Re: Cannabis use by adolescents. Author replies

Issue: BCMJ, vol. 61, No. 3, April 2019, Pages 110-111 Letters

I thank Dr Mitchell for his opinion and for standing behind the quote, “There are biochemically distinct strains of cannabis, but the sativa/indica distinction as commonly applied in the lay literature is total nonsense and an exercise in futility.”[1]

In effect, Dr Mitchell is saying “strain does not matter.” I can’t say Dr Mitchell is wrong, but it does not align with the data we collected.

Dr Mitchell proposes that my observations should be viewed more as results of the placebo effect in combination with observer bias, especially given the lack of quantification of the cannabis used.

I respectfully disagree. This is not a placebo effect. The data are based on a retrospective chart analysis of a heterogeneous population, in a naturalistic setting, with no exclusion criteria. Even after you remove the noise, our observations remained statistically more likely than expected by chance.

It seems that Dr Mitchell is suggesting that our observations are misinformation, worse because they are published in a peer-reviewed medical journal. Here’s why I see it differently:

  • Before our study, from reading the medical literature, I didn’t even know there were two distinct strains.
  • During our study, I was amazed how strong the signal remained, despite a possible placebo effect, observer bias, and regardless of the dose. Not only are the strains different, they are opposites.
  • After our study, I shared my observations with every clinician at every conference and everybody said what Dr Mitchell said, “There is no strain difference.”

In essence, what our patients consider a self-evident truth, that sativa stimulates and indica sedates, is based on millennia of trial and error. It should not be a mystery to respected cannabis scientists. But it is. That’s why I knew we had to publish it.
Whether this is a random finding or whether it represents the first stone on the scale that measures the weight of evidence, only time will tell.
—A.M. Ocana, MD, CCFP, ABAM
North Vancouver

This letter was submitted in response to “Re: Cannabis use by adolescents.”


1.    Piomelli D, Russo EB. The cannabis sativa versus cannabis indica debate: An interview with Ethan Russo, MD. Cannabis Cannabinoid Res 2016;1:44-46.

A.M. Ocana, MD, CCFP, ABAM. Re: Cannabis use by adolescents. Author replies. BCMJ, Vol. 61, No. 3, April, 2019, Page(s) 110-111 - Letters.

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