As sources of information for our study, 3 publications1,2,15 authored by the theorists were reviewed. In addition, the electronicdatabasesGoogleScholar,PubMed,and
CINAHL were searched using the key word “theory of unpleasant symptoms” to identify relevant articles. Studies were selected for review on the basis of the following criteria: studies (a) in which the TOUS was used as a conceptualortheoreticalframework,(b)published from 2000 to 2016 (because a formal critique of the TOUS was published in 2000, such studies reflected progress in use of the TOUS in nursing research), and (c) written in English. On the basis of Silva’s criteria,16 we excluded studies in which the theory was “minimally used.”