Review Question - QID 210711

A 22-year-old man presents to the emergency department for chest pain. He says that the chest pain began a few hours prior to presentation and is associated with nausea, abdominal discomfort, and sweating. He has experienced similar symptoms multiple times in the past, which brings him great concern because he believes he may be having a heart attack. This concern has persisted for 2 months. This has caused him to avoid taking long train rides or driving on divided highways. Approximately 7 months ago his parents divorced. Medical history is significant for obesity. He denies any medications or illicit drug use. Physical examination is unremarkable. An electrocardiogram demonstrates sinus tachycardia with a pulse of 110/min. Which of the following is most likely the diagnosis?