Clinical trials

Scientists have found that the immune system, the body's system dedicated to fighting infections, can be in a state of "hyperactivity" (i.e., more active than you would normally expect) in some people with depression and postnatal depression, despite the lack of any actual ongoing infection. This response is referred to as inflammation. This discovery has unveiled unique opportunities to identify new medications to help patients with this heightened inflammation who have also not been responding to their antidepressant medications. This study aims to explore how inflammation in the body may be linked to symptoms of Premenstrual Dysphoric Disorder (PMDD) across the menstrual cycle, and how thoughts, emotions, and behaviours also may change throughout the cycle. We are recruiting two groups of people: People with a clinical or provisional (suspected) diagnosis of PMDD, and healthy controls who experience mild/no premenstrual changes. Over a two-month period, participants will complete daily psychological assessments across two menstrual cycles and will come into King's College Hospital (KCH) twice during one menstrual cycle to provide blood samples to measure their inflammation. By comparing these groups, we hope to gain a better understanding of the biological and psychological factors involved in PMDD, with the long-term goal of improving treatment options.

Age related stiffening and hardening of the arteries is often a slow process, but some conditions such as chronic kidney disease (CKD), seem to increase the rate at which the arteries stiffen even during childhood. High blood pressure (BP) is well known to lead to arterial stiffening and is often seen in children and young people (CYP) with CKD. A greater risk of arterial stiffening has been reported in children CYP with CKD compared to healthy CYP and this is thought to be related to the development of high BP, heart problems, and the worsening of kidney damage. The cause is unknown and is unlikely due to age related changes in the arterial wall seen in older adults. Potential mechanisms contributing to arterial stiffening in CYP with CKD include i) abnormalities in the interaction between the heart and the aorta (the large artery pumping blood away from the heart to the rest of the body), overactivity of the sympathetic nervous system (SNS), the body's "stress response", or iii) abnormal metabolism seen in CKD, where there are high levels of phosphate and other waste products circulating in the blood as a result of damage to the kidneys. In this study, the investigators will use a variety of non invasive experimental methods to determine if arterial stiffening seen in CYP with CKD is due solely to increased BP, or whether the other potential factors listed above also contribute. This may help to eventually identify how to prevent or treat arterial stiffness in CYP with CKD and prevent its adverse impact on kidney and heart health in later life. The investigators will compare findings between those with CKD and an age, sex and BP matched control group. This control group will comprise CYP both with high BP (primary hypertension) and without high BP (healthy participants).

Colchicine is an inexpensive drug that has been available for decades. Trials, which excluded patients with kidney disease, showed that colchicine decreased the number of heart attacks and strokes. The investigators cannot be sure if these results will apply to dialysis patients and a clinical trial exploring the effect of colchicine on heart attacks and strokes specifically in dialysis patients is needed. Colchicine may also be beneficial for dialysis patients as it may help arteriovenous fistulas to last longer. An arteriovenous fistula is a connection made between an artery and a vein in the arm, allowing for access to a person's bloodstream as part of dialysis. Sometimes, these connections can get too narrow in some parts, stopping them from working properly. These narrowings can be treated with a balloon inserted into the vein with the help of an x-ray. Balloons coated with a drug called paclitaxel, which works like colchicine, can be helpful, so the investigators think colchicine may help too. At present, colchicine is often avoided in patients receiving dialysis. Patients on haemodialysis take a number of medications already and have significant comorbidity. Therefore, it is possible that a higher proportion would have difficulty tolerating colchicine. These concerns mean that a large trial assessing the potential benefits of colchicine in this population cannot begin without further data on feasibility. This feasibility study will establish whether low dose colchicine is tolerated and acceptable to dialysis patients and will help the investigators to plan recruitment to future clinical trials. The investigators will give colchicine to 100 dialysis patients. The investigators will monitor the participants for side effects and see how many continue to take it for the planned period of 3 months. If feasibility is confirmed, there are then strong rationales for large clinical trials exploring the effect of colchicine on both mortality and vascular access outcomes in dialysis patients.

