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
The increased suicidal tendency is associated with - 
Select and explain. 
A. Noraderenaline, B. Serotonin, C. Dopamine, D. GABA
B: Serotonin
Answer: B: Serotonin 
Explanation: Patient with suicide has decreased level of serotonin metabolite (5-HIAA) in urine & plasma.