Long rundowns of side effects can make drugs seem less risky, study finds
- Direct-to-consumer drug advertisements are tightly regulated, yet remain a controversial aspect of the pharmaceutical industry's marketing muscle. In an effort to protect consumers, the Food and Drug Administration requires drug companies list a medicine's safety risks along with its benefits.
- Yet these often-mocked long rundowns of side effects may have the opposite effect: weakening consumer perception of a drug's most serious risks, according to new paper published this week in Nature.
- "We contend that the FDA, in regulating DTC advertisements to list side effects that range from the serious (such as stroke and thoughts of suicide) to those less serious (such as dry mouth and headache), have diluted consumers' judgments of the overall severity of the drug's side effects," the researchers wrote.
At the core of the paper's argument is a psychological bias known as the "dilution effect." When meaningful information is grouped with less relevant information, people tend rate what's actually important as less significant.
That's what the researchers argue can happen with drug risks. DTC ads that exhaustively list side effects, both serious and minor, could unintentionally water down the overall safety message.
To test that hypothesis, Niro Sivanathan and Hemant Kakkar of the Lond Business School ran six experiments involving more than 3,000 people. In one, for example, the researchers altered a real advertisement for Eli Lilly & Co.'s depression treatment Cymbalta (duloxetine), removing three seconds of audio describing relatively minor side effects for the drug.
Participants in the study who heard the whole ad, with both major and minor risks included, rated the drug's side effects as less severe than those who listened to the shortened version.
A similar effect occurred in a second test, in which the researchers showed participants two versions of a drug facts box for Otsuka Pharmaceuticals' Abilify (aripiprazole). People were given either information containing both major and minor side effects or information highlighting just the serious adverse effects. Again, those people who viewed the truncated risk information rated the drug's safety profile as more risky.
"Further, because of these diluted severity judgments, drug advertisements containing all side effects are judged to be more attractive," the researchers added.
Other factors could be at play, too. Voiceovers for drug risks tend to be read quickly and in a more monotonous tone, both of which could sap consumer attention.
In a similar vein, the Food and Drug Administration has plans to investigate whether overwarning can overwhelm consumers, posting a proposal for a consumer study in the Federal Register in June.
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