RecruitingNot ApplicableInterventional

The effect of serotonin receptor 4 on cognition in unusual experiences

This research is exploring if a medication called prucalopride, which works on a specific brain chemical 'switch' (serotonin receptor 4), can improve thinking skills. We're testing this in healthy volunteers, aged 18-40, who've had unusual experiences like hearing things or strong beliefs, but aren't distressed by them. These experiences are called 'psychotic-like experiences' and are common, affecting about 5-10% of healthy people. Understanding how this medicine affects thinking in this group could give us clues about developing new treatments for more serious mental health conditions. Participants will take either prucalopride or an inactive placebo (sugar pill) for 7 days, and have brain scans, thinking tests, and blood tests.

At a glance

Status

Recruiting

Phase

Not Applicable

Sponsor

University of Birmingham

Enrolment target

Start

25 Sep 2025

Estimated completion

01 Sep 2027

Healthy volunteer community population with psychotic-like experiences in the last 12 months

What is this study about?

This study, called 'The SERENE study', is exploring how a particular medicine, prucalopride, affects thinking. Prucalopride is currently used to treat constipation, but we're interested in how it affects a specific chemical 'switch' in the brain called the serotonin receptor 4 (5-HT4R). We know from previous research that activating this switch might help improve how our brains work, especially in terms of thinking clearly and remembering things.

We're focusing on healthy volunteers who have had what we call 'psychotic-like experiences' (PLEs) in the last year. These are things like briefly hearing or seeing things that others can't, or having unusual beliefs, but importantly, these experiences don't cause them distress or problems in their daily lives. Around 5-10% of people have these experiences. By studying this group, we hope to learn more about the early stages of thinking changes that can sometimes be linked to more serious mental health conditions, without studying people who are already unwell. This could help us discover new ways to treat these conditions in the future.

Previous studies have already shown that prucalopride might improve thinking. Also, looking at health records, people who took prucalopride for constipation seemed to have a much lower chance of developing psychosis compared to those taking other constipation medicines. This study is a 'proof-of-concept' study, meaning we're trying to see if our idea works in principle before larger, more complex trials. It helps us understand if targeting this specific brain switch with prucalopride genuinely impacts thinking in a way that could eventually lead to new treatments.

Key takeaways

This study explores how a constipation medicine, prucalopride, might improve thinking skills.
It targets healthy volunteers (18-40) who've had non-distressing unusual experiences.
Understanding these effects could help develop future treatments for more serious mental health conditions.
Participation involves taking prucalopride or a placebo for 7 days, along with brain scans and thinking tests.
You won't get direct personal medical benefit, but could contribute valuable research.
You can withdraw from the study at any time.

Who may be eligible?

We are looking for healthy volunteers between 18 and 40 years old who have had some unusual experiences in the past year, such as hearing or seeing things that others don't, or strong beliefs that aren't shared by others. You need to be able to understand and speak English well to participate.

However, there are some reasons why you wouldn't be able to join. For example, if you are currently taking certain medications like antipsychotics or antidepressants, or if you have a history of learning difficulties or certain serious medical conditions. You also can't take part if you've ever had a diagnosed episode of psychosis or if you are pregnant, breastfeeding, or trying to conceive. We also can't include people with metal implants or severe claustrophobia, as these can be issues for the MRI scans. Finally, if you've recently taken part in other drug studies or studies with similar thinking tasks, you might not be eligible.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 18 and 40 years old?
Have you had unusual experiences (e.g., hearing things no one else does) in the last 12 months that don't bother you?
Are you able to speak and understand English fluently?
Are you NOT currently taking antipsychotic or antidepressant medications?
Have you NOT had a diagnosis of intellectual disability or a serious mental health condition?
Are you NOT pregnant, breastfeeding, or trying to become pregnant?

Answer every question to see your result.

What does participation involve?

If you join the study, you'll be randomly assigned to one of two groups: one will take prucalopride (the study medicine) and the other will take an inactive dummy pill (placebo) for 7 days. This is done to fairly compare the effects. Throughout the study, we'll ask you to do various activities. These include brain scans using methods called fMRI and MRS (these don't use radiation), and tests to check your thinking skills and memory. We'll also ask questions about your mood, anxiety levels, and how well you feel you're thinking. We'll take blood samples to measure levels of the study medicine and other body markers. The study is expected to run from February 2024 to October 2027, with volunteers joining between September 2025 and March 2027 (for 18 months to 2 years).

Potential risks and benefits

You won't directly get any medical benefits from taking part, and the results won't be used for your personal diagnosis or treatment. The main benefit is helping us understand more about how the brain works and potentially contributing to new treatments for mental health conditions in the future. We will, however, review all your blood and brain scan results. If we find anything medically important, we would let you and your GP know, if you agree, and help you arrange any necessary follow-up. Taking part involves some risks. The brain scans are safe but can feel enclosed and noisy, which might cause mild anxiety; if this becomes distressing, we'll stop. Blood tests are generally safe but may cause slight discomfort, bruising, or rarely, other minor issues. You can choose not to answer any questions you find uncomfortable and can stop participating at any time.

Locations (1)

University of Birmingham
Approximate
Birmingham, United Kingdom

Common questions

What are 'psychotic-like experiences'?

These are common experiences like briefly hearing or seeing things that others don't, or having unusual beliefs, but they don't cause distress or problems in your daily life.

What is prucalopride?

Prucalopride is a medicine currently approved and used to treat constipation, but we are studying its effects on brain function and thinking.

Will I know if I'm taking the real medicine or the dummy pill?

No, you'll be randomly assigned to either prucalopride or a placebo (inactive pill), and neither you nor the researchers will know which you're taking until the end of the study. This helps ensure fair results.

What do the brain scans involve?

You'll have fMRI and MRS scans, which are safe and don't use radiation. They involve lying still in a scanner that can be noisy and feel small for a period of time.

Who is running this study?

This study is being run by the University of Birmingham, UK, and is funded by the NIHR Mental Health Translational Research Collaboration.

How to find out more

Angharad de Cates

a.n.decates@bham.ac.uk +44 (0)1214143978 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.