Historical Review: Cannabis Medicine Has Thousands of Years of History But Modern Clinical Research Is Just Beginning | Research

The takeaway

Despite thousands of years of medicinal cannabis use, modern clinical research remained in its infancy as of 2005, with most studies being small, poorly controlled, or using unsatisfactory cannabinoid formulations, though new possibilities were emerging from endocannabinoid system discoveries.

Read this if you want to understand why clinical evidence for medical cannabis has been slow to develop despite its long history of use.

Scientific evaluation of medicinal cannabis in humans described as "still in its infancy" in 2005

What the researchers found

This review traced the arc of medicinal cannabis from its prominence in 19th century Western medicine through its early 20th century prohibition and 1960s recreational explosion, to the current state of clinical research.

The author identified major methodological challenges that had kept clinical evidence weak: studies tended to be small, imperfectly controlled, and often used synthetic cannabinoid analogs or smoked herbal material with uncertain composition and irregular bioavailability.

New research opportunities were emerging from three developments: the discovery of the endocannabinoid system, expanding knowledge of cannabinoid pharmacology, and a more sympathetic political environment in several countries. Future therapeutic targets were expected to extend beyond symptom relief into disease modification, with cannabinoids showing particular promise for inflammatory and neurodegenerative conditions.

Why it matters

This review honestly assessed the gap between thousands of years of anecdotal evidence for medical cannabis and the thin base of rigorous clinical research. By identifying why research had lagged, including the "pariah drug" status and methodological challenges, it helped set the agenda for more rigorous future studies.

The numbers in context

Cannabis medicinal use documented across several thousand years and multiple cultures. Most clinical studies described as small and imperfectly controlled. Future targets identified: inflammatory and neurodegenerative conditions.

How the study worked

Comprehensive narrative review covering the historical development and current status of medicinal cannabis research. Examined legal controls, existing clinical trial evidence across multiple conditions, safety considerations, and future research directions.

What this study cannot tell us

As a broad historical and contemporary review, it could not deeply evaluate evidence for any specific condition. The assessment of research quality was qualitative rather than systematic. The review reflected the state of evidence as of 2005.

How to read the evidence

Comprehensive historical and clinical review. Provides excellent context but is broad rather than deeply analytical for any specific condition.

When this study was published

Published in 2005. Clinical cannabis research has expanded considerably since then, though many of the methodological challenges identified here persist.

The bigger picture

The observation that medical cannabis research was still "in its infancy" in 2005 explains why many questions about cannabis therapeutics remain only partially answered today. The methodological challenges identified, particularly around standardization and delivery methods, continue to affect cannabis research.

Questions still open

Can cannabis-based medicines be standardized well enough for conventional pharmaceutical development? Will cannabinoids prove effective for disease modification in inflammatory and neurodegenerative conditions?

Common questions

Why isn't there more clinical research on medical cannabis?

This review identified several barriers: cannabis's "pariah drug" legal status made research difficult, most studies were small and poorly controlled, and standardized pharmaceutical-grade cannabis preparations were not widely available. The political and research landscape has improved since 2005 but challenges remain.

What conditions show the most promise for cannabis treatment?

As of this 2005 review, the strongest evidence existed for symptom relief (pain, nausea, spasticity). The author identified inflammatory and neurodegenerative conditions as the most promising future targets for disease-modifying applications of cannabinoids.

Read the original research

Human studies of cannabinoids and medicinal cannabis.

Handbook of experimental pharmacology, 719-56

View on PubMed ↗

Citation

Robson, P. (2005). Human studies of cannabinoids and medicinal cannabis.. Handbook of experimental pharmacology, 719-56.