Fluoxetine and Understanding Social Experiences

Summary

Adolescence is a critical developmental period marked by significant social, cognitive, and emotional changes. Unfortunately, it is also a time when the risk of depression and anxiety rises dramatically. Early, effective treatment is essential to mitigate long-term impacts on relationships, education, and life satisfaction. While psychological therapies are recommended as first-line treatment for mild to moderate depression in young people, antidepressant use (particularly SSRIs such as Prozac) has risen sharply, especially among girls aged 15-17.

Despite their widespread use, there is limited research on how SSRIs address adolescent depression, leaving clinicians with little evidence to guide treatment decisions. The Fluoxetine and Understanding Social Experiences (FUSE) study aims to shed light on how Prozac (medically known as fluoxetine) influences decision-making in healthy young people in four key areas that are known to be affected by depression: emotional processing (e.g., facial expression recognition), social function (e.g., sensitivity to peer rejection), reward processing (e.g., how people learn from rewards and punishments), and motivation (e.g., how people make decisions about whether a certain outcome or reward is worth the effort to obtain). Some of the tests employed in the study use facial expression and heart-rate recording as aditional measures. We are aiming to recruit and test 80 young people between the ages of 18 and 24.

When included in the study, participants are randomly assigned to receive either a weeklong treatment with fluoxetine, or a placebo (a pill with no active ingredients). The study follows a double-blind design, which means that neither the researchers nor the participants are aware of the treatment received so as to not influence the results.

We belive that fluoxetine will have beneficial effects on social decision-making in young people, which might manifest as increased accuracy labelling positive facial expressions, less sensitivity to negative feedback, lower self-reported negative mood in response to social exclusion and reduced heart rate/negative facial expressivity in response to unpleasant social experiences.

The FUSE study aims to deepen our understanding of how antidepressants affect decision-making in young people, at a time when antidepressant prescriptions have risen but research is scarce. By identifying the exact domains of functioning which are affected by antidepressant use in this age group, this research will help inform which young people are likely to benefit most from drug treatment.

The project results will be published in peer-reviewed journals and presented at academic conferences. We are also working with a group of young advisors who will help us decide how to best share our results with others in their age group. A brief summary of the study findings will also be provided to participants who would like to receive it. All research data, excluding information that could identify participants, will be stored safely for at least 10 years after final publication or public release.

Conditions

• Depression in Adolescence
• Antidepressant Activity in Healthy Volunteers
• Healthy Adult Participants

Interventions

DRUG

Fluoxetine

Participants will be taking a 20mg fluoxetine capsule daily for 7 days.

DRUG

Placebo

Participants will be taking a placebo capsule daily for 7 days.

Sponsors & Collaborators

• Wellcome Trust

  collaborator OTHER

• Oxford Health Biomedical Research Centre (OH BRC) support scheme

  collaborator UNKNOWN

• University of Oxford

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

24 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-03-31

Primary Completion

2027-07-20

Completion

2027-07-22

Countries

• United Kingdom

Study Locations