Thursday, May 5, 2016

Medical error - the third leading cause of death in the US

by Felipe Nogueira

Published two days on the British Medical Jorunal, study estimates that medical error is the third leading cause of death on US.

Most common causes of deaths in the United States in 2013:

1 - Heart disease: 611k
2 - Cancer: 585k
3 - Medical error: 251k
4 - COPD: 149k
5 - Suicide: 149k
6 - Firearms: 34k
7 - Motor vehicles: 34k

2013 Causes of death in the US. Source: BMJ [1]

It gets worst: according the authors,  medical error is not registered on US death certificates.

The  authors conclude that "the system for measuring national vital statistics should be revised to facilitate better understanding of deaths due to medical care" [1].

[1] Makary MA, Daniel M. Medical error-the third leading cause of death in the US. BMJ 2016;353;i2139.

Monday, November 9, 2015

Where Drugs Myths Die. An Interview with Dr. Carl Hart

Published in Skeptic Volume 20 number 2 
(article translated to portuguese on link)

By Felipe Nogueira
Interview with Hart: cover story on Skeptic
Carl Hart is an associate professor in the departments of Psychology and Psychiatry at Columbia University, and a research scientist in the Division of Substance Abuse at the New York State Psychiatric Institute. He is a member of the National Advisory Council on Drug Abuse and on the board of directors of the College on Problems of Drug Dependence and the Drug Policy Alliance. After receiving his B.S. in psychology at the University of Maryland and his Ph.D. in experimental psychology and neuroscience at the University of Wyoming, he went on to publish many papers in prestigious scientific journals for which he was made a Fellow by the American Psychological Association. In 2012 he co-authored with Charles Ksir the highly regarded textbook Drugs, Society, and Human Behavior (McGraw-Hill).

As a neuropsychopharmacologist Dr. Hart researches the effects of drugs on human physiology and behavior. For example, one of his experimental objectives was to understand how crack cocaine users would respond when given a choice between the drug and another appealing option—money. Contrary to what most people would think, Hart’s experiment revealed that drugs users can behave rationally, choosing other appealing options than destructive drugs. Thus, the medical model of addiction that treats it like a disease is not fully accurate when compared with, say, AIDS or cancer, which patients cannot simply choose not to have. Many people do quit drug use, even addicts. The question is, why?

Being a distinguished drug scientist is only part of Hart’s fascinating personal history with drugs. He was raised in a poor neighborhood in Miami where in high school he not only used drugs but also sold marijuana, and in the process committed petty crimes. To make matters worse, most of his relatives didn’t recognize the value of a formal education, so he ended up joining the United States Air Force, which gave him a deeper appreciation of the importance of knowledge, especially scientific knowledge and the ability to think critically, eventually leading him to become the first African-American tenured science professor at Columbia University.  

In 2013, he published High Price: A Neuroscientist’s Journey of Self-Discovery that Challenges Everything You Know About Drugs and Society (Harper), a book about research, myths, laws and public policy about drugs written for a general audience. The book is also a memoir, where Hart discusses his personal life and how he turned out to be the scientist he is now. High Price received the 2014 PEN E.O. Wilson Literary Science Writing Award, and he has since appeared as a regular guest on talk shows such as Bill Maher’s Real Time on HBO, where on the September 27, 2013 show the host made his usual plea for the legalization of marijuana, to which Dr. Hart added that cocaine, heroine, and methamphetamines should also be decriminalized so that people can get the help they need and we can empty out our prisons of such victimless crimes. He schooled Bill O’Reilly on the facts about addiction (texting doesn’t count), pointed out to him that the last three presidents of the United States smoked pot in their youth, and that, in fact, marijuana use among high school kids has declined from 37% in 1978 to 22% today (O’Reilly insisted it was higher, to which Dr. Hart responded bluntly “you’re wrong”).

In this sense Carl Hart is the mythbuster of drugs, the debunker of addiction myths, and a true skeptic of the pseudoscience and nonsense underlying this country’s attitudes about drugs and drug addicts.

