Dr. Aaron Carroll: It's April 20th, the 20th of April. It's 4/20 or as some like to call it, Weed Day. I guess we're doing this, this is healthcare triage. To be honest, this is an episode I thought about bailing on many times, there's just no way to talk about marijuana without somebody completely misinterpreting what I say, some of you are going to call me a fascist, for saying anything bad about pot at all, others are going to attack me for not coming down on it hard enough. So I'm going to cloak myself, as I always do, in the power of data. Marijuana works by affecting the brain. It's a drug, like many others with different effects on different people. The active ingredient is called tetrahydrocannabinol, or THC. THC bonds to protein-specific receptors in the brain to produce a number of results. It can have a mild sedative effect and it can also lower your inhibitions. Marijuana can increase your pulse, lower your blood pressure, and increase your appetite. It can also interfere with short-term memory, lower your reaction time, and make you unsteady on your feet. But so can lots of other things that we like to eat, drink, or smoke.
The real question is whether it's dangerous enough to be made illegal and that's where the screaming usually starts. There's no evidence that marijuana causes a physical dependency, like heroin does. Some argue though, that it can become psychologically addictive, some will argue that the smoke is carcinogenic and causes lung cancer or respiratory disease. Others argue that regular use can affect the immune system. Still more argue that it increases the chance of developing a psychotic illness, but as I point out again and again in many of these videos, lots of things in life have both a benefit and a harm. No one should be under the illusion that marijuana has no harms. The question that we should care about is how much harm is there in marijuana? And does that harm outweigh the benefits so much that it should be made illegal? And now the benefits, there's a growing body of evidence that marijuana has use in many medical conditions to improve quality of life, and you need only talk to one of the gazillion marijuana users out there to hear about its other benefits as well. Moreover, there are lots of things in the world that can absolutely harm us that are totally legal.
The two most obvious choices are tobacco and alcohol. Both of these substances are regulated but legal in most of the world. They can provide us with a useful benchmark against which we can compare marijuana. Don't blame the messenger, I'm just telling you what the science says. To the research! Two years ago, a study was published in the Journal of the American Medical Association investigating the effects of marijuana and tobacco on pulmonary function. Researchers followed a cohort of more than 5000 men and women over 20 years. They wanted to see how smoking tobacco and marijuana affected lung health. What did they find? Not surprisingly, tobacco use had significant negative effects on lung function, marijuana use though had none. No lung effects at all, they couldn't even show that very high use of marijuana was bad for lung function, although the study wasn't powered for that specific analysis. Their conclusions? And I quote, from the Journal of the American Medical Association, marijuana may have beneficial effects on pain control, appetite, mood, and management of other chronic symptoms. Our findings suggest that occasional use of marijuana for these or other purposes may not be associated with adverse consequences on pulmonary function. Tobacco totally does have adverse consequences on pulmonary function.
Almost in the same week, the CDC published a report on binge drinking in adults in the United States. The results were sort of shocking. More than one in six adults in the United States is a binge drinker of alcohol. Those that do binge drink do so, on average, more than four times a month, and when they do they have about eight drinks on average. More than 28% of binge drinkers were young adults, 18-24 years old, who had more than nine drinks on average when binging. But elderly binge drinkers, or those older than 65, drank the most often, about five and a half times per month. Excessive alcohol use accounted for an estimated 80,000 deaths in every year of the study. The estimated economic cost of this damage was more than 223 billion dollars in 2006 alone. Another study was published in 1990, that described a cohort of more than 45,000 Swedes, that were followed for 15 years. There was no increase in mortality in those who used marijuana after controlling for other factors. Another study was published in 1997, in the American Journal of Public Health, that followed more than 65,000 people in the United States aged 15-49 years old. They found that marijuana use had no effect at all on mortality in women and no effect on non-AIDS mortality in men either.
So let's review, tobacco, adversely impacts lung function and perfectly legal. Binge drinking of alcohol? Common, dangerous, costly to society, also totally legal. Marijuana? No impact on lung function, no impact on mortality, almost always illegal. I'm not arguing that marijuana should be sold in the aisles of drug stores or supermarkets, but here and in many other parts of the world, you need a good reason to make something illegal. There are lots of things that are dangerous, but regulated. We don't let kids buy tobacco or alcohol, totally makes sense. The same should apply to marijuana. We don't let people drive under the influence of alcohol, totally makes sense. The same should apply to marijuana, which has been shown to impair drivers significantly as well. There was even a meta-analysis published in the BMJ in 2011 confirming that and I believe the results, but it's hard to continue to make the argument that the freedom we enjoy should cover tobacco and alcohol, yet not extend to marijuana. There's plenty of evidence that the former are unhealthy and are consumed at our own risk, the evidence against marijuana is thin.There may be small errors in this transcript.