There has been an ongoing debate about placebos on SBM, both in the articles and in the comments. What does it mean that a treatment has been shown to be “no better than placebo?” If our goal is for patients to feel better and they feel better with placebos, why not prescribe them? Do placebos actually do anything useful? What can science tell us about why a patient might report diminished pain after taking an inert sugar pill? The subject is complex and prone to misconceptions. A recent podcast interview offers a breakthrough in understanding.
On her Brain Science Podcast Dr. Ginger Campbell interviewed Dr. Fabrizio Benedetti, a physician and clinical neurophysiologist who is one of the world’s leading researchers on the neurobiology of placebos. A transcript of the interview [PDF] is available on her website for those who prefer reading to listening. The information Dr. Benedetti presents and the expanded remarks by Dr. Campbell after the interview go a long way towards explaining the placebo phenomenon and its consequences for clinical medicine. Dr. Campbell also includes a handy list of references. I’ll try to provide a summary of the main points, but I recommend reading or listening to the original.
A common misconception is that the response to placebos is a purely subjective psychological response involving only the cortical level of the brain; but evidence is accumulating that real, measurable, objective subcortical neurophysiologic phenomena are involved. One of the first hints was a 1978 study showing that the placebo response to pain could be blocked by naloxone, a narcotic antagonist drug, indicating that the placebo must have actually caused an increase in endogenous opioids. (more…)
When Scientific American first announced that they would publish Scientific American Mind, I hurried to subscribe, thinking it would keep me informed about new developments in a field I am passionately interested in. I have enjoyed the magazine, particularly the regular columns, the news items about research findings, the reviews that alert me to books I will want to read, the “Ask the Brains” Q and A, the challenging “Head Games” quiz, and the presentation of many intriguing ideas. The board of advisers is impressive, and the columns by Christof Koch, Scott Lilienfeld, Hal Arkowitz, the Ramachandrans and others have been consistently excellent. Unfortunately, some of the other articles have descended into pop psychology, speculation, poor science and even pseudoscience. Contributing editor Robert Epstein’s articles have particularly raised my blood pressure.
In December 2009 I was annoyed enough to write this letter to the editor:
After reading Robert Epstein’s article in the last issue, I had to go back to the cover and verify that the word “scientific” was indeed part of the title of your magazine. The Love Building Exercises he recommends are more appropriate to a magazine of fantasy and science fiction.
Two as One — feeling that the two of you have merged?
Soul Gazing — looking into the very core of your beings?
A Mind-Reading Game — wordlessly trying to broadcast a thought to another person?
Love Aura — feeling “eerie kinds of sparks” when your palm is close to another’s?
Thought transfer? Auras? Come on! Shame on you for publishing such metaphysical pseudoscientific psychobabble!
They published my letter to the editor with the heading “Hating ‘Love’.” There was no response from the author.
Here on SBM we have frequently had cause to criticize the media for poor science reporting and for spreading misinformation. Among many other individual offenders, we have criticized Dr. Oz for promoting alternative medicine on his TV show and gullibly promoting guests who pretend to talk to the dead and pretend to heal people with carnival sideshow tricks. We tend to be negative and critical because somebody has to do it, but it’s not pleasant. For once, I have some good things to say.
The September 12 issue of TIME magazine was a Special Nutrition Issue. The cover featured pictures of food and the title “What to Eat Now: Uncovering the Myths about Food by Dr. Oz.” It devotes 7 pages to an article by him entitled “The Oz Diet: No more myths. No more fads. What you should eat — and why.” This is followed by a 5 page article by John Cloud “Nutrition in a Pill? I took 3000 supplements over five months. Here’s what happened.” Both articles have a rational, science-based perspective without any intrusions of woo-woo. (more…)
When women live together, do their menstrual cycles tend to synchronize? It’s been a long time since I first heard that claim. I didn’t believe it, for a number of reasons. I had never observed it myself, I saw no plausible mechanism to explain how it could happen, I thought the statistics to prove it would be problematic and complicated, and I suspected that confirmation bias and selective memory might have persuaded people that a spurious correlation existed. How often do women say “Oh, look! We’re having our periods at the same time”? How often do they say “Oh, look! We’re having our periods at different times”? Now that many years have passed since my first encounter, I thought it would be fun to revisit the claim and see whether science has supported it or rejected it.
A perusal of PubMed and other Internet sources left me confused and amused. (more…)
Several questionable sources are spreading alarms about the possible dangers of prenatal ultrasound exams (sonograms). An example is Christine Anderson’s article on the ExpertClick website. In the heading, it says she “Never Liked Ultrasound Technology.”
[She] has never been sold on the safety using Ultrasounds for checking on the fetuses of pregnant women, and for the last decade her fears have been confirmed with a series of studies pointing to possible brain damage to the babies from this technology.
Should We Believe Her?
Should we avoid ultrasounds because Anderson never liked them? Should we trust her judgment that her fears have been confirmed by studies? Who is she?
“Dr.” Christine Anderson is a pediatric chiropractor in Hollywood who believes a lot of things that are not supported by science or reason. Her website mission statement includes
We acknowledge the devastating effects of the vertebral subluxation on human health and therefore recognize that the spines of all children need to be checked soon after birth, so they may grow up healthy.
