The medical uses of cannabis

2009.04.27

The medical uses of cannabis have been recognized for thousands of years. Physicians in ancient China used it to relieve constipation, loss of appetite, and pain during childbirth. With the

development of synthetic drugs in the 20th century, herbal remedies in general fell into disuse.

In 1999, the NSW Working Party on the Medical Uses of Cannabis was asked to advise the NSW

Premier on the possible medical uses of cannabis and cannabinoid drugs.This fact sheet highlights some of the major issues raised by the Working Party. For access to the report, go to www.druginfo.nsw.gov.au

What do we mean by “cannabis” and “cannabinoids”?

‘Cannabis’ is a term that refers to the plant or products of the cannabis sativa plant (such as

hashish). Cannabis may be smoked in a ‘joint’ the size of a cigarette, or in a water pipe (‘bong’).

It may also be eaten; but smoking is the more common because it is the easiest way to achieve

the desired effects.

We use the term “cannabinoids” to refer to pharmaceutical quality drugs that act in the same way in

the body as some substances in the cannabis plant, such as tetrahydrocannabinol (THC).

Two examples of cannabinoids are nabilone, which is THC in a capsule and is available in the UK for

medical uses, and dronabinol, which is synthetic THC, and is available in the US. There are no

cannabinoid drugs readily available in Australia.

What are the medical conditions for which cannabis or cannabinoids might be of use?

Cannabis and cannabinoids are useful to relieve symptoms of illnesses, but do not cure the underlying disease. Many of the uses of cannabis for medical purposes revolve around its ability to reduce pain and nausea, stimulate appetite and perhaps reduce muscle spasms.

It has been agreed that cannabis or cannabinoids may be useful for some persons with the following conditions:

• HIV-related and cancer-related wasting;

• Pain unrelieved by usual pain relief treatments;

• Neurological disorders including (but not confined to) multiple sclerosis, Tourette’s syndrome, and motor neuron disease;

• Nausea and vomiting in cancer patients undergoing chemotherapy, which does not respond to the usual treatments for this problem.

Although there is a large amount of anecdotal evidence, and some research evidence, about the

usefulness of cannabis for these conditions, there is a lack of good controlled evidence. Further

research is needed to examine the benefits that cannabis and cannabinoids appear to have for these illnesses.

What are the possible risks of cannabis use?

Dependence:

There is evidence to suggest that if people use cannabis regularly over a long period of time, they

may become dependent upon it. While the risk of becoming dependent upon cannabis or cannabinoids is definitely an issue to keep in mind, many drugs that are prescribed for medical

problems carry an even greater risk. One example is morphine, an opiate drug that is sometimes

prescribed for people who have chronic pain.

If people are facing chronic or life threatening illnesses, this risk may be one that is worth facing for symptom relief.

Other illicit drug use:

The issue of whether cannabis use leads to an increased chance of using other illicit drug types is a particularly contentious one. Research has shown that people who use cannabis are more likely to use other illicit drugs. However, this issue has always referred to non-medical cannabis use by young people. It is unlikely that a similar pattern would be seen for older medical cannabis users.

Sending the wrong message about illicit drugs?

Some have argued that if people were able to use cannabis for medical reasons, this would send

the wrong message about illicit drugs, and more people might use cannabis recreationally than

before. There are a couple of reasons why this is probably not the case:

• Very few people who are dependent on opioids (such as heroin) began their use with

prescribed (legal) opioids;

• Diverted opioid drugs are not a big source of illicit opioids;

• Medical cannabis use is unlikely to be a greater problem than medical opioid use (which, as outlined above, does not appear to be an issue that is so big that medical opioid use has been stopped);

• Decriminalization of cannabis use in some countries has not had an impact on rates of

Cannabis use;

• Surveys have not found any change in people’s perception of cannabis in US states where medical cannabis use has been decriminalized.