The nature of diagnostic constructs

Classification is essential in medicine to help doctors acquire, learn, and recall clinically useful information about problems coming to healthcare professionals’ attention. There problems include both essentialist diagnostic constructs (where all examples share a quality and are distinct from other constructs) and nominalist diagnostic constructs (used to describe clinically useful concepts not necessarily separate from other constructs). Diagnostic constructs may be recognized using defined criteria and/or as prototypical examples. They are based on similarities in clinical picture, mechanisms/processes, and/or causes. They may be used to identify clinically important situations, diseases/clear-cut syndromes, spectrums of health, illness(es)/and condition(s), injuries, and other situations of interest to healthcare professionals. Thresholds established on the basis of clinical utility (e.g. level of distress or risk of complications) may be used to define conditions. Care must be taken to guard against over-medicalization of problems or situations.