Somatization, sensitization, and functional dyspepsia.

Functional dysepsia (FD) is defined as persistent or recurrent pain or discomfort centered in the upper abdomen without evidence of organic disease likely to explain the symptoms. Visceral hypersensitivity, motor dysfunction, and impaired gastric accommodation are found in some patients with FD, and psychological factors like chronic stress, attention and perception bias are also likely to play a part in the symptom formation. There is considerable overlap of non-specific symptoms like fatigue, headache, abdominal discomfort, muscle pain, and sleep disturbance in patients with different functional disorders, in this article exemplified by FD, fibromyalgia, and chronic fatigue syndrome. This overlap of symptoms indicates a common underlying sensitization process, leading to somatization.