Skeptic: Many people believe marijuana is a gateway drug. Is it?
Hart: It all depends what is meant by “gateway drug”. What people often mean is that marijuana leads to hard drugs. That is not true. It is true that the vast majority of people who use heroin and cocaine, for example, used marijuana before they used these hard drugs. But, then you look at the fact that the vast majority of marijuana smokers don’t go on to use those drugs. So, it’s not a gateway drug. It’s illogical to make that sort of statement. It would be like saying that “the last three presidents of United States used marijuana before they became president. Therefore, marijuana is a gateway drug to the white-house.”

Skeptic: Those who use crack cocaine didn’t use alcohol or tobacco before using marijuana?
Hart: Most used alcohol and tobacco before they used crack cocaine; of course, they also drank water or ate a fruit. Crack cocaine users engaged more in petty crimes than those who use marijuana, so we can also say petty crimes is a gateway to harder drugs. You can think of any number of behaviors associated with people who go on to use heroin and call those behaviors gateway, but that’s not a proper scientific conclusion to draw.

Skeptic: Is there a difference between crack and cocaine?
Hart: Pharmacologically, there is no difference. The major thing the people are seeking when they use cocaine is the cocaine base. Powder cocaine contains not only the base, but a hydrochloride salt that makes it stable and decreases the likelihood to smoke it. If you want to smoke it, you have to remove the hydrochloride portion, which does not contribute to biological effects of cocaine. When people are describing the difference between crack cocaine and powder cocaine, what they are really describing is the difference between the ways the drugs are taken. The onset of effects is faster when you smoke it than when you snort it. But you can dissolve powder cocaine in water and inject it in your veins and have the same effect as you do from smoking the crack.

Skeptic: Since it hits the brain faster, is crack more addictive than cocaine?
Hart: Smoking crack cocaine and injecting powder cocaine dissolved in water hits the brain at the same speed. Nonetheless, this is one of the arguments that some have made. But there is no drug that we punish as a result of the route of administration besides crack cocaine and powder cocaine. And we make that distinction in the United States because crack cocaine was associated with poor black people. When we look to powder cocaine in United States in the early 1980s, there was no drug that produced more violence than powder cocaine, but no one passed new laws, in part, because the people engaged were not black people; they were primarily white people. So as a society we are not being honest about this.

Skeptic: People think one dose is enough to get them addicted. Can you explain why this is not true?
Hart: By definition, drug addiction is behavior that disrupts your psychosocial functions, your job, your family life, and the behavioral disruptions have to occur on multiple occasions. So, if you use a drug once and you have a disruption once, by definition that is not an addiction. Addiction requires work. There is no one hit of anything that causes anyone to get addicted. People make these statements based on pure hyperbole attempting to get an emotional rise out of the listener.

Skeptic: How addictive is tobacco compared to other drugs?
Hart: At 1 in 3, or 33% of people who smoke will become addicted to tobacco, that is the drug that we say causes the most addiction. By comparison, 15% of those who use alcohol will become addicted. The rate for marijuana is about 10%. Heroin is about 25%, and cocaine (and crack cocaine) ranges from 15% to 20%.

Skeptic: Psychopharmacologist David Nutt, author of Drugs Without the Hot Air, published a study in 2010 that called alcohol the most harmful drug. Do you agree with this? 
Hart: I am a fan of David’s work and of his advocacy to educate the public, and I admire what he does. I think he tries to make the public understand that when we think about whether a drug is toxic, we have to look to multiple measures. And in one measure alcohol may be seen as the most toxic drug. For example, when we think about withdrawal from a drug, when people abruptly discontinue long-term use of a drug alcohol is clearly the most dangerous because you can actually die from alcohol withdrawal. You can’t die from withdrawal from heroine, crack cocaine, tobacco, or marijuana. When trying to determine the potential toxicity of a drug, it all depends on what measure you’re looking at.

