Men Experience Pain Reduction From Cannabis—But Women Don't, Study Finds

I previously reported a story for Broadly about how the cannabis industry markets weed to women. In that article, Broadly contributor and former dispensary worker Mira Gonzalez fell into the latter category.

"Once I bought this bottle of 'menstrual cramp pills' at my dispensary, but it wasn't an effective painkiller at all," she told me. "When I had a job at a dispensary, women would come up to me all the time and ask for recommendations on what to buy for cramps, and I honestly couldn't recommend anything that had worked for me."

In other words, there's a lot of conflicting information out there about what cannabis can and can't do. That's namely because weed, while reported to be wonderfully helpful for a number of conditions, is woefully under-researched and under-tested. No one really knows what it can and can't do—or how it does or does not do it. Most testing on the drug has been in preclinical animal trials, which don't always reliably translate to human models. There's a lot surveys done on people who use cannabis but those don't even test the plant itself.

Earlier this month, Dr. Ziva Cooper, a researcher with the Columbia University Medical Center who I interviewed for the weed marketing article, published an analysis of two new studies to hopefully add some clarity to cannabis and its effects on women. The double-blind studies appeared to confirm for one of the first times in a human trial, that there are measurable sex differences regarding the effects of cannabis. Specifically, she found that after comparing responses to a painful stimulus in the laboratory, the drug reduces pain more effectively in men than in women. What's truly crazy here, though, is the study found that after men smoked cannabis, they were able to tolerate more pain. For women, the drug had no effect on their pain tolerance whatsoever.

Calling Dr. Cooper, I was fully freaking out. Does this mean there's no hope for women who want to use cannabis as a medical alternative?

It could mean a number of things, Dr. Cooper explained over the phone. The studies made sure to control for the amount of cannabis all the participants used on a daily basis, examining in particular men and women who are regular cannabis users and who presumably have some level of tolerance to marijuana. She thinks this influenced the results, which were similar to what was found in an animal trial: Most animal laboratories have shown that female rats or mice or what-have-you are more sensitive to the effects of cannabis than males. But a particular study found that animals that have been treated repeatedly gain a tolerance—and the females gained a tolerance at a faster rate than males.

Dr. Cooper thinks that it's possible the women in the study just had a higher tolerance than the men. "We think the reason why we're seeing this differential effect, where males in our lab see this pain-relieving effect and females didn't, might be due to the fact that we're dealing with really heavy cannabis smokers," she said. "Another thing to keep in mind that this is not a blanket statement about cannabis or cannabinoids, or their pain-relieving effects in women."

Mostly, it means we need more research, especially on the sex-dependent effects of cannabis. "Our study indicates that future research should really make a strong effort to include females," Dr. Cooper said. "There's evidence that they do differ in this respect, and it's important to understand the variables that contribute to their differences."

A study that examined different dosages for the same women—or even a different user population altogether—could turn up some different results. Cooper's study also only looked at the effects of smoked cannabis; future research could look at edibles, oils, or even suppositories. Cooper added that this study is only measuring a specific type of pain: the kind that is laboratory-induced. A study that looked at people with chronic illnesses—or even menstrual cramps—could end up differently. It just needs to be done.

She also points out how critical double-blind studies are for research. "We talked last year about all of these products that are geared toward females," she said. "There's very minimal evidence supporting that the products are going to work. But it's not the fault of these people who are business owners; there just needs to be more clinical research. We just need to demonstrate that the people who are using these products for menstrual cramps or PMDD aren't just experiencing placebo effects. (People are quick to assume these products work.) As a scientist and someone who is interested in the effectiveness of therapeutics, I think these things have to be studied in a scientifically rigorous manner before conclusions can be made."

Hopefully, that can start to happen now that the feds are slowly opening up the possibility of weed research to scientists.