When symptoms become side effects: Development of the side effect attribution scale (SEAS)

Area of Science:

• Psychology
• Pharmacology
• Medical Sociology

Background:

• Symptom misattribution is a key component of the nocebo effect.
• Current side effect measures do not adequately assess symptom misattribution.
• A validated tool is needed to quantify the degree to which individuals attribute symptoms to treatment side effects.

Purpose of the Study:

• To develop and validate the Side Effect Attribution Scale (SEAS).
• To assess the reliability and validity of the SEAS in measuring symptom attribution beliefs.
• To determine if the SEAS is a more sensitive indicator of nocebo responding than existing measures.

Main Methods:

• The SEAS was administered to three distinct New Zealand samples: vaccination (n=225), rheumatology patients (n=102), and generic medicine switchers (n=69).
• Internal reliability was assessed using Cronbach's alpha.
• Scale validity was evaluated by correlating SEAS scores with psychological variables linked to side effect reporting.

Main Results:

• The SEAS demonstrated strong internal reliability across all studies (Cronbach's alphas 0.840–0.943).
• The Side Effect Attribution Total Score showed stronger associations with nocebo responding compared to the Binary Score.
• Higher SEAS Total Scores correlated significantly with increased expectations of side effects, worry, perceived sensitivity to medicines, anxiety, intentional non-adherence, and information seeking.

Conclusions:

• The SEAS offers a more refined assessment of symptom attribution beliefs related to medical treatments.
• The SEAS appears more sensitive than simple side effect counts, correlating with a broader range of psychological factors.
• Further research is recommended to validate the SEAS in diverse populations and clinical settings.