Worries about harm from others (also known as paranoia) are common. Thinking fast or going on gut feelings is natural but can fuel these worries. For some, fast thinking and worries start to get in the way of life. Cognitive behaviour therapy for psychosis (CBTp) is the recommended talking therapy. However, only a minority of people can access CBTp due to limited resources, and even when available, therapy can be difficult to do and use in daily life. SloMo is a digitally supported therapy that aims to overcome these barriers, and was developed by people with psychosis, designers, and psychologists. It supports people to notice worries and fast thinking habits. During therapy sessions, people learn to slow down and feel safer. Personalised spinning thought bubbles are slowed down using SloMo tips. An app provides access to helpful messages. SloMo was previously tested in a randomised trial of 361 people attending mental health services. SloMo was found to be safe to use, with no adverse events linked to the software. People in the SloMo group had lower paranoia, and better confidence and wellbeing, over 6 months compared to people who just received their usual care. People found SloMo enjoyable and easy to use. The next step is to evaluate if SloMo can be safely and effectively delivered by therapists working in NHS services. If SloMo works in routine care, the therapy will be made more widely available in the NHS. An improved version of SloMo has been co-produced based on feedback. At least sixty therapists will be trained and supervised in 3 trusts to deliver SloMo to at least 150 people who fear harm from others. Safety, technical performance, uptake, engagement and acceptability data, alongside interviews with patients, therapists, and managers, will investigate how SloMo is used. Paranoia severity and wellbeing will be measured pre, post therapy, and at 12 months follow up, to find out if SloMo helps. Service use data will evaluate costs and savings.

This project aims to establish whether an adapted extraction device is tolerable and will be able to measure chemical signals in baby's ISF. Insight into the chemical profiles found in the skin interstitial fluid (ISF) of healthy and diseased babies will identify signals that can be used to investigate the causes of eczema and propose new preventative strategies and effective treatments. Specifically, it aims to: 1. Demonstrate that the developed ISF device can be used to extract biomarkers from the skin of babies non-invasively and is tolerable (not causing significant discomfort, bruising, or blister formation). 2. Compare the profile of chemical markers present in the ISF of healthy babies with babies that have developed eczema. 3. Compare the biomarker levels extracted from babies with eczema in lesional and non-lesional skin using the developed ISF device. 4. Compare the microbiome and metabolome profiles from swabs taken from babies with healthy skin and with eczema in lesional and non-lesional skin (exploratory outcome).

Children and young people (CYP) with life-limiting conditions represent a growing population with complex care needs that span health, education, and social care systems. These children often have multiple diagnoses, rely on medical technologies, and experience prolonged trajectories of illness. Despite this, care remains fragmented, services are poorly integrated, and definitions of "complexity" are variable, inconsistent, and inadequately reflect the lived experience of families and the perspectives of professionals. The CHESS (Complexity in Health, Education, and Social Support) study aims to develop a shared, evidence-informed understanding of "complexity" in the context of CYP with life-limiting conditions. The study will be delivered by a multi-disciplinary, multisectoral research team and is funded by a National Institute for Health and Care Research (NIHR) Programme Development Grant. This research will provide the foundational work to inform the design and implementation of a future NIHR Programme Grant focused on the development and testing of a child-centred, nationally applicable case mix classification system to support integrated multisector care and resource allocation. This qualitative study involves two stages. Stage 1 consists of semi-structured interviews with (i) CYP aged 5-17 years with a life-limiting condition, (ii) parents/carers (including bereaved parents and parents of children aged under 5 years), and (iii) professionals across healthcare, social care, and education sectors. These interviews aim to elicit stakeholder understandings of "complexity," how it is experienced and enacted in care, and the implications for service access, coordination, and outcomes. Stage 2 comprises a series of stakeholder workshops to review, refine, and synthesise findings from Stage 1 and a parallel realist review. Using consensus methods including the Nominal Group Technique, the workshops will co-develop a cross-sectoral conceptual definition of "complexity" and produce a logic model to guide integrated care delivery for this population. The CHESS study seeks to address a critical evidence gap in how complexity is understood, measured, and supported across systems. By incorporating the voices of children, families, and professionals across sectors, this study will generate new conceptual clarity, build a foundation for improved outcomes, and contribute directly to the national agenda on equity, quality, and integration in paediatric palliative and complex care.

