At a 24 September 2016 Hillary Clinton campaign event in Youngstown, Ohio, her daughter Chelsea controversially asserted that “anecdotal evidence” from Colorado indicated that marijuana use (which is now legal in that state) has led to drug interaction fatalities:

But we also have anecdotal evidence now from Colorado where some of the people who were taking marijuana for [medicinal] purposes … the coroner believes … after they died, there was drug interactions with other things they were taking. Chelsea Clinton implies here that marijuana can kill you. Uhh pic.twitter.com/cdBWGgDG5P — Lee Fang (@lhfang) September 27, 2016

The younger Clinton didn’t expressly state that marijuana use itself could be fatal, but she did maintain that “anecdotal” evidence from Colorado included coroners’ reports of deaths caused by adverse interactions of marijuana (taken for medicinal purposes) with other drugs (presumably of the prescription, rather than recreational, variety).

In a broader context Clinton seemed to be saying (in response to a question from an audience member about the possible rescheduling of marijuana by the DEA) that insufficient evidence was available regarding the effects of medicinal marijuana usage in conjunction with various medical issues and medical treatments and thus there was a danger of fatal interactions

[My mother] absolutely supports more research. One of the challenges with the experiments happening around the country at the state level — she supports states making whatever choices they think are right vis-à-vis medical and recreational marijuana use — is that we have no real way to study them. So that anecdotally we have lots of evidence in the area you talked about, in epilepsy, but also in autism, in stimulating appetite for people who are on intensive chemotherapy regimens, for people who have non-epilepsy seizure disorders and challenges. But we also have anecdotal evidence now from Colorado where some of the people who were taking marijuana for those purposes, the coroner, after they died, there was drug interactions with other things they were taking. And so one of the reasons we really do need rigorous study into your point about rescheduling marijuana is one, we want to know where it works and where it doesn’t work, because probably there’s some areas where it works and probably there’s some areas where it doesn’t work, like other things that we think have medicinal uses. But two, one of the reasons the FDA has such rigorous testing, and one of the reasons our FDA approval process is the gold standard for the world, is the rigorous study of how new proposed drugs interact with drugs that are already on the market, both prescription drugs and over-the-counter drugs. That’s why if any of us get a prescription, there are all of those warnings “be careful” and “don’t use heavy machinery or drive or don’t drink alcohol,” but sometimes they’re really explicit instructions, “if you are taking these four drugs please make sure your doctor knows that before you start this prescription.” We just need so much more data than we have so that people who might benefit have the chance to benefit, people who might be in danger are protected. So absolutely my mom strongly supports the need for more rigorous study and then subjecting it as we do with everything else that might have a medicinal purpose to FDA approval, scrutiny, and ultimately regulation.



Marijuana advocate Tom Angell tweeted that he attempted to obtain additional detail from the Clinton campaign about that topic but did not receive a response:

Clinton campaign still hasn’t responded to request for clarification on Chelsea’s claim that marijuana can kill youhttps://t.co/ThWiCUQspN — Tom Angell (@tomangell) September 26, 2016

Without clarification from Clinton, it is virtually impossible to determine what purported incidents she was citing. Several high-profile deaths have occurred in Colorado in which families claimed marijuana was a contributing factor, but not as part of a drugs interaction. Moreover, those deaths largely involved recreational (not medicinal) use of cannabis:

Another death in Colorado has been listed as having “marijuana intoxication” as a factor, according to a KCNC investigation, and several other families are now saying they believed the deaths of their loved ones can be traced to recreational marijuana use. Daniel Juarez, an 18-year-old from Brighton, died Sept. 26, 2012 after stabbing himself 20 times. In an autopsy report that had never been made public before, but was obtained by KCNC, his THC level — the active ingredient in marijuana — was measured at 38.2 nanograms. In Colorado, anything over 5 nanograms is considered impaired for driving. Up until now, just three other deaths in Colorado were seen as having links to marijuana. Levy Thamba Pongi, a 19-year-old college student jumped from a Denver balcony to his death in 2014 after eating marijuana edibles. Marijuana intoxication was listed as a factor in his death. Richard Kirk of Denver is accused of killing his wife, Kristine. Before her death, she called police and said her husband seemed to be hallucinating after ingesting marijuana edibles and prescription medications … And college student Luke Goodman killed himself in Keystone in March shortly after ingesting marijuana edibles.

Three of the deaths described as “marijuana related” in Colorado were suicides, and a fourth was an alleged murder. None involved the purported interaction of marijuana with any other substance, and marijuana is largely believed to have either no adverse effect or a synergistic effect when used in concert with other medications.

On 27 September 2016, cannabis researcher Dr. Michele Ross reiterated that information, asserting Clinton’s “anecdotal evidence” claim elided vast published research into marijuana (and specifically drug interactions with cannabis):

Cannabis can synergize with certain medications such as opiates to actually increase the analgesic, or pain relieving, effects of the drug. What it doesn’t seem to synergize with is the side effect of the drugs. So, for example, whereas opiates can depress your breathing, slow it down, cannabis will not enhance that. There have been over 20,000 studies published on PubMed [a federal database of biomedical research]. This is not anecdotal. This one plant has been researched more than Tylenol, more than Adderall, more than any other medication.

Chelsea Clinton did imply “anecdotal evidence” from Colorado indicated adverse interactions involving marijuana had led to documented deaths, but we were unable to corroborate that claim. Moreover, the claim seemingly contradicts a body of research suggesting that cannabis is unlikely to interact adversely with other medications. Clinton also maintained that marijuana’s classification as a Schedule I drug meant little research had been performed on it to determine whether it was safe, but marijuana researchers have firmly rejected that claim.