assessed with a 10-minute version of the Effort Expenditure for Rewards Task (EEfRT) a behavioral computer task, tested as the strength of the association between increases in potential monetary reward for hard trials and selection of hard (vs) easy trials during the task. This is tested using generalized estimating equations, with condition (LPS vs. placebo) by time (pre vs post-injection) by reward magnitude (ranges from $1-$4.12) predicting hard (vs easy) trial choice. More positive values indicate higher reward sensitivity ( a better outcome), and lower values indicate lower reward sensitivity. The unit of measurement for the task is the proportion of hard trials chosen; the unit of measurement for the reward sensitivity outcome is a beta coefficient. For example, a positive coefficient for reward magnitude in the GEE output means that as the reward amount increases by one unit (e.g., $1), the odds of choosing the high-effort option increase.
Measured: Baseline and post-injection (2.1 hrs)
General Social Reward Response (Reward Sensitivity Via Emotional Dot Probe)
Sensitivity to general social reward cues (i.e., response to positive emotional faces) assessed as positive attentional bias with an emotional dot probe task. Attentional bias is assessed by measuring reaction times to targets that appear in the same location as emotional (e.g., happy faces) versus neutral cues (e.g., neutral faces).
Outcomes are change from baseline to post-injection in attentional bias towards positive vs neutral faces. Higher positive attentional bias scores indicate higher sensitivity to reward; negative attentional bias score indicate less sensitivity to reward. A score of 0 indicates no bias.
The attentional bias score is derived by subtracting the reaction time in ms on congruent trials (dot replaces an emotional face) from the reaction time on incongruent trials (dot replaces the neutral face).
Measured: Baseline and post-injection (2.7 hrs)
General Social Reward Response (Reward Sensitivity Via Face Morphing Task)
Sensitivity to general social reward cues (i.e., response to positive emotional faces) assessed as positive emotion detection with a face morphing task. The outcome is the absolute change from baseline to post-injection in the percent of accurate responses. Higher accuracy is an indicator of higher sensitivity to reward and lower accuracy is an indicator of lower sensitivity to reward.
Measured: Baseline and post-injection (2.8 hrs)
General Social Reward Response (Social Reward Motivation)
Motivation for general social reward is assessed via self-report; participants rate their desire to engage in 3 different activities, one of which is social, on a 1 (not at all) to 10 (extremely) Likert scale.; change in desire for the social activity from baseline to post-injection is the outcome variable. Higher values indicate higher motivation.
Measured: Baseline and post-injection (2 hrs)
Secondary outcomes (5)
Depressed Mood Subscale of the Profile of Mood States (POMS)
The Depressed Mood Subscale of the POMS is a self-reported assessment of depressed mood in which subjects rate severity of depressed mood using a visual analog scale from 1 to 10 (10 being most severe). Each timepoint is scored and analyses examine the temporal profile of change with assessment every hour. The outcome reported below is the mean score at 2-hours post-injection, which is when the response to endotoxin is known to peak. Higher values indicate more depressive symptoms.
Measured: Hourly, from pre-injection (T0) to 9 hours later (T9)
Close Social Reward Response
Participants spend 5 minutes talking about a "close other" to a research assistant trained in reflective listening and provide ratings of current negative and positive emotion on visual analogue scales (0=not at all; 100=extremely) using items from the Profile of Mood States. Outcome variables are change in self-report positive emotion from pre to post-discussion, and percentage of positive and negative emotional words used during the discussion (scored with Linguistic Inquiry and Word Count Software). Higher positive emotion and higher percentage of positive words indicates a greater social reward response.
Measured: Post-injection (2.9 hrs)
Consummatory Daily Reward Response
Participants indicate the extent to which they enjoyed 10 activities (social, non-social, close social) on a 0-100 visual analogue scale (0= not at all; 100=extremely) at five random times during the day; change in enjoyment in each of the domains from pre to post-experimental session is the outcome for consummatory reward. Higher values indicate higher reward response.
Measured: 14 days (7 days pre-injection; 7 days post-injection).