The goal of this ethnographic study is to observe how healthcare professionals work together in an intensive care unit (ICU). The main questions it aims to answer are * How do healthcare staff work together in everyday ICU settings? * What helps people work together in ICUs? * What challenges do staff face in working together in ICUs? * How have teamwork practices changed since the COVID-19 pandemic? Researchers will shadow staff during their day-to-day work. Key staff members will also be interviewed about their perceptions and experiences of teamwork.

Background Psychosis is a mental health condition that affects around 3 in 100 people in their lifetime. Most treatments for psychosis target a brain chemical called dopamine but they don't work for everyone and don't address many of the symptoms. People with psychosis and people at risk of developing psychosis show differences in a part of the brain called the hippocampus, such as smaller size and increased activity. This hyperactivity may be associated with cognitive difficulties (thinking and memory). The basis of this hippocampal hyperactivity is thought to be a deficit in excitation and inhibition of brain cells. Excitation causes brain cells to send signals more frequently, and inhibition causes cells to send signals less frequently. A balance between these signals is important for the brain, including the hippocampus, to function properly. Approach Levetiracetam is a medication that is widely used to treat epilepsy and which helps balance excitation-inhibition in the brain. We will use brain imaging, using Magnetic Resonance Imaging (MRI), to test if levetiracetam can help reduce hippocampal hyperactivity, alter connectivity and change levels of brain chemicals in people who are at risk of developing psychosis. Participants (18-40 years), identified as at risk of psychosis through the Outreach and Support in South London (OASIS) teams, will attend an initial visit at the Institute of Psychiatry, Psychology \& Neuroscience. This will involve questions about experiences and feelings, assessment of thinking and memory, and a blood test. They will then attend two scanning visits at the Centre for Neuroimaging Sciences, during which they will take capsules of either levetiracetam or placebo (in a randomised order) before having a 60 mins MRI scan. The MRI scan will look at blood flow to the hippocampus, resting activity, activity during a cognitive task and levels of brain chemicals. A case-control sample of 33 healthy individuals aged 18-40 will be recruited from Greater London. We will recruit a healthy control (HC) sample to establish the presence of hippocampal dysfunction in our CHR-P group by comparing the MRI data for CHR-P under the placebo condition with that of the HC sample. The HC individuals will attend the screening visit and one scanning visit. They will not receive any medication. Funded by the Wellcome Trust and conducted by King's College London researchers, the study spans 2-3 months per participant. Impact Our study will provide important evidence about how levetiracetam affects brain function, and how this relates to cognition. This knowledge may lead to innovative approaches for understanding and treating psychosis early.

The goal of this observational study is to determine whether genetic information, together with clinical information, can be used to improve prediction of future multiple sclerosis (MS) diagnosis after a first-time episode of optic neuritis. The study will also investigate visual outcomes, quality of life, healthcare use, and the acceptability of using genetic information to predict future health outcomes in people with optic neuritis. The main outcomes that we aim to assess are: 1. Incident diagnosis of MS following a first episode of optic neuritis, including time to MS diagnosis. 2. Visual outcomes following optic neuritis, including visual acuity, visual field, and colour vision. 3. Clinical care received following optic neuritis, including specialist review, investigations/tests 4. Health-related and vision-related quality of life. 5. Health economic impacts and healthcare utilisation after experiencing optic neuritis 6. Knowledge, attitudes, and practices/behaviours about using genetic information to predict future MS disease risk. If consented, participants will: 1. Allow researchers to review information from their medical records relating to their optic neuritis diagnosis, investigations, treatments, and outcomes. 2. Be invited to provide a saliva sample for genetic analysis. 3. Complete questionnaires about their lifestyle/risk factors, quality of life, and views on genetic risk prediction. 4. Allow researchers to track long-term health outcomes using information from their NHS records

