Academics have released yet another critical study taking aim at the validity of trigger warnings—prior indications, often used in classrooms, that notify students about forthcoming, potentially disturbing course materials—and it may finally be time to bid them farewell.

Indeed, a scientific consensus is now emerging that trigger warnings don't help the students whose mental well-being they are intended to protect—and may even have negative effects.

The latest study to reach this conclusion was conducted by Harvard psychologists Payton Jones, Richard McNally, and Benjamin Bellet. It builds on an earlier study by Jones and McNally that also gave trigger warning a negative review, but did not specifically test them on individuals with a history of PTSD.

This time, the researchers studied the effects of trigger warnings on 451 trauma survivors. The results were much the same. "We found no evidence that trigger warnings were helpful for trauma survivors, for those who self-reported a PTSD diagnosis, or for those who qualified for probable PTSD, even when survivors' trauma matched the passages' content," they wrote in the abstract. "We found substantial evidence that trigger warnings countertherapeutically reinforce survivors' view of their trauma as central to their identity. Regarding replication hypotheses, the evidence was either ambiguous or substantially favored the hypothesis that trigger warnings have no effect."

A third study, conducted by a different team of researchers and published in Clinical Psychological Science in March, gave trigger warnings the most favorable verdict of the three: They were merely useless, and not actively harmful, in this writeup.

The evidence is substantial enough at this point to prompt Slate's Shannon Palus to change her mind about trigger warnings.

"I've been convinced that we'd do better to save the minimal effort it takes to affix trigger warnings to college reading assignments or put up signs outside of theater productions and apply it to more effective efforts to care for one another," she wrote.

Student activists, who have long been the most vocal group demanding mandatory trigger warnings in college classrooms, should take note.

(For more about the rise of trigger warnings, pick up a copy of my new book, Panic Attack: Young Radicals in the Age of Trump, which received a rave review from Washington Monthly.)