FenDep
Research type
Research Study
Full title
PET imaging and serotonin release in depression and healthy controls
IRAS ID
354525
Contact name
David Erritzoe
Contact email
Sponsor organisation
Imperial College London
Duration of Study in the UK
3 years, 7 months, 0 days
Research summary
Clinical depression is a prevalent disease and global health burden categorised by persistent low mood that interferes with daily life. Neurotransmitters are molecules which enable brain cells to communicate with each other. Research suggests a neurotransmitter called serotonin regulates mood, with one theory linking depression to impaired serotonin functioning - The Serotonin Deficiency Hypothesis. Applied research into the theory has led to the development Selective Serotonin Reuptake Inhibitors (SSRIs). Direct evidence of abnormal serotonin signalling in depression, however, remains elusive.
Positron Emission Tomography (PET) scanning is a type of brain imaging that allows measurement of serotonin levels. PET scanning uses a radioactive drug (called a PET tracer) that can bind to receptors involved in biological pathways in the brain and produce images of the brain and targeted receptors following a scan. A PET tracer called [11C]Cimbi-36 allows researchers to track serotonin release in the brain. Recent studies have used dexamphetamine to stimulate serotonin release and measure serotonin levels producing promising results into the Serotonin Deficiency Hypothesis. However, amphetamines are known to stimulate a variety of neurotransmitters and research into a drug that specifically stimulates serotonin is required. To improve specificity of this research, dl-fenfluramine is a selective serotonin releasing agent that provides a more targeted approach. Such research would help elucidate whether response to antidepressants is dependent on serotonin function.
This study aims to compare serotonin levels between people who are suffering from depression and those who are not (healthy controls) using the drug dl-fenfluramine and PET scanning. Additionally, participants diagnosed with Major Depressive Disorder who decide to begin anti-depressant medication, as part of their treatment, will undergo a further remote 8-week observational period following brain imaging. Questionnaire data collected from these participants will be used to determine if there is a relationship between abnormal serotonin release and clinical improvement when taking SSRIs.REC name
East Midlands - Leicester Central Research Ethics Committee
REC reference
26/EM/0094
Date of REC Opinion
30 Jun 2026
REC opinion
Further Information Favourable Opinion