How MCPH describes medical cannabis evidence
Every condition page on MCPH includes an evidence-grade indicator. The four levels show how the evidence has been assessed and why clear labelling helps patients make more informed decisions.
Evidence grading at MCPH is based on the type, quality, and consistency of available research, not on anecdotal reports, clinic marketing, or patient testimonials. We draw primarily on NICE guidelines, NHS guidance, published systematic reviews, randomised controlled trials (RCTs), and observational studies where they are the best available source.
The four evidence levels
Strong evidence
What it means: The condition has at least one NICE-reviewed, licensed cannabis-based medicine with a defined indication, supported by multiple randomised controlled trials. NICE guidance provides a positive recommendation for a specific patient group, product, and clinical context.
Examples on MCPH: MS spasticity (Sativex/nabiximols), chemotherapy-induced nausea and vomiting (nabilone), and defined severe treatment-resistant epilepsy syndromes (Epidyolex).
This rating applies to a defined medicine, patient group and clinical context. It does not predict a prescription or result for every person, and it does not transfer to unlicensed products.
Moderate evidence
What it means: Some randomised controlled trials or systematic reviews exist suggesting possible benefit, but the evidence is limited, mixed, or not yet reflected in a positive NICE recommendation. NICE may explicitly not recommend cannabis-based medicinal products for this use, or may have no recommendation at all.
Examples on MCPH: Chronic pain (some RCTs, but NICE does not recommend), neuropathic pain (some controlled studies, mixed results).
The finding remains uncertain. It cannot establish treatment for everyone or tell a specialist what is appropriate for an individual patient.
Limited evidence
What it means: The evidence base is mostly observational studies, pre-clinical research, small uncontrolled trials, or case series. NICE does not provide a positive recommendation for cannabis-based medicinal products for this condition. Patient-reported experiences may exist but have not been validated through controlled research.
Examples on MCPH: Fibromyalgia, anxiety, PTSD, ADHD, depression, arthritis and joint pain, migraine and headache disorders, sleep problems.
The published evidence is not strong enough for a treatment claim. Be cautious about confident promises, especially where they overlook risks or clinical context.
Patient reports only
What it means: No substantial clinical trials exist for this condition, but there is strong patient-reported interest, and some people describe benefit from prescribed or self-managed cannabis. The evidence is anecdotal and has not been tested through controlled research.
Examples on MCPH: Conditions such as endometriosis, Ehlers-Danlos syndromes, and ME/CFS may fall into this category where formal trial evidence is absent but patient discussion is active.
Patient experience can raise useful questions, but it cannot establish a treatment claim. A clinician needs to weigh individual risks against the limited evidence.
How we assign a level
For each condition page, the MCPH editorial team reviews:
- NICE guidance: Does NICE NG144 or a condition-specific guideline provide a recommendation, and if so, what is its direction?
- Licensed medicine status: Is there a UK-licensed cannabis-based medicine with a marketing authorisation for this condition?
- RCT evidence: Are there published randomised controlled trials, and if so, how many and of what quality?
- Systematic reviews: Have systematic reviews or meta-analyses been published, and what do they conclude?
- NHS guidance: What does NHS patient-facing guidance say about cannabis-based medicines for this condition?
- Observational and real-world data: Where higher-quality evidence is absent, what do registries, observational studies, or patient-reported outcomes show?
The level assigned reflects the best available evidence at the time of review. Levels are re-assessed when significant new NICE guidance, systematic reviews, or large RCTs are published.
Using an evidence rating
Medical cannabis information online varies enormously in quality. Some sources present cannabis as a universal treatment with few risks. Others dismiss patient experience entirely. MCPH explains both the research and its limits in plain terms.
The evidence-grade label on each condition page is there to help you understand how strong the research foundation is before you speak to a clinician. It is not a substitute for individual clinical assessment, and it cannot tell you whether a treatment is appropriate for your specific circumstances.