FMT for Insomnia Disorder (FMT-SLEEP)

Insomnia disorder is characterized by difficulty initiating or maintaining sleep, or early morning awakening accompanied by symptoms such as irritability or fatigue during wakefulness. It is one of the most prevalent health concerns in the population and in clinical practice, with more than one-third of adults experience transient insomnia at some point in their lives. In about 40% of cases, insomnia can develop into a more chronic condition. The COVID-19 pandemic has further aggravated sleep problems, with a reported global prevalence of sleep disturbances reaching 40-49%. The implications of insomnia disorder are substantial, encompassing social, economic, psychological, and physical aspects. Behavioural, cognitive, and pharmacological interventions can all be effective for insomnia. Pharmacological treatment is commonly used but may have drawbacks such as adverse events and inconclusive safety data for certain medications. Many licensed drugs can be effective in the acute treatment of insomnia but are associated with poor tolerability, or information about long-term effects is not available. Alternatively, cognitive behavioural therapy for insomnia (CBT-I), has been recommended as the first-line treatment for chronic insomnia in adults of any age according to the American and European guidelines. But issue of accessibility, compliance/adherence, and moderate response limit the practicality and applicability of CBT-I. Recent evidence suggests that the gut microbiota plays a role in regulating sleep behaviour, both directly and indirectly. This has led to the exploration of gut microbiota modulation as a potential therapy for insomnia. Faecal microbiota transplantation (FMT), which is the infusion of faeces from healthy donors to the gut of affected subjects, has shown impressive therapeutic effects for various diseases. Several real-world studies have demonstrated improvements in symptoms of insomnia disorder following FMT. One previous study also indicated the