本文对天津大学1996年级本科学生,以专业班为单位作整群抽样,采样前经体检,身体无严重躯体疾病及精神病家族史。按以下入组标准:(1)汉族,1978年、1979年在天津市区出生,有一年以上托儿所或幼儿园经历,跟随父母在天津生活10年以上。(2)本人非抱养或领养子,父母双全,无离异。(3) In this paper, 1996 undergraduate students in Tianjin University, a professional class for the whole cluster sampling, physical examination before sampling, the body without serious physical illness and family history of mental illness. According to the following inclusion criteria: (1) Han nationality, born in Tianjin City in 1978 and 1979, with more than a year of nursery or kindergarten experience, living with his parents in Tianjin for more than 10 years. (2) I am not a child or adoptive child, both parents, no divorce. (3)