The new school year has reignited the debate on trigger warnings in classrooms. The University of Chicago stirred up controversy when Dean John Ellison revealed that their students should not expect trigger warnings at the institution.

"Our commitment to academic freedom means that we do not support so-called 'trigger warnings,'" Ellison wrote in a welcome letter to freshmen. "We do not cancel invited speakers because their topics might prove controversial, and we do not condone the creation of intellectual 'safe spaces' where individuals can retreat from ideas and perspectives at odds with their own."

According to BuzzFeed, trigger warnings are broadly defined as a disclaimer of sorts about content that could be triggering for someone with a history of trauma. These can be shown in various ways.

The publication spoke with psychologists on what people should know about trigger warnings. Here are some things that everyone, including college faculty, should be aware of in order to help students.

1. Triggering materials doesn't just make an individual uncomfortable. According to California-based clinical psychologist Ryan Howes, people with a history of trauma (such as sexual assault) or PTSD "may feel a kind of sensitivity or hyper-vigilance around words or images that could bring that trauma to mind."

2. A trigger warning can have several forms. It can be shown as a note on a syllabus about graphic depictions of violence or a heads-up at the beginning of a lecture about campus rape statistics.

3. There should also be trigger warnings for content related to suicide, self-harm, addiction as well as eating disorders. Being unexpectedly exposed to imagery or content related to the things mentioned above can be harmful for someone who has a history of mental illness.

4. It is not meant to obstruct free speech and its goal is not to avoid all triggers. Colleges are not expected to limit discussions of potentially triggering material, especially when it interferes with academic freedom. The ultimate goal is that individuals recovering from trauma will eventually be able to deal with triggers effectively.

5. Both students and professors play a part in the use of trigger warnings. It's the professors' responsibility to include warnings before showing sensitive materials while students should also take responsibility in talking to their teachers in preparing for what to do when the situation arises.