Cannabis and opioids: 20-year study findings

Cannabis should not be considered an effective long-term strategy for reducing opioid use, a long-term study has found. Credit mohammad majid

A 20-year study has found that cannabis should not be considered an effective long-term strategy for reducing opioid use.

The study into the relationship between cannabis and opioids, led by the University of Sydney, started way back in 2001 and concluded last year. It involved over 600 people who were dependent on heroin. Many of the 600-plus study participants also used cannabis.

According to an article on the News Medical website, the “Australian study has found no evidence to suggest cannabis reduces illicit opioid use, and it may not be an effective long-term method of reducing harm for those with an opioid use disorder or problematic use of opioids.”

Further analysis completed as part of the study also found no consistent evidence between cannabis and other opioid use. This includes prescribed opioids such fentanyl and oxycontin, which are a significant issue across the globe and responsible for many overdose deaths.

The long-term study has cast doubts on those who believe that cannabis is a solution to the opioid crisis.

According to the researchers in a news article published on the University of Sydney website, “Clinicians and policymakers should be cautious about relying on cannabis to reduce problematic opioid use or as a potential strategy to help manage the opioid crisis, especially given a global shift towards cannabis legalization and recognition as a therapeutic product.”

Dr Jack Wilson, lead author of the study, is quoted in the article as saying, “There are claims that cannabis may help decrease opioid use or help people with opioid use disorders keep up with treatment.

“But it’s crucial to note those studies examine short-term impact, and focus on treatment of chronic pain and pain management, rather than levels of opioid use in other contexts.”

“Opioid use disorders are complex and unlikely to be resolved by a single treatment,” says Dr Wilson. “The best way to support them is evidence-based holistic approaches that look at the bigger picture, and include physical, psychological, and pharmacotherapy therapies.”

Opioids and cannabis players in drug-induced deaths

As highlighted above, prescribed opioids such fentanyl and oxycontin, are a significant issue across the globe, including here in Australia.

In this nation last year, nearly 1700 people lost their lives due a drug-induced death. The main contributor in terms of drug class was opioids. While heroin also contributed significantly to the number of deaths, most opioid drug-induced deaths involved prescription opioids.

Incidentally, cannabis does play a role in the number of drug-induced deaths each year, although the number of deaths are much less than for opioids. In 2021, for example, there were 962 drug-induced deaths involving opioids. During the same year, there were 76 drug-induced deaths involving cannabis.

Opioids and cannabis in the workplace

While opioids are the biggest concern when it comes to drug-induced deaths, on the road and in the workplace, its cannabis that’s the biggest issue.

Drug testing conducted along roadsides across all states and territories shows that cannabis is the most common drug for positive results. It’s the same in the workplace. In 2022, for example, for all workplace drug testing conducted by Integrity Sampling, nearly 45 per cent of all positive test results were for cannabis.

To find out more about the drugs most commonly found in our workplace drug testing results, as well as other interesting statistics, you can download the 2022 report.


Cannabis should not be considered an effective long-term strategy for reducing opioid use, a long-term study has found. Credit mohammad majid

By Michael

Michael is the founder of Integrity Sampling and is responsible for overseeing all national operations. He is based at Integrity Sampling's head office in Melbourne and is also responsible for the co-ordination of drug and alcohol testing within Victoria, assisting in the implementation of drug and alcohol (fit for work) policies and the presentation of drug and alcohol education and awareness programs. You can connect with Michael Wheeldon on LinkedIn

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