Most states in the USA, and many countries across the world have passed legislation that allows the use of marijuana for medical purposes. Some of this legislation is dependent on various claims, many of which appear to be based on weak or nonexistent scientific evidence. Of all of the purported marijuana medical benefits, only a handful are supported by real evidence.
This review, Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda (pdf, which can be downloaded for free by registering or can be found online here), published by the influential and prestigious National Academies of Science, Engineering, and Medicine, examined more than ten thousand scientific studies that involved cannabis and various medical conditions. The value of such a review is that it examines not only the quantity of evidence supporting a claim but also the quality of such evidence. In the end, it gives much more weight to high-quality evidence.
I know many comments will drop on this article that “you haven’t read that incredible study published in Journal of Weed and Cancer Cures” – that misses the point. The National Academies is a highly respected institution, made up of the most respected scientists in the USA. And the committee that created this review is made up of leading public health, cancer, epidemiology, pharmacology, and psychiatry, all fields germane to understanding clinical and basic scientific research into cannabis.
Moreover, a review like this does two things – it gives more weight to well done clinical trials and pre-clinical studies, and it eliminates poorly done and biased studies. This is how science works – examine ALL of the evidence before coming to a conclusion. Pseudoscience, on the other hand, is to have a conclusion, like “weed cures cancer,” and only seeking evidence that supports that preordained conclusion.
Furthermore, and this cannot be stressed enough, this review is not opinion. It is not belief. It is not cherry picking. It is a critical analysis based on thousands of studies published in peer-reviewed journals. This is not published in a pro-cannabis website that cherry picks, misinterprets, and overrates a one-off study in an obscure journal. The report is over 400 pages long – most of you will not read even a few pages, because it is a dense scientific review written by some of the top scientists in the USA. Before you denigrate the study, I would suggest you read it carefully.
To save you time from reading the 400+ page opus, which I did, I divided up the medical evidence from strong to none of the evidence in support of benefits and of risks from smoking cannabis. Not to bury the lede, but there are only three conditions for which there is strong, overwhelming evidence benefits of marijuana. Just three. Continue reading “Marijuana medical benefits – large review finds very few”
I’ve always been amused by marijuana advocates – they vastly overstate the benefits and understate the risks, sort of the opposite of the anti-vaccine religion. Current research on cannabis shows that there is little robust evidence supporting most of its claimed medical benefits – for example, it does not cure cancer, despite what you see on the internet. On the other hand, there has been only a small amount of research examining the risks of marijuana smoking. But a 2016 article in a major journal examined the effects of secondhand marijuana smoke, and the results should cause us to examine laws to regulate public smoking of marijuana in the same way we do cigarettes.
Here in California, we would be calling the local swat teams to round up all the cigarette smokers in a public space, if the air has even a hint of cigarette smoke. Ironically, no one seems to care about cannabis smoke wafting over us and our children. Maybe some of us just assume that secondhand marijuana smoke was inherently safer than secondhand cigarette smoke. What does the scientific evidence say? Continue reading “Secondhand marijuana smoke – it may be unhealthier than cigarettes”
I’ve written extensively about marijuana treatment for various diseases. For example, using it to prevent or treat cancer? No clinical evidence support its use. In fact, a large review of published science on medical marijuana showed little evidence of it having a clinical benefit except for just a few conditions, one of which was chronic pain.
Apparently, there is little scientific evidence to draw conclusions about the benefits and harms of marijuana treatment for patients with posttraumatic stress disorder (PTSD) and chronic pain, according to two studies published recently in the respected journal Annals of Internal Medicine.
Let’s take a look at these two articles and determine what they say about marijuana treatment of PTSD and chronic pain. Continue reading “Marijuana treatment of PTSD and chronic pain – probably does not work”
Subjectively, one the wilder claims one can find on social media is that marijuana cures cancer. Or cannabis prevents cancer. It doesn’t matter what form – smoked, eaten, hemp oil (which is manufactured from the seeds of cannabis plants that don’t contain much THC, or tetrahydrocannabinol, the active hallucinogenic agent of cannabis) – some advocates for cannabis will try to make the argument that it is some miracle drug for cancer.
