Jones, P. et al. (2019)
Harvard Working Paper ("Helping or Harming?..."

Trigger warnings alert trauma survivors and those with PTSD about potentially disturbing forthcoming content. While their intentions are good, most empirical studies on trigger warnings indicate that they are either functionally inert or cause small adverse side effects. ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
This study examined 451 trauma survivors who were randomly assigned to either receive or not receive trigger warnings prior to reading potentially distressing passages from world literature. They provided their emotional reactions to each passage. ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Self-reported anxiety was higher among those who received trigger warnings. The authors concluded that TWs were “counter-therapeutic” in that they reinforce survivors’ view of their trauma as central to their identity. To this point, there is no evidence-based reason to use trigger warnings in a therapeutic or educational setting.