Theories about genetic and environmental causes of peptic ulcer abound. Both gastric and duodenal ulcers tend to occur in families. Relatives of persons with gastric ulcers have three times the expected number of gastric ulcers. The same is true of duodenal ulcers. There is evidence that the increased familial incidence of both gastric and duodenal ulcers is not just due to a shared environment.
Psychosomatic factors do play some role in the development of peptic ulcers.
Psychologic stress can and does alter gastric function. Prolonged psychologic or physiologic stress produces what is known as a stress ulcer . A stress ulcer differs pathologically and clinically from a chronic peptic ulcer. Drug-induced ulcers are most commonly caused by the ingestion of aspirin, with alcohol running a close second. Other drugs that are strongly suspected of being ulcerogenic include the glucocorticoids, indomethacin, and phenylbutazone.