What is it?

Functional disorders of the stomach are pretty common, and are characterized with gut-brain disorders of interaction. These disorders are not related to any structural abnormalities, rather the function refers to neuromuscular abnormalities. Gastroduodenal functional disorders include:
-Functional dyspepsia- symptoms of indigestion without a known cause
-Belching disorders characterized by the excessive belch and disturbance
-Nausea and vomiting disorders
-Rumination syndrome- a rare behavioral disorder in which food is brought back up from the stomach. It's either rechewed, swallowed, or spit out.
-Centrally mediated abdominal pain syndrome (CAPS) – continuous or frequently recurrent abdominal pain, either not or infrequently related to gut function, and associated with some loss of daily activities.