Reducing aversion to side effects in preventive medical treatment decisions

Laypeople tend to be overly sensitive to side effects of treatments that prevent illness, possibly leading them to refuse beneficial therapies. This Internet-based study attempted to reduce such side effect aversion by adding graphic displays to the numerical risk probabilities. It also explored whether graphics reduce side effect aversion by making it easier for respondents to determine how the treatment might change their net cancer risk. Participants (N=4,248) were presented with a hypothetical preventive treatment situation that was or was not accompanied by a small side effect. In both conditions, the net absolute risk reduction was 12%. Adding an array of stick figures to risk probabilities reduced side effect aversion substantially, but adding a bar graph was not beneficial. The ability of arrays to reduce side effect aversion was not attributable to greater accuracy in evaluating the treatment's net benefit.