CompletedInterventional

5-hydroxytryptophan, a serotonin precursor, as a novel therapy for attention-deficit hyperactivity disorder in adults

Researchers at the University of Sheffield are investigating if a natural chemical called 5-HTP can help reduce distractibility. 5-HTP is a substance your body makes from a food ingredient (tryptophan) and is involved in producing serotonin, which affects mood and attention. It's thought that low serotonin might be linked to distractibility. This study aims to see if taking 5-HTP can change how easily people get distracted, potentially helping those who struggle with attention. Volunteers between 18 and 65 years old, with either high or low levels of distractibility, are taking part. The study involves computer tasks and taking either 5-HTP or a dummy pill, with researchers observing the effects. It's hoped this research could lead to new ways to support people with attention difficulties.

At a glance

Status

Completed

Sponsor

University of Sheffield

Enrolment target

112

Start

01 May 2024

Estimated completion

27 Feb 2025

Distractibility in attention deficit hyperactivity disorder

What is this study about?

This research from the University of Sheffield is looking into how a natural substance called 5-Hydroxytryptophan, or 5-HTP for short, might affect how easily people get distracted. Your body naturally makes 5-HTP from something you eat called tryptophan, which you can find in foods like soy products, egg whites, and pumpkin seeds. 5-HTP then helps to create another important chemical in your brain called serotonin. Serotonin plays a big role in many things, including your mood, sleep, and how you pay attention. Some previous research has suggested that people who get distracted easily might have lower levels of serotonin.

The main goal of this study is to see if giving people extra 5-HTP can change how easily they are distracted. By understanding this better, the researchers hope to figure out if 5-HTP could be a helpful option in the future for people who have trouble with their attention.

To find this out, participants will do some computer tasks that measure their distractibility. They'll be given either the 5-HTP tablets or dummy tablets (a 'placebo') without knowing which one they're taking. This helps the researchers understand the true effect of 5-HTP. The study is very carefully designed to get reliable results so that if 5-HTP does show promise, it could eventually help individuals manage attention challenges.

Key takeaways

This study explores if 5-HTP, a natural substance, can reduce distractibility.
It aims to help people with attention issues by understanding serotonin's role.
Participants will do computer tasks and take either 5-HTP or a dummy pill.
The study involves a single 2.5-hour visit to the University of Sheffield.
You need to be generally healthy and aged 18-65 to take part.
Some medications and lifestyle choices mean you cannot participate.

Who may be eligible?

This study is looking for healthy adult volunteers aged between 18 and 65 years old. To join, you'll first complete a short online survey to see if you typically get distracted a lot or not very much at all. Based on your answers, you might be eligible to take part.

There are some reasons why you wouldn't be able to join. For example, if you're currently taking strong medications for your attention or mood, like those for ADHD or certain antidepressants (like SSRIs), this study isn't for you. You also can't take part if you smoke or vape, are pregnant or breastfeeding, have problems digesting milk sugars (lactose), or follow a vegan diet. People with dyslexia are also not 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 65 years old?
Do you not smoke or vape?
Are you not taking medications for ADHD or certain antidepressants (SSRIs)?
Are you not pregnant or breastfeeding?
Are you able to eat dairy products (not lactose-intolerant)?
Do you eat animal products (not vegan)?

Answer every question to see your result.

What does participation involve?

If you're interested and seem like a good fit after the online screening survey, you'll be invited to visit the University of Sheffield. The entire visit will take about 2.5 hours. Before your visit, you'll get an email reminder and a request to keep a food diary for a couple of days, as what you eat can affect the results. On the day of your study, it's important not to have any caffeine, alcohol, or nicotine, and you'll need to avoid eating for two hours beforehand.

Once you arrive, you'll meet the researcher in a quiet room with a computer. You'll read and sign a consent form, then complete some computer activities designed to test your attention and how easily you get distracted – this takes about 30 minutes. After these tasks, you'll be given two tablets with water (you won't know if they contain 5-HTP or a dummy pill) and asked to wait quietly for 90 minutes. You can relax during this time, but no food. After the waiting period, you'll repeat the computer tasks, and then you'll be finished and free to leave.

Potential risks and benefits

There isn't a direct benefit to you personally from taking part in this study, but your contribution will help scientists understand more about distractibility and potentially lead to new treatments. Possible risks include needing to fast (not eat) for a short time, and sitting at a computer may cause some eye strain, but you'll have breaks. Some people might feel a bit sick or tired after taking 5-HTP, but the researchers have chosen a dose to try and avoid this. If you feel unwell, you should tell the researcher immediately. After the study, it's advised not to drive or use heavy machinery in case you feel tired. Remember, you can decide to stop participating at any time.

Locations (1)

University of Sheffield
Approximate
Sheffield, United Kingdom

Common questions

What is 5-HTP?

5-HTP is a natural substance your body makes from food, which then helps create serotonin, a brain chemical that affects mood and attention.

What is the study trying to find out?

Researchers want to see if taking 5-HTP can reduce how easily people get distracted, with the hope of developing new ways to help those with attention problems.

How long does participating take?

The main visit to the university will take about two and a half hours, plus a short online survey beforehand.

Will I know if I'm getting 5-HTP?

No, this is a 'double-blind' study, meaning neither you nor the researchers will know who gets 5-HTP and who gets a dummy pill until the study is over.

Who is funding this research?

The study is funded by the University of Sheffield in the UK.

How to find out more

Eleanor Jackson

efjackson1@sheffield.ac.uk +44 (0)1142222000 Official trial record

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