A recent article in the journal Neurology reports the results of an observational study regarding the use of so-called complementary and alternative medicine (CAM) by patients with an incurable brain glioma. They found that 40% of patients sought some type of CAM treatment. These results are in line with prior surveys, but require closer inspection.

The study defined CAM as:

Complementary therapy was defined as methods or compounds not used in routine clinical practice and not scientifically evaluated.

This is a problematic definition, but reflects the fact that there is no universally accepted and clean definition of CAM. CAM is a hodge-podge of therapies and modalities that have only one thing in common – they have not met the science-based standard of care. It is not accurate to say that they are “not scientifically evaluated.” Some CAM therapies have not been evaluated, but many have, and have already been adequately found to lack efficacy. In the current study homeopathic remedies were the most commonly reported. Homeopathy has certainly been studied – and found to be indistinguishable from placebo.

Even my quick definition above does not constitute an operational definition of CAM. There are some modalities that have not yet been demonstrated to be safe and effective, but are used in conventional medicine because they are highly plausible and effective alternatives are lacking – so plausibility needs to be taken into account as well. I think the best definition of CAM is that it constitutes a double standard, by which therapies are promoted with a philosophical justification (because they are “natural” or empowering, for example) and deviate from the accepted ethical and science-based standard of an appropriate risk vs benefit analysis in the context of informed consent. In other words, they are therapies that should be rejected based upon the usually accepted calculus of clinical decision making, but sneak through the back door through the bait-and-switch of feel-good philosophy or deceptive marketing.

The definition of CAM used in the study is not a small detail, but a central feature of studies of CAM use that has a profound effect of the results. Many previous surveys of CAM use have used an overly broad definition of CAM and therefore have grossly elevated the apparent size of the CAM phenomenon. For example, some studies have included prayer as CAM – so any time a loved-one prays for their sick family-member, they are using CAM. Vitamin supplements are an example of something that is in the gray zone. Taking megadoses of vitamins as a therapeutic intervention should be considered CAM. But not everyone who takes vitamin supplements as nutritional insurance during a serious illness should be considered as using CAM. In fact, nutritional supplementation during chemotherapy or around surgery is standard of care. Exercise, simply getting a relaxing massage, or psychologically based therapies are too lumped in with CAM.

In the current study, which was conducted in Germany:

Of those who used alternative treatments, 39 percent used homeopathy, 31 percent used vitamin supplements and 29 percent used various psychological methods.

Therefore, 60% of those who were counted as using CAM in this study either took vitamins or used some sort of psychological therapy. These are both categories that can contain legitimate or dubious interventions, so it is impossible to know how to interpret those numbers. Homeopathy, which made up 39% (leaving only 1% for everything else) is 100% nonsense and unequivocally qualifies as CAM. It should be noted that homeopathy is fairly popular in German (and Europe generally) and so this result is not surprising.

Further, this study utilized a questionnaire, which means there was self-selection in those patients who chose to complete and return the questionnaire. It is likely that this method would artificially elevate the numbers, as those patients who are interested in CAM may be more likely to fill out a questionnaire about CAM.

The study also found that CAM use is greater in those who are younger, in women, and those with greater education. This also fits with prior surveys. The increased use in those with higher education likely relates to the availability of disposable income. However, studies have also shown that increased education correlates with increased openness to the paranormal and other pseudosciences (until you get to the level of postgraduate science eduction). This phenomenon is likely affected by other variables and at least one other study showed a slight negative correlation between education and paranormal belief.

The survey also found that people chose to use CAM primarily because they wanted to add an additional modality to their standard treatment – again, in line with prior studies. Essentially, people want to hedge their bets and make sure they are availing themselves of anything that might help. This is like playing the health-care lottery – they may know there is a small chance of benefit, but they don’t want to lose that small chance. The good news is that most people who did use CAM used it in addition to conventional therapy.

Such decisions are often based upon the false belief that CAM therapies are harmless, which is further often based upon the justification that they are “natural.” In the case of homeopathy, most homeopathic remedies are directly harmless in that they contain nothing (although some may be only slightly diluted and contain measurable amounts of substance that can be toxic – as was seen in the recent Zicam case). However, not all CAM therapies are non-toxic. Megadoses of vitamins can have side effects – even serious side effects. Herbs are drugs that have all the toxicity and drug-drug interactions of prescription medication. Even psychological therapies can cause direct harm, as is evidenced by false-memory syndrome.

However, much of the harm that comes from CAM use derives from indirect harm – mostly from a delay or absence of evidence-based therapy. In a recent article the Australian Pediatric Surveillance Unit reports that between 2001-2003 there were 39 separate reported incidences of serious harm resulting form CAM use in children. Most of the harm was caused by a delay in proper treatment.

The survey also found that patients chose to use CAM because they wanted control over their own treatment. This supports the observation that CAM is often promoted based upon that appeal – self-empowerment.

Respondents to the survey generally did not report that they chose to use CAM because they were dissatisfied with their physicians or their care. This is often the claim made by CAM proponents, that the alleged popularity of CAM is driven by deficiencies in conventional medicine. But there is not evidence to support that claim, and this and other surveys show it is not the case.


This study, which has significant weaknesses, none-the-less supports prior studies about CAM use. It demonstrates that the popularity of CAM is generally exaggerated, primarily by expanding the loose definition of CAM to include common activities. Most patients who use CAM do so in addition to conventional therapy, and primarily for philosophical reasons ad not out of dissatisfaction with conventional care.


Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also has produced two courses with The Great Courses, and published a book on critical thinking - also called The Skeptics Guide to the Universe.