Study: Cannabis May Be Safe, Effective for Chronic Pain

Doctor holding a tray of medical marijuanaMedical cannabis—or medical marijuana—may be safe and effective in moderate doses for people with chronic pain, according to a study published in The Journal of Pain.

The news may offer hope to the 100 million Americans who have chronic pain. Chronic pain is sometimes caused by conditions such as arthritis or multiple sclerosis, but the cause is often unknown, making symptoms more difficult to treat. Some chronic pain occurs alongside or as a result of psychological conditions, such as depression or posttraumatic stress.

Can Marijuana Treat Chronic Pain?

Concerns about the risks of treating people with cannabis may deter some doctors from recommending the drug, the study’s authors say. To test the safety and efficacy of cannabis, researchers followed 431 people with chronic pain for a year each between 2004 and 2008. The study involved patients at seven pain management centers across Canada.

A group of 215 participants used cannabis to treat their chronic non-cancer pain, while a control group of 216 participants abstained. The cannabis came from a licensed cannabis producer and was dispensed through the hospital pharmacy at each site. Researchers did not control the quantity participants used, but the average dose was 2.5 grams per day.

At the end of the study, cannabis users reported significant improvements in their pain levels and quality of life. They also showed no serious adverse events compared to the control group. Contrary to previous research, which suggests marijuana may affect cognitive function, researchers found no precognitive differences between the two groups.

The Need for Future Research

Though cannabis users did not report more serious adverse reactions than non-users, they did report an increased number of minor adverse reactions, such as respiratory issues associated with smoking. The study did not target first-time cannabis users, so researchers did not test how new cannabis use might affect health. About 30% of participants dropped out before the study’s end, potentially altering results and creating a possible source of selection bias.

Twenty-three states and the District of Columbia have enacted laws to legalize medical marijuana.


  1. 23 legal medical marijuana states and DC. (n.d.). Retrieved from
  2. AAPM facts and figures on pain. (n.d.). Retrieved from
  3. Van der Kolk, B. (2014). The body keeps the score: Brain, mind, and body in the healing of trauma (1st ed.). New York, NY: Viking.
  4. Ware, M. A., Wang, T., Shapiro, S., and Collet, J. (2015). Cannabis for the management of pain: Assessment of safety study (COMPASS). The Journal of Pain. doi:10.1016/j.jpain.2015.07.014

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  • Bennett

    September 30th, 2015 at 11:45 AM

    Uh have I missed something here?
    I thought that this had been the common consensus for a while now, that medically this drug could have many benefits over more prescribed medications.

  • Mac

    September 30th, 2015 at 3:31 PM

    How could people just drop out of a scientific study? Yeah this could very much affect the findings, some would say so much that it is a skewed sample and that the testing should be recreated or else have the validity questioned.

  • Walter

    September 30th, 2015 at 4:30 PM

    My biggest concern now that this has become so readily available to the public is how many people are going to become addicted where they never would have before had it not become so open and easy to get.
    I know that there are people who strongly believe that you cannot become addicted to this but I disagree. I think that it is definitely a gateway to even more hardcore drugs and then even when you use it the right way there can still be problems if you think that you have a personality that has a tendency toward addiction.
    I just think that over the next few years there has to be more research, and more concern over whether this is doing more harm than good in the lives of the general population.

  • willie

    October 3rd, 2015 at 6:45 AM

    safe is one thing
    but is it really all that effective
    and are there other solutions that could be just as useful?

  • Bret

    October 5th, 2015 at 2:26 PM

    I am not sure how this would work except maybe increasing appetites in patients like those with HIV or cancer who have lost their appetite to disease or treatment?

  • Peter S

    February 24th, 2017 at 6:25 AM

    I’ve been suffering from a back injury for months now, and been dosing my self with a lot of pain relievers. I’m starting to think that I might take away the pain of my back with the meds but at the same time punishing my liver slowly. So I started reading articles about marijuana and it’s medical aspect and found this along the way
    I am already 34 years old and haven’t tried smoking or any other means of using marijuana and I have nothing against it. My question is that if i try it would I be dependent at the same time addicted to it? And will it really ease the pain? Thanks in advance to those who’ll answer

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