Consumers' knowledge, perceptions, and responsiveness to direct-to-consumer advertising of prescription medicines.

Aim: This research explored whether direct-to-consumer-advertising of prescription medicines (DTCA) increased disadvantaged consumers' knowledge of important health issues and encouraged those with lower health knowledge to consult their doctor (as has been argued by supporters of DTCA).

Method: A mail survey of 1042 New Zealanders was undertaken between October and December 2002 using a stratified random sample drawn from the electoral roll. After two reminders were sent, 632 completed questionnaires were returned (64% response rate). We examined the relationship between respondents' self-assessed knowledge of health-related issues, their perceived health status, and their response to DTCA (using self-efficacy theory to aid interpretation of the results).

Results: Respondents with greater health knowledge found DTCA easier to understand and were more likely to have sought further information about an advertised medicine than those with less knowledge.

Conclusions: These results suggest DTCA may reinforce existing knowledge rather than educate or provide new knowledge. The results also cast doubt upon claims that DTCA enhances awareness of health issues among groups with lower health knowledge thus helping them overcome barriers to better health. Although changes to DTCA regulation could increase the information conveyed by this advertising, the advertising and pharmaceutical industries' failure to respond to well-documented concerns about DTCA raises serious questions about the power of policy refinements to control advertisers' conduct.