Medical marijuana patients who used more frequently and for more conditions reported lower general health | Research

The takeaway

A survey of 312 LA dispensary patients found that smoking marijuana, having more medical conditions, and using more times per day were associated with lower general health, though the cross-sectional design cannot determine direction of causation.

Read this if you are a medical marijuana patient interested in how use patterns relate to overall health.

Smoking method and more daily uses associated with lower general health

What the researchers found

Researchers surveyed 312 medical marijuana patients recruited from 16 dispensaries across Los Angeles.

Patients who smoked marijuana (vs. other consumption methods), had more medical conditions for which they received their recommendation, and used marijuana more times per day reported lower levels of general health.

The number of days using marijuana per month was associated with worse health over the past year.

The authors noted that medical marijuana use did not appear to improve overall health status based on these results, but emphasized that the cross-sectional design means the direction of causation is unknown. Sicker patients likely use marijuana more frequently and for more conditions, rather than marijuana use necessarily making them sicker.

Why it matters

As medical marijuana use becomes more widespread, understanding the relationship between use patterns and health outcomes matters. This study highlights the challenge of confounding by indication: sicker people use more medical marijuana, making it appear that marijuana is associated with worse health.

The numbers in context

312 patients from 16 dispensaries. Smoking method, more medical conditions, and more daily uses all associated with lower general health. More days per month associated with worse past-year health change.

How the study worked

Cross-sectional survey of 312 patients from 16 medical marijuana dispensaries in Los Angeles. Short intercept survey plus longer patient survey covering health, use behaviors, preferences, and demographics. Hierarchical linear modeling accounted for patients nested within dispensaries.

What this study cannot tell us

Cross-sectional design cannot establish causation or direction of association. Self-reported health measures are subjective. LA dispensary patients may not represent medical marijuana users elsewhere. No control group of non-users with similar conditions. Specific medical conditions and their severity were not detailed.

How to read the evidence

Cross-sectional survey design provides preliminary evidence on associations, unable to determine whether marijuana use affects health or health status drives use patterns.

When this study was published

Published in 2018 with LA dispensary data. Medical marijuana products and patient populations have evolved significantly.

The bigger picture

This study illustrates a fundamental challenge in medical marijuana research: people who use it most heavily tend to be the sickest, creating an inherent negative association between use and health that does not necessarily reflect the effects of the marijuana itself.

Questions still open

Would longitudinal tracking of medical marijuana patients show health improvement over time? Do specific conditions respond better than others to medical marijuana? How does the route of administration (smoking vs. edibles vs. vaping) affect health outcomes?

Common questions

Does medical marijuana make people healthier?

This study found no evidence of that. Patients who used more had lower health scores. However, the study design cannot tell us the direction: sicker people likely use more marijuana, rather than marijuana making them sicker.

Does how you use marijuana matter?

Yes. Patients who smoked marijuana reported lower general health compared to those using other methods. This may reflect the respiratory effects of smoking or different patient populations who prefer different methods.

Read the original research

Do characteristics of marijuana use correspond to overall health levels for medical marijuana patients?

Journal of substance use, 23(3), 307-311

View on PubMed ↗Publisher’s paper ↗

Citation

Freisthler, Bridget; Cooke, Alexis. (2018). Do characteristics of marijuana use correspond to overall health levels for medical marijuana patients?. Journal of substance use, 23(3), 307-311. https://doi.org/10.1080/14659891.2017.1394383