It’s a behavioral phenomenon called argument dilution. And when applied to pharma's direct-to-consumer advertising, it can weaken consumer perceptions about the seriousness of a drug's risks, according to a study this week in Nature.
In six different experiments, researchers at London Business School showed consumers a real pharma advertisement, along with a doctored one where some of the more minor side effects had been removed. Using a Lunesta print ad, for example, researchers Niro Sivanathan and Hemant Kakkar removed the potential side effects of dry mouth and headaches. In a Cymbalta TV ad, which they turned into an audio ad for the study, they removed three of the less-serious effects.
In results consistent across the studies, consumers were significantly more likely to rate a drug as less risky when they heard or read the full list of potential side effects versus when they heard or read only the more serious ones, Sivanathan said.
Plus, the consumers tested were more attracted to the drugs whose full laundry list of risks had been recited. The cumulative studies polled more than 3,000 U.S. consumers.
Behavioral economist Sivanathan has applied argument dilution across other disciplines, but he became interested in examining the effect in DTC ads after spending time in the U.S. and noticing the deluge of ads during television broadcasts.
“The results pose a bit of an ethical conundrum. On one hand, the FDA wants transparency and for people to have access to the full risk factors. But if you hold back on the risk information, one could argue you’re not giving all the necessary information,” he said.
However, there may be a solution. In the last study of the series, he and Kakkar tested a possible workaround. Instead of getting rid of the minor side effects entirely, they de-emphasized them by leaving them in plain text while emphasizing the major side effects by putting them in red print. The result? The argument dilution effect was mitigated.
The added weight or emphasis on the more serious risks worked to counterbalance the dilution effect because it helped the consumer “code” the information as riskier, Sivanathan said.
“There is no right answer here, and there are a lot of gray areas. We most certainly are not coming down to say do this or do that, but rather highlighting that, in its current state, listing all the side effects reduces people’s risk assessment and, in fact, increases the marketability of these drugs. The FDA regulations have, in fact, helped these direct-to-consumer ads sell more drugs,” he said.
The FDA, which currently requires the disclosure of “each specific side effect,” has already been wrestling with the question of the exhaustive list of risks in ads, which is often criticized both inside and outside of the pharma industry. Its own recent research suggests that limiting the risk statements to include only that were “serious and actionable risks” helped people remember and recognize those particular risks.