The aim of this observational study is to: (1) describe current knowledge and practices related to foot care in care homes; (2) understand how care home staff, residents and/or family caregivers perceive foot care knowledge and practices. For the first study, the investigators are conducting a survey, and this will involve recruiting care staff working in care homes, managers of care homes, and staff in regular contact with care home residents (e.g. clinicians). The second study will involve interviews with care home staff (carers, care home managers and health professionals) and care home residents and/or their family representative.

The aim of the trial is to understand whether a computerised tool designed to quickly spot problems in brain scans (MIDI) can help doctors diagnose cases faster. This will help patients by getting them the treatment they need sooner. How useful doctors find the tool will also be measured, and whether it is cost-saving for the National Health Service (NHS).

Background: The developmental absence of 1-2 upper front teeth is a common condition, affecting 1 in 50 people worldwide, and affects smile aesthetics and quality-of-life. Treatment is often undertaken in teenagers, but the outcomes have lifelong consequences. Treatment options involve either creating space for a false tooth, or closing space and disguising the adjacent tooth as the missing tooth; both options have their own advantages, disadvantages and long-term considerations, and treatment often requires input from multiple dental specialties. Advances in orthodontic techniques mean more patients can be treated with either approach, therefore, the ideal treatment plan becomes more subjective and based upon the patient's preferences. Aim: To develop a Patient Decision Aid (PDA), a decision-making support tool to help young people (and parents/guardians) with developmentally missing upper front teeth choose the best treatment option for them. Approach: First, the investigators will gather information from stakeholders involved in the decision-making process to understand their needs. Interviews will be conducted with young people with developmentally missing upper front teeth and their parents/guardians about their experiences, expectations, and preferences regarding treatment decision-making. Information will also be sought from clinicians involved in this process about their experiences of the decision-making process, via focus groups. These will be carried out across two NHS hospitals with special clinics for missing teeth. Then, the information obtained from both patient and clinician stakeholder groups will help the investigators to develop a PDA, following international guidelines. PDA development will occur alongside ongoing input and feedback from a Development Panel (which will include patients and clinician representatives) to optimise content, acceptability, and accessibility. The final approved PDA will then be trialled in a later pilot study.

The goal of this study is to learn about the body's response to cannabis based products in sleep deprived people who are currently experiencing anxiety but are otherwise healthy.

This prospective observational cohort study aims to investigate whether intracranial Local Field Potentials (LFPs) recorded from implanted Deep Brain Stimulation (DBS) devices are associated with neuropsychiatric symptoms in people with Parkinson's disease (PD). The study will focus on paroxysmal anxiety, impulse control disorders, and hallucinations. Twenty participants with Parkinson's disease and an implanted Medtronic Percept DBS device will be recruited. Participants will complete behavioural and clinical assessments and will use the event-marking functionality of the DBS device to record symptom episodes over a monitoring period of approximately 120 days. Brain activity will be passively recorded during this period. The study will evaluate relationships between LFP signals, symptom occurrence, behavioural task performance, and clinical symptom severity measures. Machine learning approaches will be used to identify electrophysiological patterns associated with neuropsychiatric symptom states at an individual level. The findings may improve understanding of the neural mechanisms underlying neuropsychiatric symptoms in Parkinson's disease and support the future development of personalised adaptive neuromodulation approaches.

