The primary aim of this Real-World Evidence trial is to establish whether short-term (2 weeks) treatment of Chloral Hydrate is effective in patients with severe insomnia which is interfering with normal daily life, and where other behavioural and pharmacologic therapies have failed in a real world setting.

Inclusion Criteria:

• Aged ≥18 years and ≤75 years
• Participant is willing and able to give informed consent
• Clinically significant impairment from severe insomnia (eg. ISI score 22-28)
• Previous treatment with sleep therapies (behavioural and pharmacologic), which have failed. Defined as the presence of ongoing severe insomnia (ISI score 22-28), despite previous use of other sleep therapies.
• Able to adhere to trial procedures
• Willingness to take a pregnancy test prior to starting IMP treatment (participants of childbearing potential)

Exclusion Criteria:

• Pregnant or breastfeeding
• Taking any substances that significantly affect sleep during the 2 week IMP treatment period
• Starting any new behavioural sleep therapies* during the 2 week IMP treatment period
• At point of enrolment taking substances that affects sleep at greater than maximum licensed doses
• Other sleep diagnosed/suspected sleep disorders (restless legs, periodic limb movements, unusual sleep timings (indicative of advanced/delayed sleep, etc), parasomnias
• Known severe hepatic impairment
• Known moderate / severe renal impairment / eGFR <60
• Known severe sleep apnea
• Known severe cardiac disease
• Known cardiac disease with QT prolongation
• History of myocardial infarction in the last 12 months
• History of stroke or TIA
• Taking medication that may cause QT prolongation
• Active gastritis, oesophagitis, gastric or duodenal ulcers or perforation
• Susceptible to acute attacks of porphyria
• Hypersensitivity to Chloral Hydrate or to any of the excipients (glycerol, liquid glucose, citric acid, sodium citrate, sodium benzoate, saccharin sodium, essence of passion fruit [containing natural flavouring, artificial flavouring, propylene glycol], and purified water)
• Individuals with a history of alcohol or drug abuse or dependence
• Patients taking antipsychotic medication in last 12 months
• History of overdose or attempted overdose
• History of significant psychiatric disease
• Patients are taking one of the drugs listed as interacting with Chloral Hydrate and would need to continue taking these during the trial: alcohol, CNS depressants, antipsychotics, hypnotics, anxiolytics/sedatives, antidepressant agents, centrally acting muscle relaxants, narcotic, analgesics, anti-epileptic drugs, anaesthetics and sedative antihistamines, intravenous furosemide, anticoagulants.
• Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial.
• Participants who have participated in another research trial involving an investigational product in the past 4 months
• Participants of childbearing potential (participants who are anatomically and physiologically capable of becoming pregnant), or have a partner of childbearing potential, not willing to use highly effective contraceptives** for the duration of the trial, and who do not confirm a negative pregnancy test prior to starting the IMP.