Proponents of the use of medical marijuana like to start speeches and articles by quickly stating that cannabinoids are of proven value in treating many diseases.

Poppycock. This site has stated repeatedly: not true, not true, not true.

Now the evidence is in, and we were right. JAMA confirms that the evidence supporting the effectiveness of cannabinoids is tenuous at best. And risk of side effects with cannabinoids to treat anything is high.

First, the details.

  • An international group of researchers conducted a systematic review of 28 databases on the benefits and adverse events (AEs) of cannabinoids.
  • Clinical studies of cannabinoids for nausea and vomiting due to chemotherapy, appetite stimulation in HIV/AIDS, chronic pain, spasticity due to multiple sclerosis or paraplegia, depression, anxiety disorder, sleep disorder, psychosis, glaucoma, or Tourette syndrome were included.

And, the results.

  • A total of 79 studies (6462 participants) were included in a meta-analysis.
    • Only 4 studies (about 5%) were judged as low risk of bias.
  • Most studies reported improvement in symptoms with cannabinoids but these observations failed to reached statistical significance in all reports.
  • Here are the response rates for placebo vs. cannabinoids:
    • Complete nausea and vomiting response (47% vs. 20%)
    • Reduction in pain (37% vs. 31%)
    • Average reduction in numerical rating scale pain assessment (on a 0-10-point scale; -0.80 to -0.11)
    • Average reduction in the Ashworth spasticity scale (-0.69 to -0.05).
  • Here is the risk of side effects.
    • Increased risk of short-term AEs with cannabinoids, including serious AEs.
    • Common AEs included dizziness, dry mouth, nausea, fatigue, somnolence, euphoria, vomiting, disorientation, drowsiness, confusion, loss of balance, and hallucination.

The bottom line?

The most important finding is that researchers of pot are not good medical scientists. They should be ashamed of themselves. They published flawed studies that supported their prejudices IMO.

Medical marijuana has not been proven to work for many illnesses that state laws have approved it for.

The authors concluded, “There was moderate-quality evidence to support the use of cannabinoids for the treatment of chronic pain and spasticity.” That’s being generous considering the overwhelming amount of bias present.

For most uses, cannabinoids are no better than placebo (aka sugar pills).

In addition, the authors concluded, “Cannabinoids were associated with an increased risk of short-term AEs.” They didn’t get into long-term complications: neuropsychological decline, psychosis, testicular cancer, and the one nobody wants to talk about — increased substance abuse.


In another study in JAMA, reported by the AP, researchers evaluated 47 brands of medical marijuana products, including candy, baked goods and drinks, bought at dispensaries in Los Angeles, San Francisco, and Seattle.

Independent laboratory testing for THC (tetrahydrocannabinol), marijuana’s main active ingredient, found accurate amounts listed on labels for just 13 of 75 (17%) products. That means that you get what you pay less than once out of every 5 purchases.

Almost 1 in 4 had higher amounts than labeled, which could cause ill effects. Of course, among pot heads that might be a benefit. Most however, had lower-than-listed amounts. There were similar findings for another active ingredient.

The biggest problem in studying marijuana is that you can’t “blind” the study participants to the treatment. Consequently, those who love it know they’re getting it and reliably report positive results, while those who have not experience cannabinoids before just get side effects.

As stated here before, pot is not a harmless, fun-times activity. In the medical arena, there is little to support it’s use. And for everyone, there are negative consequences, short- and long-term.

Everyone supports further research. Let’s hope that future studies are better than what we’ve been exposed to over the past 2 decades.

6/23/15 JR


Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at www.Vicus.com, a complementary and alternative medicine website.