Disease, illness, sickness and related terms: A note for non-epidemiologists

Background: Disease, illness, and sickness are all overlapping terms that are not entirely synonymous. Illness, disease, and sickness all characterize different aspects of morbidity and must be treated as distinct entities. Changes in one aspect may have no bearing on changes in another. Despite their widespread use, these terms are used incorrectly and ambiguously, leading to confusion in the representation of medical knowledge. Medical personnel and epidemiologists misuse these terms, and there is little literature on the subject.Methods: PubMed and Google Scholar were used to conduct a literature search. The search terms "definition," "disease," "illness," "sickness," "morbidity," "syndrome," "disorder," "predisease," and "co-morbidity" were used in various combinations. A manual search was conducted in public health, community medicine, and epidemiology textbooks. The review included the most recent and relevant literature.Results: This mini review summarizes the definition, limitations, overlap, and differences between disease, illness, and sickness, as well as other related terms.Conclusion: A measurable operational definition of disease, illness, sickness, and other related terms that is appropriate for epidemiologists and clinicians and applicable in both hospital and community settings is required.and community settings.