This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Personality disorders, Subject name: Psychiatry
[{'content': 'All of the following Personality disorders can be associated with bipolar disorder except: \nSelect and explain. \nA. Antisocial, B. Anakastic, C. Borderline, D. Narcissistic', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The three most frequent PDs were obsessive-compulsive PD, borderline PD, and narcissistic (bipolar) or avoidant (unipolar) PD. Cluster C PDs and especially avoidant PD occurred significantly more frequently in unipolar than in bipolar patients, while narcissistic PD occurred significantly more often in bipolar than in unipolar patients. Ref: Brieger P, Eh U, Marneros A. Frequency of Personality disorders in bipolar and Unipolar affective disorders. Compr Psychiatry, 2003, Jan-Feb 44(1): 28-34.', 'role': 'assistant'}]