Overdiagnosis refers to diagnosis that does not benefit patients because the diagnosed condition is not a harmful disease in those individuals. Overdiagnosis has been identified as a problem in cancer screening, diseases such as chronic kidney disease and diabetes, and a range of mental illnesses including depression and attention deficit hyperactivity disorder. In this paper, we describe overdiagnosis, investigate reasons why it occurs, and propose two different types. Misclassification overdiagnosis arises because the diagnostic threshold for the disease in question has (...) been set at a level where many people without harmful disease are nonetheless diagnosed. We illustrate misclassification overdiagnosis using the example of chronic kidney disease. Misclassification occurs in diseases diagnosed using biomarkers or based on patient reported phenomena. Maldetection overdiagnosis arises because, at the time the diagnosis is made and despite the presence of a 'gold standard' diagnostic test, it is not possible to discriminate between harmful and non-harmful cases of the index disease. We illustrate maldetection overdiagnosis using the example of thyroid cancer. While there is some overlap between misclassification and maldetection overdiagnosis, this conceptual analysis helps to clarify the phenomenon of overdiagnosis and is a necessary first step in developing strategies to address the problem. (shrink)

Medicalization is frequently defined as a process by which some non-medical aspects of human life become to be considered as medical problems. Overdiagnosis, on the other hand, is most often defined as diagnosing a biomedical condition that in the absence of testing would not cause symptoms or death in the person’s lifetime. Medicalization and overdiagnosis are related concepts as both expand the extension of the concept of disease. They are both often used normatively to critique unwarranted or contested expansion of (...) medicine and to address health services that are considered to be unnecessary, futile, or even harmful. However, there are important differences between the concepts, as not all cases of overdiagnosis are medicalizations and not all cases of medicalizations are overdiagnosis. The objective of this article is to clarify the differences between medicalization and overdiagnosis. It will demonstrate how the subject matter of medicalization traditionally has been non-medical (social or cultural everyday life) phenomena, while the subject matter of overdiagnosis has been biological or biomolecular conditions or processes acknowledged being potentially harmful. They also refer to different types of uncertainty: medicalization is concerned with indeterminacy, while overdiagnosis is concerned with lack of prognostic knowledge. Medicalization is dealing with sickness (sick role) while overdiagnosis with disease. Despite these differences, medicalization and overdiagnosis are becoming more alike. Medicalization is expanding, encompassing the more “technical” aspects of overdiagnosis, while overdiagnosis is becoming more ideologized. Moreover, with new trends in modern medicine, such as P4 (preventive, predictive, personal, and participatory) medicine, medicalization will become all-encompassing, while overdiagnosis more or less may dissolve. In the end they may converge in some total “iatrogenization.” In doing so, the concepts may lose their precision and critical sting. (shrink)