That has not been my experience. My teachers tend to suffer from secondary trauma and "compassion fatigue". The withdraw you are observing may be the mind and body emotional dealing with the trauma.

I don´t know any speficic one but it could be developed based on V. E. Frankl´s logotheory. As You have mentioned "depersonalization" for me it made connections with his book  Man's Search for Meaning  (Nevertheless, Say "Yes" to Life: A Psychologist Experiences the Concentration Camp). It could be helpful.

s, in 2009 my third year of teaching for PAISD, the majority of my students were classified as LD, LEP,504, ADHD, MHR, and EBD.I was given full responsibility of 181 students without a teacher assistant, any support from the Special Education or administrative departments.8th grade classes of minority students, who either belong with or were being initiated into members of Crips, Bloods, SF13 and SF14 gangs.

Some of these students’ classroom behaviors demonstrate their social cultural environment. On campus activities of sex, drugs, crime and violence were incorporated into a school environmental control policy of not to be discuss. I’ve personally seen teachers attacked by students and reports of students engaged in sex, drugs and violence on campus. The students sent to alternative campus return within six weeks and sent to my classroom worse than before.  The principal told me she would not allow me to lose her grant money, so I lost my job labeled as a trouble maker and being black-listed haven’t taught in four years due to filing written and verbal complaints with the school TEA rep and district administrators. 

I would suggest a much larger view of the problem you are asking. The best approach I could suggest is one that addresses not only the teacher but it would seem to be obvious that the society as a whole views these young adults as depersonlized individuals. These are the throw away kids. 

I would also look into who are the teachers, are they the least experienced? This has a major impact on the question due to the physocology of the young teacher and there enthusiasm of being a teacher. I hate to say it but if the least are teaching the most needed than both are neglected and that is not a good place to be.

It leads to a psychological place of not caring by both. In this place only the motions are gone through, not education or teaching. I have worked most of my 20 years in the schools you are referring to and the sad truth is I stopped counting after 20 the number of kids I new, took my classes are buried in potters fields.

Douglas

I taught a summer in Newark and a year in Jersey City. I found there was no formal program to discuss violence. I taught Math and Computers and I recall a 4th period class. The day was half over. Students looked beat. Nobody had discussed school shootings that were in the news. Listening is part of teaching. I am finishing my thesis this term, and may go for PhD for this reason. Feedback is needed from the students.

When there are no formal programmes as Carlo, mentioned   in schools to deal with violence this is likely to  prevent meaningful feedback to the students who need such a feedback the most. Teachers who are consistently affected by violence tend to stop taking on the children's issues and become withdrawn. In  doing this  the well needed  Culture of Care that could effectively take students from a violent and delinquent sub culture into one of peacefulness and calmness becomes missing.

It is likely that in the long run these students will become more vicious since in the first place their violent behaviour had emerged from the  lack of attention in most cases and this lack has developed with  most of their   teachers paying them limited  attention.