The Importance of Placebos
When a new medication is studied for multiple sclerosis, it must be compared to something. Most commonly, it is compared to a placebo. The placebo does not contain any real medication. Some people call them “sugar pills” though they are not often made of sugar.
Placebos are usually made to look just like the real medication. If pills are being studied, the size and shape of the placebo look just like the real medication. The binders and fillers of the real medication and the placebo are often the same. If injections are being studied, the color and volume of the placebo and real medication are the same.
Many people improve after taking a placebo. This is because the mind has a powerful influence on the way our bodies function. For example, 30-40% of patients have decreased pain with placebos. 79% of patients with depression improved with placebo, though 93% improved with antidepressants.
The procedures done during a multiple sclerosis research study can also influence how a person feels. These patients have many visits and tests; they have frequent contact with physicians and research staff from the study; they are excited about a possible new medication for multiple sclerosis.
If there is no comparison group for a new treatment, it is impossible to determine whether patients improved due to the medication or due to the placebo effect. The expectations of having an exciting new treatment, the relationship between the patient and the research staff, and the desire to get better and not disappoint others all make it difficult to evaluate treatments without a comparison group. Placebo groups are, by far, the best comparison group. Because all of the other research procedures are the same between the two groups, any difference in effectiveness can be attributed to the medication.
Some have suggested that historical controls can be substituted for placebo groups. This strategy has not worked. There are many differences in today’s multiple sclerosis patients compared to those even a few years ago. Advances in MRI technology have led to current multiple sclerosis patients being diagnosed much earlier than those in the past. The availability of treatments has caused a shift in those willing to enroll in research studies towards those with earlier disease and less disability. There are even shifts towards increased numbers of females and increased minorities in recent years that make comparisons to historical controls impossible to evaluate.
Some claim that results from uncontrolled studies are so impressive that further testing is not required. These claims are not justified. There are innumerable examples of past treatments that claimed astounding results, but which later disappointed with further study. There is no amount of testimonial claims that can substitute for a well design study.
Finally, another issue is whether a new medication can be compared to an older medication rather than to a placebo. This study design is now commonly used in multiple sclerosis trials. The weakness of this type of study is that it can only succeed if the new medication is better than the older treatment. If it is not as good as the older treatment (even though it might have some positive effect) it will be rejected. For this reason, the FDA generally required that at least one placebo-controlled study be included.
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