A comparison of patients not taking antidepressant medication found serum5- HT levels to be more than3 times lower in those patients with a recent suicide attempt than in patients with no history of suicide attempt.

• 比较两组服用抗抑郁药和未服药的病人血清5-羟色胺浓度发现，最近有自杀意图者比无自杀意图者要低3倍以上。