Skeptic: I’ve heard a lot of comments about how addictive people behave. For example, some people say crack users are “zombies”. I’m not sure what it means to be a drug zombie, but what is it people are thinking when they use such expressions to describe people under the influence of a drug? That is, how do addicted people behave?
Hart: I’m a psychologist who studies human behavior. But all of us behave, and we most of us think we’re experts in understanding human behavior because of this fact. But most people are not experts and that’s part of the problem with such subjective and anecdotal reports. People see somebody misbehaving in some way and they know that person uses a drug. Therefore, they conclude that the misbehavior is caused by that substance. No! You can’t draw that conclusion. There are multiple factors at work, and these multiple factors need to be teased apart. You have to consider the person’s psychological history, whether or not other drugs were on board, whether the person was sleep deprived, whether the person interacted with someone who angered them, etc. People often fail to consider these other factors. That’s why anecdotes alone are insufficient to provide an adequate explanation of behavior.

Skeptic: In one of your experiments you gave participants two choices, money or drugs. What did you find and what does it mean?
Hart: Of the things people say about drugs users, particular about the drug addicted, is that they only respond to their drug of choice: if you give them an opportunity to use their drug, they’re going to take it over anything else. It was a simple experiment in which we had escalating amounts of money that we offered subjects. We found that when you increase the monetary value, you decrease their choice to take the drug—they choose money instead; they behaved rationally.

Skeptic: Why do people get addicted?
Hart: It’s a difficult question and one that science should be really focused on. Recently we’ve been concentrating on finding biological mechanisms of addiction. But frankly we’ve not found any that are compelling so we must look to other things as well, such as co-occurring psychiatric illnesses like depression, anxiety, and schizophrenia, which increase the likelihood of being addicted. Addiction is a condition primarily characterized by not tempering your behavior when it comes to certain drugs. But there are people who do not temper their behavior in a wide variety of domains, not just with drugs, because they just haven’t learned the skills to do that. So, that increases the likelihood of becoming addicted if they indulge in drug-taking behavior because taking a drug requires a person to be responsible, for example when driving an automobile. You can’t be irresponsible driving automobile; you might hurt yourself or someone else. If you haven’t learned those responsibility skills, it increases the likelihood of you becoming addicted. If you don’t have many alternatives in life that are better than drugs, it increases the likelihood of you becoming addicted. All these factors are critically important when we’re trying to determine why someone became addicted compared to someone else who did not.

Skeptic: You mentioned biological mechanisms for addiction. There is the dopamine hypothesis, but you mentioned in your book that there are problems with it. Can you clarify?
Hart: Let’s talk about the simplistic version of the dopamine hypothesis first. Drugs like cocaine and amphetamines increase dopamine, which in turn increases pleasure. So researchers said drug users are trying to increase their dopamine and so dopamine was considered to be a critical factor. This was an important theory because it helped us to organize several types of experiments, but it came about in 1960s when we had identified only five or six neurotransmitters. Today, we know about more than 100 neurotransmitter substances and yet the theory hasn’t been appreciably updated. So, we’ve learned a lot about the complexity of the brain in terms of how neurotransmitters interact with each other. Rather than one neurotransmitter being released at one time, there are multiple neurotransmitters that are released together in order to produce effects. And, sometimes, they are co-localized in the same cells. The old dopamine theory does not take into account this new knowledge. For me, the dopamine hypothesis is too simple to explain complicated behavior. Plus, we have some observable information that can help people right now: Does the person have a co-occurring disorder? Is the person responsible? We can manipulate many variables to help people now; you can’t assist drug users immediately with the dopamine hypothesis, and it doesn’t help anybody in treatment; it doesn’t help in any practical level. It’s on the level that science is trying to figure it out and we’re not close, if we’re talking about dopamine.

