Reply to Barbara Martin's post:

Lots of reasons, some come down to how society chooses to deal with people with mental health problems. 

Another factor for this particular setting is a phenomenon that many refer to as a school-to-prison pipeline that particularly impacts disadvantaged groups in society.  We can argue that it doesn’t exist, but the statistics show that incarceration is significantly skewed for people of color.

Vera Institute of Justice - Divided Justice https://www.vera.org/publications/divided-justice-black-white-jail-incarceration

Education Week - 5 Facts Everyone Needs to Know About the School-to-Prison Pipeline: http://blogs.edweek.org/edweek/education_futures/2015/08/5_facts_everyone_needs_to_know_about_the_school-to-prison_pipeline.html#:~:text=%205%20Facts%20Everyone%20Needs%20to%20Know%20About,of%20the%20stick%20as%20far%20as...%20More%20

-Marshall