Psychosocial forces.
D004064:Digestive System / Q000294:innervation; D005767:Gastrointestinal Diseases / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D010437:Peptic Ulcer / Q000209:etiology / Q000503:physiopathology; D012106:Research; D013315:Stress, Psychological