I think most of us have a fair idea of the value of “medical tobacco” and even a reasonable idea about “medical alcohol”.
I am aware that “medical cannabis” is great for reducing motivation, increasing motor vehicle accidents, sedating or obtunding,
and truly does help nausea while occasionally giving intractable vomiting, plus enhancing psychotic conversion rates.
Looking around, I note that Web MD suggests usage in that classic “triad” of leprosy, piles, dandruff and obesity.
Not sure what it does for intelligence, but the term “dope” probably gives some insight. I note “medical cannabis” has
not found much mention for mental health. Please advise. With thanks and keep up the superb work.
Response from bpacnz editorial team:
The concept of “medical cannabis” has been heavily publicised recently, both in the United States, Australia and in
New Zealand. This country has one of the highest rates of cannabis use in the world,1 and approximately 5%
of people aged over 15 years report using cannabis for medical purposes.2 Patients considering using cannabis
illegally for a medical purpose should, instead, be offered approved medicines that have evidence of safety and efficacy.
Robust clinical trials using cannabis to treat medical conditions are lacking. Δ9-tetrahydrocannabinol (THC)
has traditionally been regarded as the psychoactive ingredient of cannabis. However, cannabis contains approximately 70
other different compounds, any one of which may be pharmacologically active.3 Furthermore, the levels of THC
can vary widely between strains of cannabis. These variables make it difficult to interpret research assessing the efficacy
of cannabis for medical purposes and creates problems when considering how a non-standardised product should be dosed.3,
Observational studies show long-term cannabis use is associated with adverse social and financial consequences,5 and
cannabis use increases rates of psychosis.6 As with recreational cannabis use, medical cannabis use could also
lead to other serious adverse effects, such as motor vehicle accidents.7 It is therefore reasonable to ask
whether cannabis has any place in medical practice given the availability of other medicines which have been tested in
clinical trials and met regulatory standards.
Unlike cannabis plants, manufactured medicines can be produced to a highly consistent standard, allowing specific, evidence-based
doses to be prescribed.3, 8, 9 There is one cannabinoid approved for use in New Zealand, Sativex, a combined
cannabidiol/THC oromucosal spray, for the treatment of severe spasticity associated with multiple sclerosis. A Cochrane
review and a major meta-analysis, both published in 2015, found moderate quality evidence that cannabinoids (as opposed
to cannabis) may be useful for the treatment of chronic pain, including neuropathic pain, and spasticity associated with
multiple sclerosis.10, 11 There is also moderate quality evidence that cannabinoids may be effective antiemetics
for adjunctive use in chemotherapy or to assist weight-gain in patients with HIV.10, 11 There is low quality
evidence in support of other uses such as reducing anxiety or improving sleep.10, 11 Adverse effects commonly
associated with cannabinoid use include dizziness, dry mouth, nausea and vomiting,
fatigue, sedation, dysphoria and hallucinations.11
Medical use should not be used to promote legalisation
Cannabis is now being used in the United States for the treatment of medical conditions as diverse as epilepsy, post
traumatic stress disorder, Crohn’s disease, sickle cell disease, psoriasis, and amyotrophic lateral sclerosis, with neither
clear evidence of effectiveness, nor the same robust evaluation required of other medicines.3 As a result the
medical use of cannabis has become muddled with the issue of legalisation of cannabis. An editorial published in JAMA,
in 2015, commented:3
[if the] “initiative to legalize medical marijuana is merely a veiled step toward allowing access to recreational
marijuana, then the medical community should be left out of the process, and instead marijuana should be decriminalized.
Conversely, if the goal is to make marijuana available for medical purposes, then it is unclear why the approval process
should be different from that used for other medications.”
Both Australia and the United States relaxed legislation over the availability of cannabis for medicinal purposes in
2015. The New Zealand government has indicated wider access to cannabis for medical purposes may be granted once appropriate
clinical trials have been conducted and the trial products approved, although there is no indication when this might be.
- Degenhardt L, Chiu W-T, Sampson N, et al. Toward a global view of alcohol, tobacco, cannabis, and cocaine use:
findings from the WHO World Mental Health Surveys. PLoS Med 2008;5:e141.
- Pledger M, Martin G, Cumming J. New Zealand Health Survey 2012/13: characteristics of medicinal cannabis users.
New Zealand Medical Journal;129:29–40.
- D’Souza DC, Ranganathan M. Medical Marijuana: Is the Cart Before the Horse? JAMA 2015;313:2431–2.
- Vandrey R, Raber JC, Raber ME, et al. Cannabinoid Dose and Label Accuracy in Edible Medical Cannabis Products.
JAMA 2015;313:2491–3. http://dx.doi.org/10.1001/jama.2015.6613
- Fergusson DM, Boden JM. Cannabis use and later life outcomes. Addiction 2008;103:969-976-978.
- Fergusson DM, Horwood LJ, Ridder EM. Tests of causal linkages between cannabis use and psychotic symptoms. Addiction
- Poulsen H, Moar R, Troncoso C. The incidence of alcohol and other drugs in drivers killed in New Zealand road
crashes 2004-2009. Forensic Sci Int 2012;223:364–70.
- Aamir T. New Zealand doctors should be allowed to prescribe cannabis for pain: No. J Prim Health Care 2015;7:160–1.
- Hardy PA. New Zealand doctors should be allowed to prescribe cannabis for pain: Yes. J Prim Health Care 2015;7:158–9.
- Smith LA, Azariah F, Lavender VTC, et al. Cannabinoids for nausea and vomiting in adults with cancer receiving
chemotherapy. Cochrane Database Syst Rev 2015;11:CD009464.
- Whiting PF, Wolff RF, Deshpande S, et al. Cannabinoids for Medical Use: A Systematic Review and Meta-analysis.
JAMA 2015;313:2456–73. http://dx.doi.org/10.1001/jama.2015.6358