Why Does This Database Depend on Double-blind Studies?
At first glance, it might seem that you can discover whether a treatment is successful quite simply: just try it and see. However, a close analysis of the subject reveals that it's much harder to identify effective treatments than one might think. Decades of investigation have led scientists gradually to the conclusion that there's only one truly trustworthy source of information on whether a medical therapy really works: the double-blind, placebo-controlled study. The reasons behind this conclusion are complicated, and run counter to almost everybody's intuition. In this article, we explore this crucial topic in depth. For a hint why double-blind studies are so important, consider the following examples: in medical trials of drugs used to treat the symptoms of menopause, many of the participants were given a fake treatment (placebo) without being informed that it was fake. 1 The combined results of multiple studies showed that women given placebo experienced a 51% reduction in hot flashes! Similarly, in a large study of men with prostate enlargement, participants given placebo therapy showed significantly improved symptoms and maintained at least some improvement for a full two years. 2Effects like these can be highly misleading to both physicians and patients. Suppose, for example, a physician prescribes a new drug for menopausal symptoms or prostate enlargement, and his or her patients report wonderful improvements. Does this indicate that the drug is effective? Not at all. As we know from the results described in the previous paragraph, many patients will report improvement no matter what they are taking. Thus, a drug can seem to be effective even if it doesn't possess any healing powers beyond the power of suggestion.For a particularly dramatic example of this phenomenon, consider what happened when orthopedic surgeon Bruce Moseley, team physician for the Houston Rockets, decided he needed to properly evaluate the efficacy of an operation commonly used to treat the pain caused by arthritic knees. This surgery involves scraping away rough areas in the knee's cartilage. It is widely believed to be effective, and as many as 400,000 such surgeries are performed each year.Mosely decided to see if the surgery really worked. He conducted a study in which five patients were given the real surgery and five were given fake surgery consisting of little incisions over the knee. He then followed his patients for two years.The results were amazing. Interviews showed that pain and swelling were reduced just as much in the placebo group as in the group that received the real surgery. Four out of the five participants who experienced the fake surgery said it was so helpful they'd gladly recommend it to a friend. Glowing testimonials, in other words, mean nothing. A follow-up trial of 180 individuals confirmed these results, 6 and this surgical approach is on its way to well-deserved oblivion. However, if these properly designed trials had not been undertaken, surgeons might have continued to scrape arthritic knees. No doubt, there are other ineffective surgeries that pass for effective, as well as ineffective herbs, supplements, and alternative therapies, as well. The double-blind, placebo-controlled trial is the best way to eliminate such misleading results. Such trials are the foundation of modern evidence-based medicine, and they are the foundation of the information in the Natural & Alternative Treatments database, as well.In the following discussion, we'll begin by exploring the many factors that can deceive medical researchers. We'll follow that with an explanation of how the double-blind study design solves these problems. After that, we'll analyze the many difficulties involved in performing a meaningful double-blind study and properly interpreting the results. Finally, we'll look at other forms of scientific evidence and explain their limitations.