The role of adherence in mediating the relationship between depression and health outcomes.

Depression has been linked to poor health outcome in a number of studies; however, the mechanism underlying this relationship has received little attention. This paper explores the possibility that adherence mediates the relationship between depression and outcome. Principal findings regarding the relationship between depression, adherence, and outcome are reviewed. The data suggest that depression is related, at least moderately, to poorer adherence to a variety of treatment components. The relationship between adherence and outcome is more difficult to establish. In addition, current data, albeit limited, do not support the hypothesis that adherence mediates the relationship between depression and outcome. An alternative model in which adherence precedes and influences both mood state and health outcome is discussed. Finally, possible explanations for these relationships are explored and suggestions for future research provided.