Social contagion of vasovagal reactions in the blood collection clinic: a possible example of mass psychogenic illness.

Objective: Observing or hearing about illness in another person can lead to reports of similar symptoms. Reports can occasionally be widespread. However, it has been difficult to document whether this is the result of genuine illness or the expression of anxiety with physical terminology. This study examined the effects of being able to see another blood donor experience vasovagal symptoms.
Methods: Data were collected in mobile university blood collection clinics. Bedside research assistants coded whether the donor was able or not able to see another donor being treated for vasovagal symptoms. Dependent variables included subjective vasovagal symptoms indicated on the Blood Donation Reactions Inventory (BDRI) and the need for treatment oneself. Given the population of inexperienced donors, many (26% of the 1,209 participants) were able to see another donor treated for symptoms.
Results: Being able to see another donor treated was associated with higher scores on the BDRI and an increased likelihood of treatment for vasovagal symptoms oneself. However, this was limited to non-first-time blood donors, perhaps because of higher levels in first-time donors (ceiling effects) or greater attention to the environment in less "overwhelmed" repeat donors. In general, donors who were able to see another react rated themselves as less relaxed and had smaller increases in heart rate. During the 2-year follow-up, first-time donors who were able to see another react were slower to return to give blood again.
Conclusions: Seeing another donor being treated for symptoms contributed to the vasovagal process in many donors. This environment provides a useful context to study social influences on symptoms and illness.