The study of qualitative differences in underlying reasons for our health actions and their relevance to health behavior outcomes has expanded in recent years, through the application of Self-Determination Theory (Deci & Ryan, 1985, 2002). Results of studies promoting lifestyle changes for various health problems have demonstrated empirical support for the theory's proposed relations between autonomy-supportive health environments, increased autonomous reasons for recommended health behaviors, and improved health outcomes. Simultaneously, the medical literature is calling for more research to address the increasing disparity of hypertension prevalence and associated poor outcomes with African American persons. The current study sought to extend the literature examining the potential utility of Self-Determination Theory in a disenfranchised African American population, at risk of adverse health outcomes from hypertension. Study participants (N=78) were recruited from a Midwest Free Clinic while attending their regular three-month outpatient appointments. Participants were randomly assigned to one of two groups, receiving either an autonomy-supportive intervention or a control standard education intervention, both focused on promoting recommended lifestyle changes for hypertension management. The Theory of Self-Determination was used as the conceptual lens for examining the effectiveness of the autonomy-supportive intervention, which was based in the principles of Motivational Interviewing (Miller & Rollnick, 1991, 2002).
Results did not support any of the proposed relations between the constructs of Self-Determination Theory, or between any of those constructs and lifestyle health outcomes. In particular, the lack of an association between perception of the health environment as autonomy supportive and autonomous reasons for adopting recommended health behaviors was contrary to the underlying assumptions of both Motivational Interviewing and Self-Determination Theory. Conversely, results indicated a strong association between perception of autonomy support and controlled reasons for making health changes related to blood pressure control. Eighteen percent of participants reported moderate or severe levels of depression. Although there was some support for the direct relation between perception of autonomy support and improved dietary health outcomes, this association was eliminated after controlling for depression.