Updated 14 March 2018

2 common dagga myths busted

Even though marijuana has been legalised in many parts of the world, there are still many issues about the use of this controversial plant.


Mention legalising medical marijuana (dagga), and people often think two things:

  • This will prompt teens to think marijuana use is OK, and more will start using it.
  • Legalising marijuana will reduce the number of adults overdosing on opioids (pain medication).

As it turns out, neither has proven to be true, according to new research.

Since medical marijuana first became legal in California in 1996, it's been legalised across nearly three-fifths of the United States. However, that's had virtually no impact on the rate of recreational marijuana use among teens, a broad review of published studies has found.

The results of both studies are published online in the journal Addiction.

In South Africa, a state legal team has brought the Western Cape High Court’s decision to legalise the private use of dagga to the Constitutional Court, in the hope of reversing it.

The State has asked the Constitutional Court to rule in favour of returning the case on the legality of dagga to the high court to be debated thoroughly. The Constitutional Court has however reserved judgement and says it will make a ruling soon.

Sending the wrong message

"Several years ago, before the group of papers we [analysed] started to be published, people thought that US medical marijuana laws would increase teen marijuana consumption by 'sending the message' to teens that marijuana was safe and acceptable to use," explained Deborah Hasin – a professor of epidemiology at Columbia University's College of Physicians and Surgeons in New York City, and the new study's lead author.

Professor Hasin however said, "It doesn't seem that teens were impacted much by this – perhaps because they didn't find the legalisation of medical use very relevant to them or didn't even know about the laws."

Little chance of overdosing

The impact of marijuana legalisation also has been minimal on the risk for fatal overdosing among adult users of opioid pain medications, a separate study team has found.

American, Australian and British researchers found little to suggest that increased access to medical marijuana as an alternative way to manage chronic pain has led to any measurable drop in deaths from opioid abuse.

In fact, lead author Wayne Hall warned that research suggesting any substantive link between the two is "weak". He is a professor with the Center for Youth Substance Abuse Research at the University of Queensland in Brisbane, Australia.

Professor Hall and his colleagues caution that "it is premature to recommend the expansion of access to medical dagga as a policy to reduce opioid overdose risks in the United States and Canada".

Though the chances of overdosing on marijuana are low, the drug has been shown to have only a "modest" effect for pain control, according to the researchers.

"There are much better treatments [than marijuana] that have been shown to reduce [opioid] overdose deaths that are not currently being widely used in the USA," Hall said. "Foremost among these is medication-assisted treatment, using methadone or buprenorphine."

Marijuana does have some risks

Despite the findings of both research teams, legalising medical marijuana is not consequence-free, Professor Hasin said.

"Passing laws legalising marijuana use has some social benefits – business and tax revenues, job creation, and reduction in unfair race-based arrests," she said.

"And while not every marijuana user experiences harms, using marijuana does have some risks, including withdrawal, addiction and increased chances of vehicle crashes," Professor Hasin said.

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