A Randomized Survey of the Public’s Expectancies and Willingness to Participate in Clinical Trials of Antidepressants Versus Psychotherapy for Depression

Background: Expectancies and treatment preferences are known to affect the outcomes of patients enrolled in clinical trials for depression, but there is little research on their influence when the public is considering participation in these trials.

Method: We conducted an online survey (May 2013) in which participants (N = 615) were randomly assigned to read hypothetical descriptions of clinical trials for depression based on 1 of the following study designs: medication versus placebo, medication versus medication, psychotherapy versus placebo, or psychotherapy versus psychotherapy. Afterward, individuals rated willingness to participate in the trial, logic and credibility of the treatments, and expected success and improvement in symptoms.

Results: There were no differences in expectancies for ratings of credibility and logic or success and improvement among clinical trial designs. However, self-reported willingness to participate in the study was rated significantly higher in the 2 psychotherapy trial designs (active-comparator and placebo-controlled) compared with the active-comparator medication design (P < .05). Psychiatric treatment history, general treatment preferences, and depression severity were positively correlated with willingness to participate primarily in the active-comparator medication design.

Conclusions: Consistent with the broader treatment preference literature, individuals reported a greater willingness to participate in psychotherapy compared with antidepressant studies. Thus, people’s perceptions of different treatments are likely to influence not only the outcomes of clinical trials for depression but also decisions to participate in these trials in the first place.