This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Pharmacology
[{'content': 'Increased suicidal tendency is associated with alteration in the brain levels of: \nSelect and explain. \nA. Noradrenaline, B. Serotonin, C. Dopamine, D. GABA', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (B) Serotonin(Ref: KDT 8/e p188)Decreased serotonin levels in brain is associated with depression (and suicidal tendencies) whereas elevated levels of 5-HT are associated with anxiety.', 'role': 'assistant'}]