事实上，这些疾病中的最常见者 — — 单向抑郁症从症状来说是最不复杂的，但也是最致命的：据统计，20%的抑郁症患者会走上自杀之路。
Indeed, the most common of these illnesses, unipolar depression, is the least complex in terms of its symptoms, but also the most lethal: 20% of depressed patients are estimated to commit suicide.