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Results
from Two Studies
of Marijuana and Multiple Sclerosis
Medical Update Memo
November 24, 2003
SUMMARY
Two recent studies – one conducted
in Great Britain and one in Canada – provide new information
about the possible effectiveness of marijuana or its derivatives
as a treatment for MS symptoms.
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The British study involved 657 people
with MS. For 13 weeks, participants received either cannabis
oil, synthetic tetrahydrocannabinol (THC, the active ingredient
in marijuana) or inactive placebo. Following the treatment
period, those on active treatment had no objective improvement
in muscle spasticity as measured by a standardized scale.
However, treated participants reported improvements in
walking speed, another measure of spasticity, and symptoms
of spasticity, muscle spasms, sleep and pain.
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The Canadian study investigated marijuana
use among people living in southern Alberta. Researchers
mailed questionnaires to 780 adults with MS registered with
the MS Clinic in Calgary. Of the 420 who responded, 43 percent
reported they had used marijuana at some point in their lives,
not necessarily related to MS. However, 96 percent said they
were aware that marijuana was potentially helpful for MS
symptoms, and 72 percent said it should be legal for people
to use medicinally. The most common reason for not using
marijuana was its illegal status.
DETAILS
British Study – Cannabinoids
for treatment of spasticity and other symptoms related to
multiple sclerosis
The results from the largest clinical trial of marijuana
derivatives for the treatment of MS symptoms was published
in The Lancet, Nov. 8, 2003. The study involved 657 people
with MS at 33 clinical centres across the United Kingdom of
Great Britain and Northern Ireland. For a 13 week period, participants
received either cannabis oil, synthetic tetrahydrocannabinol
(THC, the active ingredient in marijuana) or inactive placebo.
All substances were taken orally (by mouth). The study was
double-blinded so neither participants nor the examining physicians
knew who was receiving which treatment.
The primary outcome was the measurement
of muscle spasticity as assessed by the standardized Ashworth
scale. Secondary outcomes were mobility and participant perception
of symptom improvement including irritability, depression,
tiredness, muscle stiffness, tremor, pain, sleep, muscle spasms,
energy levels and bladder function.
Results
Data was obtained from 630 participants.
There was no objective evidence of a treatment effect on muscle
spasticity, the primary outcome of the study, using the standardized
Ashworth scale. The Ashworth scale, a 5-point scale, measures
restriction of movement in specific muscle groups and has been
widely used in prior studies of spasticity and its treatment,
however, it is known to measure only one aspect of spasticity.
At the end of the study, physicians asked participants to rate
their own sense of whether the agent they had taken had improved
their symptoms. Significantly more participants taking either
cannabis oil or THC reported subjective improvements in spasticity,
spasms, sleep and pain, but not tremor or bladder symptoms.
Among secondary outcomes studied was the
time it took to walk 10 metres. Walking times before and during
treatment were obtained from 278 participants; there was a
reduction in walking time by 12% in the group taking THC, compared
to a reduction of 4% in both the cannabis oil and placebo groups.
This difference was statistically significant. There was no
improvement on another mobility test.
There were serious adverse events in all
three groups: 20 in the placebo group, 18 in the THC group
and 12 in the cannabis oil group. More episodes of dizziness/
light-headedness, dry mouth, and gastrointestinal symptoms
occurred in the treatment groups.
The investigators also noted there were
fewer relapses in the treatment groups. Of the nine MS relapses
that occurred during the study period, seven were in the placebo
group and one each in the treatment groups. However, the study
was not designed to investigate impact on relapses so no conclusions
can be drawn from this finding.
Canadian Study – Cannabis
Use as Described by People with Multiple Sclerosis
In the Canadian study, researchers at the
MS Clinic, University of Calgary, researchers mailed questionnaires
to 780 adults in southern Alberta who were registered with
the clinic. A total of 480 people (62 percent) completed the
questionnaire. Mean sample age was 48 years and 75 percent
were women. They level of disability ranged from mildly to
severely impaired. The study was reported in The Canadian Journal
of Neurological Sciences, August 2003. It was funded by the
MS Society of Canada.