Dopaminergic Activity
Count of eye blinks (resting eye blink rate; EBR) over a five minute period; the outcome is change in EBR from pre to post-injection. Higher values indicate higher dopaminergic activity.
Measured: Baseline and post-injection (1.9 hrs)
Anticipatory Daily Reward Response
Participants rate how much they are currently looking forward to different categories of rewarding activities on an analogue scale (0= not at all; 100=extremely); change from pre to post-experimental session is the outcome for anticipatory reward. Higher values indicate higher reward response.
Measured: 14 days (7 days pre-injection; 7 days post-injection).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Feb 2019
- Study start2 Oct 2019
- Primary completion22 Jul 2022
- Study completion22 Jul 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for AnhedoniaStudies of the same condition, open and under way.
- More trials run by University of California, Los AngelesThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Endotoxin vs Placebo
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 40 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of California, Los Angeles
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Chloe Boyle, PhD, University of California, Los Angeles
- Investigators
- Chloe C Boyle, PhD, Principal investigator, University of California, Los AngelesMichael R Irwin, MD, Principal investigator, University of California, Los Angeles
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03848715
- Sponsor's protocol ID
- 16-000583-AM-00016
- Status last verified
- Jan 2026
- First submitted
- 19 Feb 2019
- Last updated
- 27 Jan 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Boyle CC, Cho JH, Eisenberger NI, Olmstead R, Sadeghi N, Castillo D, Irwin MR. Inflammation-induced depressed mood and reward responsivity as a function of age in female adults: a randomized controlled trial of endotoxin. Transl Psychiatry. 2025 Nov 26;16(1):6. doi: 10.1038/s41398-025-03752-2.
PubMed 41298372Boyle CC, Rahal D, Meinert J, Ko V, Olmstead R, Eisenberger NI, Irwin MR. Consummatory deficits in close social reward predict inflammation-induced depressed mood. Psychoneuroendocrinology. 2026 Jan;183:107673. doi: 10.1016/j.psyneuen.2025.107673. Epub 2025 Oct 30.
PubMed 41192236
Study at a glance
From the registry record, last updated by the sponsor on 27 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Sleep and Healthy Aging Research on Depression for Younger Women
- ClinicalTrials.gov ID
- NCT03848715
- Acronym / sponsor ID
- 16-000583-AM-00016
- Conditions
- Anhedonia, Depression
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 40 participants (actual)
- Lead sponsor
- University of California, Los AngelesUniversity, hospital or other
- Study start
- 2 Oct 2019 (actual)
- Primary completion
- 22 Jul 2022 (actual)
- Study completion
- 22 Jul 2024 (actual)
- First posted
- 21 Feb 2019 (actual)
- Results
- Posted 3 Jan 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Compelling evidence indicates inflammation plays a role in depression, but potential mechanisms linking inflammation to depression, such as dysregulated reward processing, are poorly understood. This study comprehensively evaluates effects of inflammation on reward across dimensions (e.g., anticipating versus receiving a reward) and types (e.g., money vs. smiling faces) in younger and older women. Characterizing how inflammation shapes the dynamic and multidimensional reward system, and how this may differ by age, may give insight into risk factors for depression and help identify critical points for intervention.
