Two-Thirds of Danish Medical Cannabis Patients Report Moderate to Large Benefits | Research

The takeaway

67% of Danish medical cannabis patients reported moderate to large treatment effects, but over 10% experienced three or more side effects, and side effects were equally common regardless of perceived benefit.

Medical cannabis patients and providers interested in real-world benefit and side effect data.

67% reported moderate to large effect; side effects unrelated to benefit

What the researchers found

Among 1,044 Danish medical cannabis users, 67% reported moderate to large perceived benefit. Over half experienced side effects, with more than 10% reporting three or more. Side effects were equally common among those reporting strong benefit and those reporting little to no benefit. Side effects clustered into four groups: cognitive dysfunction, dizziness, xerostomia (dry mouth), and feeling high.

Why it matters

Understanding the side effect landscape is crucial for informed decisions about medical cannabis. The finding that side effects are unrelated to perceived benefit means patients can't assume that experiencing benefit means they'll avoid side effects, or vice versa.

The numbers in context

1,044 patients surveyed. 67% reported moderate to large effect. Over 50% experienced side effects. 10%+ reported 3+ side effects. Four side effect clusters identified.

How the study worked

Danish nationwide online survey in 2020 among patients with predefined indications (n=258) and other indications (n=786). Perceived benefit and side effects were self-reported. Heat plot correlation and exploratory factor analysis identified side effect patterns.

What this study cannot tell us

Self-report data. Online survey may not represent all patients. Cross-sectional design. No verification of diagnoses or cannabis products used.

How to read the evidence

Moderate: large nationwide survey with structured methodology, but self-report data and cross-sectional design.

When this study was published

Published in 2025, with survey data from 2020.

The bigger picture

This Danish data adds to the growing international picture of medical cannabis in practice. The independence of side effects from perceived benefit suggests that side effects and therapeutic effects may operate through different mechanisms.

Questions still open

Could different formulations reduce side effects while maintaining benefit?
Do the four side effect clusters correspond to different cannabinoid profiles?
How do Danish patient experiences compare to other countries?

Common questions

How effective is medical cannabis according to patients?

In this Danish survey, 67% of patients reported a moderate to large effect from medical cannabis. Benefits were reported across multiple diagnostic indications.

What are the most common side effects of medical cannabis?

Side effects clustered into four groups: cognitive dysfunction, dizziness, dry mouth, and feeling high. Over 10% of patients experienced three or more side effects, regardless of how much benefit they perceived.

Read the original research

Patients' perceived benefit and side effects from the use of medicinal cannabis - a cross-sectional survey study from Denmark.

Journal of complementary & integrative medicine

View on PubMed ↗Publisher’s paper ↗

Citation

Rosenbæk, Frederik; Pedersen, Line Bjørnskov; Wehberg, Sonja; Nielsen, Jesper Bo; Søndergaard, Jens. (2025). Patients' perceived benefit and side effects from the use of medicinal cannabis - a cross-sectional survey study from Denmark.. Journal of complementary & integrative medicine. https://doi.org/10.1515/jcim-2025-0277