But is it? Yes, there are systematic reviews that indicate that cannabis may be effective in reducing nausea and vomiting in chemotherapy. But research has generated negative results in some well done clinical trials and some positive results in others. But that has nothing to do with actually curing or preventing the cancer itself, just dealing with the effects of the treatment.
So what has real research said about “marijuana cures cancer?” Well, not to give away the conclusion, but not very much. Let’s take a look.
Continue reading “Marijuana cures cancer? Scientific research says probably not”
This is Part 5 of a series of six articles discussing various medical uses for cannabis or marijuana. In this article, I review and summarize some of the evidence that marijuana supporters have used to claim that smoking weed during pregnancy is safe. And I look at data from high quality reviews that shows it isn’t. So let’s assess the science regarding marijuana and pregnancy.
As I have written previously, consumption of and growing marijuana should be completely decriminalized. And the laws need to be rewritten, not in the haphazard way it is now, but with protection and respect of rights of people to consume or grow (for personal use) cannabis. The criminal prosecution of marijuana use and distribution is a ridiculous waste of public resources.
There are numerous health claims made about marijuana, including its use for cancer, neurological disorders, and other medical uses. There’s even a whole area of belief that claims smoking cannabis is perfectly safe during pregnancy. Let’s look at this. Continue reading “Part 5. Marijuana and pregnancy – assessing the science”
Those of you who follow this website know that I frequently take down myths about the medical usefulness of marijuana. Let’s just say the evidence barely reaches the level of “sparse.” Recently, Tara Haelle pointed me to an article that trumpeted using marijuana for ADHD, attention deficit hyperactivity disorder.
ADHD is a psychological disorder in which the individual is unable to focus, is overactive, is unable to control behavior, or a combination of these, not appropriate for the age of the individual. Diagnosing ADHD is often difficult, because the differential diagnosis for the condition can be confused with or related to other emotional, psychiatric or neurodevelopmental disorders such as anxiety, major depressive disorder, and bipolar disorder.
There are some treatments available for ADHD, including stimulants such as the well-known medications, methylphenidate, or better known by its trademarked name, Ritalin, and Adderall, a mixture of two amphetamines. These stimulants are very effective for treating ADHD, but there are some risks to its use, and the effectiveness appears to lower over time.
So let’s look at marijuana for ADHD – it’s pretty weak, but let’s give it a good scientific skeptical analysis.
Continue reading “Marijuana for ADHD – what’s the evidence?”
On Sunday evening (8 May 2016), John Oliver, the English comedian and political satirist, talked about science and how we should embrace it during his HBO show, Last Week Tonight. The upshot is that John Oliver promotes real science – and critical thinking about bad science. And states that vaccines don’t cause autism.
Oliver is one of the best satirists on TV. His attacks on stupidity in politics and culture are classics. He’s been doing his shtick for many years on American TV, being one of featured correspondents for the Daily Show with Jon Stewart. I always looked forward to his reports, though always funny, they were generally pointed and quite intelligent.
His recent segment on science on his HBO show was a classic. And let’s take a look at how John Oliver promotes real science – and why it’s kind of sad that a comedian has to hit it out of the park.
Continue reading “John Oliver promotes real science – a comedian gets it right”
Yes, you read that right. This so-called shill for the pharmaceutical industry is calling them as I see them – most published medical research is a failure – but stay tuned for the full story.
Now by failure I mean that more often than not, claims that are supported by one or two published articles, rarely lead to a clinically significant product (such as a pharmaceutical). Of course, I don’t mean that the research is fraudulent, although some are, especially in low level journals frequented by pseudoscience pushers.
And I don’t mean it’s bad science, although there’s evidence of that, which I’ll discuss below.
And I don’t mean that there’s some grand conspiracy between Big Pharma and everyone else (again, no evidence to support that nonsense), although there is some evidence that research sponsored by Big Pharma is poorly done.
