You Can’t Always Get What You Want: The Influence of Choice on Nocebo and Placebo Responding.

Objective
Choice may be an important influence on the effectiveness and side effects of medical treatments.

Purpose
We investigated the impact of having a choice of medication compared to no choice on both nocebo and placebo responding.

Methods
Sixty-one participants were randomly assigned to either choose between or be assigned to one of the two equivalent beta-blocker medications (actually placebos) for preexamination anxiety.

Results
There was a greater nocebo response in the no choice group and an increased placebo response in the choice group. Participants in the no choice group attributed significantly more side effects to the tablet than the choice group (p = 0.045), particularly at the 24-h follow-up (p=0.002).

The choice group showed a stronger placebo response in heart rate than the non-choice group.

Conclusion
Not being given a choice of medication increased the nocebo effect and reduced the placebo response to the treatment.