Direct-to-consumer prescription drug advertising (DTCAd) is a growing, yet unique form of product advertising about which research evidence is emerging. This dissertation was undertaken to explore questions about perceived DTCAd effects and the relationships of those perceptions and other perceptual, attitudinal, and demographic variables to two specific behavioral outcomes (support for regulation and patient behaviors), using the third-person effect framework. A mail survey of 600 randomly selected adults was executed to address nine hypotheses and three research questions. 264 useable questionnaires were returned. Among other things, the research found: The third-person DTCAd effect is a multidimensional construct. Four DTCAd-effect factors emerged from respondents perceptions of DTCAd effects. Respondents believed that DTCAd had more influence on other peoples behavior than on their own behavior. Respondents differentiated between the negative and positive DTCAd effects, and perceived negative DTCAd effects to be more pronounced in other peoples behavior than in their own behavior. Perceived DTCAd importance, prescription drug use, perceived DTCAd credibility/informativeness, and global DTCAd attitude were negatively associated with third-person DTCAd effects. Perceived health and DTCAd recognition were positively associated with third-person DTCAd effects. Ability of the third-person DTCAd effect to predict support for DTCAd regulation did not vary by global DTCAd attitude. When global DTCAd attitude was controlled for, third-person DTCAd effects did not predict support for DTCAd regulation. Older, employed, less educated respondents, who disliked DTCAd, but who perceived themselves more familiar and knowledgeable of DTCAd were more likely to support DTCAd regulation. Those who perceived DTCAd as credible were less likely to support DTCAd regulation. The third-person effect associated with the DTCAd factor, "learning & involvement," was a significant negative predictor of patient behavior. Perceived DTCAd importance and respondent race were significant positive predictors of patient behavior. Ability of third-person DTCAd effects to predict DTCAd-targeted patient behavior did not vary by respondents global DTCAd attitudes. No matter how much the respondents liked or disliked DTCAd, those who perceived greater third-person DTCAd effects were less likely to engage in ad-targeted patient behaviors. The significance of the results is discussed relative to the research literature. Methodological imitations are presented, followed by implications for advancing DTCAd research.