Scientists often interpret research to suit funding goals. Why is that problematic? BY ADRIAN DEVITT-LEE ON JANUARY 20, 2020

A black-handled magnifying glass over a cannabis leaf on a bright yellow background.

The research is in. Scientists have discovered a cure for cannabis addiction — and it turns out to be cannabis!

That was the gist of a headline-generating paper published in JAMA Internal Medicine, a Journal of the American Medical Association, which wasn’t trying to be satirical.

The July 2019 report, titled “Nabiximols for the Treatment of Cannabis Dependence: A Randomized Clinical Trial,” described an Australian study that probed the use of a standardized cannabis extract for treating cannabis dependence. The extract, called nabiximols (and marketed under the brand name Sativex), is an ethanol-based sublingual spray containing roughly equal parts THC and CBD, which has been approved for treating multiple sclerosis in many countries around the world.

The researchers hoped to show that this particular pharmaceutical formulation of cannabis would stop participants from smoking marijuana. Of course, the research would also need to show that nabiximols actually improves the quality of life of people trying to wean themselves off weed — rather than just changing their source of THC.


The practice of treating drug addiction with other drugs is nothing new. Nicotine replacement therapy (NRT) – utilizing a patch, gum, lozenge, etc. – can help to ease cravings for tobacco without inhaling all the toxic smoke. NRT isn’t perfect, but it can be a useful harm reduction technique.

For years the National Institute on Drug Abuse has been funding research into medication-assisted treatment for marijuana dependence.

Not all formulations are equal, even those comprised of the same drug. E-cigarettes are not considered a valid treatment for tobacco smoking in the United States, thanks to a handful of studies suggesting E-cigarettes are considerably less effective than other NRTs and can act as an entry point for teens to start using tobacco.

Opioid replacement therapy is another common practice in clinics. Methadone and buprenorphine are both highly addictive, but getting a heroin addict onto a legal supply of consistent, unadulterated opioids can save lives. Replacement therapies are a double-edged sword, however. After all, heroin was considered a treatment for morphine addiction in the late 1800s.

Eager to find a replacement therapy to facilitate cannabis cessation, the National Institute on Drug Abuse and other institutions have been funding research into medication-assisted treatment for marijuana dependence. Thus far, no meds have been approved for this purpose, but not for lack of trying.


At first glance, the 2019 JAMA article may seem like a regular study seeking to test a potential substitute medication for marijuana. As a randomized clinical trial, the Australian study was pre-registered with the hypothesis and methods laid out before data collection began.

In their trial, the Australian researchers listed three primary aims and a handful of secondary aims of the clinical trial, along with the statistical methods that would be used to analyze the data. The primary goals were to compare nabiximols to placebo in three ways:

  1. Would nabiximols improve abstinence from cannabis use, compared to placebo? Reductions in the frequency of use?
  2. Would nabiximols affect treatment retention?
  3. What are the side effects of nabiximols, compared to placebo?

They described the first question as follows: “Unsanctioned cannabis use will be quantified as 4-weekly point prevalence abstinence during the 12 week maintenance phase by combining self-report data from researcher interviews … with objective measures of unsanctioned cannabis use (weekly UDS [urine drug screen] with quantitative analysis of urinary THC, CBD and their metabolites). Unsanctioned cannabis use will also be reported as mean days used, and percentage of positive urine drug screens.”

This registered aim should have immediately raised a red flag, given that nabiximols is a formulation of cannabis.

This registered aim should have immediately raised a red flag, given that nabiximols (Sativex) is a formulation of cannabis. The THC and CBD in nabiximols is not chemically different from the THC and CBD in “unsanctioned cannabis.” So, all clinical trial participants who receive nabiximols would test positive for marijuana, according to the usual “objective measures.” Practically speaking, this means that assessing whether the first goal had been achieved would be limited to self-reporting, rather than a urine analysis.

The registration for the study went up in early 2016, followed by over a year of patient recruitment. Slightly less than half of all recruited patients completed the full 12-week abstinence program. Afterwards, the researchers analyzed the data and wrote up the results, which were accepted by JAMA in April 2019.

But, come publication, the study referred only to a single primary outcome, rather than three. What happened to the two other outcomes that were promised when the study was registered?


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