Many first-year students experience bullying, underlining the need for secondary schools to have effective policies to combat this, a new report has found.
Stories about the "first-year beating" contributed to nervousness among boys, according to the study.
However, on average girls take longer than boys to settle into secondary school.
The joint NCCA/ESRI study also revealed that while most students settle into post-primary school quickly, one in six takes longer than a month to do so.
These students are more likely to be suffering from low self-confidence and poor self-image and are frequently drawn from ethnic minorities such as the Travelling community.
Schools should be encouraged to move away from streaming into mixed-ability classes, the authors of the report, entitled Moving Up: The Experiences of First-Year Students in Post-Primary Education, recommend.
In streamed schools, many students have difficulties with the teaching pace, taking longer to settle into the new school, and making less progress academically.
While students were generally positive about the subjects they take at second-level, a significant number feel there is a "mismatch" between primary and post-primary schools.
This is particularly true of Irish, English and maths, and can be helped by familiarity with the primary curriculum among second-level teachers.
Schools should also be required to provide a range of subjects in first year, including ones with a more practical emphasis which help to promote student interest and engagement, the report said.