Comprehensive evidence map finds medical cannabis most effective for pain, spasticity, and seizures | Research

The takeaway

Across 194 studies covering 71 health outcomes, medical cannabis showed positive or potentially positive effects in 57% of all treatment descriptions, with the strongest high-quality evidence for pain, insomnia, seizures, anxiety, and muscle spasticity.

Health policymakers, clinicians evaluating medical cannabis programs, researchers identifying evidence gaps, and patients seeking information about specific conditions.

What the researchers found

Of 489 descriptions of treatment effects across 71 health outcomes, 278 (57%) reported positive or potentially positive effects. When limited to high-quality systematic reviews (AMSTAR 2), 42 of 67 treatment descriptions (63%) across 20 outcomes were positive or potentially positive. Top outcomes: pain, insomnia, seizures, anxiety, muscle spasticity, MS symptoms, urinary incontinence, anorexia, and patient safety.

Why it matters

This is one of the most comprehensive evidence maps of medical cannabis to date, covering 71 distinct health outcomes. It moves beyond condition-by-condition reviews to show the full landscape of where cannabis medicine has demonstrated benefit.

The numbers in context

1,840 initial references. 194 included. 71 health outcomes. 489 treatment effect descriptions. 278 (57%) positive/potentially positive. High-quality subset: 42/67 (63%) positive across 20 outcomes.

How the study worked

Systematic evidence mapping of 194 studies selected from 1,840 initial references, using two independent blinded researchers and Rayyan screening software. Quality assessed with AMSTAR 2.

What this study cannot tell us

Evidence maps identify and categorize evidence but do not meta-analyze effect sizes. Quality varies widely across included studies. Cannabis formulations and doses vary enormously.

How to read the evidence

Rigorous systematic mapping methodology with AMSTAR 2 quality assessment. The breadth of coverage is a strength, though evidence depth varies by condition.

When this study was published

2024 publication.

The bigger picture

Policy debates about medical cannabis often rely on cherry-picked studies. This evidence map provides a structured, comprehensive view showing that while evidence is strongest for pain and neurological conditions, positive signals exist across a much wider range of health outcomes.

Questions still open

For the 43% of treatment descriptions that were not positive, is the cannabis ineffective or is the evidence simply insufficient?
Which of the 71 health outcomes have enough preliminary positive evidence to justify definitive clinical trials?

Common questions

What conditions does medical cannabis help with?

The strongest high-quality evidence supports its use for various types of pain, insomnia, seizures, anxiety, muscle spasticity, MS symptoms, urinary incontinence, and anorexia.

Is the evidence for medical cannabis strong?

It varies by condition. When limited to only high-quality systematic reviews, 63% of treatment descriptions were still positive. Pain and neurological conditions have the most robust support.

Read the original research

Charting the therapeutic landscape: a comprehensive evidence map on medical cannabis for health outcomes.

Frontiers in pharmacology, 15, 1494492

View on PubMed ↗Publisher’s paper ↗

Citation

Montagner, Patrícia; de Salas Quiroga, Adán; Ferreira, Arthur Schveitzer; Duarte da Luz, Barbara Marinho; Ruppelt, Bettina Monika; Schlechta Portella, Caio Fabio; Abdala, Carmen Verônica Mendes; Tabach, Ricardo; Ghelman, Ricardo; Blesching, Uwe; Perfeito, João Paulo Silvério; Schveitzer, Mariana Cabral. (2024). Charting the therapeutic landscape: a comprehensive evidence map on medical cannabis for health outcomes.. Frontiers in pharmacology, 15, 1494492. https://doi.org/10.3389/fphar.2024.1494492