Skeptic: What about pharmacological treatments for drug addiction, such as cocaine?
Hart: A large part of my career has been spent trying to develop medications to help people with cocaine addiction, but we have been unsuccessful in finding a medication that works. It seems the best medication for cocaine addiction is cocaine itself. In Switzerland heroin is used to treat heroin addiction, and successfully so. When we think about treatment there are a variety of components that are necessary, not only the drug: psychosocial support, therapy to figure it out what’s going on with the person’s addiction, do they have employment, do they have a social network? All of these factors are incorporated into the heroin treatment program in Switzerland, and it’s been successful. You can do a similar thing with cocaine, but you have to have all these other auxiliary components in place.

Skeptic: What are the harms caused by amphetamines?  
Hart: The first lesson people should really know is that there are potential harms for all the drugs that we’ve talked about it. However, when you only emphasize the potential harms, people who use drugs stop listening to you, because they know there are other effects (that’s why they use them). The major concern about amphetamines is that they have a powerful effect on the cardiovascular system; it increases blood pressure and heart rate. This is not good for people who have a compromised cardiovascular system; they should not take large doses of amphetamines. Amphetamines disrupt sleep, and sleep deprivation can cause several physical and psychological problems, even without any drugs use. Amphetamines also disrupt food intake, which is critically important for the proper functioning of the body. Those are the concerns that people who take amphetamines should be aware of, rather than other concerns that are often emphasized in the media and even by scientists. About cognitive decline, amphetamines are approved to enhance cognitive functioning in order to treat attention deficit disorder. So, the notion that amphetamines are causing cognitive dysfunction is simply inconsistent with the history of behavioral science we have with these drugs.
Skeptic: Another idea you hear a lot is that marijuana or cocaine kills nerve cells. Is that any evidence of that?
 Hart: Any psychoactive drugs in large doses can kill brain cells. However, these doses are so large that they the drugs would be so unpleasant to humans that they wouldn’t take those doses again after experiencing their effects, if they survived it. These doses are 20-80 times of what people usually takes. In addition, there is no evidence that long-term use of doses within the range that humans take produces neurotoxicity. Neurotoxicity certainly can happen, but the likelihood that it happens to people using drugs within the range that humans take is very low.
Skeptic: Why do you advocate for decriminalization rather than legalization of drugs?
Hart: Of all these drugs that we’ve talked about, nicotine in tobacco is probably the one that kills you with the smallest amount of it. 50 mg of nicotine would kill half of us. In contrast, with 50 mg of cocaine or heroin, you just feel really nice. So, we have to think why nicotine is legal even though so little of it is necessary to kill people. It’s legal because we have societal structures, we have education about nicotine, and we know how to keep people safe with it. One cigarette contains 1 mg of nicotine and one pack contains 20 cigarettes. It requires people to smoke multiple packs immediately to kill themselves. We’ve packaged nicotine in a way that substantially decreases the likelihood of someone getting immediately harmed. We have to figure out how to package other drugs and educate people in a way to keep them safe. We have not done that yet, because we don’t have the social structures in place. I see decriminalization, in part, as the intermediary step to regulation, like we regulate alcohol and tobacco. But we have to put those structures in place to keep people safe, because all of these drugs are potentially dangerous, although all of them can be used safely.
Skeptic: We can compare different places (countries, states, cities) with different drugs laws (prohibited, decriminalized, legalized) regarding several outcomes, such as rates of drug use, drug-related deaths, drug-related homicides, and crime. What can we say about these kinds of measurements? That is, what are the effects of decriminalization and legalization on such outcomes?
Hart: I think a comparison of Portugal and the U.S. would be instructive here. In 2001, Portugal decriminalized all drugs including heroin and cocaine. Overall, they have increased spending on prevention and treatment, and decreased spending for criminal prosecution and imprisonment. The number of drug-induced deaths has dropped, as have overall rates of drug use, especially among young people (15-24 years old). In general, drug use rates in Portugal are similar, or slightly better, than other European Union countries, and they are doing better than us in the U.S. In other words, Portugal’s decriminalization has been successful. No, it didn’t stop all illegal drug use. That would have been an unrealistic expectation. Portuguese continue to get high, just like their contemporaries and all human societies before them. But they don’t seem to have the problem of stigmatizing, marginalizing, and incarcerating substantial proportions of their citizens for minor drug violations. Together, these are some of the reasons that I think decriminalization, or even legalization should be considered as potential options in the United States.
Skeptic: If you were the director of drug control polices in United States, what would be your short- and long-term policies? 
Hart: I would first work to decriminalize all drugs so that people no longer run the risk of being incarcerated for drug possessions. Too many of our citizens are languishing in prison unnecessarily for drug violations. I would also work to change the way we educate about drugs such that it would no longer be acceptable to exaggerate the harms of drugs as a scare tactic. Education would first function to keep our citizens safe. In the long-term, I’d work to regulate all drugs so that we decrease the likelihood of drug users obtaining and using drugs that are adulterated with chemicals more dangerous than the drugs themselves. My major goal as director would be keeping people safe, with the understanding that some people will use drugs as humans have always done.
Skeptic: What was your goal when you wrote the book High Price?
Hart: The goal was to communicate to the general public. The first goal of the scientific community is to keep their lab funded and, sometimes, this is inconsistent with larger goals of society. The research on drug abuse is mainly focused on the bad effects of drugs, because the major funder is National Institute of Drug Abuse, which funds 90% of world’s research in this area. National Institute of Drug Abuse goal is focused on the bad things that happen with drugs, and scientists are shaped by this goal. Society at large has the goal of being safe, and scientists have the goal of “don’t use these drugs”, so it’s inconsistent. I wanted to make the public understand that their goal and the scientist’s goal are different, that their goal and the goal of the police man who is talking to them are different, and that their goal is also different from the goal of media person who writes stories about drugs.
Skeptic: At Skeptic we advocate for evidence-based instead of faith-based thinking, as do you. What do you think is the best approach to shift people from faith-based to evidence-based thinking?
Hart: When you try to change people’s view about something that they think they know, in some cases they feel threatened and insulted because they worked really hard to acquire this knowledge. Now you tell them they’re wrong, and that’s hard for most of us to accept. So, the approach has to be one that acknowledges the work they have put in to acquire their knowledge, even if their knowledge is outdated or inaccurate. On the one hand, you say “you know, I was just like you, I got fooled. They fooled me, like they just fooled you. Here it’s how I see it differently now, and how you can see it differently too.” You have to make some connection with the audience, with the people, in order to move them along. Sometimes we all get impatient because we don’t have the time to make the connection, so we say “the evidence shows this and you’re wrong.” That usually doesn’t work. I understand why people become impatient because they hope others will just follow the evidence like they do, but it doesn’t work that way on a regular enough basis.
Skeptic: What do you think is critical to being a good scientist?
Hart: Always to try to disprove your own hypothesis. If you’re not doing that, you increase the likelihood of following dogma. So the critical thing is to design experiments that can disprove your own hypothesis.

