The impact of the preventive medical message on intention to change behavior.

Clinicians counsel patients to adopt behaviors to reduce health risks. We studied, in the case of coronary artery disease, the impact of those parts of the preventive medical message clinicians can vary. We asked 150 French people (86 aged 20-30, 64 aged 60-80) to rate their intention to adopt a specific behavior-take medication, change their diet, or start exercising-in 64 scenarios, composed of two severities of disease manifestations (angina pectoris or heart attack); four levels of its probability of occurrence (5, 10, 15, or 20%) and the associated time horizon (20, 15, 10, or 5 years, respectively); and two levels of controllability of the risk (entirely under your control or not much you can do to reduce it). We found that all four parts of the message had significant main effects and did not interact with each other. Older participants had greater intention to adopt preventive behavior when the time horizon was short and younger ones when it was long. The only gender effect was that older women were more sensitive to time horizon. The message's parts were combined additively. Participants intended to change behavior even when told this would be of little use. We concluded that clinicians should, when possible, discuss all key parts of the preventive medical message; that they can, however, focus on one without reducing the others' impact; and that, at least for outcomes such as angina and heart attack, they should speak of risk with young patients using a long time horizon, with old patients using a short time horizon.