So what do I mean? Results from lot of medical research that get splashed in the news rarely, and I mean rarely, end up having any clinical utility. Rarely, but not never.
This does not mean that medical procedures, pharmaceuticals and devices that have been vetted through lots of research that repeat and confirm the original data and that form the basis of a scientific consensus are bad research. Almost everything that passes by the FDA and other regulatory agencies in other countries meets high standards for risk and benefit analysis.
Finally, arriving at a scientific consensus is a brutal, time-consuming process. It means that the theory or idea has been repeated many times, and the analysis and data are solid. So even though “most” research ends up in a failure, that’s because science is harsh to research that can’t be repeated, or was badly designed.
The best research isn’t a failure, even if it finds negative results. And the best ideas in medicine, let’s say vaccines, have been so thoroughly vetted that the consensus is nearly unassailable. Though people try with their poorly designed, unrepeatable research.
Continue reading “Published medical research is a failure – not what you think”
This is Part 6 of a series of six articles discussing various medical uses for cannabis or marijuana. In this part, I summarize all of the five previous articles into some bullet points so that you have quick and fast access to some scientific information about medical uses for cannabis or marijuana.
In case you missed them, here are the first five articles in this series:
Part 1. Marijuana and medicine assessing the science.
Part 2. Marijuana and cancer – assessing the science
Part 3. Marijuana and neurological disorders – assessing the science
Part 4. Marijuana and health risks – assessing the science
Part 5. Marijuana and pregnancy – assessing the science
Maybe you don’t agree with the science about marijuana’s role in medicine. But that’s not how science works. The evidence should lead you to a conclusion (actually, the acceptance or rejection of a hypothesis). One shouldn’t form an a prior conclusion, then go hunt for data. That’s not how it works.
As new systematic or meta reviews bring more clinical evidence of the benefits of the medical uses for cannabis – this takes time – maybe evidence based medicine can incorporate marijuana into the armamentarium of medical practice. But only real clinical evidence matters.
So let’s review where the evidence leads us. Continue reading “Part 6. Medical uses for cannabis – the TL;DR version”
I suspect, like legal same sex marriage, social norms are changing across the USA (and the world), which has lead to the decriminalization of marijuana in 23 states and the District of Columbia for some medical conditions. The US Federal Government, has shown little enthusiasm in enforcing Federal law about cannabis, although the Federal government retains the highest authority in regulating certain drugs like marijuana. So let’s look at marijuana and medicine assessing the science critically.
It’s clear that rational people still want regulations for marijuana, including prohibitions against public smoking (I don’t want second hand cannabis smoke wafting over me or my children, as much as I don’t want to inhale other people’s tobacco smoke). And a safe society would have strict regulations that would forbid marijuana smoking by individuals who have roles in public health and safety like physicians, pilots, mass transit drivers, and others.
But I think those would be reasonable boundaries for legalization of cannabis that would be reasonable to most people. But this is not the point of this article.
As the push to legalize marijuana for personal or medical use gains traction in the USA, there has developed a strong belief, unsupported by evidence, of the value of the medical uses of cannabis. What is troublesome is that the pro-marijuana side seems to make claims about the medical uses of cannabis that appear to be only tenuously supported by real scientific evidence.
In fact, some of the claims are downright dangerous. The reasons for pushing this is probably, though I can only speculate, to make it appear that marijuana is some miracle product, so let’s speed up the legalization of it. It’s like the Food Babe telling us that kale is the miracle food, except that kale isn’t illegal. It does taste awful (but again, not the point).
Because of the amount of scientific information, this article is part 1 of a 5-part series about marijuana and medicine – assessing the science. For detailed analysis of various aspects of the science of marijuana and medicine, check out each of the subtopics:
Part 2 – Marijuana and cancer
Part 3 – Marijuana and neurological disorders
Part 4 – Marijuana health risks
Part 5 – Summary of marijuana and medicine
Continue reading “Part 1. Marijuana and medicine assessing the science”
