As a medical resident some 30 years ago I chose to do my required “grand rounds” talk on cannabis research. All the published references I could find focused on defining the toxicity or other dangers of cannabis and THC (tetrahydracannabinol), its active compound. Most were animal studies, and significant adverse effects were seen in some laboratory rats. They were being given doses roughly equivalent to a human smoking hundreds of “joints” at a time. The term “LD-50”refers to the amount of any ingested substance that will cause death in half of the subjects (LD=lethal dose—the lower the number, the more deadly). In several lab rat studies the LD-50 for THC was calculated at either 666 mg/kg body weight or 1,270 mg/kg. The equivalent dose in humans would therefore predict that half of the subjects who ate 40 pounds of marijuana would die. The other half would no doubt wish they were dead.
By comparison the LD-50 for nicotine is 60 mg/kg, for heroin it’s 22, and for sugar it’s 30,000 (five pounds can kill you). Five to 10 alcohol drinks consumed within an hour will kill most people (pass out, stop breathing). This certainly does not prove that cannabis is “safe,” only that it’s extremely non-toxic. (There has never been a record of anyone dying from cannabis/THC ingestion.) My stated conclusion at the end of grand rounds was that laboratory rats should definitely avoid marijuana.
In my practice I was not opposed to personal cannabis use by adults, but I was not a supporter of medical marijuana. Good scientific evidence of medical efficacy was (is) deficient. Plus the drug Marinol is THC available by legal prescription (for control of chemotherapy-induced nausea). Herbalist-type claims that whole plants are better or safer than purified extracts lack proof. And the laughable medical marijuana program in California confirmed my suspicions that it’s mostly a backdoor approach to full legalization under the guise of medical care. For me it insults the medical profession and is a goldmine for shameless physicians running prescription mills for the money. Walk in, name your disease, get the Rx, pay the fee and head to the pot shop. The Vermont program is not like that at all, but I believe it is flawed nevertheless. Medical prescription of cannabis still strikes me as experimental at best, albeit quite safe, but with very weak science behind it.
The trouble is, the government has not been funding and has essentially been blocking any research into potential medical benefits of cannabinoids. Things have improved somewhat, but it remains very difficult. There are many obstacles and delays. This is a real shame because the fact that tiny amounts of THC have such a strong effect on humans (and rats) demonstrates that we have sensitive internal cannabinoid “receptors” and that we all produce internal “endocannabinoids” for some good reason(s).
An example is the drug company Schering, which tested a cannabinoid-blocking agent some years back, as a potential anti-obesity drug—an attempt to block the dreaded munchies, I presume. It didn’t work, but Schering did beautiful, fascinating research defining one role of endocannabinoids as a cog in the complex biochemical cycle controlling hunger and satiety. Yes, munchies are real. Perhaps there is hope yet.
It somehow strikes me funny that, despite extremely low toxicity, widespread covert (and not so covert) use and cultivation, mounting anecdotal evidence for medical efficacy, law enforcement failure and the many uses of hemp fiber, it wasn’t until legislators saw the opportunity for big tax revenues that they got serious about legalization. That’s just how things work. I believe Vermont’s debate on this topic has been a good one, with reasonable opinions expressed on all sides, minimal name calling and grandstanding, and no return visits by Willie Nelson (yet).
Legalization is a complex issue, although it seems most folks agree that the criminal penalties are way out of line. Perhaps legalization does send “the wrong message,” as some claim. Maybe it is a ramp drug to the harder, addictive ones (like alcohol and tobacco, or worse). But seriously, let’s get real. To legalize adult cannabis does not implicitly condone or encourage its use; it simply recognizes that we have no good basis for keeping it illegal and that current use is huge and current law misguided and ineffective. (In 2015 Vermonters consumed 15-25 metric tons of marijuana. Enough to kill thousands of rats.)
Those opposed to cannabis use can still voice their opposition and concerns and can still discourage its use, even if it is legal. And misuse can be better addressed with counselors than with cops. Really, if you don’t want your kids smoking pot you better discuss it with them directly, right now, because chances are they’ve already tried it (now 24 percent of Vermont high schoolers have used it, while tobacco use has dropped).
I can understand why law enforcement feels particularly threatened by all this, concerned, among other things, that legalization will lead to an increase in cannabis-impaired drivers, perhaps true. Recognizing drugged drivers too impaired to drive must be quite challenging when it’s not obvious. It’s a much more complex assessment than the sobriety test and breathalyzer for alcohol. State police do have a few specially trained officers to do non-alcohol “drugged” driver assessment, and this is good but cumbersome. More trained officers are needed, as well as special training for all law officers. Also many police still support the notion of pot as a gateway drug. The National Institute on Drug Abuse (part of the National Institutes of Health) published this in 2015: “…These findings are consistent with the idea of marijuana as a ‘gateway drug.’ However, most people who use marijuana do not go on to use other, ‘harder’ substances.”
Could it be that cannabis use actually discourages progression to hard drugs? I think the police concerns are legitimate, but the problems already exist, now, with no likelihood of improvement, though maybe some worsening with legalization. It’s hard to predict with any certainty. But to leave things as they are now would do nothing … except to leave things as they are now.
For our legislators to create a whole new organizational structure to control legal marijuana use has to be a daunting, scary task. It will take guts and determination and climbing a steep learning curve to craft a good program on such a complex issue. I’m sure they’ll screw it up. But maybe they’ll only screw it up a little, and it would still make things better, more sensible than the way things are now. Luckily they can draw heavily on the experience from five states where it’s already legal. Those states’ systems are screwed up, too, and subject to abuse. But overall they actually work pretty well; they bring in a lot of money, they haven’t caused widespread societal degradation, and they don’t turn potheads into criminals.
I recommend, along with 54 percent of all Vermonters, that adult cannabis use be legalized and regulated in Vermont. Yes, for the new and welcome revenue. Yes, too, because it’s an amazing plant that folks should be able to grow at home next to their tomatoes and kale for home consumption. Yes, because it has extremely low toxicity and definite potential medical benefits.
OK, I gotta get back to work.
Lee Weisman, M.S., M.D. (retired), Formerly of Charlotte Family Health
Emeritus professor, UVM Dept. of Family Medicine