Motivation and reward mechanisms in health behavior change processes.

With increasing prevalence of lifestyle-related chronic diseases worldwide, understanding health behavior change and the development of successful interventions to support lifestyle modification is gaining increasing interest among politicians, scientists, therapists and patients alike. A number of health behavior change theories have been developed aiming at explaining health behavior change and understanding the domains that make change more likely. Until now, only few studies have taken into account automatic, implicit or non-cognitive aspects of behavior, including emotion and positive affect. Recent progress in the neuroscience of motivation and reward systems can provide further insights into the relevance of such domains. In this integrative review, we present a description of the possible motivation and reward systems (approach/wanting = pleasure; aversion/avoiding = relief; assertion/non-wanting = quiescence) involved in behavior change. Therefore, based on established theories encompassing both initiation and maintenance of behavior change, we create a flexible seven-stage behavior change process with three engagement phases (non-engagement, motivational engagement, executive engagement) and relate the motivation and reward systems to each of these stages. We propose that either appetitive (preferably) or aversive motivational salience is activated during motivational engagement, that learning leads to continued behavior and that assertive salience prevails when the new behavior has become habitual. We discuss under which circumstances these mechanisms and reward-motivation pathways are likely to occur and address potential shortcomings of our proposed theoretical framework. We highlight implications for future interventions aiming at lifestyle modification.