What causes sudden hiccups?

Eating too much, causing hiccups, hiccups are often caused by overeating. Including stomach, esophageal function or organic changes. Also caused by external substances, biochemical, physical stimulation. Too much air into the stomach and overflow from the mouth, mental nerve factors, poor eating habits, excessive swallowing movements, etc., and gastrointestinal neurosis, gastrointestinal chronic diseases caused by gastric motility weakened when the incidence is frequent and difficult to improve treatment.