What Science Actually Knew About Medical Cannabis in 2001 | Research

The takeaway

A comprehensive review found strong evidence for cannabinoids in nausea and appetite stimulation, emerging evidence for pain and spasticity, but argued that oral or rectal delivery was preferable to smoking.

Read this if you want a thorough snapshot of what the medical cannabis evidence looked like before most modern clinical trials.

Strong evidence for nausea/appetite; emerging for pain/spasticity; weak for glaucoma/asthma

What the researchers found

THC and several analogues showed significant therapeutic benefits for nausea, vomiting, and appetite stimulation in patients with wasting syndrome. Recent evidence demonstrated analgesic and anti-spasticity effects that the author considered likely to become clinically useful.

However, cannabinoid effects on intraocular pressure in glaucoma and bronchodilation in asthma were not sufficiently strong, long-lasting, or reliable for therapeutic use. Cannabidiol showed promising anticonvulsant effects warranting further clinical trials.

The author argued that for all established and probable future uses, pure cannabinoids administered orally, rectally, or parenterally were effective and avoided the risks of chronic airway inflammation and upper respiratory cancer associated with smoking crude cannabis.

Why it matters

This review provided one of the more balanced and thorough assessments of the medical cannabis evidence base at the time. By sorting conditions into those with strong evidence (nausea, appetite), emerging evidence (pain, spasticity), and weak evidence (glaucoma, asthma), it helped establish a framework for prioritizing clinical research that largely held up over subsequent decades.

The numbers in context

THC doses of 5-10 mg were referenced for therapeutic applications. The review covered multiple conditions but did not provide pooled statistical analyses.

How the study worked

This was a narrative review that assessed the literature on therapeutic uses of cannabis and cannabinoids. Studies were evaluated by design type, data quality, independent replication, effect size, comparison with other treatments, and adverse effects. Results were compared with major international reviews from the preceding five years.

What this study cannot tell us

As a narrative review rather than a systematic review or meta-analysis, the study selection and interpretation reflected the author's judgment. Long-term pharmacokinetic data and drug interaction information were acknowledged as major gaps. The review predated many of the large clinical trials conducted in subsequent years.

How to read the evidence

This is a comprehensive narrative review comparing findings across multiple international reviews, providing moderate-level evidence through synthesis.

When this study was published

Published in 2001, this review predated many of the landmark clinical trials on cannabinoids for pain and spasticity conducted in subsequent years.

The bigger picture

Many of this review's conclusions have been validated by subsequent research. Cannabinoids are now approved for chemotherapy-induced nausea (dronabinol, nabilone) and appetite stimulation. Pain and spasticity indications have gained regulatory approvals in some jurisdictions. The prediction about new synthetic analogues with better therapeutic profiles has been partially realized.

Questions still open

Have non-smoked cannabis delivery methods proven sufficient for patient populations, or has smoking remained common despite these concerns? Has the development of synthetic analogues with reduced psychoactivity met the predictions made in this review?

Common questions

Is smoking cannabis the best way to use it medically?

This review argued that oral, rectal, or injectable cannabinoids were preferable to smoking because they avoided respiratory risks while maintaining therapeutic effectiveness. This view has influenced the development of non-smoked medical cannabis products.

Why was the evidence for cannabis and glaucoma considered weak?

While cannabinoids can lower intraocular pressure, the effect was not strong enough, long-lasting enough, or reliable enough to serve as a practical treatment compared to existing glaucoma medications.

Read the original research

Medicinal use of cannabis: history and current status.

Pain research & management, 6(2), 80-91

View on PubMed ↗

Citation

Kalant, H. (2001). Medicinal use of cannabis: history and current status.. Pain research & management, 6(2), 80-91.