The Middle-Range Theory of Unpleasant Symptoms: An Update

A detailed description of the newly revised and updated theory of unpleasant symptoms is provided. Revisions have resulted in a more accurate representation of the complexity and interactive nature of the symptom experience. Examples are provided to demonstrate the implications of the revised theory for measurement and research, and its application in practice. A detailed exemplar describes how it guided the design of a multifaceted intervention to encourage successful breastfeeding.