Cannabis-Based Medicines Show Promise for Insomnia, UK Study Finds

A recently published study found that cannabis-based medicines may help patients with insomnia symptoms (1). Worldwide about 10% of the adult population is affected by insomnia, the study explains. Current treatments are cognitive behavioral therapy for insomnia (CBT-I) and prescription medications, though these come with the challenges of a shortage of providers and little evidence of long-term effects, respectively. Examinations of the therapeutic potential of cannabis-based treatments for insomnia have grown, it adds. However, the research on the efficacy of cannabinoid medicinal products for insomnia is limited.

UK Medical Cannabis Registry Study Methods

Researchers aimed to investigate how prescribed cannabis-based medicinal products affected patient-reported outcome measures (PROMs) for insomnia as well as any adverse events (AE). “UK Medical Cannabis Registry: A clinical outcomes analysis for insomnia,” was published in PLOS Mental Health in August 2025. In this study, data was analyzed from 124 adult patients enrolled in the UK Medical Cannabis Registry (UKMCR) who were prescribed cannabis-based medicinal products for insomnia. Changes in PROMS score were analyzed at months 1, 3, 6, 12, and 18 during follow ups.

The UKMCR was founded in 2019 and currently under private ownership of Curaleaf Clinic. The cannabis prescriptions were given after a confirmed diagnosis of insomnia and after confirmation that at least two other licensed medications did not result in improvements.

The Cannabis Prescriptions

• At baseline, the median daily CBD dose was 1 mg /day increased to 10 mg/day by month 3 and sustained to month 18
• At baseline the median daily dose of THC was 20 mg/day increased to 120 mg/day by month 18

Benefits Reported by Patients

Improvements were seen in subjective sleep quality, anxiety, and health-related quality of life (HRQoL) PROMs.

• Single-Item Sleep Quality Score (SQS) improved from baseline (2.66 ± 2.41) to 18 (3.81 ± 2.90) months
• Generalized Anxiety Diorder-7 (GAD-7) scores improved from baseline (9.59 ± 6.31) to 1 month (4.99 ± 4.91), though improvements over the subsequent months were small yet still statistically significant
• The EuroQol-5 Dimension-5 Level health questionnaire dimensions of pain/discomfort, anxiety/depression, and index values were all shown to be significant

Adverse Events Reported

A total of 112 AE were reported 11 participants, and out of these, 53 were considered mild, 48 were moderate, and 11 were severe. None were considered disabling or life threatening. The most common were fatigue, insomnia, and dry mouth, though the researchers noted that the AEs could be indicative of symptoms from insomnia.

Limitations and Future Research

Limitations to the study include the lack of long-term data collection greater than one week prior. Additionally, recall bias is possible from PROM questionnaires; possible selection bias of the study group for higher socioeconomic backgrounds; the limited generalizability of the results for the greater population due to the limited cohort size; and limited data on the potential impacts of cannabis strains, insomnia sub-types, and patient comorbidities.

Overall, the researchers stated that the results indicated a positive association between the cannabis-based medications and improvements in sleep. “Whilst the study demonstrates good tolerability and improvement in PROMs within 18-months, the findings also indicate that this improvement may not be sustained over a longer period, and tolerance could develop,” they explained. “These findings can be used to inform future RCTs.”

“Conducting this long-term study provided valuable real-world evidence on patient outcomes that go beyond what we typically see in short-term trials,” stated study author Simon Erridge, MBBS, in a news article from CuraLeaf Clinic, where he is the Research Director (2). ”It was particularly interesting to observe signs of potential tolerance over time, which highlights the importance of continued monitoring and individualized treatment plans.”

References

1. Aggarwal, A.; Erridge,S.; Cowley, I.; Evans, L.; Varadpande, M.; Clarke, E.; McLachlan, K.; Coomber, R.; Rucker, JJ.; Weatherall, MW.; Sodergren, MH. UK Medical Cannabis Registry: A clinical outcomes analysis for insomnia, PLOS Mental Health. 2025. DOI: 10.1371/journal.pmen.0000390
2. Curaleaf Clinic. Medical Cannabis for Insomnia: Latest Findings from the UK Medical Cannabis Registry. September 9, 2025. https://curaleafclinic.com/medical-cannabis-for-insomnia-latest-findings-from-the-uk-medical-cannabis-registry/ (accessed Sep 18, 2025).