Self-determination theory: its application to health behavior and complementarity with motivational interviewing

An impressive body of research has provided convincing evidence for the pivotal role of behavior in well-being, and morbidity and mortality, as well as health care costs [1]. Indeed, some estimates indicate that nearly 3/4 of all health care costs are attributable to chronic diseases resulting from health behaviors such as tobacco use and exposure, poor diet, and physical inactivity [2]. Other research has shown that adherence to five key lifestyle behaviors (eliminating tobacco exposure, body mass index (BMI) < 25, engaging in 30 minutes of physical activity or more per day, consuming alcohol in moderation, and eating a healthy diet) reduced coronary events by 62% over 16 years in a cohort of 42,000 US adult men. Further, men who adopted at least two of these behaviors had 27% lower risk for cardiovascular events compared to those who did not [3]. Lifestyle behaviors account for some 40% of mortality in industrialized countries and have been implicated in up to 2/3 of all cancers [4] as well as the onset and management of obesity, diabetes, cardiovascular disease, heart attacks, and stroke. Given the importance of health behaviors to well-being, health outcomes, and disease processes, developing a rigorous science of health behavior, its change and maintenance is critical to prolonging both length and quality of life.In recent years, the science of health behavior change has increasingly emphasized theory- based approaches to intervention. The use of theory to inform and test interventions is important both for expanding basic science and for developing interventions that have real-world practical utility. From the perspective of basic science, theories must be tested in multiple domains and through multiple methods to refine and expand them appropriately. Further, the use of theory is important to applications in health behavior change and maintenance because theories often inform us on how interventions work by identifying underlying mechanisms, thus providing mo