Marijuana medical benefits – large review finds very few

Marijuana medical benefits

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”

Marijuana for ADHD – what’s the evidence?

Marijuana for ADHD

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?”

Part 6. Medical uses for cannabis – the TL;DR version

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”

Part 1. Marijuana and medicine assessing the science

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”

Part 2. Marijuana and cancer – assessing the science

This is Part 2 of a series of six articles discussing marijuana’s use in medicine and health care. In this part, we discuss marijuana and cancer – probably one of the most passionate and controversial “debates” associated with the use of cannabis.

It’s clear that there are numerous claims about the value of marijuana in preventing or treating various cancers. But what are facts? And what is smoke?

In this article, I’ll look at some of the more prominent claims, along with a skeptical analysis of those claims.

Continue reading “Part 2. Marijuana and cancer – assessing the science”

Part 3. Marijuana and neurological disorders – assessing the science

This is Part 3  of a series of six articles discussing marijuana’s use in medicine and health care. In this part, we discuss marijuana and neurological disorders – probably the only field of study regarding medical uses of cannabis that has a robust area of clinical research.

Although research into the use of marijuana and cancer takes all the news these days, there is probably just as vigorous research into neurological disorders.  If you read the story regarding CNN’s chief medical correspondent, Dr. Sanjay Gupta, who claimed he changed his mind about marijuana, you’d know he was also convinced that marijuana had some great potential in mental health. But is there really any high quality evidence?

In this article, I’ll look at some of the more prominent claims, along with a skeptical analysis of those claims. Continue reading “Part 3. Marijuana and neurological disorders – assessing the science”

Part 4. Marijuana and health risks – assessing the science

This is Part 4  of a series of six articles discussing marijuana’s use in medicine and health care. In this part, we discuss marijuana and health risks – even if there is evidence that marijuana had medical benefits, there must be a review of the risks of using it.

Only in junk medicine (see homeopathy or chiropractic, for example) is there a promise of great results with no risks. In real medicine, all benefits are balanced against the real risks of any medication or procedure.

The whole foundation of evidence (or science) based medicine is science – “it is the only set of methods for investigating and understanding the natural world.” Thus, the best factual evidence includes clinical research that describes not only the effectiveness, but also the risks, of a particular medical procedure.

In this article, I’ll look at marijuana and health risks – along with a skeptical analysis of those claims. Continue reading “Part 4. Marijuana and health risks – assessing the science”

Marijuana and cancer – what are facts and what’s just smoke

Editor’s note–this article has been updated and included into a multi-part series on marijuana and medicine. Check it out there. 

If you spend any amount of time on Twitter, Facebook, or just researching cancer treatments on the internet, you will run across something about marijuana and cancer – someone will claim that smoking pot, eating pot, 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), or some other consumption of cannabis will cure or prevent cancer.

Of one hand, studies of cannabis’ effectiveness in reducing nausea and vomiting in chemotherapy, one of the the most common claims,  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. Continue reading “Marijuana and cancer – what are facts and what’s just smoke”

Medical uses of marijuana–hitting the bong of science (updated again)

Marijuana_Cures_CancerEditor’s note–this article has been updated and included into a multi-part series on marijuana and medicine. Check it out there. 

As the push to legalize marijuana for personal or medical use gains traction in the USA, the “pro-pot” arguments become more enthusiastic and more off the beaten track of real science. I suspect, like legal same sex marriage, social norms have changed, and legal marijuana is something that will become commonplace across the country, except in some deeply conservative areas. The Federal Government has shown little enthusiasm in enforcing Federal law, which retains the highest authority in regulating certain drugs, in states that allow legal marijuana.

I personally have no issue with smoking marijuana, since other “drugs”, like alcohol, are completely legal and socially acceptable. I think that legalizing marijuana will reduce much of drug trafficking, reduce the burden of law enforcement and penal system costs, and have other beneficial effects to society.

I still want regulations such as control over 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), there needs to be regulations about when it might be illegal to be high (I don’t want my Delta Airlines pilot to be smoking weed before flying my jet, and I don’t want automobile drivers to be under the influence), and I want age regulations no different than there is for alcohol and cigarettes (despite . But I think those are reasonable boundaries for legalization of cannabis that would be reasonable to most people. But this isn’t the point of this article.

What troubles me about the “debate” about legalization of cannabis is that the pro-pot side seems to make claims about various medical benefits that appear to be only tenuously supported by real scientific evidence–in fact, some of the claims are downright dangerous. The reasons for doing 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 not the point). Continue reading “Medical uses of marijuana–hitting the bong of science (updated again)”

Marijuana and cancer – Sanjay Gupta’s anecdotes are not science

Editor’s note–this article has been updated and included into a multi-part series on marijuana and medicine. Check it out there. 

Unless you were hiking in the Amazon River jungles, with no access to the internet or American TV, you probably have heard that CNN’s chief medical correspondent, Dr. Sanjay Gupta, changed his mind about marijuana (or “weed” as he keeps saying). Of course, this has become big news, because he’s such a “respected doctor” (why is that? Because he’s on TV?), and because a few years ago he was vociferously anti-cannabis.

I have no doubt that Dr. Gupta’s “conversion” to being pro-weed is genuine (and that his previous stance of anti-weed was similarly authentic), but we need to weed out what is real and what’s just smoke about his comments. His first major point about cannabis* was that the United States Drug Enforcement Agency (DEA) considers marijuana to be a Schedule 1 drug, which is defined as “drugs with no currently accepted medical use and a high potential for abuse.”

Dr. Gupta thinks this classification is ridiculous, and on the surface, many people, even those who are not devoted pot smokers, would probably agree. However, this is a political discussion, at least in the USA, and it is hardly a medical/scientific one. The chances of any political party having the fortitude to correct this classification is about as close to 0 as you can get, without actually stating that there is a 0 chance. But if Gupta wants to make a big deal of this, or that he’s so self-centered that he thinks he’ll change the mind of politicians, more power to him. But for me as a skeptic, it is not the most important thing he says.

In his article, he mentions a young girl who “started having seizures soon after birth. By age 3, she was having 300 a week, despite being on seven different medications. Medical marijuana has calmed her brain, limiting her seizures to 2 or 3 per month.” This is simply an anecdote of no quality whatsoever. Did he thoroughly investigate her case to determine if the number of seizures actually went down? Do we know that cannabis has anything to do with the change? Is this nothing more than a Post hoc ergo propter hoc fallacy, that just because she consumed cannabis and the seizures decreased does not mean anything about cannabis’ causative properties with regards to this type of seizure. And then, Dr. Gupta continues with the anecdotes by stating, “I have seen more patients like Charlotte first hand, spent time with them and come to the realization that it is irresponsible not to provide the best care we can as a medical community, care that could involve marijuana.” Why do these TV doctors (like Dr. Oz) think that their anecdotes are better than anyone else’s.

Anecdotes are useless because they aren’t controlled, because they are subject to all levels of bias, and because these stories aren’t peer-reviewed. In other words, anecdotes have no value in science-based medicine. Anecdotes do have value in formulating testable scientific hypotheses, but assuming that anecdote=data, and more anecdotes=more data is simply pseudoscientific. I don’t care what Sanjay Gupta writes or says publicly, but providing these stories as “evidence” that marijuana has a medical benefit is essential like telling me that he observed homeopathy (which is just water) working. It’s laughable.

Continue reading “Marijuana and cancer – Sanjay Gupta’s anecdotes are not science”