It also states that “drugs interfere… and weaken the mind, body, and spirit.” Anderson is a homeopath, a craniosacral practitioner, a vegan, and a yoga teacher. She advises her pregnant patients to avoid toxins by only drinking filtered water and only eating organic foods. She sells her own yoga DVD. (more…)
During the early days of the 2009 H1N1 influenza A pandemic, the popular herbal formula maxingshigan–yinqiaosan was used widely by TCM practitioners to reduce symptoms. (It’s hard to pronounce and spell, so I’ll refer to it as M-Y.) A new study was done to test whether M-Y worked and to compare it to the prescription drug oseltamivir. It showed that M-Y did not work for the purpose it was being used for: it did not reduce symptoms, although it did reduce the duration of one sign, fever, allowing researchers to claim they had proved that it works as well as oseltamivir.
“Oseltamivir Compared With the Chinese Traditional Therapy: Maxingshigan–Yinqiaosan in the Treatment of H1N1 Influenza” by Wang et al. was published in the Annals of Internal Medicine earlier this month. The study was done in China, which is notorious for only publishing positive studies. Even if it were an impeccable study, we would have to wonder if other studies with unfavorable results had been “file-drawered.” It’s not impeccable; it’s seriously peccable.
It was randomized, prospective, and controlled; but not placebo controlled, because they couldn’t figure out how to prepare an adequate placebo control. They considered that including a no treatment group compensated for not using a placebo control, and that objective temperature measurement could be expected to get around any bias. It might not: the nurses who took the temperatures were blinded to the study, but the patients were not. It’s possible that those who knew they were getting M-Y might have believed in it and their bias might have somehow subtly influenced data gathering so that M-Y appeared more equivalent to oseltamivir than it actually was.
There are other problems besides the lack of blinding. (more…)
Common warts (verruca vulgaris) are more of a nuisance than a serious health problem, but they are interesting. There is a whole mythology surrounding their cause (touching toads?) and treatment (everything from banana peels to vitamin C). Many people believe they can be made to vanish by suggestion or hypnosis. I used to believe that too.
Every doctor has wart stories. Here are some of mine.
- A patient made an appointment to see me because he had a wart, but when he tried to show me his wart he discovered that it had vanished! Apparently, just making the appointment cured it.
- Another patient did have obvious warts and I prescribed the “wart medicine” that our pharmacy tech compounded, based on salicylic acid. He was out of one of the ingredients and had to ask my patient to return in a week. When she returned, her warts were already gone. The wart medicine apparently worked so well that you didn’t even have to use it!
- I worked with a dermatologist who used a colorful laminated card with a picture of a toad to stroke children’s warts, telling them it was a wart remover. In his experience, this would frequently make the wart vanish over the next few days. Was this ethical? Was he lying and deliberately deceiving patients, or could this be excused as playing make-believe to distract the child and improve his attitude about the wart?
A correspondent asked me to review the book What to Expect When You’re Expecting by Heidi Murkoff and Sharon Mazel. She wrote “I’m very worried about this book.”
She had just seen an NPR article about the book and was alarmed because it provided an excerpt from the book recommending that patients with morning sickness “Try Sea-Bands” and “Go CAM Crazy.” She knew from reading SBM and other science blogs that “going CAM crazy” is not a good idea. She was savvy enough to search Google Books with the title and “CAM” and found more alarming advice. (more…)
Note: The study discussed here has also been covered by Mark Crislip. I wrote this before his article was published, so please forgive any repetition. I approached it from a different angle; and anyway, if something is worth saying once it’s probably worth saying twice.
Echinacea purpurea, or purple coneflowers – not a cure for the common cold.
Is Echinacea effective for preventing and treating the common cold or is it just a placebo? My interpretation of the evidence is that Echinacea does little or nothing for the common cold. Initial reports were favorable, but were followed by four highly-credible negative trials in major medical journals. A Cochrane systematic review was typically wishy-washy. The Natural Medicines Comprehensive Database rates it as only “possibly effective” commenting that:
Clinical studies and meta-analyses show that taking some Echinacea preparations can modestly reduce cold symptom severity and duration, possibly by about 10% to 30%; however, this level of symptom reduction might not be clinically meaningful for some patients. Several other clinical studies found no benefit from Echinacea preparations for reducing cold symptoms in adults or children…
A review on the common cold in American Family Physician stated that Echinacea is not recommended as a treatment.
I have a friend who believes in Echinacea. She says for the last several years she has taken Echinacea at the first hint of a cold, and she hasn’t developed a single cold in all that time. I told her that if that was valid evidence that it worked, I had just as valid evidence that it didn’t. For the last several years I have been careful not to take Echinacea at the first hint of a cold, and I haven’t had a single cold in all that time either. So I could claim that not taking Echinacea is an effective cold preventive! I thought my “evidence” cancelled out hers; she said we would just have to agree to disagree.
A recent study looked at the effect of belief on response to Echinacea and dummy pills. “Placebo Effects and the Common Cold: A Randomized Controlled Trial” was published by Barrett et al. in the Annals of Family Medicine. (more…)
Marcia Angell has written a two-part article for The New York Review of Books: “The Epidemic of Mental Illness: Why?” and “The Illusions of Psychiatry.” It is a favorable review of 3 recent books:
and an unfavorable review of the most recent version of the Diagnostic and Statistical Manual of Mental Disorders, DSM-IV-TR. It paints a disturbing picture of psychiatry. It raises a number of serious concerns but it borders on psychiatry-bashing, a sport that I deplored in a previous post. (more…)