These are not known for sure. The number of acid-secreting cells is high, with greater outpouring of acid. Excessive acid flow is consequential, in comparison to gastric ulcer where defective mucosal resistance is the cause. Genetic factors appear to be important. Alcohol and cigarettes are potent causative and aggravating factors.
Stress produces and aggravates duodenal ulcer in any situation.
Of this there is no doubt. All patients experience increase in pain with stress. The classic symptom is pain in the epigastric area present two to three hours after a meal. It is a burning, painful, gnawing or aching sensation, with fullness or bloating, even awakening the patient from sleep. It is relieved by intake of food or antacids.