The goal of this observational study (a single-site, prospective longitudinal cohort study) is to understand how the health information needs and information-seeking behaviours of pregnant women and their partners change over time, and to identify the factors linked to unmet information needs, in pregnant women aged 18 or over attending routine first-trimester care in the UK, together with one optional nominated partner (also aged 18 or over), followed from early pregnancy (11-13 weeks' gestation) to around 6-8 weeks postpartum. The main questions it aims to answer are: How do health information needs and information-seeking behaviours evolve across pregnancy and the postpartum period for women and their partners (measured as longitudinal change in the Information Mismatch Index)? What barriers, facilitators, and sociodemographic factors are associated with unmet information needs, and how do the needs of women and their partners align or diverge? This study has no comparison group or intervention; it is non-interventional and does not involve randomisation, treatment allocation, or any change to clinical care. Instead of comparing arms, researchers will examine how needs change over time and will explore differences between women and partners, and associations with health literacy, wellbeing, and optional passive digital data. Participants will: Complete short app-delivered questionnaires at four milestone timepoints (around 11-13 weeks, 20-22 weeks, 35-36 weeks' gestation, and 6-8 weeks postpartum), each taking no longer than about 20 minutes and covering information needs, information-seeking behaviour, trust, health and digital literacy, mental health, quality of life, social support, and relationship satisfaction. Optionally complete brief biweekly check-in surveys between milestones (about 2-3 minutes each) on recent information needs. Optionally consent to electronic health record linkage and to sharing passive smartphone- and wearable-derived health metrics (e.g. steps, sleep, heart rate) via their own devices.

Supporting people with psychosis to manage their emotions using virtual reality Many people who have experienced psychosis feel overwhelmed by their emotions. Emotions get in the way of doing what matters to them. They want support to manage emotions differently. There is evidence that people with psychosis find talking therapies that teach skills for managing emotions helpful. People said it helped them to understand and manage their emotions. However, they also wanted more help to apply skills they learned to their lives. It is hard to help people to use therapy skills in real-life situations. Therapists cannot be present when the skills are needed. One solution is to use virtual reality (VR) to bridge the gap between the clinic and real-life. VR involves using a headset to see and hear a very life-like computer-generated simulation of everyday life situations. People with psychosis find VR therapies engaging and helpful. It can feel safer to try things out in VR. Guided by the feedback of people with psychosis, this research will evaluate a novel therapy to help people with psychosis manage their emotions. Face-to- face therapy will be combined with VR so that people can practice emotion regulation skills safely with "live" coaching from a therapist. This should support people to use these skills when they need them. Fifteen people with psychosis will be offered the therapy. Everyone will be asked what they think of it and complete questionnaires before and after therapy to see what impact it had on their lives. A lived experience advisory group will support all aspects of the research process.

This is a clinical trial aimed to investigate if a novel phytochemical and fibre-rich snack can improve perimenopausal symptoms and well-being in perimenopausal women aged 40-55 and not on hormone replacement therapy. Hypothesis: The investigators hypothesise that the phytochemical and fibre-rich snack will improve perimenopausal symptoms via a gut microbiota mediated mechanism. Main research questions: Does eating the snack every day lower menopause symptoms such as hot flushes, night sweats, mood changes, and sleep problems? Does the snack improve mood, stress, anxiety, sleep, and overall quality of life? Does the snack improve the balance of bacteria in the gut, and could this be part of how it helps symptoms?

The aim of this randomised controlled trial is to investigate the effects of plant foods on gastrointestinal and cardiometabolic health in healthy adults aged 30-70 years old. The main question it will answer is "what is the effect of plant foods on alpha-diversity of the gut microbiota?". Researchers will compare two diets containing plant foods to see if they have different effects on gastrointestinal and cardiometabolic health. Participants will be asked to replace all their meals, snacks and drinks with those provided by the study team for four weeks (6 days/week). Participants will also be asked to attend the research facility on three occasions to: * Provide a blood sample * Provide a urine sample * Provide a stool sample * Have their body composition assessed * Have an ultrasound of their artery (arm) * Have their blood pressure measured * Answer questionnaires related to dietary intake, mental health, physical activity, quality of life, diet acceptability and adherence