Skeptic: Thank you for this thoughtful interview.

Thursday, June 4, 2015

Cover Story on Skeptic Magazine

by Felipe Nogueira

Skeptic magazine is published by The Skeptics Society, an organization focused on the promotion of science, skepticism and critical thinking and are direct by psychologist Michael Shermer.

Skeptic magazine deals with "extraordinary claims, revolutionary ideas and the promotion of science."

The cover story of the most recent issue (vol. 20 n.2) is the interview about drugs and dependence I did with neuropsychopharmacologist Carl Hart. The cover is bellow:

 Other interesting topics on this issue:
  • Eight Myths of Child Development; 
  • How to Make Young Kids Smarter;
  • Why Near-Death Experiences Vary So Much; 
  • What Does “Supernatural” Mean, Anyway?; 
  • A Psychologist’s Innumeracy: A Guide to Recognizing Pseudo-Mathematics in the Social Sciences; 
  • The Diet-Heart Hypothesis: The Contested Roles of Fats and Carbohydrates in Heart Disease;
UPDATE: the original article published in Skeptic is also available online here 

Friday, January 30, 2015

Second Column in Skeptical Briefs

by Felipe Nogueira

As I explained in a previous post, I am regular columnist for Skeptical Briefs, the Newsletter of The Committe of Skeptical Inquiry, a leading skeptical organization. 

