Danish medical cannabis users had significantly lower health-related quality of life scores than non-users with the same diagnoses, likely reflecting that the most severely affected patients turn to cannabis as a last resort.
Patients and providers weighing medical cannabis decisions, and researchers interpreting observational cannabis data.
MC users QALY 0.44 vs non-users 0.74
What the researchers found
Among 9,265 Danish patients, medical cannabis users had a QALY score of 0.44 compared to 0.74 for non-users (general adult population: 0.87). Patients with more prescriptions had progressively lower QALY scores.
Why it matters
The lower quality of life among cannabis users likely reflects confounding by indication: patients with the most severe symptoms are more likely to try medical cannabis. This is important context for interpreting observational cannabis studies.
The numbers in context
9,265 patients surveyed. MC user QALY: 0.44 vs non-user: 0.74 vs adult population: 0.87. Users with 7+ prescriptions scored 0.26-0.32 lower than non-users.
How the study worked
Danish nationwide online survey distributed to 23,846 patients in October 2020. Quality-adjusted life years (QALYs) measured using EQ-5D-3L. Compared QALY scores across diagnostic groups between MC users and non-users.
What this study cannot tell us
Cross-sectional design cannot determine direction of association. Confounding by indication likely explains much of the difference. Small numbers when stratified by prescription count.
How to read the evidence
Moderate: large nationwide sample with validated quality of life measure, but cross-sectional and likely confounding by indication.
When this study was published
Published in 2025, with survey data from 2020.
The bigger picture
This study illustrates a classic challenge in medical cannabis research: patients who use it tend to be sicker than those who don't, making it difficult to determine whether cannabis helps or harms quality of life without randomized trials.
Questions still open
- Would longitudinal data show quality of life improvement after starting medical cannabis?
- Does confounding by indication fully explain the lower QALY scores?
Common questions
Does medical cannabis improve quality of life?
Why do medical cannabis users report lower quality of life?
Read the original research
Patients' Health-Related Quality of Life and Use of Medicinal Cannabis: A Cross-Sectional Survey Study.
Drugs - real world outcomes, 12(1), 125-133
Citation
Rosenbæk, Frederik; Wehberg, Sonja; Pedersen, Line Bjørnskov; Nielsen, Jesper Bo; Søndergaard, Jens. (2025). Patients' Health-Related Quality of Life and Use of Medicinal Cannabis: A Cross-Sectional Survey Study.. Drugs - real world outcomes, 12(1), 125-133. https://doi.org/10.1007/s40801-024-00479-2
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