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: Psychiatry
[{'content': 'Nihilistic ideas are seen in - \nSelect and explain. \nA. Depression, B. Schizophrenia, C. Mania, D. OCN', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Delusions of nihilism (nihilistic ideas) are characteristic of major depression.', 'role': 'assistant'}]