It has been reported that dexmedetomidine, alpha-2 adrenoceptor agonist, can activate endogenous neural sleep pathways in the central nervous system. This randomised, double-blinded and controlled trial was designed to investigate whether dexmedetomidine can improve/treat chronic insomnia patients. Its effects on sleep quality and improvement, EEG and circadian rhythm, brain connectivity, cognition and biomarker changes are determined.

Insomnia is a common sleep disorder characterized by difficulty in starting or maintaining sleep, or poor sleep quality and shortened sleep time. The prevalence of insomnia is about 10-20% of population worldwide; Of which about approximately 50% are chronic. Insomnia is a risk factor for cognitive impairment and mental disorder development, and other diseases. Non-pharmacological interventions, e.g. physio-therapy, are often ineffective. Benzodiazepines and their derivatives are commonly prescribed for those patients but their side effects and long-time residual sleepy actions are very risky.

Dexmedetomidine is a highly selective α2 adrenergic receptor agonist with sedative, analgesic and anti-anxiety effects together with remarkable cytoprotective effects. It is widely used as a sedative. Dexmedetomidine was reported promote sleep. It can also modulate "clock" protein expression and hence afford a regulatory effects on the circadian rhythm. This randomised, double-blinded and controlled trial was designed to investigate whether dexmedetomidine can treat chronic insomnia patients. Its effects on sleep quality and improvement, EEG and circadian rhythm, brain connectivity, cognition and biomarker changes are determined. All participants are randomly assigned to receive either dexmedetomidine (a 0.5μg/kg bolus injection for 10 minutes followed by 0.1µg/kg/hr) or placebo (normal saline infusion with an identical protocol as Dex) for 8 hrs from 10pm to 6 am.

Inclusion Criteria:

• Age between 18- 65 years old
• Body mass index (BMI) between 18 and 35 kg/m^2；
• Clinical diagnosis of chronic insomnia；
• Must be able to communicate with site personnel

Exclusion Criteria:

• Clinical diagnosis of mental disorders;
• Pregnancy;
• Current use of psychotropic drug ;
• Clinical diagnosis of neurological diseases

All of the individual participant data collected during the trial, after deidentification.

Immediately following publication.No end date.

Anyone who wishes to access the data for any research purpose.They can get all of the individual participant data collected during the trial, after deidentification.Proposals should be directed to d.ma@imperial.ac.uk/yqz12471@rjh.com.cn.To gain access, data requestors will need to sign a data access agreement. Proteomics data will be available at a website(iprox) following publication.