Recent Supreme Court Decision

On June 6, 2005, the Supreme Court ruled that the federal government has the power to prohibit and prosecute the possession and use of marijuana for medical purposes, even in the 11 states (Alaska, Arizona, California, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Vermont, and Washington) that currently permit it. The decision overturned a 2003 ruling by a federal appeals court that shielded California's Compassionate Use Act, the medical-marijuana initiative adopted by the state's voters nine years ago, from federal drug enforcement.

The appeals court had held that Congress lacked constitutional authority to regulate the non-commercial cultivation and use of marijuana that did not cross state lines. The current decision reinforces the government's authority over intra-state activities that might impact inter-state commerce.

Background

A great deal of attention has been focused on the potential role of marijuana and its derivatives in the treatment of MS. In spite of large numbers of anecdotal reports from individuals who indicate they have received relief from some of their symptoms, it is important for everyone to realize that we still do not have the necessary scientific information to determine the safety and efficacy of marijuana for medical use in MS.

Anecdotal reports, that smoking marijuana (produced from the plant, Cannabis sativa ) reduced MS spasticity, led to a number of very small clinical trials in people with MS to evaluate the safety and efficacy of tetrahydrocannabinol (THC—the active ingredient in marijuana) in treating spasticity, tremor, and balance control. The results of these studies were quite mixed, and participants reported experiencing uncomfortable side effects, including weakness, dry mouth, dizziness, mental clouding, short-term memory problems, and some general discomfort, as well as feelings of being "high." In addition, smoked marijuana carries health risks that are similar to, or more severe than, those associated with tobacco. Other, well-tested, FDA-approved drugs are available to treat spasticity—including baclofen and tizanidine—which produce few side effects and pose no significant threats to overall health.

In addition to these small human trials, investigators in the United Kingdom and the United States have tested the ability of two of the derivatives of marijuana—called cannabinoids), as well as three synthetic cannabinoids, to control spasticity and tremor in mice with the MS-like disease called EAE. Based on the somewhat positive results in EAE, a large, double-blind, placebo-controlled clinical trial involving 657 people with MS at 33 clinical centres was carried out in Britain to determine if extracts of marijuana and its component THC (taken in capsule form) can relieve spasticity and other symptoms of MS.

Each participant was randomly assigned to receive cannabis oil, synthetic THC, or inactive placebo. Spasticity was measured using the standardized Ashworth scale, a 5-point scale that measures restriction of movement in specific muscle groups. No objective evidence (detectable by the examining physician) of a treatment effect was found on this standardized measure. However, significantly more participants taking either cannabis oil or THC reported subjective improvements in spasticity and pain (but not in tremor or bladder symptoms).

In other words, participants reported feeling improvements in spasticity and pain that could not be confirmed by a physician using a standardized assessment tool). Unfortunately, the study became unblinded because episodes of dizziness/light-headedness, dry mouth, and gastrointestinal symptoms that occurred in the treatment group made it apparent to these participants that they were receiving the treatment rather than the placebo.

These results provided the first systematically-gathered data on the effects of marijuana extracts for the treatment of MS-associated symptoms. The data indicated that these oral derivatives of marijuana do not provide improvement in spasticity as measured by an objective scale. The data did confirm, however, that people using marijuana feel better in ways that cannot be measured by their physicians.

In the view of the National MS Society's Chief Medical Officer, Aaron Miller, MD, "Oral cannabis oil or synthetic THC appears to have significant benefits on pain and on patient perceptions of spasticity, but not on objective measurement of spasticity. Whether the positive effects that patients reported resulted from a specific chemical effect of cannabinoids or a heightened placebo effect cannot be determined from this study, because unpleasant side effects allowed more than three-quarters of patients to recognize that they were taking the active drug. Also, the study provided no quantitative information about the extent of pain relief, so it is unclear whether patients perceived the benefits of cannabinoids to outweigh the side effects."

In April 2005, Health Canada, the drug regulatory agency for Canada, approved the use of the cannabis-derived drug Sativex® (GW Pharmaceuticals) to treat MS-related pain. The approval was based on a small, four-week clinical trial conducted in the United Kingdom in 66 people with MS, the results of which have not yet been published in a peer-reviewed medical journal. Sativex contains extracts from the marijuana plant and is administered as a spray into the mouth. Details about the Sativex approval are available on the Web site of the MS Society of Canada. This drug is not approved in the United States.

Other Potential Uses for Marijuana and Its Derivatives

In addition to studying the potential role of marijuana and its derivatives in the treatment of MS-related symptoms, scientists are exploring the potential of cannabinoids to inhibit neurodegeneration. In a recent study published in Brain (Pryce, Ahmed, Hankey et al., 2003), it was demonstrated that cannabinoids were able to slow the disease process in mice with EAE. While this is an interesting and potentially exciting finding, it is important to keep in mind that EAE is an animal model of MS that is similar, but not identical to MS. Many substances that have had positive effects in EAE trials have subsequently had no effects—or even negative effects—when tested in people with MS. Therefore, we need to wait for outcomes of human trials of cannabinoids in order to determine if these substances have a disease-modifying effect in MS.

In the meantime, it is the opinion of the National MS Society's Medical Advisory Board that there are currently insufficient data to recommend cannabinoids in any form as a treatment for MS. More research is needed to determine the potential role of cannabinoids in MS treatment. Smoking marijuana is unwise because the toxic effects appear to exceed those associated with tobacco smoking.

If you have any information on health that you would want to share, you can email editor@anAurora.co.uk

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