The primary objective of the current study is to examine the acute effect of lithium on the visual and non-visual responses to light in a sample of healthy participants. Our experiments will investigate the effects of lithium on light sensitivity at the level of the retina as well as central visual and non-visual pathways.
Our primary hypothesis is that the administration of lithium to healthy volunteers will reduce the magnitude of a range of non-visual responses to light including melatonin suppression, alertness, performance, mood and electrophysiology in a manner that is dependent of the amount of lithium in the brain. To better understand the postulated effects of lithium on light sensitivity and to examine its relationship at the level of the retina, we will assess the visual and non-visual responses to light, as well as the distribution of lithium in the brain using a non-invasive imaging technique. In addition to that, we also aim to examine the impact of both lithium and light on a molecular level through whole blood transcriptome sequencing.
Who can participate
Age range
18 Years – 40 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Aged between 18 and 40 years old
* Fluent in English (both spoken and written)
* Sleep duration between 6.5 and 9 hours daily
* Have a regular normal sleep schedule with bedtime (weekdays) between 21:30 and 01:00.
* BMI between 18 and 28kg/m2
* Currently enrolled and registered with a general practitioner
* Female participants only: should use effective contraception or refrain from engaging in sexual activity that could result in pregnancy during participation in the study.
Exclusion Criteria:
* History of psychiatric or neurological disorders
* First-degree family history of psychosis or severe mood disorder
* Current or past suicidal ideation or self-harm
* Current, chronic infections or diseases.
* Life-threatening allergies, specifically a nut allergy.
* Known visual disorders e.g., colour blindness, glaucoma, cataracts, diabetic retinopathy.
* Known medical conditions that could affect the conduct of the study including
* sleep disorders
* cancer
* diabetes
* anaemia
* epilepsy
* psoriasis
* thyroid disorders
* kidney disease
* severe eczema
* anemia
* migraines
* Taking any long-term or regular medications other than oral contraceptives (e.g., antidepressants, diuretics (water-tablets), pain killers or anti-inflammatory drugs (such as ibuprofen) or medications for high blood pressure).
* Have donated blood in the past 1 month
* Regular or recent recreational drug use
* Chronic alcohol addiction/misuse
* Known contraindica…
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Plasma melatonin change in response to light stimulation
Timeframe: Measured during the 90-minute light exposure session after 7 days of lithium treatment and after 7 days in the no-lithium condition (days 9-11 and 19-21).
2
Brain lithium signal intensity measured by 7Li-MRI
Timeframe: Measured once following 9 days of lithium carbonate administration (Day 21)