In the Winter 2014/2015 issue, released this month, my second column, an article titled Pseudoscience and Bad Science in the Brazilian Scientific American has been published. 

In this column, I talked about some bad articles that had been published under the siege of the Scientific American Brazil. It's important to emphasize, as I did in the column, that Scientific American Brazil is a different magazine from the one published in United States, with its own editorial process. The Brazilian magazine has the rights to translate contents from the original magazine and to add another articles written by Brazilian journalists or researchers.

The motive for my column was an article about anxiety published in October 2014 issue of Mind and Brain, another Brazilian magazine that has Scientific American's name on its cover. The article was written by a Brazilian journalist and Mind and Brain's sub-editor in chief. The problem of the article is that its last section is anything but science. It was a defense and recommendation of the use of accupuncture to treat anxiety flooded with pseudocientific claims, such as "Each emotion is related with an organ - anxiety is associated with the heart". You can see my translation of that section in the image below.

I also mentioned other two articles, both published in Scientific American Brazil. One was a pseudoscience piece of homeopathy published in 2012 and Harriet Hall have criticized it properly on Science Based Medicine blog here.

The other article I covered wasn't pseudoscience, but the author's conclusions about the marijuana health effects weren't supported by the data he presented, overstating the risks, saying, for example, that causality was established between marijuana use and psychotic episodes. However, the authors of the paper Adverse Health Effects of Marijuana Use, published in New England Journal of Medicine in 2014, concluded that we can't confidently say marijuana causes psychothic episodes, even that marijuana users are more likely to experience them than non-users.

Popularization of science is already lacking in Brazil. We certainly don't need to get things worse with such a big name as Scientific American featuring pseudocience and bad science in its Brazilians magazines.


Sunday, January 25, 2015

Anomalistic Psychology

by Felipe Nogueira

Several psychologists have studied why and how people believe in different things. In popular science, Michael Shermer, psychologist and the founder of The Skeptics Society, has written several books on this topic, such as The Believing Brain and Why People Believe in Weird Things. As another example, psychologist Bruce Hood is the author of the book SuperSense

Sometime ago, I discovered a field called Anomalistic Psychology. 
Psychologist Christopher French is the founder and director of Anomalistic Psychology Research Unit at Goldsmiths, University of London. According to French, anomalistic psychology 
attempts to explain paranormal and related beliefs and ostensibly paranormal experiences in terms of know (or knowable) physical and psychological factors. It is direct at understanding bizarre experiences that many people have, without assuming that there is anything paranormal involved.
With Anna Stone, professor of anomalistic psychology and critical thinking, French authored the interesting book Anomalistic Psychology. The book presents a comprehensive overview of anomalistic psychology research. For example, Chapter 2 presents research regarding individual differences associated with paranormal beliefs, such as age, gender, socio-economical status, etc.  

I always remember that there are people that insist that there are scientific evidence for the existence of paranormal (ghosts, communication with the dead, extrasensorial perceptial, etc). However, French and Stone are very clear in the following quote from the book:
It is possible of course that some people believe in the paranormal because paronormal forces really do exist and these people have had direct personal experience of them. This a possibility that has been taken seriously by many of the finest intellects of the history of science and a consideral amount of time and effort has been spent in trying to prove that paranormal forces really do exist. After well over a century of serious scientific research investigating this possibility, however, the wider scientific community remains unconvinced by the evidence produced to date. Chapter 10 of this book will present an overview of parapsychology that will conclude that although some current approaches appear to at least merit further reaserch, the wider scientific community is fully justified in its scepticism. 
Considering the evidence from controlled tests of spirit mediums, the authors say that many studies have been done asking the medium to give a reading for different sitters, and then asking each sitter to select the reading that best apply to them. According to the authors, results shows that sitters cannot select the readings that apply to them correctly, offering no support for the survival hypothesis (the possibility of some aspect of consciouness survives death).  

