FUSE

The study involves taking a commonly prescribed antidepressant medication (fluoxetine) and completing a series of questionnaires and computer tests, both in-person and online. We will first ask you to complete a brief eligibility questionnaire online. If you meet these initial criteria, you will be invited to book a 1h online screening call with one of your study researchers, who will explain the study in detail and collect relevant information regarding your medical and mental health history. If it is safe for you to take the study drug, you will be invited to visit the Department of Psychiatry at Warneford Hospital where you will be randomly assigned to take fluoxetine or placebo for 7 days at home. On your 7th day of taking the medication, you will return to the Department of Psychiatry to complete a half-day of computer tasks (approximately 3h). Some of the tasks will require anonymously interacting with other study participants, while others will use ECG measurements (a non-invasive measurement of your heart's electrical activity and rhythm) and video recording. During the screening call, the researcher will ask questions about your background and medical history to ensure it is safe for you to take part. They will also ask you about your mental health history. You will visit us at the Department of Psychiatry to confirm your eligibility and to receive the study medication and instructions for use You will take a capsule each day for 7 days, at home. This can contain either 20mg of fluoxetine or a placebo (a pill without active medication). You will visit us again on the day of your last capsule to complete questionnaires and computer tasks. Some of the tasks will involve taking video recordings while you complete them.