With an increasing number of stars appearing in drug and disease specific adverts, including Brooke Shields and Jessica Simpson, do consumers really trust those who make money from endorsing prescription-drugs? New research published in the latest issue of the International Journal of Pharmaceutical and Healthcare Marketing from global publisher, Emerald Group Publishing, has found that it is the personal relevance of the adverts and not the celebrity selling them that has an impact on what consumers actually buy.

In the study, 'Impact of celebrity endorsements in disease-specific direct-to-consumer (DTC) advertisements', respondents were randomly shown a fictitious print advert for a website offering depression advice. One had an image of Harrison Ford or Ashley Judd (both who have known issues with depression), the other with a digital image to mirror the age, look and demeanour of the celebrity image.

Interestingly, the majority of respondents went against recent research and viewed the celebrities within the ads as significantly more credible, but this did not reflect in their consumer behaviour. The study found that it is the level of personal relevance to the advert which is the primary differentiating factor in consumer response - and the effect of the celebrity in the advert was independent of this factor. This suggests the presence of a celebrity endorser has negligible impact on consumers.

Brent Rollins, of the Philadelphia College of Osteopathic Medicine (PCOM) and joint author of the study, comments: "This research demonstrates that even if consumers deem the celebrity as more credible and pay significantly greater attention to the ad, it does not change the desire to act and search for more information, discuss the disease with their physician or ask for a prescription."

With the Internet now the number one choice among respondents for seeking information on depression, Professor Rollins, adds: "Moving forward, pharmaceutical marketers must learn to harness and maximize the Internet's potential, including the use of disease education focused websites and trend toward personalization in all forms of marketing."