Research Digest

Excerpted from Capital Ideas 

Itchy, Watery Eyes? Try Watching TV

kamenicaLooking to master the quiet sneeze or get continuous relief from those itchy, watery eyes? If so, consider watching television, at least long enough to catch an allergy commercial.

Research by Emir Kamenica, professor of economics, with Robert Naclerio of the University of Chicago's Pritzker School of Medicine, and Anup Malani of the University of Chicago Law School, suggests these ads may improve the efficacy of drugs for some allergy sufferers. Their research, "Advertisements impact the physiological efficacy of a branded drug," was published in the Proceedings of the National Academy of Sciences in August 2013.

Pharmaceutical companies spent $4.8 billion in 2006 alone on direct-to-consumer advertising in the United States, four times more than they spent in 1996. The spending is controversial, as commercials can motivate patients to seek prescriptions for the drugs advertised, regardless of whether the drug is medically necessary. Kamenica, Naclerio, and Malani wondered if the commercials cause placebo-like effects in patients.

To find out, they designed a trial to measure the impact of ads for one of these drugs - Claritin, the top-selling antihistamine brand in the United States. The researchers split 340 participants into two groups, those who tested positive to at least one common allergen and those without allergies. They injected all of the participants with histamine to induce an allergic reaction, which occurred whether or not a person had previously tested positive for an allergy. Having done that, the researchers gave each participant a 10-mg tablet of Claritin.

In both groups, half of the participants were randomly assigned to watch a movie spliced with Claritin ads, while the other half watched the same movie spliced with ads for Zyrtec, a competing antihistamine. After the movie, the researchers asked each participant to rate his or her perceived efficacy of Claritin on a scale from 1 to 7, with 7 meaning highly effective. The researchers also measured the efficacy of the drug in each participant by measuring the allergic reaction, which manifests itself as a localized swelling known as a "wheal reaction." They compared the results to baseline answers and measurements they had taken before showing the movie.

Among subjects with a history of allergies, the researchers found no statistically significant change in Claritin's efficacy or in the belief of its efficacy. However, among people without allergies, the results were different: in that group, the people who had watched Claritin ads reported an increased belief in Claritin's effectiveness at eliminating allergy symptoms. They increased their belief substantially more than those who had watched Zyrtec commercials.

Among people without allergies, the placebo-like effect boosted efficacy, too. When researchers measured wheal reactions, they saw that people who had watched Claritin ads had smaller areas of swelling than people who had watched Zyrtec ads.

Why were the nonallergy sufferers more swayed by Claritin ads? The researchers hypothesize that allergy sufferers had previous experience with Claritin and therefore already knew it was effective at treating allergy symptoms. Two decades of antihistamine studies have shown that medications such as Claritin work. But nonallergy sufferers didn't have prior experience with the drug.

The observed results support the view "that television advertising can impact the physiological efficacy of a branded drug, at least in subpopulations of consumers whose beliefs about the drug's efficacy are sufficiently malleable," the researchers write.

This may be particularly relevant for new allergy sufferers. They, like the most affected participants in the study, feel the physical effects of allergies but don't have prior, firsthand experience with allergy medications. As new allergy sufferers account for up to 15 percent of all patients using antihistamines, this group may appreciate the results, especially if their runny noses and chronic sneezing subside after a dose of Claritin and an evening spent in front of the TV. - David Phillips

Photo by Dan Dry

Last Updated 2/21/14