Why does choice enhance treatment effectiveness? Using placebo treatments to demonstrate the role of personal control.

Abstract

In modern health care, individuals frequently exercise choice over health treatment alternatives. A growing body of research suggests that when individuals choose between treatment options, treatment effectiveness can increase, although little experimental evidence exists clarifying this effect. Four studies were conducted to test the hypothesis that exercising choice over treatment alternatives enhances outcomes by providing greater personal control. Consistent with this possibility, in Study 1 individuals who chronically desired control reported less pain from a laboratory pain task when they were able to select between placebo analgesic treatments. Study 2 replicated this finding with an auditory discomfort paradigm. In Study 3, the desire for control was experimentally induced, and participants with high desire for control benefited more from a placebo treatment when they were able to choose their treatment. Study 4 revealed that the benefit of choice on treatment efficacy was partially mediated by thoughts of personal control. This research suggests that when individuals desire control, choice over treatment alternatives improves treatment effectiveness by enhancing personal control.