Pain control: “no evidence” cannabis improves outcomes

I absolutely loathe how many "news" outlets out there employ people with little to no knowledge of science or statistics to write articles on published journals. This interpretation is wrong for so many reasons, but allow me to highlight a few.

1. The Australian government legalized marijuana in 2016. However, this study recruited people from August 2012 to August 2014. All data points except for the 3 year and 4 year follow-up questionnaire happened prior to legalization and the 3 year follow-up happened in early 2017, before the law may have been reasonably in effect. This implies that much of the cannabis use may have not been medically supervised. They even highlight this in the discussion:

Few data in our 4-year follow-up were collected after this change, and very few individuals nationally have accessed cannabinoids for medicinal purposes, so our cohort primarily used illicitly produced cannabis.

And

Additionally, in our study it is unlikely cannabis was consumed under the guidance of a medical practitioner. Expectations that cannabis will reduce pain and opioid use might differ for participants using medicinal cannabis compared with those using illicit cannabis.

2. This was a survey. Correlation is not causation. In fact, since we're measuring pain, we have a huge self-selection bias. Those in the most pain are going to be most desperate to try anything to help resolve their pain and will consistently report back more pain than their peers, even if they find some relief through alternative means.

3. Here's a direct quote from the article

All participants were asked “If you had access to cannabis, would you want to use it?” at each wave (excluding the 1-year follow-up).

This is known as a leading question. This will change how people react to the questions about cannabis, because it's reminding them that it is an illegal substance (until it is legal, and even at that point it reminds them that society might look down upon this).

4. Just about anywhere they talk about using adjusted models, the results are inconclusive.

In adjusted longitudinal analyses, we found no association between cannabis and pain severity or interference.

We ran post-hoc mixed-effects models among participants who self-reported neuropathic pain and adjusted for neuropathic pain and found no significant effect of past cannabis use on pain severity, interference, or oral morphine equivalent

In adjusted models, after controlling for age, sex, previous pain interference, pain factors (eg, duration of pain, pain severity, and pain self-efficacy), and oral morphine equivalent, previous cannabis use was not independently associated with current pain interference.

In adjusted models that included clinical covariates and pain self-efficacy, we found no association between past cannabis use and current pain severity.

To be clear, I have zero issue with the scientific article as it stands. The author's rightly point out all the potential biases, windfalls, and potential problems with their method of measurement. They call for more research to be done, since their findings either conflict with or do not support what the body of evidence does.

However, I do think they are over-reaching a bit with their interpretations. There is a huge difference between what marijuana you can get illicitly and what is prescribed medically, especially for pain. Medical applications are often highly dose-controlled. In addition, pain practitioners don't just give people drugs and tell them to go on their way - there's a whole lot going on... therapy, check-ins, self-evaluation and other treatment methodology that goes into making sure that pain is treated as both a mental and a physical disease and that it's managed appropriately.

Finally, and perhaps most importantly, across the US and in many other places in the world there's a growing morphine epidemic as we changed how we fundamentally treated pain in the 1980s. Anything that can potentially reduce morphine equivalent doses (MEDs) is something that should be investigated (and likely one of the main drivers as to why this received funding). Even if this means it only applies to a subset of the pain population (those the author points out rightly may be screened out of previous studies due to comorbidities), reducing MEDs to any population is a step in the right direction.

It's an interesting study, marred by a bad headline. To me, I see this as a win for "cannabis". If you're telling me that a quarter of the patients looked at were able to usurp opiodes and switch to street cannabis for pain relief, that's pretty huge in my eyes.

I can't help but feel that title was crafted for the type that won't read the article and just confirm thier biases. They kind of buried the lede, evidence that it helps with nausea from chemotherapy, helps with eplilepsy and despite not clinically reducing pain subjects rated it highly in thier ability to manage thier pain even if only psychologically.

Then again the validity of the study is pretty suspect since it was done before the subjects couldn't legally obtain marijuana so it could not control thc/cbd ratios.