A randomized clinical trial published in the Journal of Sleep Research found that cannabinol (CBN), a naturally occurring compound derived from cannabis, improved several key measures of sleep quality and reduced the time it took participants to fall asleep, though it did not significantly reduce time spent awake during the night.

The study was conducted by researchers from Macquarie University and The University of Sydney and enrolled 20 adults between the ages of 25 and 65 with physician-diagnosed insomnia disorder. All participants met DSM-5 and ICSD-3 criteria and had an Insomnia Severity Index score of 15 or higher. The trial took place at the Woolcock Institute of Medical Research in Sydney over a 13-month period.

In the double-blind, placebo-controlled, three-arm crossover study, participants received a single 2 mL oral dose of either 30 milligrams or 300 milligrams of CBN, or a matched placebo, with a two-week washout period between treatments. Sleep was measured using overnight polysomnography, with wake after sleep onset (WASO) serving as the primary outcome.

Neither the 30 mg nor 300 mg dose significantly reduced WASO compared to placebo. However, the 300 mg dose was associated with a statistically significant increase in non-rapid eye movement stage 2 sleep, improved subjective sleep quality, shorter time to fall asleep, and reduced electroencephalographic arousal indices.

The authors concluded that while CBN did not significantly impact the primary endpoint, secondary outcomes suggest that CBN could lead to sleep-related improvements that warrant larger and longer-term trials.