10 August 2004

Cannabis interventions in dual diagnosis and opioid dependent patients

10th August, 2004


Dr Jan Copeland and Ms Etty Matalon, NDARC, UNSW.

Chair: Dr Ray Seidler
This seminar raised issues that we face every day in our practices regarding behavioural change associated with drug use. Although the worst consequences of cannabis pale in comparison with alcohol and other drugs, it is still a widely used drug which many perceive to be a major problem in their lives.

Dr Copeland began by giving an overview of the use of cannabis in the Australian community. The best figures come from household studies showing that about a third of Australians have ever used cannabis and about one in six young people aged 14-19 are daily smokers of the drug. Hospital admission details show that while rare in the over 50s, cannabis use problems were commonly reported on admission in the younger age groups. We were told that up to 31.7% of 'current users' met criteria for DSM IV cannabis use disorder and 21% for dependence on the drug. Even ignoring the DSM criteria, the extent of the problem is shown by the numbers seeking treatment in Australia which, Dr Copeland told us, have tripled in a decade.

Of a large sample of Australian heroin injectors, 40% had current cannabis dependence diagnosis, being almost as common as anxiety disorder (51%) and alcohol problems (49%). US findings were similar but one wonders if the patients were prescribed adequate doses of methadone where the mean daily dose should be over 70mg and possibly higher.

We were reminded that cannabis smoke was more potent than tobacco smoke in some respects, although much less in quantity is consumed by the average cannabis smoker. There is thus a potential for causing or exacerbating cancer, asthma, bronchitis, etcetera. UNSW surveys show that nearly all the cannabis used in Australia is smoked, even though oral absorption was possible, it was often delayed and unpredictable. New methods of delivery were being developed using sprays or 'super-heated' rather than burned material from the cannabis sativa plant. High potency forms of the drug such as hashish resin or oil contain high concentrations of the active ingredients, the main one being tetra-hydro cannabinol (THC). Paradoxically, they may therefore be less harmful in some respects, having fewer impurities. Various street myths about cannabis were discussed, especially regarding drug delivery, absorption, deep breaths, bongs (dry and wet varieties), etcetera.

Even in those who are not yet intent on quitting, Dr Copeland said that there was much useful advice to give people to reduce the harms from cannabis use. They should be advised not to use bongs, especially of the 'dry' variety. They should be taught that it is illogical to inhale deeply and keep the breath for as long as possible, as is often practised. They should probably avoid leaves, stems and seeds . and just use the high concentration 'heads' of the cannabis plant. This results in a higher concentration of THC and thus a lower amount of exposure to CO, tars, soot, etc for the given amount of intoxicant. Mixing cannabis with tobacco was probably unwise although the practice is almost universal, at least in Sydney. [I wonder if it is true that Melbourne practice is more commonly to smoke straight cannabis without added tobacco.]

Next Etty Malyon showed us a number of impressive, professional publications, some aimed at patients, others at health care workers to use in formal treatment programs. One was a self-help explanatory program aimed at assisting those who are ready to quit. Another contained a step by step program of implementing goals towards lasting change in those prepared for a more formal series of face to face interventions. The programs dealt with drug use cues, drug diary entries, choosing dates for change, writing up pros and cons of drug use, discussing all of the above, etc. Depression was raised on numerous occasions as needing to be seriously addressed in those trying to quit cannabis, meaning both drug and non-drug approaches need to be considered. These interventions would be ideal in general practice and some could be initiated in pharmacies, methadone clinics or needle outreach services.

These hand-outs are available at modest cost to practitioners. Contact Dr Jan Copeland at UNSW for details.

Like all drugs, cannabis may have good and bad effects. Hence, although it was not part of the evening's 'main feature', I include a recent newspaper report from Dr Copeland's own research centre (NDARC). They found that nearly two-thirds of people using cannabis for medical reasons had decreased or stopped taking other medications. Participants also reported that cannabis was useful in preventing side effects caused by conventional medicines. The most common medical conditions the cannabis users suffered were arthritis, chronic pain, depression, nausea, muscle spasms and weight loss. Up to 70 per cent of those using 'medical cannabis' would be willing to be involved in a trial of an alternative form of cannabis, such as a spray, according to their survey. Last year NSW Premier Bob Carr announced a trial of possible therapeutic benefits of cannabis. The NDARC survey was a recommendation of the working party on the medical use of cannabis.

In another item from London, Wolff, Winstock (yes, our own 'Adam', from Bankstown) and co-workers in an SSA conference abstract published in Addiction Biology, March issue, gave the results of self-report questionnaires given to 337 multiple sclerosis patients in three English hospitals (2 London, one county). With a 75% response rate, almost half had used cannabis at some point and about one in five used the drug monthly. Only four (4%) of the 110 who had ever used cannabis developed increased weakness while one (1%) reported hallucinations. Almost three quarters stated that they would try the drug if it were legal. It would appear to have benefits for certain patients and a low side-effect profile. Yet dependence develops in a proportion and the dangers of smoked products are ever-present, each limiting the usefulness of therapeutic cannabis at present.

It is intriguing that tincture of cannabis was very widely prescribed in Australia prior to the current prohibitions of the 1950s. I could find no reports of ill-effects or dependence.

comments by Andrew Byrne ..


Cannabis use in patients with multiple sclerosis. Wolff K, Chong MS, Wise K, Tanton C, Winstock A, Ennis M, Silber K. SSA Symposium Abstracts (in Addiction Biology March 2004 p103-104)