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Trial Design: Pain Sections
Author Bio
Introduction
Currently selected section: Placebo Effects
Single Dose Trials
Repeated Dose Trials
Explanatory Versus Pragmatic
Dose-Response
Parallel Group Versus Crossover
Conclusion
 

 

Chapter 1: Clinical Trials of Pain Treatment: Placebo Effects: Problem 2.1
 
        What is a reasonable conclusion?

You answered:

Selection C  One really cannot tell how much of the improvement is due specifically to the steroid without including a group that gets a placebo injection.

OR

Selection B  The improvement may be due to "regression to the mean," the tendency for patients with chronic symptomatic disorders to enter studies at times of exacerbation and to then improve spontaneously.

CORRECT

C and B are both correct.

Regarding answer C, one needs to include a placebo control group in order to infer how much of the pain relief was due to the steroid and how much to the suggestive value of the procedure.

Regarding answer B, patients in most chronic pain studies show some improvement, even when treated with placebo. One cannot tell whether this represents "regression to the mean" or placebo effect unless one includes a no treatment group to compare to the group given a placebo.

We suggest that you click here to return to the problem and select each of the three possible answers. Here and in many of the following problems, new material is presented in each of our responses.