The book is very comprehensive, exploring several topics related to paranormal beliefs or experiences.  Besides what I've described, some examples of what is covered in the book:
  • childhood beliefs;
  • near-death experiences and out-of-body experiences;
  • cognitive bias and memory bias;
  • cold reading; 
  • pattern recognition in random data;
  • alien contact claims;
  • scientific status of parapsychology.
I predict that anyone interested in the psychology of belief, as I am, will consider the book very interesting and a must read. 

Thursday, November 6, 2014

First Column in Skeptical Briefs

Trying to publish the interviews I had done in magazines of scientific disclosure, Benjamin Radford invited me to be a regular columnist of Skeptical Briefs newsletter.

Skeptical Brifes is published four times a year to the Associate Member of Committee of Skeptical Inquiry, a skeptic organization dedicated to promote skepticism and science. This organization also publishes the famous skeptical magazine Skeptical Inquirer.

My first column was the interview I had done with evolutionary biologist Jerry Coyne (available here). He posted about it on his site, as the images below shows.

It's interesting to see that Coyne said was prepared for the interview: "... Brazilian writer Felipe Nogueira who was clearly well read about my stuff". 

One reader of Coyne's website said the questions were great, especially the question "Mayr vs Dawkins"

Sunday, April 13, 2014

Assessment of Homeopathy by NHMRC

by Felipe Nogueira

Homeopathy is type of complementary and alternative (CAM) medicine based on two principles. The first, "like cure like", states that substances can be used to treat the same symptoms they cause. The second principle is the potentisation: the substance is diluted and agitated several times. Homeopaths use the C notation to indicate that 1 part of the substance was diluted in 100 parts of water (or alcohol). Then, 200C, used in the prepation of Oscillococcinum, indicates that, firstly, 1 part of the substance was diluted in 100 parts of water. After that, 1 part of the result of each dilution was diluted in 100 parts of water until it totalizes 200 dilutions. This means that, by the end of 200 dilutions, 1 part of the original substance was diluted in 100200 parts of water. Homeopaths called this process potentisation because they believe - as crazy as it sounds - the more diluted the homeopathic preparation, more strong it is.

The National Health and Medical Research Council (NHMRC), as stated on its website, is Australia’s leading expert body promoting the development and maintenance of public and individual health standards. Its mission is working to a make a more healthy Australia.  

Recently, NHMRC realized a big assessment of the evidence of the effectiveness of Homeopathy. This assessment had been done because is NHMRC's role to provide the best evidence to help australians to make health decisions. And this includes decisions regarding the use of CAM. NHMRC published a draft for public consultation*. Any aditional evidence may be submitted for analysis until the end of May. 

Evidence analysed by NHMRC
As described on the draft, the assessment objective is to answer the question "Is homeopathy an effective treatment for health conditions, compared with no homeopathy, or compared to other treatments?". To achieve that goal, NHMRC considered 57 systematic reviews that assessed the effectiveness of homeopathy for tretating 68 health conditions. It is important to highlight the following:
  • NHMRC considered "evidence" only prospective and controlled studies in humans; it does not included individual experience, testimonials or case reports, or research that was not done using standard methods
  • NHMRC considered papers submitted by the public, Australian Homeopathy Association and Australian Medical Fellowship of Homeopathy
  • NHMRC did not consider evidence whether or not homeopathy is effective for preventing health conditions or whether it's good for general health. 
Homeopathy compared with placebo
The systematic reviews considered by NHMRC found studies that compared homeopathy with placebo for 55 health conditions.

For 13 health conditions, it was found that homeopathy was reported to be not better than placebo in at least the large majority of reliable studies (well-done and with enough participants). These conditions were: adenoid vegetation in children, asthma, anxiety or strees-related conditions, diarrhoea in children, headache and migraine, muscle soreness, inducing or shortening labour, pain due to dental work, pain due to orthopaedic surgery, postoperative ileus, premenstrual syndrome, upper respiratory tract infections, warts.

