Design
chronic illness, anxiety
CHRONIC ILLNESS
We employed a 2 × 5 between-within subjects design and measured three dependent variables. This included (1) the general acceptability of a treatment offered in a hypothetical patient scenario (measured on a 5-point Likert scale ranging from “highly unacceptable” to “highly acceptable”), (2) the personal acceptability of a treatment offered in a hypothetical patient scenario (measured on 5-point Likert scale ranging from “very unhappy to receive this treatment” to “very happy to receive this treatment”), and (3) expected effectiveness of a treatment offered in a hypothetical patient scenario (measured on 5-point Likert scale ranging from “very ineffective” to “very effective”). Participants were randomly assigned to one of two between-subjects framing groups (“placebo” vs. “sugar pill”), which determined the wording of treatment options in the patient scenario they were shown. All participants completed five within-subjects treatment conditions in randomised order, including (1) blinded + pure placebo, (2) open-label + pure placebo, (3) open-label + impure placebo, (4) antibiotic treatment, and (5) no treatment. In the “sugar pill” framing group, the term “placebo” was consistently replaced with the term “sugar pill”.Additionally, we assessed three individual difference variables: (1) health anxiety (Likert rating ranging from 1 to 4, with low scores indicating low health anxiety), (2) health risk literacy (Likert rating ranging from 1 to 3, with low scores indicating low health risk literacy) and (3) health risk aversion (Likert rating ranging from 1 to 5, with low scores indication low risk-seeking). Finally, we tested the impact of several quasi-experimental between-subject variables including sex (female/male) and age (high/low) and four medical history variables: “doctor’s visits over the past year” (yes/no), “antibiotics used during the past year” (yes/no), “previous use of placebos” (yes/no) and “affected by chronic illness and/or an immunocompromised state” (yes/no).