The massive workload, demanding schedule, and culture shock combine to make university life far more stressful than high school.
High school homework would be a welcome vacation to the college student that is carrying a full credit load. The necessity of solving a complex problem and writing a research paper on the results can bring the new student to the brink of a nervous breakdown. The desire to do well on a mathematics test can result in beads of perspiration and sweaty palms that were never there in high school. The intensity never ends as the stress of the university's standards makes the student long for the ease of high school subjects.
A major component of doing well in college is doing the work on time. In high school the schedule is made for the student and there is little left to chance. However, college life demands that the student confront the challenges of 18 hour workdays, early morning classes, and conflicting schedules. College social life can be fun, but the student will risk their mental health by squeezing in a party in an already cramped routine. The high school student may suffer from the boredom of nothing to do, but the university freshman suffers the stress of never having enough time to do it.
Confronting a new situation can be as stressful as it is rewarding.