This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Eating Disorders, Subject name: Psychiatry
Repeated involuntary regurgitation of food is associated with which of the following disorders? 
Select and explain. 
A. Binge eating disorder, B. Rumination disorder, C. Bulimia nervosa, D. Anorexia nervosa
B: Rumination disorder
Answer: B: Rumination disorder 
Explanation: Rumination disorder: Effoless and painless regurgitation of paially digested food into the mouth soon after a meal, which iseither swallowed or spit out According to DSM-5, the disordermust be present for at least 1 month after a period of normal functioning, and not better accounted for by gastrointestinal illness, or psychiatric or medical conditions. Can be observed in normal infants It's a functional gastrointestinal disorder Occurs between 3 months and 12 months of age.