This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': "A 27-yrs-old woman has been feeling low for the past 2 weeks. She has little energy and has trouble concentrating. She states that 6 weeks ago she had been feeling very good, with lots of energy and no need for sleep. She states this pattern has been occurring for at least the past 3 years, though the episodes have never been so severe that she couldn't work. Most likely diagnosis is? \nSelect and explain. \nA. Borderline personality disorder, B. Seasonal affective disorder, C. Cyclothymic disorder, D. Major depression, recurrent", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Cyclothymic disorder *Cyclothymic disorder is characterized by recurrent periods of mild depression alternating with periods of hypomania. *This pattern must be present for at least 2 years (1 year for children and adolescents) before the diagnosis can be made. *During these 2 years, the symptom-free intervals should not be longer than 2 months. Cyclothymic disorder usually stas during adolescence or early adulthood and tends to have a chronic course. *The marked shifts in mood of cyclothymic disorder can be confused with the affective instability of borderline -, personality disorder or may suggest a substance abuse problem.', 'role': 'assistant'}]