Cannabis Medicines Show Promise for Treating Insomnia

The Growing Challenge of Insomnia

Insomnia is one of the most common sleep disorders worldwide, affecting an estimated 10% of adults chronically and even more in the United States.  Beyond the restless nights, poor sleep leads to anxiety, depression, cardiovascular issues, and lower productivity.  Traditional treatments—like benzodiazepines, Z-drugs, and melatonin—offer short-term relief but carry risks of dependence, limited effectiveness, and high relapse rates.

Against this backdrop, researchers are investigating cannabis as a medical product and potential solution.  A recent example of this comes from the UK Medical Cannabis Registry and a study¹ which was published in PLOS Mental Health (August 2025), adding fresh evidence that cannabis may help those struggling with chronic insomnia.

UK Medical Cannabis Registry Study: Key Results

In it, the study analyzed data from 124 adults diagnosed with primary insomnia and treated with cannabis-based medicines at Curaleaf Clinic locations across the UK.  Patients were tracked for up to 18 months, making this the longest-running real-world analysis of cannabis for insomnia to date.

Key Findings

Researchers observed notable improvements across several measures.  Sleep quality, measured by the Single-Item Sleep Quality Scale (SQS), improved significantly from baseline across all follow-up points.

Patients also reported reduced anxiety levels, as shown by lower scores on the Generalized Anxiety Disorder-7 (GAD-7) scale, pointing to cannabis’ dual benefit for both sleep and mental health.

Quality of life also improved, with gains in usual activities, pain/discomfort, and anxiety/depression scores from the EuroQol-5 Dimension-5 Level (EQ-5D-5L).

Importantly, cannabis was generally well tolerated: only about 9% of participants reported side effects such as fatigue, dry mouth, or mild dizziness, and none were severe or life-threatening.

While the most substantial improvements were evident in the early months, benefits generally persisted, albeit with a slight decline over time.  Researchers noted this trend may reflect tolerance development, where patients required higher doses of THC and CBD for the same effect.

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Why Cannabis May Work for Sleep

Cannabis interacts with the endocannabinoid system (ECS), which regulates mood, pain, and sleep.  THC, a partial agonist of the CB1 receptor, has been shown to shorten the time it takes to fall asleep, while CBD may reduce anxiety and promote relaxation.

The UK study used varying combinations of cannabis oils and dried flower, with many patients prescribed both.  By the 18-month mark, average daily doses were around 120 mg THC and 10 mg CBD, though individual regimens varied.

How This Fits Into Global Cannabis Sleep Research

This study is not an isolated finding.  It is just the latest to add weight to a growing body of evidence suggesting cannabis can improve sleep quality:

• A 2024 study² in Neuropsychopharmacology found that cannabinoids improved subjective sleep measures in patients with psychiatric disorders, particularly those with comorbid anxiety.
• A 2019 study³ in the Journal of Psychoactive Drugs reported that many adults purchasing cannabis at dispensaries cited improved sleep as a primary benefit, echoing patient experiences from clinical settings.

Together, these studies paint a consistent picture: whether in structured trials, observational registries, or patient surveys, cannabis shows potential to relieve insomnia symptoms.

Limitations and Cautions

As with most studies, there are clear limitations and cautions to be mindful of.  For example, this study was observational and not a randomized controlled trial (RCT).  That means placebo effects, patient expectations, or selection bias could influence results.

Additional concerns include the risk of tolerance, where patients may need higher doses for the same benefit; potential withdrawal effects such as disrupted sleep when stopping; and the fact that most participants had prior cannabis experience, limiting generalizability to cannabis-naïve patients.

The Bigger Picture

For now, cannabis-based medicines should be viewed as an emerging option for insomnia, particularly for patients who have not responded to conventional therapies.  The UK study suggests they can deliver short- to medium-term improvements in sleep quality, additional benefits for anxiety and quality of life, and generally safe outcomes when prescribed and monitored by physicians.

Insomnia is not only a personal struggle—it carries heavy economic and social costs.  Missed work, healthcare utilization, and mental health decline all trace back to inadequate sleep.  The UK’s latest findings highlight how cannabis could play a role in modern sleep medicine, alongside established tools.  If ongoing trials confirm these early results, cannabis may shift from an alternative remedy to a mainstream treatment option.

References:

<sup>1. Aggarwal, A., Erridge, S., Cowley, I., Evans, L., Varadpande, M., Clarke, E., McLachlan, K., Coomber, R., Rucker, J. J., Weatherall, M. W., & Sodergren, M. H. (2025). UK Medical Cannabis Registry: A clinical outcomes analysis for insomnia. PLOS Mental Health, 2(8), e0000390. https://doi.org/10.1371/journal.pmen.0000390
2. Arnold, J. C., Occelli Hanbury-Brown, C. V., Anderson, L. L., et al. (2025). A sleepy cannabis constituent: cannabinol and its active metabolite influence sleep architecture in rats. Neuropsychopharmacology, 50, 586–595. https://doi.org/10.1038/s41386-024-02018-7
3. Bachhuber, M., Arnsten, J. H., & Wurm, G. (2019). Use of cannabis to relieve pain and promote sleep by customers at an adult use dispensary. Journal of Psychoactive Drugs, 51(5), 400–404. https://doi.org/10.1080/02791072.2019.1626953</sup>