Adolescent major depressive disorder (MDD) is a significant health problem, associated with substantial morbidity, cost, and mortality. Depression is a significant risk factor for suicide, which is now the second leading cause of death in young people. Up to twenty per cent of adolescents will experience MDD before adulthood, and while a substantial proportion will improve with standard‐of‐care treatments (psychotherapy and medication), roughly one third will not.

中文翻译：

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年度研究回顾：定义和治疗儿科难治性抑郁症

青少年重度抑郁症 (MDD) 是一个重要的健康问题，与大量的发病率、成本和死亡率相关。抑郁症是自杀的一个重要危险因素，而自杀现在是年轻人的第二大死因。多达 20% 的青少年会在成年前经历 MDD，虽然很大一部分会通过标准治疗（心理治疗和药物治疗）改善，但大约三分之一不会。