Detailed description
This study will use an inflammatory challenge (i.e., endotoxin) to assess effects of inflammation on the behavioral response to social and non-social rewards, using tasks that assess reward motivation, sensitivity, and learning. Both elevated inflammation and reward dysregulation are associated with depression and have been shown to predict depression onset; understanding how inflammation alters the reward system in the laboratory setting may provide insight into risk factors and help identify potential areas for intervention. In this placebo-controlled, randomized, double-blind study of low dose endotoxin in 40 adult premenopausal women (25-44 y), the investigators will examine effects of endotoxin on reward responsiveness across dimensions (i.e., motivation, sensitivity, learning) and reward types (e.g., social and non-social). The investigators hypothesize that as compared to placebo, endotoxin will 1) decrease non-social reward responses across reward dimensions; 2) decrease "general" social reward responses across reward dimensions; 3) increase "close" social reward responses across reward dimensions; 4) decrease resting eye blink rate (EBR); EBR will be correlated with learning and motivation for non-social reward. The second component of the study is to examine whether effects of endotoxin on reward differ as a function of age; in particular it is hypothesized that effects will be more robust in younger compared to older women. In order to test for age differences, this study will use data from 40 older women (65+ y) participating in a parallel ongoing randomized controlled trial (ClinicalTrials.gov Identifier: NCT03256760). Thus, the investigation aims to: 1) Evaluate effects of inflammation on non-social reward as a function of age; 2) Evaluate effects of inflammation on general and close social reward as a function of age; 3) Examine changes in dopaminergic activity as a mechanism linking effects of inflammation on non-social reward processing as a function of age.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 2
- Model description
- Endotoxin vs Placebo
| Arm | Type | Receives |
|---|---|---|
| Endotoxin | Experimental | Biological: EndotoxinEndotoxin 0.8 ng/kg body weight; 1 infusion |
| Placebo | Placebo comparator | Biological: Placebosame volume of 0.9% saline |
Who may qualify
- Ages
- 25 to 44 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Participants will be required to be in good general health (as evaluated during the phone and in-person baseline session)
- Participants will be biologically female and premenopausal (as evaluated by self report).
- Participants will 25-44 years of age.
Key exclusion criteria (18 listed)
- Presence of chronic mental or physical illness
- History of allergies, autoimmune, liver, or other severe chronic diseases,
- Current and regular use of prescription medications such as steroids, non-steroid anti-inflammatory drugs, aspirin, immune modifying drugs, opioid analgesics, statins, antihypertensive drugs, anti-arrhythmic drugs, and antidepressant medications (none in the last 6 months).
- Nightshift work or time zone shifts (> 3hrs) within the previous 6 weeks
- Previous history of fainting during blood draws.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| EndotoxinEndotoxin | Biological | Endotoxin |
| PlaceboPlacebo | Biological | Placebo |
Primary outcome
Non-social (Monetary) Reward Response (Reward Learning and Sensitivity)
Time frame: Baseline and post-injection (2.25 hrs)
Implicit reward learning and sensitivity to monetary reward is assessed with the probabilistic reward task (PRT) a behavioral computer task; change in the magnitude of response bias from baseline to post-injection is the outcome measure. More positive response bias indicates a bias towards the more frequently reward stimuli (a better outcome); more negative response bias indicates a bias towards the less frequently reward stimuli (a worse outcome). This is not a standardized scale with minimum and maximum values. Response bias is calculated using a formula from signal detection theory and is a logarithmic ratio derived from choice frequencies. The formula is log b=1/2log((Rich-correct+.5) *(Lean-incorrect+.5)/(rich-incorrect+.5) * (lean-incorrect+.5)), where rich refers to the more frequently rewarded option and lean refers to the less frequently rewarded option.
Non-social (Monetary) Reward Response (Reward Motivation)
Time frame: Baseline and post-injection (2.1 hrs)
Motivation for monetary reward is assessed with a 10-minute version of the Effort Expenditure for Rewards Task (EEfRT), a behavioral computer task; change in the amount of hard trials chosen (relative to total trials) from baseline to post-injection is the outcome measure. The task is analyzed using generalized estimating equations (GEE) with a binary outcome; outcome values at each timepoint therefore range from 0 to 1, with higher numbers indicating higher motivation (a better outcome). The predictor for the GEE model is a time (coded as 0 and 1) by condition (coded as 0 and 1) interaction term. A negative result in the boxes below for each condition separately indicates a pre-to post-injection decrease in the proportion of hard trials chosen.
