Clinical trial Recruiting at 1 site Interventional Ages 18 to 24

Fluoxetine's effect on anger-related emotional responses in young adults

Official title: The Effect of Fluoxetine Treatment on Anger Processing in Healthy Young People

Run by University of Oxford · NCT07424781 · Data updated 2026-11-12

This study will test whether taking fluoxetine for one week changes how healthy 18–24-year-olds react to anger-related words, faces, memories, and frustrating tasks compared with a placebo.

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Quick facts

Study typeInterventional
Ages18 Years to 24 Years
SexAll
Enrollment80 (estimated)
SponsorUniversity of Oxford
Academic / other
Locations1 site (Oxford, Oxfordshire)
StatusRecruiting
StartedOctober 1, 2025
Main results expectedDecember 31, 2026
Study endsDecember 31, 2026
Registry record updatedFebruary 20, 2026
Trial IDNCT07424781 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Healthy people aged 18–24 who live in the UK, have normal or corrected vision, are fluent in English, can give informed consent, and have no current or past psychiatric diagnosis are ideal candidates.

Probably not a fit

People with any current or past psychiatric disorder, a first-degree relative with mania, heavy smoking/vaping or high caffeine use, or those unable to attend the Oxford site or remain UK residents for the study duration are unlikely to qualify or derive benefit.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

Healthy volunteers aged 18–24 are given either 20 mg fluoxetine or a matching placebo each day for seven days and then attend the university for questionnaire and behavioural task assessments. Tasks probe responses to anger-related stimuli (words, faces, autobiographical recall) and include frustration-inducing paradigms such as frustrative non-reward and threat tasks. During some tasks researchers record physiological measures including heart rate variability and facial expressions to capture bodily markers of emotional response. The trial compares behavioural and physiological responses between the fluoxetine and placebo groups to see if short-term dosing alters anger processing.

Why it matters

Potential benefit: If successful, the study could show how fluoxetine quickly changes anger processing in young people and help guide more targeted approaches to treating irritability and mood problems.

How similar studies have gone: Previous work in adults has shown that SSRIs including fluoxetine can change emotional processing, but short-term placebo-controlled testing focused specifically on anger in healthy young people is relatively novel.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Be aged 18-24 years (inclusive)
* Be resident in the UK for the duration of the study
* Have normal or corrected to normal vision
* Participant is willing and able to give informed consent for participation in the research
* Sufficiently fluent English to understand and complete the study

Exclusion Criteria:

The participant may not enter the study if ANY of the following apply:

Psychiatric History:

* Current or past diagnosis of any psychiatric disorder, as determined by the Structured Clinical Interview for the DSM-5 (SCID-5) and self-report. This includes, but is not limited to, depression, anxiety disorders, alcohol or drug dependency, personality disorders, suicidal ideation, and other psychiatric conditions;
* First degree relative with a diagnosis of mania;

Lifestyle:

* Heavy smoker or vaper (\> 10 cigarettes per day, or \>2 mL e-liquid, or \>15mg/day from a nicotine patch);
* Heavy use of caffeine (drink \> 4 of 250ml cups/cans of coffee or energy drinks per day);
* Heavy drinker (drink \>14 standard alcoholic drinks per week);
* Current or recent use (in the last 3 months) of any psychoactive substance according to self-report and a urine drug test screening for recent use of 10 common recreational substances;

Physical Health:

* Severely underweight or overweight in a manner that renders them unsuitable for the study in the opinion of the study medical advisor;
* Known contraindication to fluoxetine, such as hypersensitivity to fluoxetine or any component in its formulation;
* Pregnancy, as determined by a urine pregnancy test or plans to become pregnant within the next 3 months;
* Breastfeeding;
* Not able to consume gelatine;

Medical History:

* Past or ongoing health issue which, in the opinion of the study medical advisor, may interfere with the safety of the participant or the scientific integrity of the study, including but not limited to: seizures or epilepsy, heart rhythm problem, renal disease, hepatic disease, glaucoma, diabetes, bleeding disorders or clotting conditions (e.g., haemophilia, thrombocytopenia);
* Diagnosis of a significant neurological condition (e.g., epilepsy, multiple sclerosis, traumatic brain injury).
* Diagnosis of a neurodevelopmental condition, such as autism spectrum disorder (ASD) or attention-deficit/hyperactivity disorder (ADHD);
* Current or recent use of medication that might interfere or interact with the effects of fluoxetine, in the opinion of the study medical advisor, including but not limited to: monoamine oxidase inhibitors (MAOIs), medications affecting serotonin levels (e.g., tramadol, triptans, St. John's Wort), anticoagulants or blood thinners (e.g., warfarin), anti-inflammatory medications (e.g., aspirin, ibuprofen), or medications known to affect heart rhythm;

Prior Study Participation:

* Participation in any other psychological or medical experiment involving taking any kind of drug/medication/vaccine, within the last 3 months;
* Participation in any other study involving the current or similar tasks, within the last 6 months;

Others

•Any other significant finding which may arise during the screening process and which, in the opinion of the Principal Investigator/medical advisor, may influence the scientific integrity of the study, or the participant's ability to participate in the study.

Where it's running

  • Department of Psychiatry, University of Oxford
    Oxford, Oxfordshire, United Kingdom
    Recruiting

Study contacts

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How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.