1·Subsyndromal symptomatic depression (SSD) is a type of subthreshold depression.
亚综合征抑郁（SSD）属阈下抑郁的一种类型。
2·Objective to study the clinical symptomatic features of senile depression patients.
目的了解老年期抑郁症患者的临床症状特点。
3·Objective: to compare the clinical symptomatic features of senile depression and younger than 60 years depression.
目的：比较老年期与非老年期抑郁症的临床症状特点。