Explanations for side effect aversion in preventive medical treatment decisions.

Area of Science:

• Behavioral Economics
• Medical Decision Making
• Health Psychology

Background:

• Laypeople often exhibit heightened sensitivity to medical treatment side effects, potentially leading to the refusal of beneficial therapies.
• This 'side effect aversion' poses a significant challenge to informed medical decision-making and treatment adherence.

Purpose of the Study:

• To investigate the psychological mechanisms underlying 'side effect aversion' in medical treatment decisions.
• To test explanations derived from mental accounting, the mere presence of side effects, and computational difficulties.

Main Methods:

• An Internet-based experiment involving 5,379 participants presented with a hypothetical cancer preventive treatment scenario.
• Variations included the presence of one or two small side effects (beneficial or harmful), with a constant 15% net risk reduction.
• Participants reported treatment acceptance and perceived effects on overall cancer risk.

Main Results:

• Findings supported the 'mere presence' explanation: side effects act as a potent negative cue influencing treatment appraisal.
• The number of negative side effects did not significantly impact participants' willingness to accept treatment.
• Treatment acceptance was solely influenced by the presence of side effects, irrespective of their valence or quantity.

Conclusions:

• Side effect aversion is significantly influenced by the simple presence of negative cues, impacting informed decision-making.
• Identifying specific psychological mechanisms driving side effect aversion is crucial for improving patient engagement with beneficial medical treatments.