This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cognitive development and defence mechanism, Subject name: Psychiatry
[{'content': 'Derealisation and depersonalisation seen in which type of disorder \nSelect and explain. \nA. Dissociative disorder, B. Personality disorder, C. Mania, D. Depression', 'role': 'user'}, {'content': "Answer: A \nExplanation: Depersonalisation: an altered sense of one's physical being, including feeling that one is outside of one's own body, physically cut off or distanced from people, floating, observing oneself from distance, as though in a dream. Derealisation: experiencing the environment as unreal or distoed. These are seen in Dissociative disorders. Ref: Synopsis of Psychiatry, 11e, pg 295.", 'role': 'assistant'}]