For 14 conditions, some studies reported that homeopathy was more effective than placebo, but NHMRC considered those studies not reliable, because they were not well done or had too few participants. These conditions were: allergic rhinitis, attention deficit/hyperactivity disorder in children, bruising, chronic fatigue syndrome, diarrhoea in children, fibromyalgia, hot flushes in women who have had brest cancer, HIV infection, influenza-like illness, rheumatoid arthritis, sinusitis, sleep disturbances or circadian rhythm disturbances, stomatitis due to chemotherapy, ulcers.

For 29 health condition, only one study that compared homeopathy with placebo was found. These studies were considered not realible, because they were poor or unknow quality, or they had too few participants It was not possible to make any conclusion about whether homeopathy was effective or not for these conditions that were the following: acne vulgaris, acute otitis media in children, acute ankle sprain, acute trauma, amoebiasis and giardiasis, ankylosing spondylitis, boils and pyoderma, Broca's aphasia in people who have had a stroke, bronchitis, cholera, cough,  chronic polyarthritis,  dystocia, eczema,  heroin addiction, knee joint haematoma,  lower pack pain, nausea and vomiting associated with chemotherapy, oral lichen planus, osteoarthrits, proctocolitis, postoperative pain-agitation syndrome, radiodermatitis, seborrhoeic dermatitis, supression in lactation after childbirth in woman who elect not to breastfeed, stroke, traumatic brain injury, uraemic pruritis, vein problems due to cannulas in people receiving chemotherapy. 

Homeopathy compared with other treatments
For 8 conditions, some studies reported that homeopathy was more effective than Placebo. NHMRC considered those studies not reliable, because they were not well done or had few participants. Those conditions were: acute otitis media or acute otitis media with effusion in children, allergic rhinitis, anxiety or stress-related conditions, depression, eczema, non-allergic rhinitis, osteoarthritis, upper respiratory tract infection. 

For 7 conditions, only one study that compared with homeopathy with placebo was found. These studies were considered not realible, because they were poor or unknow quality, or they had too few participantsFor these conditions, it was not possible to make any conclusion about whether homeopathy was effective or not. These conditions were: burns (second and third degree), fibromyalgia, irritable bowel syndrome, malaria, proctocolitis, recurrent vulvovaginal candidiasis, rheumatoid arthritis. 

Studies that were not found
The sytematic reviews considered by NHMRC searched but didn't find studies for the following 7 health conditions: borderline personality disorder, dementia, constipation in children, glaucoma, nocturnal enuresis, lower urinary tract symptoms in men, and chronic facil pain. 

The conclusion by NHMRC is very clear and can be read on the page 10 of the draft's document: 

NHMRC concludes that the assessment of the evidence from research in humans does not show that homeopathy is effective for treating the range of health conditions considered. 
There were no health conditions for which there was reliable evidence that homeopathy was effective. No good-quality, well-designed studies with enough participants for a meaningful result reported either that homeopathy caused greater health improvements than a substance with no effect on the health condition (placebo), or that homeopathy caused health improvements equal to those of another treatment.  
NHMRC published four very detailed documents*. The systematic reviews considered were extensively discussed on those documents; the forms for assessment of the quality of each study were published. These information are all avaiable on-line.  Not surprisingly, Edzard Ernst, the first professor of CAM in the world, considered the NHMRC's assessment the most through and most independent in the history of homeopathy. According to Enrst, this assessment merged two perspectives on homeopathy - skeptics' and evidence based medicine advogates' - isolating the believers and rendering their position no longer tenable. I don't think I need to say anything else besides the following comment by Ernst:
it appears more and more as though homeopathy is fast degenerating into a cult characterised by the unquestioning commitment and unconditional submission of its members who are too heavily brain-washed to realize that their fervour has isolated them from the rational sections of society. And a cult is hardly what we need in heath care, I should think. It seems to me therefore that these intriguing developments might finally end the error that homeopathy represented for nearly 200 years.
All documents published by NHMRC regarding its assessment of homeopathy can be found here