An Integrative Review of the Theory of Unpleasant Symptoms

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The aim of this study was to explore how the theory of unpleasant symptoms (TOUS) has been used in the methodological design and analysis of symptom research.


An integrative review, using Whittemore and Knafl's approach.

Data Sources

Searches were conducted between 26 January–10 February 2018. Databases included CINAHL Complete, PubMed, Proquest Nursing and Allied Health Source, Health Source: Nursing/Academic Edition, Academic Search Complete and Google Scholar.

Review Methods

A systematic approach to searching, screening and analysing the literature was applied. The matrix method, content analysis, constant comparison, counting and clustering were used.


Sixty‐four records were included. Most studies were quantitative, cross‐sectional, instrument‐based and conducted in the USA. Various symptoms and patient populations were represented and each of the TOUS concepts were explored.


Although the theory has a role to play in furthering symptom science, attention should be paid to the areas of the model and of symptom research that have received less attention. More complex statistical approaches and big data will help to illuminate symptom experiences. Additional focus on intervention studies and all symptom dimensions will help to advance symptom science research.


This review is the first to provide a comprehensive, systematic summary of the uses of the TOUS across the research literature to date. This theory is a diverse, holistic middle‐range theory capable of being applied to multiple symptoms and populations. Researchers should consider using the theory as a conceptual framework for studies to advance symptom science and explore symptoms holistically.


This article was published in Journal of Advanced Nursing 75, no. 5 (2019): 946-961.