This study will explore whether a daily probiotic drink containing Lactobacillus casei Shirota (LcS) can help improve immune function and reduce inflammation in women going through the menopausal transition. Hormonal changes during this stage of life can affect the immune system, gut health, and skin, sometimes leading to increased inflammation or conditions such as eczema, acne or rosacea. Participants will consume either a low-sugar LcS probiotic drink or a skimmed milk control drink every day for eight weeks. The study will assess markers of immune ageing, inflammation, skin health, wellbeing, and hormone levels. The results will help determine whether a safe, non-hormonal probiotic approach may support immune and skin health during the menopausal transition.

HFpEF (heart failure with preserved ejection fraction) is a condition in which the heart muscle becomes stiff and can't pump blood properly. People living with HFpEF also often have coronary artery disease, where the blood vessels that supply the heart are narrowed or blocked. It is not yet know whether opening these arteries with stents improves symptoms or quality of life with HFpEF. REPRIEVED is a randomised clinical trial that aims to find out if heart stents can improve quality of life for people living with heart failure with preserved ejection fraction (HFpEF) and coronary artery disease. Researchers will compare two groups of people; those who have a stent procedure to those who have a placebo procedure. The placebo procedure feels the same as a stent procedure but does not include a stent. 350 people with HFpEF and coronary artery disease will be asked to take part. Participants will be monitored over a period of 6 months to see if and how quality of life changes. Before the procedure, participants will be asked to complete a short health questionnaire, have a blood test, undergo an electrocardiogram (heart tracing) and scans of their heart. On the day of the procedure, the participant will come to the hospital for an angiogram and will be randomly allocated to have either treatment with a stent or the placebo procedure without a stent. Participants will not know whether they have received heart stents. This helps researchers know that any improvements in their quality of life are not just related to how they feel about the stenting treatment. Participants will then be contacted by a member of the research team at 3 months and 6 months after their procedure. At 3 months, participants will complete a short health questionnaire either by phone or during a hospital visit. At 6 months, participants will attend the hospital to complete a short health questionnaire, have blood tests, a scan of the heart (echocardiogram) and an electrocardiogram (heart tracing) to measure any changes in the heart. Participants will be told whether they received the stent procedure or the placebo procedure.

Bipolar depression is a long-lasting and disabling condition, and many people continue to experience depressive symptoms despite standard treatments. Transcranial direct current stimulation (tDCS) is a non-invasive form of brain stimulation that uses a very small electrical current applied through the scalp and has shown promise as a treatment for depression. This study aims to find out whether a home-based tDCS device is effective and safe in reducing symptoms of bipolar depression when compared with a placebo (sham) treatment. The study will also look at how acceptable the treatment is to participants and how well people are able to use the device at home. Who can participate? Adult patients aged 18 years and over who have a diagnosis of bipolar disorder and are currently experiencing a depressive episode. What does the study involve? Participants must meet specific eligibility criteria, which will be assessed by the research team. People who do not meet the study criteria or for whom tDCS is not suitable will not be able to take part. Participants will be randomly assigned to receive either active tDCS or a placebo (sham) treatment. Neither the participant nor the researchers assessing outcomes will know which treatment has been assigned. Participants will use a study device at home over a defined treatment period and will complete a series of assessments at set time points. These include clinician-rated interviews and self-reported questionnaires about mood and well-being. Device use and adherence data will be collected electronically. Participants will also be monitored for any side effects throughout their involvement in the study. Although the study is multi-site, participation is primarily remote, with most study activities completed from the participant's home. What are the possible benefits and risks of participating? Participants may experience an improvement in depressive symptoms. Information gained from this study may help improve future treatments for bipolar depression. tDCS is generally well tolerated. Possible side effects include mild and temporary sensations such as tingling, itching, headache, or skin irritation at the electrode sites. All participants will be monitored for adverse events, and appropriate support will be available if needed. Where is the study run from? The study is run from King's College London in collaboration with NHS research sites across the UK. When is the study starting and how long is it expected to run for? April 2026 to October 2027 Who is funding the study? The National Institute for Health and Care Research (NIHR), UK. Who is the main contact? Professor Cynthia Fu, the Chief Investigator at King's College London, [email protected]