Non-social (Monetary) Reward Response (Reward Sensitivity)
Time frame: Baseline and post-injection (2.1 hrs)
Sensitivity for monetary reward is assessed with a 10-minute version of the Effort Expenditure for Rewards Task (EEfRT) a behavioral computer task, tested as the strength of the association between increases in potential monetary reward for hard trials and selection of hard (vs) easy trials during the task. This is tested using generalized estimating equations, with condition (LPS vs. placebo) by time (pre vs post-injection) by reward magnitude (ranges from $1-$4.12) predicting hard (vs easy) trial choice. More positive values indicate higher reward sensitivity ( a better outcome), and lower values indicate lower reward sensitivity. The unit of measurement for the task is the proportion of hard trials chosen; the unit of measurement for the reward sensitivity outcome is a beta coefficient. For example, a positive coefficient for reward magnitude in the GEE output means that as the reward amount increases by one unit (e.g., $1), the odds of choosing the high-effort option increase.
General Social Reward Response (Reward Sensitivity Via Emotional Dot Probe)
Time frame: Baseline and post-injection (2.7 hrs)
Sensitivity to general social reward cues (i.e., response to positive emotional faces) assessed as positive attentional bias with an emotional dot probe task. Attentional bias is assessed by measuring reaction times to targets that appear in the same location as emotional (e.g., happy faces) versus neutral cues (e.g., neutral faces). Outcomes are change from baseline to post-injection in attentional bias towards positive vs neutral faces. Higher positive attentional bias scores indicate higher sensitivity to reward; negative attentional bias score indicate less sensitivity to reward. A score of 0 indicates no bias. The attentional bias score is derived by subtracting the reaction time in ms on congruent trials (dot replaces an emotional face) from the reaction time on incongruent trials (dot replaces the neutral face).
General Social Reward Response (Reward Sensitivity Via Face Morphing Task)
Time frame: Baseline and post-injection (2.8 hrs)
Sensitivity to general social reward cues (i.e., response to positive emotional faces) assessed as positive emotion detection with a face morphing task. The outcome is the absolute change from baseline to post-injection in the percent of accurate responses. Higher accuracy is an indicator of higher sensitivity to reward and lower accuracy is an indicator of lower sensitivity to reward.
General Social Reward Response (Social Reward Motivation)
Time frame: Baseline and post-injection (2 hrs)
Motivation for general social reward is assessed via self-report; participants rate their desire to engage in 3 different activities, one of which is social, on a 1 (not at all) to 10 (extremely) Likert scale.; change in desire for the social activity from baseline to post-injection is the outcome variable. Higher values indicate higher motivation.
5 secondary outcomes
Depressed Mood Subscale of the Profile of Mood States (POMS)
Time frame: Hourly, from pre-injection (T0) to 9 hours later (T9)
Close Social Reward Response
Time frame: Post-injection (2.9 hrs)
Consummatory Daily Reward Response
Time frame: 14 days (7 days pre-injection; 7 days post-injection).
Dopaminergic Activity
Time frame: Baseline and post-injection (1.9 hrs)
Anticipatory Daily Reward Response
Time frame: 14 days (7 days pre-injection; 7 days post-injection).
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Jan 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 41298372Boyle CC, Cho JH, Eisenberger NI, Olmstead R, Sadeghi N, Castillo D, Irwin MR. Inflammation-induced depressed mood and reward responsivity as a function of age in female adults: a randomized controlled trial of endotoxin. Transl Psychiatry. 2025 Nov 26;16(1):6. doi: 10.1038/s41398-025-03752-2.
- Derived from this study: PubMed 41192236Boyle CC, Rahal D, Meinert J, Ko V, Olmstead R, Eisenberger NI, Irwin MR. Consummatory deficits in close social reward predict inflammation-induced depressed mood. Psychoneuroendocrinology. 2026 Jan;183:107673. doi: 10.1016/j.psyneuen.2025.107673. Epub 2025 Oct 30.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Chloe C Boyle, PhD principal investigator
University of California, Los Angeles
Michael R Irwin, MD principal investigator
University of California, Los Angeles
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Endotoxin in people with Anhedonia and Depression, run by University of California, Los Angeles at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 18 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 27 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 3 Jan 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Non-social (Monetary) Reward Response (Reward Learning and Sensitivity) (time frame: Baseline and post-injection (2.25 hrs)). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03848715, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Jan 2026.