Marijuana plants have been used since antiquity for both herbal medication and intoxication. The current debate over the medical use of marijuana is essentially a debate over the value of its medicinal properties relative to the risk posed by its use.
Marijuana's use as an herbal remedy before the 20th century is well documented.1,10,11
However, modern medicine adheres to different standards from those used in the past. The question is not whether marijuana can be used as an herbal remedy but rather how well this remedy meets today's standards of efficacy and safety. We understand much more than previous generations about medical risks. Our society generally expects its
licensed medications to be safe, reliable, and of proven efficacy;
contaminants and
inconsistent ingredients in our health treatments are not tolerated. That refers not only to prescription and over-the-counter drugs but also to vitamin supplements and herbal
remedies purchased at the grocery store. For example, the essential amino acid l-
tryptophan was widely sold in health food stores as a natural remedy for insomnia until
early 1990 when it became linked to an epidemic of a new and potentially fatal
illness
(eosinophilia-myalgia syndrome).9,12 When it was removed from the market shortly
thereafter, there was little protest, despite the fact that it was safe
for
the vast majority of
the population. The 1,536 cases and 27 deaths were later traced to contaminants in a
batch produced by a single Japanese manufacturer.
Although few herbal medicines meet today's standards, they have provided the
foundation for modern Western pharmaceuticals. Most current prescriptions have their roots either directly or indirectly in plant remedies.7 At the same time, most current
prescriptions are synthetic compounds that
are only distantly related to the natural
compounds that led to their development. Digitalis was discovered in foxglove, morphine
in
poppies, and taxol in the yew tree. Even aspirin (acetylsalicylic acid) has its
counterpart in herbal medicine: for many generations, American Indians relieved headaches by chewing the bark of the willow tree, which is rich in a related form of
salicylic acid.
Although plants continue to be valuable resources for medical advances, drug
development is likely to be less and less reliant on plants and more reliant on the tools of
modern science. Molecular biology, bioinformatics software, and DNA array-based analyses of
genes and chemistry are all beginning to yield great advances in drug
discovery and development. Until recently, drugs could only be discovered;
now they can
be designed. Even the discovery process has been accelerated through the use of modern
drug-screening techniques. It
is
increasingly possible to identify or isolate the chemical compounds in a plant, determine which compounds are responsible for the plant's effects,
and
select the most effective and safe compounds--either for use as purified substances or
as
tools to develop even more effective, safer, or less expensive compounds.
Yet even as the modern pharmacological toolbox becomes more sophisticated and biotechnology yields an ever
greater abundance of therapeutic drugs, people increasingly seek alternative, low-technology therapies.4,5 In 1997, 46 percent of Americans sought nontraditional medicines and spent over 27 billion unreimbursed dollars; the total
number
of visits to alternative medicine practitioners appears to have
exceeded the number of visits to primary care physicians.5,6 Recent interest
in
the medical use of marijuana coincides with this trend toward self-help and a search for "natural" therapies. Indeed,
several people who spoke at the IOM public hearings in support of the medical use of
marijuana said that
they generally preferred herbal medicines to standard
pharmaceuticals. However, few alternative therapies have been carefully and systematically tested for safety and efficacy, as is required for medications approved by the FDA (Food and Drug Administration).2
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