Definition:
Functional disorders are health conditions that are diagnosed based solely on symptoms because no visible inflammation, injury, structural abnormality, or any other disease process (biomarkers) can be identified. Functional disorders can be found in many branches of medicine, including gastroenterology, urology, cardiology and rheumatology. The term "functional disorder" may also refer to mental health diagnoses.
Irritable bowel syndrome (IBS) is an example of a functional gastrointestinal disorder.
