The Mother of a 9-Year-Old Girl Brings Her to the Clinic

The mother of a 9-year-old girl brings her to the clinic for an examination of regular stomach problems. According to the mother, her daughter has always had a "sensitive stomach," but it has become worse since she started attending a new school a few months ago. The girl has been missing class owing to frequent visits to the nurse's office. When her mother arrives to pick her up, the patient's symptoms improve. "She has friends but never likes sleepovers," the mother says in answer to the doctor's questioning regarding the girl's peer interactions. When the patient visits a friend, she frequently complains of stomach pain and nausea. She has dreams of being alone and wakes up weeping on occasion. Although both parents are healthy, the patient says she worries about them "dying of a terrible illness, like cancer."  Abdominal examination shows no abnormalities.  Which of the following is the most likely diagnosis in this patient?

A) Adjustment disorder with anxious mood
B) Dependent personality disorder
C) Generalized anxiety disorder
D) Illness anxiety disorder
E) Separation anxiety disorder
F) Social anxiety disorder
G) Somatic symptom disorder