The aim of this project is to look at the impact of 5-Hydroxytryptophan (5-HTP) on distractibility. 5-HTP is the precursor to the neurotransmitter serotonin and is a chemical that the body produces naturally. There is evidence that distractibility is associated with a decreased level of serotonin. This research aims to see if giving people 5-HTP will alter their distractibility, which will form part of an initial assessment as to whether 5-HTP could be used to support people with attention problems. The study involves completing a short survey about mental health and behaviours, and if eligible, participation in an in-person study at the University of Sheffield. The in-person session involves completing some cognitive tasks to look at eye movement, taking 5-HTP or a sugar tablet with no active ingredients, and then completing the tasks again after a 90-minute wait.
18-65 years of age
Normal or corrected to normal vision with contact lenses.
Score of <9 or >14 on the ASRS v5 (assessed in pre screen questionnaire)
Current use of psychostimulant medication or medication for the treatment of ADHD
Current use of medications known to impact the serotonergic system (e.g., SSRIs).
Smoking or vaping
Pregnancy
Parallel
5-hydroxytryptophan (food supplement) 200mg
Dietary supplement200mg 5-HTP delivered in two tablets. Tablets obtained from Nature's Best supplements. Each tablet contains 3982mg of Griffonia seed extract, providing 100mg of 5-HTP. The tablets consist of calcium carbonate, griffonia seed extract, Anti-caking Agents (Silicon Dioxide, Stearic Acid, \& Magnesium Stearate) and Tablet Coating (Hydroxypropyl Methylcellulose, Glycerol).
5-hydroxytryptophan (food supplement) 300mg
Dietary supplement300mg 5-HTP delivered in three tablets. Tablets obtained from Nature's Best supplements. Each tablet contains 3982mg of Griffonia seed extract, providing 100mg of 5-HTP. The tablets consist of calcium carbonate, griffonia seed extract, Anti-caking Agents (Silicon Dioxide, Stearic Acid, \& Magnesium Stearate) and Tablet Coating (Hydroxypropyl Methylcellulose, Glycerol).
Placebo
Other interventionUnmedicated lactose-sucrose tablets provided by Ainsworth's homoeopathic remedies
6
Treatment groupsSee each treatment group below.
Change in distractibility - microsaccades
Frequency of microsaccades in a simple fixation task
Change in distractibility - reaction time
Measurement of reaction time on a visual search task with varying auditory stimuli.
Change in distractibility- fixations
Number of fixations on distractor letters in a visual search task with varying auditory stimuli.
Click on the lead sponsor to view all of their trials.
