Patients suffering from chronic insomnia have shown sustained improvements in sleep quality after treatment with cannabis-based medicinal products over an 18-month period, according to new research published in PLOS Mental Health.
The study, led by researchers from Imperial College London, followed 124 patients with primary insomnia who had failed to respond to at least two conventional treatments. Results showed significant improvements in sleep quality that were maintained throughout the entire study period.
“Over an 18-month period, our study showed that treatment for insomnia with cannabis-based medicinal products was associated with sustained improvements in subjective sleep quality and anxiety symptoms,” said Dr Simon Erridge, Research Director at Curaleaf Clinic and co-author of the study. “These findings support the potential role of medical cannabis as a medical option where conventional treatments have proven ineffective, though further randomised trials are needed to confirm long-term efficacy.”
The research tracked patients using standardised sleep quality assessments and found marked improvements from baseline measurements. Sleep quality scores improved significantly at one, three, six, 12, and 18-month intervals, though the magnitude of improvement showed some decline over time, potentially indicating tolerance development.
Beyond sleep improvements, patients also reported substantial reductions in anxiety symptoms and enhanced quality of life measures. The study found improvements in usual activities, pain management, and mood-related indicators.
Safety concerns often associated with sleep medications were notably limited in this study. Only 11 patients (8.87%) reported adverse events, with the most common being fatigue, temporary insomnia, and dry mouth. No life-threatening or disabling side effects were recorded.
The research represents one of the longest follow-up studies examining cannabis-based treatments for insomnia, providing valuable real-world evidence for a condition that affects approximately 10% of adults globally.
Traditional insomnia treatments, including benzodiazepines and Z-drugs, carry risks of dependence and withdrawal symptoms when used long-term. Cognitive behavioural therapy for insomnia (CBT-I), whilst effective, remains difficult to access due to limited trained providers.
The endocannabinoid system, which cannabis compounds interact with, plays a crucial role in sleep regulation. The study examined various cannabis formulations, with dried flower products being the most commonly prescribed treatment.
“Conducting this long-term study provided valuable real-world evidence on patient outcomes that go beyond what we typically see in short-term trials,” noted Dr Erridge. “It was particularly interesting to observe signs of potential tolerance over time, which highlights the importance of continued monitoring and individualised treatment plans.”
The researchers acknowledge several limitations, including the observational nature of the study and the absence of a control group. The findings may not be generalisable to the broader population, as participants were primarily from private medical cannabis clinics and many had previous cannabis experience.
The study’s authors emphasise that randomised controlled trials will be necessary to establish definitive evidence of safety and efficacy before widespread clinical adoption can be recommended.
