A Phase 2 interventional study of Dexmedetomidine and Placebo in Insomnia, sponsored by Woolcock Institute of Medical Research. Recruiting at 1 site in Australia. Open to participants aged 30 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-08-19.
Sponsored by Woolcock Institute of Medical Research · Phase 2, Interventional, and Other
This research project aims to better understand the neurobiological mechanistic underpinnings of insomnia disorder. The main question is whether cortical hyperarousal in individuals with insomnia disorder, measured by electroencephalograhic (EEG) infraslow oscillation coupling of sigma power during non-rapid eye movement (NREM) sleep and theta power during rapid eye movement (REM) sleep, is related to locus coeruleus activity.
This trial is a double-blinded, placebo-controlled, randomised controlled cross over trial of dexmedetomidine or placebo in adults with insomnia disorder. Participants will be recruited using social media, bulletin boards and patient referrals from the Woolcock Institute of Medical Research clinics. Participants will be asked to complete an online pre-screening webpage (RedCap) to check for eligibility, and provided with the Participant Information Sheet (PIS) and asked for contact details for an in-person screening visit. The participants will have the study explained in detail during the screening visit followed by written informed consent. The participant will then undergo a medical screening for diagnosis of insomnia disorder and the medical officer will sign the consent form. Thereafter, the participant will complete baseline questionnaires and be randomised to either dexmedetomidine or placebo for the 2 sleep laboratory visits. Participants will then be instructed to maintain their regular sleep-wake patterns for seven days before the first sleep laboratory visit (Visit 1). During Visit 1, participants will undergo a number of assessments (pre-sleep locus coeruleus activity measured using pupillometry, electroencephalography (EEG), functional near-infrared spectroscopy (fNIRS) before and during sleep and questionnaires about subjective hyperarousal. Participants will receive either dexmedetomidine or placebo. Following Visit 1, participants will have a 14-day washout, before Visit 2, which will repeat the procedures of Visit 1, but participants will receive the alternate condition (placebo or dexmedetomidine). The study will be coordinated from the Woolcock Institute of Medical Research, Sydney, Macquarie University, NSW, 2113, Australia.
Exclusion Criteria:
A 96 µg dexmedetomidine tablet taken during the sleep laboratory visit only
Drug: Dexmedetomidine
Matching placebo tablet taken during the sleep laboratory visit only
Drug: Placebo
A buccal tablet containing 96 µg dexmedetomidine will be taken before habitual bedtime.
Placebo tablets will contain identical excipient without the active ingredient (dexmedetomidine) and manufactured under the same condition as the active. Placebo tablets, packs and instructions will be identical in every respect to enable the double-blind study design.
Electrographic (EEG) signatures
Electrographic (EEG) infraslow oscillations (\~50 sec) of sigma power and sleep spindle coupling during non-rapid eye movement (NREM) sleep and theta power during rapid eye movement (REM) sleep.
Time frame: Baseline and 14 days
Sleep Fragmentation
Polysomnography (PSG) measure conducted during the intervention and control (wake after sleep onset)
Time frame: Baseline and 14 days
EEG power
Electroencephalographic (EEG) power during non-rapid eye movement (NREM) (stages 2 and 3) and rapid eye movement (REM) sleep. Unit of measurement is μV\^2.
Time frame: Baseline and 14 days
Neurovascular activity (fNIRS)
Measurement of global blood flow using functional near-infrared spectroscopy (fNIRS).
Time frame: Baseline and 14 days
Cardiopulmonary Coupling (CPC)
Cardiopulmonary coupling provides a global measure of autonomic function
Time frame: Baseline and 14 days
Pupillometry
Pupil sizes will be assessed as a surrogate of locus coeruleus activity
Time frame: Baseline and 14 days
Subjective hyperarousal
Pre-Sleep Arousal Scale (PSAS) before sleep. Scored by summing 16 items (rated 1 (not at all) to 5 (extremely)) with a total score between 16 to 80
Time frame: Baseline and 14 days
Subjective sleep quality
Self-reported rating of sleep quality (0-9) with higher scores indicating worse sleep. This will assessed in the morning after the overnight sleep study.
Time frame: Baseline and 14 days
Plan to share: Yes — Non-identifiable IPD will be shared upon reasonable request to the Principal Investigators.
Supporting information: Study protocol, Icf, Analytic code
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Sleep Initiation and Maintenance Disorders→
Woolcock Institute of Medical Research