Some people experience chest pain and shortness of breath, but when they have tests, no blockages are found in their main heart arteries. The most common cause of symptoms is related to abnormalities in the small blood vessels, also known as 'small vessel angina' or Coronary Microvascular Dysfunction (CMD). Currently, the diagnosis of CMD requires additional measurements of blood flow in the heart vessel during a minimally invasive procedure known as a coronary angiogram. CMD affects many people and can lead to repeated hospital visits and a lower quality of life, and diagnosing the condition leads to better patient outcomes. However, there are still no widely available, proven treatments for this condition and therefore several patients remain symptomatic. This study aims to find better ways to treat CMD, especially by understanding how the heart uses energy and how this might relate to symptoms.

The aim of this study is to investigate the role of the immune system in psychotic symptoms and their response to treatment. The investigators will collect blood and cerebrospinal fluid samples from participants with psychosis symptoms who are about to start or change to a new regular antipsychotic treatment as well as a control group for comparison. Participants will be assessed at two main timepoints, at visit 1 (Week 0) and at visit 2 (4 +/-2 weeks). For participants with psychosis symptoms visit 1 will take place at the start or change of antipsychotic medication. The studies goal is to identify biomarkers that can aid in diagnosis, prognosis, treatment selection, and tracking treatment response. The investigators aim to recruit participants from the following groups: 1. Individuals with psychosis symptoms presenting to acute or outpatient services who are due to be started on or change to a new regular antipsychotic medication. 2. Age- and sex-matched control participants without neuropsychiatric disease. Findings could potentially impact the treatment of psychotic illnesses by offering mechanistic insights into targeted immune-based interventions for these disorders through high-resolution immunophenotyping techniques alongside targeted immunological assays. Ultimately, the research aims to contribute valuable resources for future studies exploring the connection between immune processes and neuropsychiatric conditions.

Cannabis contains delta-9-tetrahydrocannabinol (THC), which causes intoxication. People who use cannabis frequently often develop tolerance, meaning they need to use more THC to feel the same effects. Cannabidiol (CBD) is another compound found in cannabis that is not intoxicating and may influence how THC affects the body and brain. This study will examine whether taking CBD changes how much THC heavy cannabis users consume to reach their usual level of intoxication. The study will also develop a new laboratory method that allows participants to safely and gradually self-administer THC using a vaporiser, similar to how cannabis is used in real-world settings. The study will include around 30 adults who use cannabis heavily. In the first stage, participants will take part in pilot sessions to help refine the THC administration procedure. In the second stage, participants will attend two study sessions and receive a single oral dose of CBD or placebo, in a random order. After this, they will inhale THC using a vaporiser and decide when to stop based on how intoxicated they feel. Researchers will measure how much THC is used, along with mood, mental health symptoms, thinking abilities, physical measures such as heart rate and blood pressure, and blood levels of THC and CBD. The results will help improve understanding of cannabis tolerance and whether CBD alters responses to THC in heavy cannabis users.

A feasibility trial called PROFIT has previously shown that FMT administered endoscopically into the jejunum in patients with cirrhosis is safe and feasible and have identified some potential mechanisms of action that warrant further interrogation. The aim of the PROMISE Trial is to evaluate the efficacy and mechanisms of action of encapsulated FMT (versus placebo) to reduce infection and mortality in patients with alcohol-related and metabolic dysfunction-Associated Steatotic Liver (MASLD) cirrhosis.