Being threatened causes fear but what role does it play in the cognitive processes involved in individuals accepting a healthcare approach? Our study predicts that a strong expression of fear by the vividness and framing of a message from a diabetes health campaign should threaten the subjects (threat severity, perceived vulnerability) and lead them to react emotionally, cognitively (recommendation efficacy related to the ability to adopt it) and conatively (intention to be screened for diabetes). The results show that fear due to the perceived threat mediates the persuasive effect of the vividness of the message on its efficacy, which itself mediates the effect of fear (and threat) on behavioural intention. In this context, fear could not only be felt in the face of a strong threat but could also mobilise cognitive resources and personal motivation influencing decision-making.