To improve teen students' mental health, some schools in the US start later. Many experts argue starting school later can help students get the sleep they need. California became the first state to mandate a later school start time. Public middle and high schools cannot start earlier than 8 AM and 8:30 AM, respectively. In the state of Pennsylvania, some high schools have pushed the start time back by two hours, from 7:30 to 9:30.
  It's a welcome shift for many students. “I’ll be honest, I’ve been much happier in the mornings. I’ve been more positive, and I’ve come to school smiling more rather than, you know, grudging out of bed and stuff like that at 7:30,” said one student.
  Also, school officials said much of the mental health struggle and social anxiety students felt after coming back to in-person learning has dissipated.

 為了改善青少年的心理健康,一些美國學校決定延後上學時間。許多專家認為,延後上學時間可以幫助學生獲得所需的睡眠。加州率先規定中小學必須延後上學時間,公立中學和高中的上課時間必須分別在8 點和8點半之後。在賓州,則有一些高中將上學時間推遲了兩個小時之多,從7 點半推遲到9點半。
 對於許多學生而言,他們歡迎這個新政策。一名學生說:「老實說,早上我更開心了。我變得更積極,更常面帶笑容來到學校,而不是,你知道,因為得在7 點半勉強起床而垂頭喪氣之類的。」