Results
While 72 percent of respondents said it
should be legal to use marijuana for medical use and 96 percent
were aware that it might potentially be useful as a treatment,
just 43 percent reported having used marijuana. Not all of
that use was for medical purposes. For those who had not tried
marijuana, 64 percent were concerned that it is illegal, 34
percent were concerned about side effects, 34 percent lacked
knowledge of how to obtain it and 24 percent didn’t believe
it would help symptoms. (Responses add up to more than 100
percent since more than one answer was permitted.)
Of the 176 people who had tried marijuana,
35 percent said it was to help relieve MS symptoms. Sixty-four
percent of these were currently using marijuana. Symptoms perceived
to be relieved were anxiety/depression (67 percent), spasticity
(58 percent), chronic pain (49 percent) and fatigue (40 percent).
Of those using marijuana, 54 percent said they felt much better
and 39 percent said they felt a little better. As with the
British study, fewer said they had experienced improvement
in bladder problems.
Of those who had stopped, they mentioned
cost, dislike of side effects, legal concerns and lack of effectiveness.
Summary
The British study is the largest examination
on the effect of marijuana extracts on MS symptoms. It shows
that the oral derivatives of marijuana do not provide objective
measures of improvement related to spasticity. However, both
the British clinical trial and the Canadian survey, support
previous observations by people with MS that marijuana does
result in subjective improvements that could not be measured
by physicians.
Both research groups noted the dangers of
smoked marijuana because of the risk associating with inhaling
potentially dangerous substances in the smoke. Commenting in
an editorial in The Lancet that accompanied the British marijuana
research study, Drs. Luanne Metz and Stacey Pace, both involved
in the Canadian research, stated:
“Hopefully [this]…study will
stimulate further research to develop safe and effective formulation
of cannabis, and will inform debate over the social and legal
restrictions that limit its use. In the meantime when other
treatment inadequately controls spasticity, oral cannabinoids
should be considered where law permits their possession and
use.”
Legal Status in Canada
In Canada, federal government regulations
allow people with certain illnesses including MS to apply for
permits to possess and/or grow marijuana for personal medical
purposes or to designate another person to grow it for the
person who has the permit. All usages must be prescribed by
physicians. Details about how to apply for permits are available
at www.hc-sc.gc.ca/hecs-sesc/ocma/index.htm Information
is also available by calling the Health Canada Cannabis Medical
Access Office toll-free: 1-866-337-7705 or 613 954-6540.
In July 2003, federal Minister of Health
Anne McLellan announced an interim policy to allow Health Canada
to provide dried marijuana and/or marijuana seeds to individuals
holding federal permits. This decision was in response to complaints
by some permit holders that they were not able to access marijuana.
The product and seeds will come from Prairie Plant Systems
Inc., the company currently under contract with Health Canada
to produce marijuana for clinical trials. Details about how
to apply for dried marijuana and/or marijuana seeds are available
at www.hc-sc.gc.ca/hecs-sesc/ocma/index.htm Information
is also available by calling the Health Canada Cannabis Medical
Access Office toll-free: 1-866-337-7705 or 613 954-6540.
Some physician organizations have advised
their members not to prescribe marijuana because of the lack
of information about optimum prescribing and potential legal
issues. It is not yet clear if these recommendations will change
with respect to oral cannabis given the results of the Lancet
study.
Individuals interested in the medical use
of marijuana should speak to their own physicians or contact
Health Canada.
National Research Department
National Communications & Social Action Department
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Disclaimer
The Multiple Sclerosis Society of Canada is an independent,
voluntary health agency and does not approve, endorse or
recommend any specific product or therapy but provides information
to assist individuals in making their own decisions.
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